Sample records for oil-free rotorcraft propulsion

  1. Advancements Toward Oil-Free Rotorcraft Propulsion

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; Bruckner, Robert J.; Radil, Kevin C.

    2010-01-01

    NASA and the Army have been working for over a decade to advance the state-of-the-art (SOA) in Oil-Free Turbomachinery with an eye toward reduced emissions and maintenance, and increased performance and efficiency among other benefits. Oil-Free Turbomachinery is enabled by oil-free gas foil bearing technology and relatively new high-temperature tribological coatings. Rotorcraft propulsion is a likely candidate to apply oil-free bearing technology because the engine size class matches current SOA for foil bearings and because foil bearings offer the opportunity for higher speeds and temperatures and lower weight, all critical issues for rotorcraft engines. This paper describes an effort to demonstrate gas foil journal bearing use in the hot section of a full-scale helicopter engine core. A production engine hot-core location is selected as the candidate foil bearing application. Rotordynamic feasibility, bearing sizing, and load capability are assessed. The results of the program will help guide future analysis and design in this area by documenting the steps required and the process utilized for successful application of oil-free technology to a full-scale engine.

  2. Preliminary Analysis for an Optimized Oil-Free Rotorcraft Engine Concept

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; Bruckner, Robert J.; DellaCorte, Christopher; Radil, Kevin C.

    2008-01-01

    Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include Oil-Free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This paper presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section.

  3. Oil-Free Rotor Support Technologies for an Optimized Helicopter Propulsion System

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Bruckner, Robert J.

    2007-01-01

    An optimized rotorcraft propulsion system incorporating a foil air bearing supported Oil-Free engine coupled to a high power density gearbox using high viscosity gear oil is explored. Foil air bearings have adequate load capacity and temperature capability for the highspeed gas generator shaft of a rotorcraft engine. Managing the axial loads of the power turbine shaft (low speed spool) will likely require thrust load support from the gearbox through a suitable coupling or other design. Employing specially formulated, high viscosity gear oil for the transmission can yield significant improvements (approx. 2X) in allowable gear loading. Though a completely new propulsion system design is needed to implement such a system, improved performance is possible.

  4. System Analysis and Performance Benefits of an Optimized Rotorcraft Propulsion System

    NASA Technical Reports Server (NTRS)

    Bruckner, Robert J.

    2007-01-01

    The propulsion system of rotorcraft vehicles is the most critical system to the vehicle in terms of safety and performance. The propulsion system must provide both vertical lift and forward flight propulsion during the entire mission. Whereas propulsion is a critical element for all flight vehicles, it is particularly critical for rotorcraft due to their limited safe, un-powered landing capability. This unparalleled reliability requirement has led rotorcraft power plants down a certain evolutionary path in which the system looks and performs quite similarly to those of the 1960 s. By and large the advancements in rotorcraft propulsion have come in terms of safety and reliability and not in terms of performance. The concept of the optimized propulsion system is a means by which both reliability and performance can be improved for rotorcraft vehicles. The optimized rotorcraft propulsion system which couples an oil-free turboshaft engine to a highly loaded gearbox that provides axial load support for the power turbine can be designed with current laboratory proven technology. Such a system can provide up to 60% weight reduction of the propulsion system of rotorcraft vehicles. Several technical challenges are apparent at the conceptual design level and should be addressed with current research.

  5. Propulsion System Models for Rotorcraft Conceptual Design

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2014-01-01

    The conceptual design code NDARC (NASA Design and Analysis of Rotorcraft) was initially implemented to model conventional rotorcraft propulsion systems, consisting of turboshaft engines burning jet fuel, connected to one or more rotors through a mechanical transmission. The NDARC propulsion system representation has been extended to cover additional propulsion concepts, including electric motors and generators, rotor reaction drive, turbojet and turbofan engines, fuel cells and solar cells, batteries, and fuel (energy) used without weight change. The paper describes these propulsion system components, the architecture of their implementation in NDARC, and the form of the models for performance and weight. Requirements are defined for improved performance and weight models of the new propulsion system components. With these new propulsion models, NDARC can be used to develop environmentally-friendly rotorcraft designs.

  6. Rotorcraft flight-propulsion control integration

    NASA Technical Reports Server (NTRS)

    Mihaloew, James R.; Ballin, Mark G.; Ruttledge, D. G. C.

    1988-01-01

    The NASA Ames and Lewis Research Centers, in conjunction with the Army Research and Technology Laboratories have initiated and completed, in part, a joint research program focused on improving the performance, maneuverability, and operating characteristics of rotorcraft by integrating the flight and propulsion controls. The background of the program, its supporting programs, its goals and objectives, and an approach to accomplish them are discussed. Results of the modern control governor design of the T700 and the Rotorcraft Integrated Flight-Propulsion Control Study, which were key elements of the program, are also presented.

  7. Progress in NASA Rotorcraft Propulsion

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Johnson, Susan M.

    2008-01-01

    This presentation reviews recent progress made under NASA s Subsonic Rotary Wing (SRW) propulsion research activities. Advances in engines, drive systems and optimized propulsion systems are discussed. Progress in wide operability compressors, modeling of variable geometry turbine performance, foil gas bearings and multi-speed transmissions are presented.

  8. Development of a rotorcraft. Propulsion dynamics interface analysis, volume 2

    NASA Technical Reports Server (NTRS)

    Hull, R.

    1982-01-01

    A study was conducted to establish a coupled rotor/propulsion analysis that would be applicable to a wide range of rotorcraft systems. The effort included the following tasks: (1) development of a model structure suitable for simulating a wide range of rotorcraft configurations; (2) defined a methodology for parameterizing the model structure to represent a particular rotorcraft; (3) constructing a nonlinear coupled rotor/propulsion model as a test case to use in analyzing coupled system dynamics; and (4) an attempt to develop a mostly linear coupled model derived from the complete nonlinear simulations. Documentation of the computer models developed is presented.

  9. Development of a rotorcraft. Propulsion dynamics interface analysis, volume 1

    NASA Technical Reports Server (NTRS)

    Hull, R.

    1982-01-01

    The details of the modeling process and its implementation approach are presented. A generic methodology and model structure for performing coupled propulsion/rotor response analysis that is applicable to a variety of rotorcraft types was developed. A method for parameterizing the model structure to represent a particular rotorcraft is defined. The generic modeling methodology, the development of the propulsion system and the rotor/fuselage models, and the formulation of the resulting coupled rotor/propulsion system model are described. A test case that was developed is described.

  10. Technical Seminar: Oil-Free Turbomachinery for Rotorcraft - Duration: 1:14:34.

    NASA Video Gallery

    Rotorcraft engines are among the most demanding applications for conventional oil-lubricated bearings because they must operate with extreme reliability and the highest possible power density. Rece...

  11. Rotorcraft flight-propulsion control integration: An eclectic design concept

    NASA Technical Reports Server (NTRS)

    Mihaloew, James R.; Ballin, Mark G.; Ruttledge, D. C. G.

    1988-01-01

    The NASA Ames and Lewis Research Centers, in conjunction with the Army Research and Technology Laboratories, have initiated and partially completed a joint research program focused on improving the performance, maneuverability, and operating characteristics of rotorcraft by integrating the flight and propulsion controls. The background of the program, its supporting programs, its goals and objectives, and an approach to accomplish them are discussed. Results of the modern control governor design of the General Electric T700 engine and the Rotorcraft Integrated Flight-Propulsion Control Study, which were key elements of the program, are also presented.

  12. Assessment of High Temperature Superconducting (HTS) electric motors for rotorcraft propulsion

    NASA Technical Reports Server (NTRS)

    Doernbach, Jay

    1990-01-01

    The successful development of high temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. Applications of high temperature superconductors have been envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft and solar powered aircraft. The potential of HTS electric motors and generators for providing primary shaft power for rotorcraft propulsion is examined. Three different sized production helicopters were investigated; namely, the Bell Jet Ranger, the Sikorsky Black Hawk and the Sikorsky Super Stallion. These rotorcraft have nominal horsepower ratings of 500, 3600, and 13400 respectively. Preliminary results indicated that an all-electric HTS drive system produces an improvement in rotorcraft Takeoff Gross Weight (TOGW) for those rotorcraft with power ratings above 2000 horsepower. The predicted TOGW improvements are up to 9 percent for the medium-sized Sikorsky Black Hawk and up to 20 percent for the large-sized Sikorsky Super Stallion. The small-sized Bell Jet Ranger, however, experienced a penalty in TOGW with the all-electric HTS drive system.

  13. NASA/Army Rotorcraft Technology. Volume 2: Materials and Structures, Propulsion and Drive Systems, Flight Dynamics and Control, and Acoustics

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Conference Proceedings is a compilation of over 30 technical papers presented which report on the advances in rotorcraft technical knowledge resulting from NASA, Army, and industry research programs over the last 5 to 10 years. Topics addressed in this volume include: materials and structures; propulsion and drive systems; flight dynamics and control; and acoustics.

  14. High speed rotorcraft propulsion concepts to control power/speed characteristics

    NASA Technical Reports Server (NTRS)

    Bettner, J. L.; Hawkins, J. M.; Blandford, C. S.

    1992-01-01

    Recent NASA sponsored rotorcraft airframer studies have demonstrated the desire for constant power over a wide range of output speed for turboshaft propulsion systems. This study interrogated several different concepts aimed at maintaining constant power over a speed variation from 100-50 percent with minimum increase in fuel consumption. The baseline engine was an advanced technology 8000 shp, fixed turbine geometry, turboshaft engine. The concepts investigated included variable geometry turbines, variable geometry compressors, power transfer from the HP to LP shafts, counterrotating power turbine with a combiner gearbox, and variable speed transmission integrated with the baseline turboshaft engine. The concept that best satisfies the program objectives with superior engine performance and with the least technical risk is the baseline (fixed geometry turbines) turboshaft engine integrated with the variable speed transmission.

  15. Rotorcraft convertible engine study

    NASA Technical Reports Server (NTRS)

    Gill, J. C.; Earle, R. V.; Mar, H. M.

    1982-01-01

    The objective of the Rotorcraft Convertible Engine Study was to define future research and technology effort required for commercial development by 1988 of convertible fan/shaft gas turbine engines for unconventional rotorcraft transports. Two rotorcraft and their respective missions were defined: a Fold Tilt Rotor aircraft and an Advancing Blade Concept (ABC) rotorcraft. Sensitivity studies were conducted with these rotorcraft to determine parametrically the influence of propulsion characteristics on aircraft size, mission fuel requirements, and direct operating costs (DOC). The two rotorcraft were flown with conventional propulsion systems (separate lift/cruise engines) and with convertible propulsion systems to determine the benefits to be derived from convertible engines. Trade-off studies were conducted to determine the optimum engine cycle and staging arrangement for a convertible engine. Advanced technology options applicable to convertible engines were studied. Research and technology programs were identified which would ensure technology readiness for commercial development of convertible engines by 1988.

  16. Comprehensive Modeling and Analysis of Rotorcraft Variable Speed Propulsion System With Coupled Engine/Transmission/Rotor Dynamics

    NASA Technical Reports Server (NTRS)

    DeSmidt, Hans A.; Smith, Edward C.; Bill, Robert C.; Wang, Kon-Well

    2013-01-01

    This project develops comprehensive modeling and simulation tools for analysis of variable rotor speed helicopter propulsion system dynamics. The Comprehensive Variable-Speed Rotorcraft Propulsion Modeling (CVSRPM) tool developed in this research is used to investigate coupled rotor/engine/fuel control/gearbox/shaft/clutch/flight control system dynamic interactions for several variable rotor speed mission scenarios. In this investigation, a prototypical two-speed Dual-Clutch Transmission (DCT) is proposed and designed to achieve 50 percent rotor speed variation. The comprehensive modeling tool developed in this study is utilized to analyze the two-speed shift response of both a conventional single rotor helicopter and a tiltrotor drive system. In the tiltrotor system, both a Parallel Shift Control (PSC) strategy and a Sequential Shift Control (SSC) strategy for constant and variable forward speed mission profiles are analyzed. Under the PSC strategy, selecting clutch shift-rate results in a design tradeoff between transient engine surge margins and clutch frictional power dissipation. In the case of SSC, clutch power dissipation is drastically reduced in exchange for the necessity to disengage one engine at a time which requires a multi-DCT drive system topology. In addition to comprehensive simulations, several sections are dedicated to detailed analysis of driveline subsystem components under variable speed operation. In particular an aeroelastic simulation of a stiff in-plane rotor using nonlinear quasi-steady blade element theory was conducted to investigate variable speed rotor dynamics. It was found that 2/rev and 4/rev flap and lag vibrations were significant during resonance crossings with 4/rev lagwise loads being directly transferred into drive-system torque disturbances. To capture the clutch engagement dynamics, a nonlinear stick-slip clutch torque model is developed. Also, a transient gas-turbine engine model based on first principles mean-line compressor and turbine approximations is developed. Finally an analysis of high frequency gear dynamics including the effect of tooth mesh stiffness variation under variable speed operation is conducted including experimental validation. Through exploring the interactions between the various subsystems, this investigation provides important insights into the continuing development of variable-speed rotorcraft propulsion systems.

  17. Test stand performance of a convertible engine for advanced V/STOL and rotorcraft propulsion

    NASA Technical Reports Server (NTRS)

    Mcardle, Jack G.

    1987-01-01

    A variable inlet guide vane (VIGV) convertible engine that could be used to power future high-speed V/STOL and rotorcraft was tested on an outdoor stand. The engine ran stably and smoothly in the turbofan, turboshaft, and dual (combined fan and shaft) power modes. In the turbofan mode with the VIGV open, fuel consumption was comparable to that of a conventional turbofan engine. In the turboshaft mode with the VIGV closed, fuel consumption was higher than that of present turboshaft engines because power was wasted in churning fan-tip air flow. In dynamic performance tests with a specially built digital engine control and using a waterbrake dynamometer for shaft load, the engine responded effectively to large steps in thrust command and shaft torque.

  18. Oil-Free Turbomachinery Being Developed

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    2001-01-01

    NASA and the Army Research Laboratory (ARL) along with industry and university researchers, are developing Oil-Free technology that will have a revolutionary impact on turbomachinery systems used in commercial and military applications. System studies have shown that eliminating an engine's oil system can yield significant savings in weight, maintenance, and operational costs. The Oil-Free technology (foil air bearings, high-temperature coatings, and advanced modeling) is being developed to eliminate the need for oil lubrication systems on high-speed turbomachinery such as turbochargers and gas turbine engines that are used in aircraft propulsion systems. The Oil-Free technology is enabled by recent breakthroughs in foil bearing load capacity, solid lubricant coatings, and computer-based analytical modeling. During the past fiscal year, a U.S. patent was awarded for the NASA PS300 solid lubricant coating, which was developed at the NASA Glenn Research Center. PS300 has enabled the successful operation of foil air bearings to temperatures over 650 C and has resulted in wear lives in excess of 100,000 start/stop cycles. This leapfrog improvement in performance over conventional solid lubricants (limited to 300 C) creates new application opportunities for high-speed, high-temperature Oil-Free gas turbine engines. On the basis of this break-through coating technology and the world's first successful demonstration of an Oil-Free turbocharger in fiscal year 1999, industry is partnering with NASA on a 3-year project to demonstrate a small, Oil-Free turbofan engine for aeropropulsion.

  19. Outdoor test stand performance of a convertible engine with variable inlet guide vanes for advanced rotorcraft propulsion

    NASA Technical Reports Server (NTRS)

    Mcardle, Jack G.

    1986-01-01

    A variable inlet guide van (VIGV) type convertible engine that could be used to power future high-speed rotorcraft was tested on an outdoor stand. The engine ran stably and smoothly in the turbofan, turboshaft, and dual (combined fan and shaft) power modes. In the turbofan mode with the VIGV open fuel consumption was comparable to that of a conventional turbofan engine. In the turboshaft mode with the VIGV closed fuel consumption was higher than that of present turboshaft engines because power was wasted in churning fan-tip airflow. In dynamic performance tests with a specially built digital engine control and using a waterbrake dynamometer for shaft load, the engine responded effectively to large steps in thrust command and shaft torque. Previous mission analyses of a conceptual X-wing rotorcraft capable of 400-knot cruise speed were revised to account for more fan-tip churning power loss than was originally estimated. The new calculations confirm that using convertible engines rather than separate lift and cruise engines would result in a smaller, lighter craft with lower fuel use and direct operating cost.

  20. Rotorcraft Health Management Issues and Challenges

    NASA Technical Reports Server (NTRS)

    Zakrajsek, James J.; Dempsey, Paula J.; Huff, Edward M.; Augustin, Michael; Safa-Bakhsh, Robab; Ephraim, Piet; Grabil, Paul; Decker, Harry J.

    2006-01-01

    This paper presents an overview of health management issues and challenges that are specific to rotorcraft. Rotorcraft form a unique subset of air vehicles in that their propulsion system is used not only for propulsion, but also serves as the primary source of lift and maneuvering of the vehicle. No other air vehicle relies on the propulsion system to provide these functions through a transmission system with single critical load paths without duplication or redundancy. As such, health management of the power train is a critical and unique part of any rotorcraft health management system. This paper focuses specifically on the issues and challenges related to the dynamic mechanical components in the main power train. This includes the transmission and main rotor mechanisms. This paper will review standard practices used for rotorcraft health management, lessons learned from fielded trials, and future challenges.

  1. Rotorcraft Diagnostics

    NASA Technical Reports Server (NTRS)

    Haste, Deepak; Azam, Mohammad; Ghoshal, Sudipto; Monte, James

    2012-01-01

    Health management (HM) in any engineering systems requires adequate understanding about the system s functioning; a sufficient amount of monitored data; the capability to extract, analyze, and collate information; and the capability to combine understanding and information for HM-related estimation and decision-making. Rotorcraft systems are, in general, highly complex. Obtaining adequate understanding about functioning of such systems is quite difficult, because of the proprietary (restricted access) nature of their designs and dynamic models. Development of an EIM (exact inverse map) solution for rotorcraft requires a process that can overcome the abovementioned difficulties and maximally utilize monitored information for HM facilitation via employing advanced analytic techniques. The goal was to develop a versatile HM solution for rotorcraft for facilitation of the Condition Based Maintenance Plus (CBM+) capabilities. The effort was geared towards developing analytic and reasoning techniques, and proving the ability to embed the required capabilities on a rotorcraft platform, paving the way for implementing the solution on an aircraft-level system for consolidation and reporting. The solution for rotorcraft can he used offboard or embedded directly onto a rotorcraft system. The envisioned solution utilizes available monitored and archived data for real-time fault detection and identification, failure precursor identification, and offline fault detection and diagnostics, health condition forecasting, optimal guided troubleshooting, and maintenance decision support. A variant of the onboard version is a self-contained hardware and software (HW+SW) package that can be embedded on rotorcraft systems. The HM solution comprises components that gather/ingest data and information, perform information/feature extraction, analyze information in conjunction with the dependency/diagnostic model of the target system, facilitate optimal guided troubleshooting, and offer decision support for optimal maintenance.

  2. Design Study of Propulsion and Drive Systems for the Large Civil TiltRotor (LCTR2) Rotorcraft

    NASA Technical Reports Server (NTRS)

    Robuck, Mark; Wilkerson, Joseph; Zhang, Yiyi; Snyder, Christopher A.; Vonderwell, Daniel

    2013-01-01

    Boeing, Rolls Royce, and NASA have worked together to complete a parametric sizing study for NASA's Large Civil Tilt Rotor (LCTR2) concept 2nd iteration. Vehicle gross weight and fuel usage were evaluated as propulsion and drive system characteristics were varied to maximize the benefit of reduced rotor tip speed during cruise conditions. The study examined different combinations of engine and gearbox variability to achieve rotor cruise tip speed reductions down to 54% of the hover tip speed. Previous NASA studies identified that a 54% rotor speed reduction in cruise minimizes vehicle gross weight and fuel burn. The LCTR2 was the study baseline for initial sizing. This study included rotor tip speed ratios (cruise to hover) of 100%, 77% and 54% at different combinations of engine RPM and gearbox speed reductions, which were analyzed to achieve the lightest overall vehicle gross weight (GW) at the chosen rotor tip speed ratio. Different engine and gearbox technology levels are applied ranging from commercial off-the-shelf (COTS) engines and gearbox technology to entry-in-service (EIS) dates of 2025 and 2035 to assess the benefits of advanced technology on vehicle gross weight and fuel burn. Interim results were previously reported1. This technical paper extends that work and summarizes the final study results including additional engine and drive system study accomplishments. New vehicle sizing data is presented for engine performance at a single operating speed with a multispeed drive system. Modeling details for LCTR2 vehicle sizing and subject engine and drive sub-systems are presented as well. This study was conducted in support of NASA's Fundamental Aeronautics Program, Subsonic Rotary Wing Project.

  3. Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2007-01-01

    Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit.. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This overview presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section. In addition, system level foil bearing testing capabilities at NASA Glenn Research Center are presented along with analysis work being conducted under NRA Cooperative Agreements.

  4. Propulsion

    ERIC Educational Resources Information Center

    Air and Space, 1978

    1978-01-01

    An introductory discussion of aircraft propulsion is included along with diagrams and pictures of piston, turbojet, turboprop, turbofan, and jet engines. Also, a table on chemical propulsion is included. (MDR)

  5. Rotorcrafts for Mars Exploration

    NASA Astrophysics Data System (ADS)

    Balaram, J.; Tokumaru, P. T.

    2014-06-01

    Rotorcraft mobility provides a number of useful capabilities to potential Mars missions. We present some recent results relating to the design and test of Mars rotorcraft mobility elements, and aspects of rotorcraft system and mission design.

  6. Oil-Free Turbomachinery Team Passed Milestone on Path to the First Oil-Free Turbine Aircraft Engine

    NASA Technical Reports Server (NTRS)

    Bream, Bruce L.

    2002-01-01

    The Oil-Free Turbine Engine Technology Project team successfully demonstrated a foil-air bearing designed for the core rotor shaft of a turbine engine. The bearings were subjected to test conditions representative of the engine core environment through a combination of high speeds, sustained loads, and elevated temperatures. The operational test envelope was defined during conceptual design studies completed earlier this year by bearing manufacturer Mohawk Innovative Technologies and the turbine engine company Williams International. The prototype journal foil-air bearings were tested at the NASA Glenn Research Center. Glenn is working with Williams and Mohawk to create a revolution in turbomachinery by developing the world's first Oil-Free turbine aircraft engine. NASA's General Aviation Propulsion project and Williams International recently developed the FJX-2 turbofan engine that is being commercialized as the EJ-22. This core bearing milestone is a first step toward a future version of the EJ-22 that will take advantage of recent advances in foil-air bearings by eliminating the need for oil lubrication systems and rolling element bearings. Oil-Free technology can reduce engine weight by 15 percent and let engines operate at very high speeds, yielding power density improvements of 20 percent, and reducing engine maintenance costs. In addition, with NASA coating technology, engines can operate at temperatures up to 1200 F. Although the project is still a couple of years from a full engine test of the bearings, this milestone shows that the bearing design exceeds the expected environment, thus providing confidence that an Oil-Free turbine aircraft engine will be attained. The Oil-Free Turbomachinery Project is supported through the Aeropropulsion Base Research Program.

  7. Variable/Multispeed Rotorcraft Drive System Concepts

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2009-01-01

    Several recent studies for advanced rotorcraft have identified the need for variable, or multispeed-capable rotors. A speed change of up to 50 percent has been proposed for future rotorcraft to improve vehicle performance. Varying rotor speed during flight not only requires a rotor capable of performing effectively over the extended operation speed and load range, but also requires an advanced propulsion system to provide the required speed changes. A study has been completed, which investigated possible drive system arrangements to accommodate up to the 50 percent speed change. These concepts are presented. The most promising configurations are identified and will be developed for future validation testing.

  8. Advanced rotorcraft technology: Task force report

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The technological needs and opportunities related to future civil and military rotorcraft were determined and a program plan for NASA research which was responsive to the needs and opportunities was prepared. In general, the program plan places the primary emphasis on design methodology where the development and verification of analytical methods is built upon a sound data base. The four advanced rotorcraft technology elements identified are aerodynamics and structures, flight control and avionic systems, propulsion, and vehicle configurations. Estimates of the total funding levels that would be required to support the proposed program plan are included.

  9. Comprehensive rotorcraft analysis methods

    NASA Technical Reports Server (NTRS)

    Stephens, Wendell B.; Austin, Edward E.

    1988-01-01

    The development and application of comprehensive rotorcraft analysis methods in the field of rotorcraft technology are described. These large scale analyses and the resulting computer programs are intended to treat the complex aeromechanical phenomena that describe the behavior of rotorcraft. They may be used to predict rotor aerodynamics, acoustic, performance, stability and control, handling qualities, loads and vibrations, structures, dynamics, and aeroelastic stability characteristics for a variety of applications including research, preliminary and detail design, and evaluation and treatment of field problems. The principal comprehensive methods developed or under development in recent years and generally available to the rotorcraft community because of US Army Aviation Research and Technology Activity (ARTA) sponsorship of all or part of the software systems are the Rotorcraft Flight Simulation (C81), Dynamic System Coupler (DYSCO), Coupled Rotor/Airframe Vibration Analysis Program (SIMVIB), Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD), General Rotorcraft Aeromechanical Stability Program (GRASP), and Second Generation Comprehensive Helicopter Analysis System (2GCHAS).

  10. Oil-Free Turbomachinery Research Enhanced by Thrust Bearing Test Capability

    NASA Technical Reports Server (NTRS)

    Bauman, Steven W.

    2003-01-01

    NASA Glenn Research Center s Oil-Free Turbomachinery research team is developing aircraft turbine engines that will not require an oil lubrication system. Oil systems are required today to lubricate rolling-element bearings used by the turbine and fan shafts. For the Oil-Free Turbomachinery concept, researchers combined the most advanced foil (air) bearings from industry with NASA-developed high-temperature solid lubricant technology. In 1999, the world s first Oil-Free turbocharger was demonstrated using these technologies. Now we are working with industry to demonstrate Oil-Free turbomachinery technology in a small business jet engine, the EJ-22 produced by Williams International and developed during Glenn s recently concluded General Aviation Propulsion (GAP) program. Eliminating the oil system in this engine will make it simpler, lighter (approximately 15 percent), more reliable, and less costly to purchase and maintain. Propulsion gas turbines will place high demands on foil air bearings, especially the thrust bearings. Up until now, the Oil-Free Turbomachinery research team only had the capability to test radial, journal bearings. This research has resulted in major improvements in the bearings performance, but journal bearings are cylindrical, and can only support radial shaft loads. To counteract axial thrust loads, thrust foil bearings, which are disk shaped, are required. Since relatively little research has been conducted on thrust foil air bearings, their performance lags behind that of journal bearings.

  11. NASA PS304 Lubricant Tested in World's First Commercial Oil-Free Gas Turbine

    NASA Technical Reports Server (NTRS)

    Weaver, Harold F.

    2003-01-01

    In a marriage of research and commercial technology, a 30-kW Oil-Free Capstone microturbine electrical generator unit has been installed and is serving as a test bed for long-term life-cycle testing of NASA-developed PS304 shaft coatings. The coatings are used to reduce friction and wear of the turbine engine s foil air bearings during startup and shut down when sliding occurs, prior to the formation of a lubricating air film. This testing supports NASA Glenn Research Center s effort to develop Oil-Free gas turbine aircraft propulsion systems, which will employ advanced foil air bearings and NASA s PS304 high temperature solid lubricant to replace the ball bearings and lubricating oil found in conventional engines. Glenn s Oil-Free Turbomachinery team s current project is the demonstration of an Oil-Free business jet engine. In anticipation of future flight certification of Oil-Free aircraft engines, long-term endurance and durability tests are being conducted in a relevant gas turbine environment using the Capstone microturbine engine. By operating the engine now, valuable performance data for PS304 shaft coatings and for industry s foil air bearings are being accumulated.

  12. NDARC NASA Design and Analysis of Rotorcraft

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne R.

    2009-01-01

    The NASA Design and Analysis of Rotorcraft (NDARC) software is an aircraft system analysis tool intended to support both conceptual design efforts and technology impact assessments. The principal tasks are to design (or size) a rotorcraft to meet specified requirements, including vertical takeoff and landing (VTOL) operation, and then analyze the performance of the aircraft for a set of conditions. For broad and lasting utility, it is important that the code have the capability to model general rotorcraft configurations, and estimate the performance and weights of advanced rotor concepts. The architecture of the NDARC code accommodates configuration flexibility; a hierarchy of models; and ultimately multidisciplinary design, analysis, and optimization. Initially the software is implemented with lowfidelity models, typically appropriate for the conceptual design environment. An NDARC job consists of one or more cases, each case optionally performing design and analysis tasks. The design task involves sizing the rotorcraft to satisfy specified design conditions and missions. The analysis tasks can include off-design mission performance calculation, flight performance calculation for point operating conditions, and generation of subsystem or component performance maps. For analysis tasks, the aircraft description can come from the sizing task, from a previous case or a previous NDARC job, or be independently generated (typically the description of an existing aircraft). The aircraft consists of a set of components, including fuselage, rotors, wings, tails, and propulsion. For each component, attributes such as performance, drag, and weight can be calculated; and the aircraft attributes are obtained from the sum of the component attributes. Description and analysis of conventional rotorcraft configurations is facilitated, while retaining the capability to model novel and advanced concepts. Specific rotorcraft configurations considered are single main-rotor and tailrotor helicopter; tandem helicopter; coaxial helicopter; and tiltrotors. The architecture of the code accommodates addition of new or higher-fidelity attribute models for a component, as well as addition of new components.

  13. Study and Sub-System Optimization of Propulsion and Drive Systems for the Large Civil TiltRotor (LCTR2) Rotorcraft

    NASA Technical Reports Server (NTRS)

    Robuck, Mark; Wilkerson, Joseph; Snyder, Christopher A.; Zhang, Yiyi; Maciolek, Bob

    2013-01-01

    In a series of study tasks conducted as a part of NASA's Fundamental Aeronautics Program, Rotary Wing Project, Boeing and Rolls-Royce explored propulsion, drive, and rotor system options for the NASA Large Civil Tilt Rotor (LCTR2) concept vehicle. The original objective of this study was to identify engine and drive system configurations to reduce rotor tip speed during cruise conditions and quantify the associated benefits. Previous NASA studies concluded that reducing rotor speed (from 650 fps hover tip speed) during cruise would reduce vehicle gross weight and fuel burn. Initially, rotor cruise speed ratios of 54% of the hover tip speed were of most interest during operation at cruise air speed of 310 ktas. Interim results were previously reported1 for cruise tip speed ratios of 100%, 77%, and 54% of the hover tip speed using engine and/or gearbox features to achieve the reduction. Technology levels from commercial off-the-shelf (COTS), through entry-in-service (EIS) dates of 2025 and 2035 were considered to assess the benefits of advanced technology on vehicle gross weight and fuel burn. This technical paper presents the final study results in terms of vehicle sizing and fuel burn as well as Operational and Support (O&S) costs. New vehicle sizing at rotor tip speed reduced to 65% of hover is presented for engine performance with an EIS 2035 fixed geometry variable speed power turbine. LCTR2 is also evaluated for missions range cases of 400, 600, 800, 1000, and 1200 nautical miles and cruise air speeds of 310, 350 and 375 ktas.

  14. Rotorcraft Conceptual Design Environment

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Sinsay, Jeffrey

    2009-01-01

    Requirements for a rotorcraft conceptual design environment are discussed, from the perspective of a government laboratory. Rotorcraft design work in a government laboratory must support research, by producing technology impact assessments and defining the context for research and development; and must support the acquisition process, including capability assessments and quantitative evaluation of designs, concepts, and alternatives. An information manager that will enable increased fidelity of analysis early in the design effort is described. This manager will be a framework to organize information that describes the aircraft, and enable movement of that information to and from analyses. Finally, a recently developed rotorcraft system analysis tool is described.

  15. Solid Lubricants for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2005-01-01

    Recent breakthroughs in gas foil bearing solid lubricants and computer based modeling has enabled the development of revolulionary Oil-Free turbomachinery systems. These innovative new and solid lubricants at low speeds (start-up and shut down). Foil bearings are hydrodynamic, self acting fluid film bearings made from thin, flexible sheet metal foils. These thin foils trap a hydrodynamic lubricating air film between their surfaces and moving shaft surface. For low temperature applications, like ainrafl air cycle machines (ACM's), polymer coatings provide important solid lubrication during start-up and shut down prior to the development of the lubricating fluid film. The successful development of Oil-Free gas turbine engines requires bearings which can operate at much higher temperatures (greater than 300 C). To address this extreme solid lubrication need, NASA has invented a new family of compostie solid lubricant coatings, NASA PS300.

  16. Oil-free compressor benefits explained.

    PubMed

    Allen, Mark

    2014-09-01

    Oil-free technology for the production of medical air is used in many medical gas systems around the world, and is a requirement of the standards in many places. Under the Department of Health's Health Technical Memorandum, HTM O2-O1, this is not the case, although 'oil-free' is an option. Mark Allen, vice-president of Medical Marketing at Atlas Copco/BeaconMedaes, who is involved with the National Fire Protection Association (NFPA) in the US, the Canadian Standards Association (CSA) in Canada, and the ISO SC-6 (a technical committee on indoor air), discusses how harnessing such technology impacts on production of medical air under the pharmacopeia, and the potential opportunities to reduce maintenance and system problems. PMID:25282984

  17. Milestones in Rotorcraft Aeromechanics

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2011-01-01

    The subject of this paper is milestones in rotorcraft aeromechanics. Aeromechanics covers much of what the engineer needs: performance, loads, vibration, stability, flight dynamics, noise. These topics cover many of the key performance attributes, and many of the often-encountered problems in rotorcraft designs. A milestone is a critical achievement, a turning point, an event marking a significant change or stage in development. The milestones identified and discussed include the beginnings of aeromechanics with autogyro analysis, ground resonance, aeromechanics books, unsteady aerodynamics and airloads, nonuniform inflow and wakes, beams and dynamics, comprehensive analysis, computational fluid dynamics, and rotor airloads tests. The focus on milestones limits the scope of the history, but allows the author to acknowledge his choices for key steps in the development of the science and engineering of rotorcraft.

  18. Rotorcraft Dynamics 1984

    NASA Technical Reports Server (NTRS)

    1985-01-01

    In the conference proceedings are 24 presented papers, their discussions, and material given in two panels. The presented papers address the general areas of the dynamics of rotorcraft or helicopters. Specific topics include the stability of rotors in hover and forward flight, the stability of coupled rotor-fuselage systems in hover, the loads on a rotor in forward flight including new developments in rotor loads calculations, and the calculation of rotorcraft vibration and means for its control or suppression. Material in the first panel deals with the successful application of dynamics technology to engineering development of flight vehicles. Material in the second panel is concerned with large data bases in the area of rotorocraft dynamics and how they are developed, managed, and used.

  19. The Role of Tribology in the Development of an Oil-Free Turbocharger

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    1997-01-01

    Gas-turbine-based aeropropulsion engines are technologically mature. Thus, as with any mature technology, revolutionary approaches will be needed to achieve the significant performance gains that will keep the U.S. propulsion manufacturers well ahead of foreign competition. One such approach is the development of oil-free turbomachinery utilizing advanced foil air bearings, seals, and solid lubricants. By eliminating oil-lubricated bearings and seals and supporting an engine rotor on an air film, significant improvements can be realized. For example, the entire oil system including pipes, lines, filters, cooler, and tanks could be removed, thereby saving considerable weight. Since air has no thermal decomposition temperature, engine systems could operate without excessive cooling. Also, since air bearings have no diameter-rpm fatigue limits (D-N limits), engines could be designed to operate at much higher speeds and higher density, which would result in a smaller aeropropulsion package. Because of recent advances in compliant foil air bearings and high temperature solid lubricants, these technologies can be applied to oil-free turbomachinery. In an effort to develop these technologies and to demonstrate a project along the path to an oil-free gas turbine engine, NASA has undertaken the development of an oil-free turbocharger for a heavy duty diesel engine. This turbomachine can reach 120000 rpm at a bearing temperature of 540 C (1000 F) and, in comparison to oil-lubricated bearings, can increase efficiency by 10 to 15 percent because of reduced friction. In addition, because there are no oil lubricants, there are no seal-leakage-induced emissions.

  20. Analysis of Advanced Rotorcraft Configurations

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2000-01-01

    Advanced rotorcraft configurations are being investigated with the objectives of identifying vehicles that are larger, quieter, and faster than current-generation rotorcraft. A large rotorcraft, carrying perhaps 150 passengers, could do much to alleviate airport capacity limitations, and a quiet rotorcraft is essential for community acceptance of the benefits of VTOL operations. A fast, long-range, long-endurance rotorcraft, notably the tilt-rotor configuration, will improve rotorcraft economics through productivity increases. A major part of the investigation of advanced rotorcraft configurations consists of conducting comprehensive analyses of vehicle behavior for the purpose of assessing vehicle potential and feasibility, as well as to establish the analytical models required to support the vehicle development. The analytical work of FY99 included applications to tilt-rotor aircraft. Tilt Rotor Aeroacoustic Model (TRAM) wind tunnel measurements are being compared with calculations performed by using the comprehensive analysis tool (Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD 11)). The objective is to establish the wing and wake aerodynamic models that are required for tilt-rotor analysis and design. The TRAM test in the German-Dutch Wind Tunnel (DNW) produced extensive measurements. This is the first test to encompass air loads, performance, and structural load measurements on tilt rotors, as well as acoustic and flow visualization data. The correlation of measurements and calculations includes helicopter-mode operation (performance, air loads, and blade structural loads), hover (performance and air loads), and airplane-mode operation (performance).

  1. Advanced rotorcraft transmission program

    NASA Technical Reports Server (NTRS)

    Bill, Robert C.

    1990-01-01

    The Advanced Rotorcraft Transmission (ART) program is an Army-funded, joint Army/NASA program to develop and demonstrate lightweight, quiet, durable drivetrain systems for next generation rotorcraft. ART addresses the drivetrain requirements of two distinct next generation aircraft classes: Future Air Attack Vehicle, a 10,000 to 20,000 lb. aircraft capable of undertaking tactical support and air-to-air missions; and Advanced Cargo Aircraft, a 60,000 to 80,000 lb. aircraft capable of heavy life field support operations. Both tiltrotor and more conventional helicopter configurations are included in the ART program. Specific objectives of ART include reduction of drivetrain weight by 25 percent compared to baseline state-of-the-art drive systems configured and sized for the next generation aircraft, reduction of noise level at the transmission source by 10 dB relative to a suitably sized and configured baseline, and attainment of at least a 5000 hr mean-time-between-removal. The technical approach for achieving the ART goals includes application of the latest available component, material, and lubrication technology to advanced concept drivetrains that utilize new ideas in gear configuration, transmission layout, and airframe/drivetrain integration. To date, candidate drivetrain systems were carried to a conceptual design stage, and tradeoff studies were conducted resulting in selection of an ART transmission configuration for each of the four contractors. The final selection was based on comparative weight, noise, and reliability studies. A description of each of the selected ART designs is included. Preliminary design of each of the four selected ART transmission was completed, as have mission impact studies wherein comparisons of aircraft mission performance and life cycle costs are undertaken for the next generation aircraft with ART and with the baseline transmission.

  2. Concepts for Variable/Multi-Speed Rotorcraft Drive System

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2008-01-01

    In several recent studies and on-going developments for advanced rotorcraft, the need for variable or multi-speed capable rotors has been raised. A speed change of up to 50 percent has been proposed for future rotorcraft to improve overall vehicle performance. Accomplishing rotor speed changes during operation requires both a rotor that can perform effectively over the operation speed/load range, and a propulsion system that can enable these speed changes. A study has been completed to investigate possible drive system arrangements that can accommodate up to the 50 percent speed change. Several concepts will be presented and evaluated. The most promising configurations will be identified and developed for future testing in a sub-scaled test facility to validate operational capability.

  3. Modeling Tool Advances Rotorcraft Design

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Continuum Dynamics Inc. (CDI), founded in 1979, specializes in advanced engineering services, including fluid dynamic modeling and analysis for aeronautics research. The company has completed a number of SBIR research projects with NASA, including early rotorcraft work done through Langley Research Center, but more recently, out of Ames Research Center. NASA Small Business Innovation Research (SBIR) grants on helicopter wake modeling resulted in the Comprehensive Hierarchical Aeromechanics Rotorcraft Model (CHARM), a tool for studying helicopter and tiltrotor unsteady free wake modeling, including distributed and integrated loads, and performance prediction. Application of the software code in a blade redesign program for Carson Helicopters, of Perkasie, Pennsylvania, increased the payload and cruise speeds of its S-61 helicopter. Follow-on development resulted in a $24 million revenue increase for Sikorsky Aircraft Corporation, of Stratford, Connecticut, as part of the company's rotor design efforts. Now under continuous development for more than 25 years, CHARM models the complete aerodynamics and dynamics of rotorcraft in general flight conditions. CHARM has been used to model a broad spectrum of rotorcraft attributes, including performance, blade loading, blade-vortex interaction noise, air flow fields, and hub loads. The highly accurate software is currently in use by all major rotorcraft manufacturers, NASA, the U.S. Army, and the U.S. Navy.

  4. Remaining Technical Challenges and Future Plans for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Bruckner, Robert J.

    2010-01-01

    The application of Oil-Free technologies (foil gas bearings, solid lubricants and advanced analysis and predictive modeling tools) to advanced turbomachinery has been underway for several decades. During that time, full commercialization has occurred in aircraft air cycle machines, turbocompressors and cryocoolers and ever-larger microturbines. Emerging products in the automotive sector (turbochargers and superchargers) indicate that high volume serial production of foil bearings is imminent. Demonstration of foil bearings in APU s and select locations in propulsion gas turbines illustrates that such technology also has a place in these future systems. Foil bearing designs, predictive tools and advanced solid lubricants have been reported that can satisfy anticipated requirements but a major question remains regarding the scalability of foil bearings to ever larger sizes to support heavier rotors. In this paper, the technological history, primary physics, engineering practicalities and existing experimental and experiential database for scaling foil bearings are reviewed and the major remaining technical challenges are identified.

  5. NASA/Army Rotorcraft Technology. Volume 1: Aerodynamics, and Dynamics and Aeroelasticity

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Conference Proceedings is a compilation of over 30 technical papers presented at this milestone event which reported on the advances in rotorcraft technical knowledge resulting from NASA, Army, and industry rotorcraft research programs over the last 5 to 10 years. The Conference brought together over 230 government, industry, and allied nation conferees to exchange technical information and hear invited technical papers by prominent NASA, Army, and industry researchers covering technology topics which included: aerodynamics, dynamics and elasticity, propulsion and drive systems, flight dynamics and control, acoustics, systems integration, and research aircraft.

  6. Community rotorcraft air transportation benefits and opportunities

    NASA Technical Reports Server (NTRS)

    Gilbert, G. A.; Freund, D. J.; Winick, R. M.; Cafarelli, N. J.; Hodgkins, R. F.; Vickers, T. K.

    1981-01-01

    Information about rotorcraft that will assist community planners in assessing and planning for the use of rotorcraft transportation in their communities is provided. Information useful to helicopter researchers, manufacturers, and operators concerning helicopter opportunities and benefits is also given. Three primary topics are discussed: the current status and future projections of rotorcraft technology, and the comparison of that technology with other transportation vehicles; the community benefits of promising rotorcraft transportation opportunities; and the integration and interfacing considerations between rotorcraft and other transportation vehicles. Helicopter applications in a number of business and public service fields are examined in various geographical settings.

  7. Rotorcraft and Enabling Robotic Rescue

    NASA Technical Reports Server (NTRS)

    Young, Larry A.

    2010-01-01

    This paper examines some of the issues underlying potential robotic rescue devices (RRD) in the context where autonomous or manned rotorcraft deployment of such robotic systems is a crucial attribute for their success in supporting future disaster relief and emergency response (DRER) missions. As a part of this discussion, work related to proof-of-concept prototyping of two notional RRD systems is summarized.

  8. NDARC-NASA Design and Analysis of Rotorcraft Theoretical Basis and Architecture

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2010-01-01

    The theoretical basis and architecture of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are described. The principal tasks of NDARC are to design (or size) a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft consists of a set of components, including fuselage, rotors, wings, tails, and propulsion. For each component, attributes such as performance, drag, and weight can be calculated. The aircraft attributes are obtained from the sum of the component attributes. NDARC provides a capability to model general rotorcraft configurations, and estimate the performance and attributes of advanced rotor concepts. The software has been implemented with low-fidelity models, typical of the conceptual design environment. Incorporation of higher-fidelity models will be possible, as the architecture of the code accommodates configuration flexibility, a hierarchy of models, and ultimately multidisciplinary design, analysis and optimization.

  9. 14 CFR 29.181 - Dynamic stability: Category A rotorcraft.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Aeronautics and Space 1 2010-01-01 2010-01-01 false Dynamic stability: Category A rotorcraft. 29.181 Section 29...ROTORCRAFT Flight Flight Characteristics § 29.181 Dynamic stability: Category A rotorcraft. Any short-period...

  10. Noise Prediction for Maneuvering Rotorcraft

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Jones, Henry E.

    2000-01-01

    This paper presents the initial work toward first-principles noise prediction for maneuvering rotors. Both the aeromechanical and acoustics aspects of the maneuver noise problem are discussed. The comprehensive analysis code, CAMRAD 2. was utilized to predict the time-dependent aircraft position and attitude, along - with the rotor blade airloads and motion. The major focus of this effort was the enhancement of the acoustic code WOPWOP necessary to compute the noise from a maneuvering rotorcraft. Full aircraft motion, including arbitrary transient motion, is modeled together with arbitrary rotor blade motions. Noise from a rotorcraft in turning and descending flight is compared to level flight. A substantial increase in the rotor noise is found both for turning flight and during a transient maneuver. Additional enhancements to take advantage of parallel computers and clusters of workstations, in addition to a new compact-chordwise loading formulation, are also described.

  11. Oil-Free Shaft Support System Rotordynamics: Past, Present, and Future Challenges and Opportunities

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2011-01-01

    Recent breakthroughs in Oil-Free technologies have enabled new high-speed rotor systems and turbomachinery. Such technologies can include compliant-surface gas bearings, magnetic bearings, and advanced solid lubricants and tribo-materials. This presentation briefly reviews critical technology developments and the current state-of-the-art, emerging Oil-Free rotor systems and discusses obstacles preventing more widespread use. Key examples of "best practices" for deploying Oil-Free technologies will be presented and remaining major technical questions surrounding Oil-Free technologies will be brought forward.

  12. Oil-Free shaft support system rotordynamics: Past, present and future challenges and opportunities

    NASA Astrophysics Data System (ADS)

    DellaCorte, Christopher

    2012-05-01

    Recent breakthroughs in Oil-Free technologies have enabled new high-speed rotor systems and turbomachinery. Such technologies can include compliant-surface gas bearings, magnetic bearings and advanced solid lubricants and tribo-materials. This presentation briefly reviews critical technology developments and the current state-of-the-art, emerging Oil-Free rotor systems and discusses obstacles preventing more widespread use. Key examples of "best practices" for deploying Oil-Free technologies will be presented and remaining major technical questions surrounding Oil-Free technologies will be brought forward.

  13. A review of NASA's propulsion programs for aviation

    NASA Technical Reports Server (NTRS)

    Stewart, W. L.; Johnson, H. W.; Weber, R. J.

    1978-01-01

    A review of five NASA engine-oriented propulsion programs of major importance to civil aviation are presented and discussed. Included are programs directed at exploring propulsion system concepts for (1) energy conservation subsonic aircraft (improved current turbofans, advanced turbofans, and advanced turboprops); (2) supersonic cruise aircraft (variable cycle engines); (3) general aviation aircraft (improved reciprocating engines and small gas turbines); (4) powered lift aircraft (advanced turbofans); and (5) advanced rotorcraft.

  14. Rotorcraft researchers and operators - Is there is common ground

    NASA Technical Reports Server (NTRS)

    Talbot, P. D.; Snyder, W. J.

    1981-01-01

    An investigation is conducted concerning the extent to which a program for rotorcraft research presented by NASA meets the user needs. Problems of civil operators are examined, taking into account powerplants, reliability and maintainability, environment, noise and vibration, and lack of space for passengers' baggage. A description of applicable technology is provided, giving attention to aerodynamics and structures, propulsion, power transfer methodology, flight control, avionic systems, human factors, and vehicle configurations. One of the most difficult challenges in trying to bring research to bear on operator problems is that in general researchers are working on long-term solutions while operators are seeking short-term answers. Attention is also given to potential technological bright spots, higher risk technologies, highest technological risks, and advanced vehicle configurations.

  15. NASA Heavy Lift Rotorcraft Systems Investigation

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Yamauchi, Gloria K.; Watts, Michael E.

    2005-01-01

    The NASA Heavy Lift Rotorcraft Systems Investigation examined in depth several rotorcraft configurations for large civil transport, designed to meet the technology goals of the NASA Vehicle Systems Program. The investigation identified the Large Civil Tiltrotor as the configuration with the best potential to meet the technology goals. The design presented was economically competitive, with the potential for substantial impact on the air transportation system. The keys to achieving a competitive aircraft were low drag airframe and low disk loading rotors; structural weight reduction, for both airframe and rotors; drive system weight reduction; improved engine efficiency; low maintenance design; and manufacturing cost comparable to fixed-wing aircraft. Risk reduction plans were developed to provide the strategic direction to support a heavy-lift rotorcraft development. The following high risk areas were identified for heavy lift rotorcraft: high torque, light weight drive system; high performance, structurally efficient rotor/wing system; low noise aircraft; and super-integrated vehicle management system.

  16. Public acceptance of urban rotorcraft operations

    NASA Astrophysics Data System (ADS)

    Marcolini, Michael A.; Powell, Clemans A.; Posey, Joe W.

    2001-05-01

    Even though tiltrotor operations from city center to city center could greatly shorten travel times over moderate ranges, public opposition to intense urban rotorcraft activity has kept this possibility from being realized. One significant factor in this opposition is rotorcraft noise. Over the last 25 years, NASA has explored the subjective response to rotorcraft noise and developed low noise design concepts and noise abatement flight procedures. While low noise designs can be applied for future rotorcraft, this is not an effective near-term means of reducing rotorcraft noise, because of the costs associated with replacement of helicopter rotor blades. Recent noise abatement research, which has been focusing on the development of tools and techniques to facilitate the design of quieter flight procedures for existing vehicles, has much more immediate application. While very little subjective response work has occurred recently, prior work at NASA in this area from the 1970s and 1980s is discussed. Lastly, thoughts on future research areas that might help improve the public acceptance of rotorcraft will be described.

  17. 78 FR 12254 - Interest in Restructure of Rotorcraft Airworthiness Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-22

    ...and nine or less passenger seats.'' Rotorcraft...with 10 or more passenger seats are certificated as transport category rotorcraft...Authorities, and Transport Canada Civil Aviation...Gross Weight and Passenger Issues Working...

  18. Techniques for designing rotorcraft control systems

    NASA Technical Reports Server (NTRS)

    Levine, William S.; Barlow, Jewel

    1993-01-01

    This report summarizes the work that was done on the project from 1 Apr. 1992 to 31 Mar. 1993. The main goal of this research is to develop a practical tool for rotorcraft control system design based on interactive optimization tools (CONSOL-OPTCAD) and classical rotorcraft design considerations (ADOCS). This approach enables the designer to combine engineering intuition and experience with parametric optimization. The combination should make it possible to produce a better design faster than would be possible using either pure optimization or pure intuition and experience. We emphasize that the goal of this project is not to develop an algorithm. It is to develop a tool. We want to keep the human designer in the design process to take advantage of his or her experience and creativity. The role of the computer is to perform the calculation necessary to improve and to display the performance of the nominal design. Briefly, during the first year we have connected CONSOL-OPTCAD, an existing software package for optimizing parameters with respect to multiple performance criteria, to a simplified nonlinear simulation of the UH-60 rotorcraft. We have also created mathematical approximations to the Mil-specs for rotorcraft handling qualities and input them into CONSOL-OPTCAD. Finally, we have developed the additional software necessary to use CONSOL-OPTCAD for the design of rotorcraft controllers.

  19. Advanced Rotorcraft Transmission (ART) program summary

    NASA Technical Reports Server (NTRS)

    Krantz, T. L.; Kish, J. G.

    1992-01-01

    The Advanced Rotorcraft Transmission (ART) Program was initiated to advance the state of the art for rotorcraft transmissions. The goal of the ART Program was to develop and demonstrate the technologies needed to reduce transmission weight by 25 pct. and reduce noise by 10 dB while obtaining a 5000 hr 'mean time between failure'. The research done under the ART Program is summarized. A split path design was selected as best able to meet the program goals. Key part technologies needed for this design were identified, studied, and developed. Two of these technologies are discussed in detail: the load sharing of split path designs including the use of a compliant elastomeric torque splitter and the application of a high ratio, low pitch line velocity gear mesh. Development of an angular contact spherical roller bearing, transmission error analysis, and fretting fatigue testing are discussed. The technologies for a light weight, quiet, and reliable rotorcraft transmission were demonstrated.

  20. Advanced Rotorcraft Transmission (ART) Program summary

    NASA Astrophysics Data System (ADS)

    Krantz, T. L.; Kish, J. G.

    1992-07-01

    The Advanced Rotorcraft Transmission (ART) Program was initiated to advance the state of the art for rotorcraft transmissions. The goal of the ART Program was to develop and demonstrate the technologies needed to reduce transmission weight by 25 pct and reduce noise by 10 dB while obtaining a 5000 hr 'mean time between failure'. The research done under the ART Program is summarized. A split path design was selected as best able to meet the program goals. Key part technologies needed for this design were identified, studied, and developed. Two of these technologies are discussed in detail: the load sharing of split path designs including the use of a compliant elastomeric torque splitter and the application of a high ratio, low pitch line velocity gear mesh. Development of an angular contact spherical roller bearing, transmission error analysis, and fretting fatigue testing are discussed. The technologies for a light weight, quiet, and reliable rotorcraft transmission were demonstrated.

  1. Planning for rotorcraft and commuter air transportationn

    NASA Technical Reports Server (NTRS)

    Stockwell, W. L.; Stowers, J.

    1981-01-01

    Community planning needs, criteria, and other considerations such as intermodal coordination and regulatory requirements, for rotorcraft and fixed wing commuter air transportation were identified. A broad range of community planning guidelines, issues, and information which can be used to: (1) direct anticipated aircraft technological improvements; (2) assist planners in identifying and evaluating the opportunities and tradeoffs presented by rotorcraft and commuter aircraft options relative to other modes; and (3) increase communication between aircraft technologists and planners for the purpose of on going support in capitalizing on rotorcraft and commuter air opportunities are provided. The primary tool for identifying and analyzing planning requirements was a detailed questionnaire administered to a selected sample of 55 community planners and other involved in planning for helicopters and commuter aviation.

  2. Influence of Lift Offset on Rotorcraft Performance

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2009-01-01

    The influence of lift offset on the performance of several rotorcraft configurations is explored. A lift-offset rotor, or advancing blade concept, is a hingeless rotor that can attain good efficiency at high speed by operating with more lift on the advancing side than on the retreating side of the rotor disk. The calculated performance capability of modern-technology coaxial rotors utilizing a lift offset is examined, including rotor performance optimized for hover and high-speed cruise. The ideal induced power loss of coaxial rotors in hover and twin rotors in forward flight is presented. The aerodynamic modeling requirements for performance calculations are evaluated, including wake and drag models for the high-speed flight condition. The influence of configuration on the performance of rotorcraft with lift-offset rotors is explored, considering tandem and side-by-side rotorcraft as well as wing-rotor lift share.

  3. The selection of convertible engines with current gas generator technology for high speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Eisenberg, Joseph D.

    1990-01-01

    NASA-Lewis sponsored two studies to determine the most promising convertible engine concepts for high speed rotorcraft. These studies projected year 2000 convertible technology limited to present gas generator technology. Propulsion systems for utilization on aircraft needing thrust only during cruise and those aircraft needing both power and thrust at cruise were investigated. Mission calculations for the two contractors involved were based upon the fold tilt rotor concept. Analysis and comparison of the General Electric concepts (geared UDF, clutched fan, and Variable Inlet Guide Vane (VIGV) fan), and the Allison Gas Turbine concepts (clutched fan, VIGV fan, variable pitch fan, single rotation tractor propfan, and counter rotation tractor propfan) are presented.

  4. The selection of convertible engines with current gas generator technology for high speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Eisenberg, Joseph D.

    1990-01-01

    NASA-Lewis has sponsored two studies to determine the most promising convertible engine concepts for high speed rotorcraft. These studies projected year 2000 convertible technology limited to present gas generator technology. Propulsion systems for utilization on aircraft needing thrust only during cruise and those aircraft needing both power and thrust at cruise were investigated. Mission calculations for the two contractors involved were based upon the fold tilt rotor concept. Analysis and comparison of the General Electric concepts (geared UDF, clutched fan, and VIGV fan), and the Allison Gas Turbine concepts (clutched fan, VIGV fan, variable pitch fan, single rotation tractor propfan, and counter rotation tractor propfan) are presented.

  5. Design of Quiet Rotorcraft Approach Trajectories

    NASA Technical Reports Server (NTRS)

    Padula, Sharon L.; Burley, Casey L.; Boyd, D. Douglas, Jr.; Marcolini, Michael A.

    2009-01-01

    A optimization procedure for identifying quiet rotorcraft approach trajectories is proposed and demonstrated. The procedure employs a multi-objective genetic algorithm in order to reduce noise and create approach paths that will be acceptable to pilots and passengers. The concept is demonstrated by application to two different helicopters. The optimized paths are compared with one another and to a standard 6-deg approach path. The two demonstration cases validate the optimization procedure but highlight the need for improved noise prediction techniques and for additional rotorcraft acoustic data sets.

  6. A practical approach to rotorcraft systems identification

    NASA Technical Reports Server (NTRS)

    Du Val, R. W.; Wang, J. C.; Demiroz, M. Y.

    1984-01-01

    A standard for rotorcraft system identification is proposed to facilitate the exchange of data and technology within the industry. This integrated approach utilizes simulations to validate methodology and flight data to validate simulations. A new technique allowing results obtained from separate maneuvers to be systematically combined is also presented and shown to be a fundamental tool in providing a practical approach to rotorcraft identification. The proposed methodology is evaluated using data generated by nonlinear blade-element simulation of the Rotor Systems Research Aircraft.

  7. Passive obstacle location for rotorcraft guidance

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Chatterji, G. B.; Sridhar, B.

    1991-01-01

    Nap-of-the-earth flight mode is extremely demanding on the rotorcraft pilots. This fact has motivated the research in automating various components of low altitude rotorcraft flight operations. Concurrent with the development of guidance laws, efforts are under way to develop systems for locating the terrain and the obstacles using inputs from passive electrooptical sensors such as TV cameras and infrared imagers. A passive obstable location algorithm that uses image sequences from cameras undergoing translational and rotational motion is developed. The algorithm is in a general form and can operate in multicamera imaging environments. Performance results using an image sequence from an airborne camera are given.

  8. Mystery of Foil Air Bearings for Oil-free Turbomachinery Unlocked: Load Capacity Rule-of-thumb Allows Simple Estimation of Performance

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    2002-01-01

    The Oil-Free Turbomachinery team at the NASA Glenn Research Center has unlocked one of the mysteries surrounding foil air bearing performance. Foil air bearings are self-acting hydrodynamic bearings that use ambient air, or any fluid, as their lubricant. In operation, the motion of the shaft's surface drags fluid into the bearing by viscous action, creating a pressurized lubricant film. This lubricating film separates the stationary foil bearing surface from the moving shaft and supports load. Foil bearings have been around for decades and are widely employed in the air cycle machines used for cabin pressurization and cooling aboard commercial jetliners. The Oil-Free Turbomachinery team is fostering the maturation of this technology for integration into advanced Oil-Free aircraft engines. Elimination of the engine oil system can significantly reduce weight and cost and could enable revolutionary new engine designs. Foil bearings, however, have complex elastic support structures (spring packs) that make the prediction of bearing performance, such as load capacity, difficult if not impossible. Researchers at Glenn recently found a link between foil bearing design and load capacity performance. The results have led to a simple rule-of-thumb that relates a bearing's size, speed, and design to its load capacity. Early simple designs (Generation I) had simple elastic (spring) support elements, and performance was limited. More advanced bearings (Generation III) with elastic supports, in which the stiffness is varied locally to optimize gas film pressures, exhibit load capacities that are more than double those of the best previous designs. This is shown graphically in the figure. These more advanced bearings have enabled industry to introduce commercial Oil-Free gas-turbine-based electrical generators and are allowing the aeropropulsion industry to incorporate the technology into aircraft engines. The rule-of-thumb enables engine and bearing designers to easily size and select bearing technology for a new application and determine the level of complexity required in the bearings. This new understanding enables industry to assess the feasibility of new engine designs and provides critical guidance toward the future development of Oil-Free turbomachinery propulsion systems.

  9. Rotorcraft Blade-Vortex Interaction Controller

    NASA Technical Reports Server (NTRS)

    Schmitz, Fredric H. (Inventor)

    1995-01-01

    Blade-vortex interaction noises, sometimes referred to as 'blade slap', are avoided by increasing the absolute value of inflow to the rotor system of a rotorcraft. This is accomplished by creating a drag force which causes the angle of the tip-path plane of the rotor system to become more negative or more positive.

  10. ROTORCRAFT AEROMECHANICS APPLICATIONS OF A COMPREHENSIVE ANALYSIS

    Microsoft Academic Search

    Wayne Johnson; Johnson Aeronautics

    1998-01-01

    Results from the comprehensive analysis CAMRAD II are presented, illustrating recent developments in the aerodynamics and dynamics models, and demonstrating the technology that is needed for an adequate calculation of rotorcraft behavior. Calculations of rotor performance, airloads, structural loads, and stability are presented, including comparisons with experimental data.

  11. Rotorcraft research in India: recent developments

    Microsoft Academic Search

    Ranjan Ganguli

    2010-01-01

    Purpose – The purpose of this paper is to discuss published research in rotorcraft which has taken place in India during the last ten years. The helicopter research is divided into the following parts: health monitoring, smart rotor, design optimization, control, helicopter rotor dynamics, active control of structural response (ACSR) and helicopter design and development. Aspects of health monitoring and

  12. 77 FR 50576 - Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures; OMB Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-22

    ...RIN 2120-AJ52 Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures...final rule, ``Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures...final rule, ``Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft...

  13. 14 CFR 133.17 - Requirements for issuance of a rotorcraft external-load operator certificate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Requirements for issuance of a rotorcraft external-load operator certificate. 133...CERTIFICATION AND OPERATIONS ROTORCRAFT EXTERNAL-LOAD OPERATIONS Certification Rules...Requirements for issuance of a rotorcraft external-load operator certificate. If...

  14. 14 CFR 61.161 - Aeronautical experience: Rotorcraft category and helicopter class rating.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...experience: Rotorcraft category and helicopter class rating. 61.161 Section...experience: Rotorcraft category and helicopter class rating. (a) A person who...certificate with a rotorcraft category and helicopter class rating, must have at least...

  15. 14 CFR 61.161 - Aeronautical experience: Rotorcraft category and helicopter class rating.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...experience: Rotorcraft category and helicopter class rating. 61.161 Section...experience: Rotorcraft category and helicopter class rating. (a) A person who...certificate with a rotorcraft category and helicopter class rating, must have at least...

  16. 14 CFR 61.161 - Aeronautical experience: Rotorcraft category and helicopter class rating.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...experience: Rotorcraft category and helicopter class rating. 61.161 Section...experience: Rotorcraft category and helicopter class rating. (a) A person who...certificate with a rotorcraft category and helicopter class rating, must have at least...

  17. 14 CFR 61.161 - Aeronautical experience: Rotorcraft category and helicopter class rating.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...experience: Rotorcraft category and helicopter class rating. 61.161 Section...experience: Rotorcraft category and helicopter class rating. (a) A person who...certificate with a rotorcraft category and helicopter class rating, must have at least...

  18. 14 CFR 61.161 - Aeronautical experience: Rotorcraft category and helicopter class rating.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...experience: Rotorcraft category and helicopter class rating. 61.161 Section...experience: Rotorcraft category and helicopter class rating. (a) A person who...certificate with a rotorcraft category and helicopter class rating, must have at least...

  19. SMALLSAT PROPULSION

    Microsoft Academic Search

    Pete Smith; Roland McLellan; Dave Gibbon

    This paper presents an overview of the components, systems and technologies used by Marotta UK and SSTL for smallsat propulsion over the last 5 years, and gives a brief insight into current developments for future smallsat, scientific and other satellite applications. Components which have been developed by Marotta UK have been used extensively in the propulsion systems of the satellites

  20. Rotorcraft noise: Status and recent developments

    NASA Technical Reports Server (NTRS)

    George, Albert R.; Sim, Ben WEL-C.; Polak, David R.

    1993-01-01

    This paper briefly reviews rotorcraft noise mechanisms and their approximate importance for different types of rotorcraft in different flight regimes. Discrete noise is due to periodic flow disturbances and includes impulsive noise produced by phenomena which occur during a limited segment of a blade's rotation. Broadband noise results when rotors interact with random disturbances, such as turbulence, which can originate in a variety of sources. The status of analysis techniques for these mechanisms are reviewed. Also, some recent progress is presented on the understanding and analysis of tilt rotor aircraft noise due to: (1) recirculation and blockage effects of the rotor flow in hover; and (2) blade-vortex interactions in forward and descending flight.

  1. A model for rotorcraft flying qualities studies

    NASA Technical Reports Server (NTRS)

    Mittal, Manoj; Costello, Mark F.

    1993-01-01

    This paper outlines the development of a mathematical model that is expected to be useful for rotorcraft flying qualities research. A computer model is presented that can be applied to a range of different rotorcraft configurations. The algorithm computes vehicle trim and a linear state-space model of the aircraft. The trim algorithm uses non linear optimization theory to solve the nonlinear algebraic trim equations. The linear aircraft equations consist of an airframe model and a flight control system dynamic model. The airframe model includes coupled rotor and fuselage rigid body dynamics and aerodynamics. The aerodynamic model for the rotors utilizes blade element theory and a three state dynamic inflow model. Aerodynamics of the fuselage and fuselage empennages are included. The linear state-space description for the flight control system is developed using standard block diagram data.

  2. In-Flight Rotorcraft Acoustics Program

    NASA Technical Reports Server (NTRS)

    Peterson, Randall L.; Warmbrodt, William (Technical Monitor)

    1996-01-01

    A key part of NASA's aeronautics research is reducing noise to make helicopters and tiltrotors more acceptable to the public. The objective of the In-Flight Rotorcraft Acoustics Program (IRAP) is to acquire rotorcraft. noise data in flight for comparison to wind tunnel data. The type of noise of concern is "blade-vortex-interaction," or BVI, noise. Microphones on the wing tips and tail fin of the quiet NASA YO-3A Acoustics Research Aircraft measure BVI noise while the YO-3A descends in close formation with the helicopter or tiltrotor emitting the noise.The data acquired through IRAP is needed to validate wind-tunnel test results, or, where the results cannot be validated, to provide researchers with clues as to how to improve testing methods.

  3. A History of Rotorcraft Comprehensive Analyses

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2013-01-01

    A history of the development of rotorcraft comprehensive analyses is presented. Comprehensive analyses are digital computer programs that calculate the aeromechanical behavior of the rotor and aircraft, bringing together the most advanced models of the geometry, structure, dynamics, and aerodynamics available in rotary wing technology. The development of the major codes of the last five decades from industry, government, and universities is described. A number of common themes observed in this history are discussed.

  4. Robust Crossfeed Design for Hovering Rotorcraft

    NASA Technical Reports Server (NTRS)

    Catapang, David R.

    1993-01-01

    Control law design for rotorcraft fly-by-wire systems normally attempts to decouple angular responses using fixed-gain crossfeeds. This approach can lead to poor decoupling over the frequency range of pilot inputs and increase the load on the feedback loops. In order to improve the decoupling performance, dynamic crossfeeds may be adopted. Moreover, because of the large changes that occur in rotorcraft dynamics due to small changes about the nominal design condition, especially for near-hovering flight, the crossfeed design must be 'robust'. A new low-order matching method is presented here to design robust crossfeed compensators for multi-input, multi-output (MIMO) systems. The technique identifies degrees-of-freedom that can be decoupled using crossfeeds, given an anticipated set of parameter variations for the range of flight conditions of concern. Cross-coupling is then reduced for degrees-of-freedom that can use crossfeed compensation by minimizing off-axis response magnitude average and variance. Results are presented for the analysis of pitch, roll, yaw and heave coupling of the UH-60 Black Hawk helicopter in near-hovering flight. Robust crossfeeds are designed that show significant improvement in decoupling performance and robustness over nominal, single design point, compensators. The design method and results are presented in an easily used graphical format that lends significant physical insight to the design procedure. This plant pre-compensation technique is an appropriate preliminary step to the design of robust feedback control laws for rotorcraft.

  5. Stiffness and Damping Coefficient Estimation of Compliant Surface Gas Bearings for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2010-01-01

    Foil gas bearings are a key technology in many commercial and emerging Oil-Free turbomachinery systems. These bearings are non-linear and have been difficult to analytically model in terms of performance characteristics such as load capacity, power loss, stiffness and damping. Previous investigations led to an empirically derived method, a rule-of-thumb, to estimate load capacity. This method has been a valuable tool in system development. The current paper extends this tool concept to include rules for stiffness and damping coefficient estimation. It is expected that these rules will further accelerate the development and deployment of advanced Oil-Free machines operating on foil gas bearings

  6. REXOR 2 rotorcraft simulation model. Volume 1: Engineering documentation

    NASA Technical Reports Server (NTRS)

    Reaser, J. S.; Kretsinger, P. H.

    1978-01-01

    A rotorcraft nonlinear simulation called REXOR II, divided into three volumes, is described. The first volume is a development of rotorcraft mechanics and aerodynamics. The second is a development and explanation of the computer code required to implement the equations of motion. The third volume is a user's manual, and contains a description of code input/output as well as operating instructions.

  7. Development of fully functional miniature unmanned rotorcraft systems

    Microsoft Academic Search

    Guowei Cai; Feng Lin; Ben M. CHEN; Tong H. LEE

    2010-01-01

    We document in this article a general introduction to modern miniature unmanned rotorcraft systems. More specifically, we present a fairly detailed overview on the hardware configuration, software integration, aerodynamic modeling, automatic flight control system, and computer vision system involved in forming an unmanned rotorcraft system.

  8. HIGH-SPEED LOW POWER RADIAL TURBOCOMPRESSOR FOR OIL FREE HEATPUMPS

    Microsoft Academic Search

    Jurg SCHIFFMANN; Daniel FAVRAT

    The presence of oil in domestic heat pumps is a hindrance, particularly for enhanced surface evaporators and for advanced concepts based on two-stage cycles. Very compact oil-free dynamic compressor directly driven by high speed electric motors and supported on refrigerant vapor bearings represent a promising alternative. This paper presents a design analysis of the first stage prototype with the various

  9. Integration Methodology For Oil-Free Shaft Support Systems: Four Steps to Success

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.; DellaCorte, Christopher; Bruckner, Robert J.

    2010-01-01

    Commercial applications for Oil-Free turbomachinery are slowly becoming a reality. Micro-turbine generators, highspeed electric motors, and electrically driven centrifugal blowers are a few examples of products available in today's commercial marketplace. Gas foil bearing technology makes most of these applications possible. A significant volume of component level research has led to recent acceptance of gas foil bearings in several specialized applications, including those mentioned above. Component tests identifying such characteristics as load carrying capacity, power loss, thermal behavior, rotordynamic coefficients, etc. all help the engineer design foil bearing machines, but the development process can be just as important. As the technology gains momentum and acceptance in a wider array of machinery, the complexity and variety of applications will grow beyond the current class of machines. Following a robust integration methodology will help improve the probability of successful development of future Oil-Free turbomachinery. This paper describes a previously successful four-step integration methodology used in the development of several Oil-Free turbomachines. Proper application of the methods put forward here enable successful design of Oil-Free turbomachinery. In addition when significant design changes or unique machinery are developed, this four-step process must be considered.

  10. Focused technology: Nuclear propulsion

    NASA Technical Reports Server (NTRS)

    Miller, Thomas J.

    1993-01-01

    Five viewgraphs are presented that outline the objectives and elements of the Nuclear Propulsion Program, mission considerations, propulsion technologies, and the logic flow path for nuclear propulsion development.

  11. Fatigue Crack Growth Threshold Testing of Metallic Rotorcraft Materials

    NASA Technical Reports Server (NTRS)

    Newman, John A.; James, Mark A.; Johnson, William M.; Le, Dy D.

    2008-01-01

    Results are presented for a program to determine the near-threshold fatigue crack growth behavior appropriate for metallic rotorcraft alloys. Four alloys, all commonly used in the manufacture of rotorcraft, were selected for study: Aluminum alloy 7050, 4340 steel, AZ91E Magnesium, and Titanium alloy Ti-6Al-4V (beta-STOA). The Federal Aviation Administration (FAA) sponsored this research to advance efforts to incorporate damage tolerance design and analysis as requirements for rotorcraft certification. Rotorcraft components are subjected to high cycle fatigue and are typically subjected to higher stresses and more stress cycles per flight hour than fixed-wing aircraft components. Fatigue lives of rotorcraft components are generally spent initiating small fatigue cracks that propagate slowly under near-threshold cracktip loading conditions. For these components, the fatigue life is very sensitive to the near-threshold characteristics of the material.

  12. NASA/HAA Advanced Rotorcraft Technology and Tilt Rotor Workshops. Volume 3: Aerodynamics and Structures Session

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Advanced rotorcraft technology and tilt rotor aircraft were discussed. Rotorcraft performance, acoustics, and vibrations were discussed, as was the use of composite materials in rotorcraft structures. Rotorcraft aerodynamics, specifically the aerodynamic phenomena of a rotating and the aerodynamics of fuselages, was discussed.

  13. The NASA/Army Autonomous Rotorcraft Project

    NASA Technical Reports Server (NTRS)

    Whalley, M.; Freed, M.; Takahashi, M.; Christian, D.; Patterson-Hine, A.; Schulein, G.; Harris, R.

    2002-01-01

    An overview of the NASA Ames Research Center Autonomous Rotorcraft Project (ARP) is presented. The project brings together several technologies to address NASA and US Army autonomous vehicle needs, including a reactive planner for mission planning and execution, control system design incorporating a detailed understanding of the platform dynamics, and health monitoring and diagnostics. A candidate reconnaissance and surveillance mission is described. The autonomous agent architecture and its application to the candidate mission are presented. Details of the vehicle hardware and software development are provided.

  14. Perception and control of rotorcraft flight

    NASA Technical Reports Server (NTRS)

    Owen, Dean H.

    1991-01-01

    Three topics which can be applied to rotorcraft flight are examined: (1) the nature of visual information; (2) what visual information is informative about; and (3) the control of visual information. The anchorage of visual perception is defined as the distribution of structure in the surrounding optical array or the distribution of optical structure over the retinal surface. A debate was provoked about whether the referent of visual event perception, and in turn control, is optical motion, kinetics, or dynamics. The interface of control theory and visual perception is also considered. The relationships among these problems is the basis of this article.

  15. Visual cueing aids for rotorcraft landings

    NASA Technical Reports Server (NTRS)

    Johnson, Walter W.; Andre, Anthony D.

    1993-01-01

    The present study used a rotorcraft simulator to examine descents-to-hover at landing pads with one of three approach lighting configurations. The impact of simulator platform motion upon descents to hover was also examined. The results showed that the configuration with the most useful optical information led to the slowest final approach speeds, and that pilots found this configuration, together with the presence of simulator platform motion, most desirable. The results also showed that platform motion led to higher rates of approach to the landing pad in some cases. Implications of the results for the design of vertiport approach paths are discussed.

  16. Finite-element analysis and multibody dynamics issues in rotorcraft dynamic analysis

    NASA Technical Reports Server (NTRS)

    Ruzicka, Gene C.; Ormiston, Robert A.

    1991-01-01

    There is general agreement that the development of effective rotorcraft analysis software will require the use of modern computational mechanics methodologies, especially finite element analysis and multibody dynamics. This paper examines the analysis of rotorcraft dynamics from the perspective of these methodologies. First, a general discussion of rotorcraft analysis and modeling is presented. Then, a hierarchy of rotorcraft analyses is presented, ranging from simple to complex kinematics, where it is shown that in comprehensive rotorcraft software, finite element analysis must be augmented by multibody dynamics in order to properly analyze large motions of rotorcraft components. Finally, a review of multibody dynamics is presented to further familiarize the rotorcraft community with this technology.

  17. Smart structures for rotorcraft control (SSRC) II

    NASA Astrophysics Data System (ADS)

    Jacot, A. Dean; Dadone, Leo

    1998-06-01

    The Smart Structures for Rotor Control (SSRC) is a consortium under the Defense Advanced Research Projects Agency (DARPA) Smart Structures program. Phase I of the program was administered by the Air Force Office of Scientific Research, with Boeing Seattle as the consortium administrator, and MIT, PSU and Boeing Helicopters as the other principal consortium members. Phase II, renamed Smart Materials and Structures Demonstration Consortium (SMSDC), is a combination of the proposed Phase II efforts of SSRC and the Boeing MESA Smart Materials Actuated Rotor Technology (SMART) program. This paper summarizes the SSRC efforts, introduces the SMSDC program, and provides a framework for the relationships between specific SSRC technical papers in this conference. The SSRC objectives were to research smart structure methods to achieve reduced rotorcraft vibration, reduce acoustic noise, and increased performance. The SSRC program includes dynamic piezoelectric actuation of flaps on the rotor blades, distributed dynamic piezo actuation of the rotor twist, and quasi-steady rotor twist control using shape memory alloys. The objective of Phase II is then to fly a rotorcraft to demonstrate such a system.

  18. Advanced Rotorcraft Transmission (ART) program status

    NASA Technical Reports Server (NTRS)

    Kish, Jules

    1991-01-01

    A weight reduction of 23 percent, noise reduction greater than 10 dB, and almost a fourfold increase in mean time between transmission removals has been demonstrated for a helicopter gearbox having a high output reduction ratio split path gear arrangement. These performance gains have been achieved by application of advanced transmission technology concepts in areas which offer high gain but are outside of normal design practices. New technology is being developed in such areas as split power gear concepts, composites, double helical gears, new gear materials, high speed spring clutches, and ceramic rolling element bearings. The programs, when completed, will provide demonstrated component and drive arrangement technology supported by analytical tools. The work is being accomplished under a CR&D program funded by NASA/Army termed the Advanced Rotorcraft transmission (ART) program. It is expected that the ART technology will be incorporated in future rotorcraft of the 1990s and 2000s. This paper summarizes the work accomplished to date on the program by Sikorsky Aircraft.

  19. Digital control of highly augmented combat rotorcraft

    NASA Technical Reports Server (NTRS)

    Tischler, Mark B.

    1987-01-01

    Proposed concepts for the next generation of combat helicopters are to be embodied in a complex, highly maneuverable, multiroled vehicle with avionics systems. Single pilot and nap-of-the-Earth operations require handling qualities which minimize the involvement of the pilot in basic stabilization tasks. To meet these requirements will demand a full authority, high-gain, multimode, multiply-redundant, digital flight-control system. The gap between these requirements and current low-authority, low-bandwidth operational rotorcraft flight-control technology is considerable. This research aims at smoothing the transition between current technology and advanced concept requirements. The state of the art of high-bandwidth digital flight-control systems are reviewed; areas of specific concern for flight-control systems of modern combat are exposed; and the important concepts are illustrated in design and analysis of high-gain, digital systems with a detailed case study involving a current rotorcraft system. Approximate and exact methods are explained and illustrated for treating the important concerns which are unique to digital systems.

  20. Obstacle Detection Algorithms for Rotorcraft Navigation

    NASA Technical Reports Server (NTRS)

    Kasturi, Rangachar; Camps, Octavia I.; Huang, Ying; Narasimhamurthy, Anand; Pande, Nitin; Ahumada, Albert (Technical Monitor)

    2001-01-01

    In this research we addressed the problem of obstacle detection for low altitude rotorcraft flight. In particular, the problem of detecting thin wires in the presence of image clutter and noise was studied. Wires present a serious hazard to rotorcrafts. Since they are very thin, their detection early enough so that the pilot has enough time to take evasive action is difficult, as their images can be less than one or two pixels wide. After reviewing the line detection literature, an algorithm for sub-pixel edge detection proposed by Steger was identified as having good potential to solve the considered task. The algorithm was tested using a set of images synthetically generated by combining real outdoor images with computer generated wire images. The performance of the algorithm was evaluated both, at the pixel and the wire levels. It was observed that the algorithm performs well, provided that the wires are not too thin (or distant) and that some post processing is performed to remove false alarms due to clutter.

  1. A Novel Approach to Rotorcraft Damage Tolerance

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; Everett, Richard A.; Newman, John A.

    2002-01-01

    Damage-tolerance methodology is positioned to replace safe-life methodologies for designing rotorcraft structures. The argument for implementing a damage-tolerance method comes from the fundamental fact that rotorcraft structures typically fail by fatigue cracking. Therefore, if technology permits prediction of fatigue-crack growth in structures, a damage-tolerance method should deliver the most accurate prediction of component life. Implementing damage-tolerance (DT) into high-cycle-fatigue (HCF) components will require a shift from traditional DT methods that rely on detecting an initial flaw with nondestructive inspection (NDI) methods. The rapid accumulation of cycles in a HCF component will result in a design based on a traditional DT method that is either impractical because of frequent inspections, or because the design will be too heavy to operate efficiently. Furthermore, once a HCF component develops a detectable propagating crack, the remaining fatigue life is short, sometimes less than one flight hour, which does not leave sufficient time for inspection. Therefore, designing a HCF component will require basing the life analysis on an initial flaw that is undetectable with current NDI technology.

  2. Space Station propulsion system

    NASA Technical Reports Server (NTRS)

    Henderson, J.

    1990-01-01

    Viewgraphs on space station propulsion systems are presented. Topics covered include: space station propulsion system requirements; space station propulsion system design; space station propulsion system drivers; hydrazine technology development; waste fluid disposal system; space station propulsion system evolution; propellant selection trade study; technology needs to water electrolysis/oxygen-hydrogen propulsion system; and technology needs for bipropellant systems.

  3. Performance of Advanced Heavy-Lift, High-Speed Rotorcraft Configurations

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Yeo, Hyeonsoo; Acree, C. W., Jr.

    2007-01-01

    The aerodynamic performance of rotorcraft designed for heavy-lift and high-speed cruise is examined. Configurations considered include the tiltrotor, the compound helicopter, and the lift-offset rotor. Design conditions are hover and 250-350 knot cruise, at 5k/ISA+20oC (civil) or 4k/95oF (military); with cruise conditions at 4000 or 30,000 ft. The performance was calculated using the comprehensive analysis CAMRAD II, emphasizing rotor optimization and performance, including wing-rotor interference. Aircraft performance was calculated using estimates of the aircraft drag and auxiliary propulsion efficiency. The performance metric is total power, in terms of equivalent aircraft lift-to-drag ratio L/D = WV/P for cruise, and figure of merit for hover.

  4. Rotorcraft digital advanced avionics system (RODAAS) functional description

    NASA Technical Reports Server (NTRS)

    Peterson, E. M.; Bailey, J.; Mcmanus, T. J.

    1985-01-01

    A functional design of a rotorcraft digital advanced avionics system (RODAAS) to transfer the technology developed for general aviation in the Demonstration Advanced Avionics System (DAAS) program to rotorcraft operation was undertaken. The objective was to develop an integrated avionics system design that enhances rotorcraft single pilot IFR operations without increasing the required pilot training/experience by exploiting advanced technology in computers, busing, displays and integrated systems design. A key element of the avionics system is the functionally distributed architecture that has the potential for high reliability with low weight, power and cost. A functional description of the RODAAS hardware and software functions is presented.

  5. Isolation and identification of volatile flavor compounds in commercial oil-free soybean lecithin

    Microsoft Academic Search

    Heasook Kim; Chi-Tang Ho; Stephen S. Chang

    1984-01-01

    Volatile compounds were isolated from 150 lb of commercial oil-free soybean lecithin by vacuum distillation. The isolated\\u000a volatile compounds were subjected to extensive gas chromatographic fractionation, and the pure fractions thus obtained were\\u000a identified by mass spectrometry. A total of 79 compounds have been identified. Most of the compounds identified can be postulated\\u000a as autoxidative decomposition products of unsaturated fatty

  6. Oil-Free Turbomachinery Technologies for Long-Life, Maintenance-Free Power Generation Applications

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher

    2013-01-01

    Turbines have long been used to convert thermal energy to shaft work for power generation. Conventional turbines rely upon oil-lubricated rotor supports (bearings, seals, etc.) to achieve low wear, high efficiency and reliability. Emerging Oil-Free technologies such as gas foil bearings and magnetic bearings offer a path for reduced weight and complexity and truly maintenance free systems. Oil-Free gas turbines, using gaseous and liquid fuels are commercially available in power outputs to at least 250kWe and are gaining acceptance for remote power generation where maintenance is a challenge. Closed Brayton Cycle (CBC) turbines are an approach to power generation that is well suited for long life space missions. In these systems, a recirculating gas is heated by nuclear, solar or other heat energy source then fed into a high-speed turbine that drives an electrical generator. For closed cycle systems such as these, the working fluid also passes through the bearing compartments thus serving as a lubricant and bearing coolant. Compliant surface foil gas bearings are well suited for the rotor support systems of these advanced turbines. Foil bearings develop a thin hydrodynamic gas film that separates the rotating shaft from the bearing preventing wear. During start-up and shut down when speeds are low, rubbing occurs. Solid lubricants are used to reduce starting torque and minimize wear. Other emerging technologies such as magnetic bearings can also contribute to robust and reliable Oil-Free turbomachinery. In this presentation, Oil-Free technologies for advanced rotor support systems will be reviewed as will the integration and development processes recommended for implementation.

  7. Rotorcraft Research at the NASA Vertical Motion Simulator

    NASA Technical Reports Server (NTRS)

    Aponso, Bimal Lalith; Tran, Duc T.; Schroeder, Jeffrey A.

    2009-01-01

    In the 1970 s the role of the military helicopter evolved to encompass more demanding missions including low-level nap-of-the-earth flight and operation in severely degraded visual environments. The Vertical Motion Simulator (VMS) at the NASA Ames Research Center was built to provide a high-fidelity simulation capability to research new rotorcraft concepts and technologies that could satisfy these mission requirements. The VMS combines a high-fidelity large amplitude motion system with an adaptable simulation environment including interchangeable and configurable cockpits. In almost 30 years of operation, rotorcraft research on the VMS has contributed significantly to the knowledge-base on rotorcraft performance, handling qualities, flight control, and guidance and displays. These contributions have directly benefited current rotorcraft programs and flight safety. The high fidelity motion system in the VMS was also used to research simulation fidelity. This research provided a fundamental understanding of pilot cueing modalities and their effect on simulation fidelity.

  8. Designs and Technology Requirements for Civil Heavy Lift Rotorcraft

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Yamauchi, Gloria K.; Watts, Michael E.

    2006-01-01

    The NASA Heavy Lift Rotorcraft Systems Investigation examined in depth several rotorcraft configurations for large civil transport, designed to meet the technology goals of the NASA Vehicle Systems Program. The investigation identified the Large Civil Tiltrotor as the configuration with the best potential to meet the technology goals. The design presented was economically competitive, with the potential for substantial impact on the air transportation system. The keys to achieving a competitive aircraft were low drag airframe and low disk loading rotors; structural weight reduction, for both airframe and rotors; drive system weight reduction; improved engine efficiency; low maintenance design; and manufacturing cost comparable to fixed-wing aircraft. Risk reduction plans were developed to provide the strategic direction to support a heavy-lift rotorcraft development. The following high risk areas were identified for heavy lift rotorcraft: high torque, light weight drive system; high performance, structurally efficient rotor/wing system; low noise aircraft; and super-integrated vehicle management system.

  9. Challenges in Rotorcraft Acoustic Flight Prediction and Validation

    NASA Technical Reports Server (NTRS)

    Boyd, D. Douglas, Jr.

    2003-01-01

    Challenges associated with rotorcraft acoustic flight prediction and validation are examined. First, an outline of a state-of-the-art rotorcraft aeroacoustic prediction methodology is presented. Components including rotorcraft aeromechanics, high resolution reconstruction, and rotorcraft acoustic prediction arc discussed. Next, to illustrate challenges and issues involved, a case study is presented in which an analysis of flight data from a specific XV-15 tiltrotor acoustic flight test is discussed in detail. Issues related to validation of methodologies using flight test data are discussed. Primary flight parameters such as velocity, altitude, and attitude are discussed and compared for repeated flight conditions. Other measured steady state flight conditions are examined for consistency and steadiness. A representative example prediction is presented and suggestions are made for future research.

  10. Toward Right-Fidelity Rotorcraft Conceptual Design

    NASA Technical Reports Server (NTRS)

    Sinsay, Jeffrey D.; Johnson, Wayne

    2010-01-01

    The aviation Advanced Design Office (ADO) of the US Army Aeroflightdynamics Directorate (AMRDEC) performs conceptual design of advanced Vertical Takeoff and Landing (VTOL) concepts in support of the Army's development and acquisition of new aviation systems. In particular, ADO engages in system synthesis to assess the impact of new technologies and their application to satisfy emerging warfighter needs and requirements. Fundamental to ADO being successful in accomplishing its role; is the ability to evaluate a wide array of proposed air vehicle concepts, and independently synthesize new concepts to inform Army and DoD decision makers about the tradespace in which decisions will be made (Figure 1). ADO utilizes a conceptual design (CD) process in the execution of its role. Benefiting from colocation with NASA rotorcraft researchers at the Ames Research Center, ADO and NASA have engaged in a survey of the current rotorcraft PD practices and begun the process of improving those capabilities to enable effective design and development of the next generation of VTOL systems. A unique aspect of CD in ADO is the fact that actual designs developed in-house are not intended to move forward in the development process. Rather, they are used as reference points in discussions about requirements development and technology impact. The ultimate products of ADO CD efforts are technology impact assessments and specifications which guide industry design activity. The fact that both the requirement and design are variables in the tradespace adds to the complexity of the CD process. A frequent need is ability to assess the relative "cost" of variations in requirement for a diverse set of VTOL configurations. Each of these configurations may have fundamentally different response characteristics to this requirement variation, and such insight into how different requirements drive different designs is a critical insight ADO attempts to provide decision makers. The processes and tools utilized are driven by the timeline in which questions must be answered. This can range from quick "back-of-the-envelope" assessments of a configuration made in an afternoon, to more detailed tradespace explorations that can take upwards of a year to complete. A variety of spreadsheet based tools and conceptual design codes are currently in use. The in-house developed conceptual sizing code RC (Rotorcraft) has been the preferred tool of choice for CD activity for a number of years. Figure 2 illustrates the long standing coupling between RC and solid modeling tools for layout, as well as a number of ad-hoc interfaces with external analyses. RC contains a sizing routine that is built around the use of momentum theory for rotors, classic finite wing theory, a referred parameter engine model, and semi-emperical weight estimation techniques. These methods lend themselves to rapid solutions, measured in seconds and minutes. The successful use of RC, however requires careful consideration of model input parameters and judicious comparison with existing aircraft to avoid unjustified extrapolation of results. RC is in fact a legacy of a series of codes whose development started in the early 1970s, and is best suited to the study of conventional helicopters and XV-15 style tiltrotors. Other concepts have been analyzed with RC, but typically it became necessary to modify the source code and methods for each unique configuration. Recent activity has lead to the development of a new code, NASA Design and Analysis of Rotorcraft (NDARC). NDARC uses a similar level of analytical fidelity as RC, but is built on a new framework intended to improve modularity and ability to rapidly model a wider array of concepts. Critical to achieving this capability is the decomposition of the aircraft system into a series of fundamental components which can then be assembled to form a wide-array of configurations. The paper will provide an overview of NDARC and its capabilities.

  11. Technology needs for high-speed rotorcraft

    NASA Technical Reports Server (NTRS)

    Rutherford, John; Orourke, Matthew; Martin, Christopher; Lovenguth, Marc; Mitchell, Clark

    1991-01-01

    A study to determine the technology development required for high-speed rotorcraft development was conducted. The study begins with an initial assessment of six concepts capable of flight at, or greater than 450 knots with helicopter-like hover efficiency (disk loading less than 50 pfs). These concepts were sized and evaluated based on measures of effectiveness and operational considerations. Additionally, an initial assessment of the impact of technology advances on the vehicles attributes was made. From these initial concepts a tilt wing and rotor/wing concepts were selected for further evaluation. A more detailed examination of conversion and technology trade studies were conducted on these two vehicles, each sized for a different mission.

  12. Techniques for designing rotorcraft control systems

    NASA Technical Reports Server (NTRS)

    Yudilevitch, Gil; Levine, William S.

    1994-01-01

    Over the last two and a half years we have been demonstrating a new methodology for the design of rotorcraft flight control systems (FCS) to meet handling qualities requirements. This method is based on multicriterion optimization as implemented in the optimization package CONSOL-OPTCAD (C-O). This package has been developed at the Institute for Systems Research (ISR) at the University of Maryland at College Park. This design methodology has been applied to the design of a FCS for the UH-60A helicopter in hover having the ADOCS control structure. The controller parameters have been optimized to meet the ADS-33C specifications. Furthermore, using this approach, an optimal (minimum control energy) controller has been obtained and trade-off studies have been performed.

  13. Fundamental Rotorcraft Acoustic Modeling From Experiments (FRAME)

    NASA Technical Reports Server (NTRS)

    Greenwood, Eric

    2011-01-01

    A new methodology is developed for the construction of helicopter source noise models for use in mission planning tools from experimental measurements of helicopter external noise radiation. The models are constructed by employing a parameter identification method to an assumed analytical model of the rotor harmonic noise sources. This new method allows for the identification of individual rotor harmonic noise sources and allows them to be characterized in terms of their individual non-dimensional governing parameters. The method is applied to both wind tunnel measurements and ground noise measurements of two-bladed rotors. The method is shown to match the parametric trends of main rotor harmonic noise, allowing accurate estimates of the dominant rotorcraft noise sources to be made for operating conditions based on a small number of measurements taken at different operating conditions. The ability of this method to estimate changes in noise radiation due to changes in ambient conditions is also demonstrated.

  14. NASA's Role in Aeronautics: A Workshop. Volume 5: Rotorcraft

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The potential roles for NASA relating to rotorcraft are reviewed. The agency's participation is delineated for each role, a rationale is provided, the current level of activity is summarized, and suggestions are given for the kinds of research still needed. In examining opportunities for the most beneficial deployment of its resources, NASA should consider societal benefits as well as the military and civil markets in formulating the role it can play to support the development of a stronger rotorcraft technology base.

  15. U.S. Civil Rotorcraft Accidents, 1963 Through 1997

    NASA Technical Reports Server (NTRS)

    Harris, Franklin D.; Kasper, Eugene F.; Iseler, Laura E.

    2000-01-01

    Narrative summary data produced by the U.S. National Transportation Safety Board (NTSB) has been obtained and analyzed for all 8,436 U.S. civil registered rotorcraft accidents which occurred from mid-1963 through 1997. This analysis was based on the NTSB's assignment of each mishap into one of 21 "first event" categories. The number of U.S. civil registered rotorcraft as recorded by the Federal Aviation Administration (FAA) for the same period has also been obtained. Taken together, these data indicate the civil rotorcraft accident rate (on a per 1,000 registered rotorcraft basis) has decreased by almost a factor of 10 (i.e., from 130 accidents per 1,000 rotorcraft in 1964 to 13.4 per 1,000 in 1997). Analysis of the mishap data indicates over 70% of the rotorcraft accidents were associated with one of the following four NTSB "first event" categories: 2408 Loss of engine power (28.5%); 1,322 In-flight collisions with objects (15.7%); 1,114 Loss of control (13.2%); 1,083 Airframe/component/system failure or malfunction (12.8%).

  16. Laser propulsion

    NASA Technical Reports Server (NTRS)

    Rom, F. E.; Putre, H. A.

    1972-01-01

    The use of an earth-based high-power laser beam to provide energy for earth-launched rocket vehicle is investigated. The laser beam energy is absorbed in an opaque propellant gas and is converted to high-specific-impulse thrust by expanding the heated propellant to space by means of a nozzle. This laser propulsion scheme can produce specific impulses of several thousand seconds. Payload to gross-weight fractions about an order of magnitude higher than those for conventional chemical earth-launched vehicles appear possible. There is a potential for a significant reduction in cost per payload mass in earth orbit.

  17. Damage Tolerance Issues as Related to Metallic Rotorcraft Dynamic Components

    NASA Technical Reports Server (NTRS)

    Everett, R. A., Jr.; Elber, W.

    2005-01-01

    In this paper issues related to the use of damage tolerance in life managing rotorcraft dynamic components are reviewed. In the past, rotorcraft fatigue design has combined constant amplitude tests of full-scale parts with flight loads and usage data in a conservative manner to provide "safe life" component replacement times. In contrast to the safe life approach over the past twenty years the United States Air Force and several other NATO nations have used damage tolerance design philosophies for fixed wing aircraft to improve safety and reliability. The reliability of the safe life approach being used in rotorcraft started to be questioned shortly after presentations at an American Helicopter Society's specialist meeting in 1980 showed predicted fatigue lives for a hypothetical pitch-link problem to vary from a low of 9 hours to a high in excess of 2594 hours. This presented serious cost, weight, and reliability implications. Somewhat after the U.S. Army introduced its six nines reliability on fatigue life, attention shifted towards using a possible damage tolerance approach to the life management of rotorcraft dynamic components. The use of damage tolerance in life management of dynamic rotorcraft parts will be the subject of this paper. This review will start with past studies on using damage tolerance life management with existing helicopter parts that were safe life designed. Also covered will be a successful attempt at certifying a tail rotor pitch rod using damage tolerance, which was designed using the safe life approach. The FAA review of rotorcraft fatigue design and their recommendations along with some on-going U.S. industry research in damage tolerance on rotorcraft will be reviewed. Finally, possible problems and future needs for research will be highlighted.

  18. Damage Tolerance Issues as Related to Metallic Rotorcraft Dynamic Components

    NASA Technical Reports Server (NTRS)

    Everett, R. A., Jr.; Elber, W.

    1999-01-01

    In this paper issues related to the use of damage tolerance in life managing rotorcraft dynamic components are reviewed. In the past, rotorcraft fatigue design has combined constant amplitude tests of full-scale parts with flight loads and usage data in a conservative manner to provide "safe life" component replacement times. In contrast to the safe life approach over the past twenty years the United States Air Force and several other NATO nations have used damage tolerance design philosophies for fixed wing aircraft to improve safety and reliability. The reliability of the safe life approach being used in rotorcraft started to be questioned shortly after presentations at an American Helicopter Society's specialist meeting in 1980 showed predicted fatigue lives for a hypothetical pitch-link problem to vary from a low of 9 hours to a high in excess of 2594 hours. This presented serious cost, weight, and reliability implications. Somewhat after the U.S. Army introduced its six nines reliability on fatigue life, attention shifted towards using a possible damage tolerance approach to the life management of rotorcraft dynamic components. The use of damage tolerance in life management of dynamic rotorcraft parts will be the subject of this paper. This review will start with past studies on using damage tolerance life management with existing helicopter parts that were safe life designed. Also covered will be a successful attempt at certifying a tail rotor pitch rod using damage tolerance, which was designed using the safe life approach. The FAA review of rotorcraft fatigue design and their recommendations along with some on-going U.S. industry research in damage tolerance on rotorcraft will be reviewed.

  19. Propulsion Systems Panel deliberations

    NASA Technical Reports Server (NTRS)

    Bianca, Carmelo J.; Miner, Robert; Johnston, Lawrence M.; Bruce, R.; Dennies, Daniel P.; Dickenson, W.; Dreshfield, Robert; Karakulko, Walt; Mcgaw, Mike; Munafo, Paul M.

    1993-01-01

    The Propulsion Systems Panel was established because of the specialized nature of many of the materials and structures technology issues related to propulsion systems. This panel was co-chaired by Carmelo Bianca, MSFC, and Bob Miner, LeRC. Because of the diverse range of missions anticipated for the Space Transportation program, three distinct propulsion system types were identified in the workshop planning process: liquid propulsion systems, solid propulsion systems and nuclear electric/nuclear thermal propulsion systems.

  20. The design and development of an oil-free compressor for Spacelab Refrigerator/Freezer

    NASA Technical Reports Server (NTRS)

    Hye, A.

    1984-01-01

    Design features and test results of an oil-free compressor developed for Spacelab Mission-4 Refrigerator/Freezer are detailed. The compressor has four identical pistons activated by a common eccentric shaft, operated by a brushless dc motor at 1300 rpm. The stroke of each piston is 0.28 cm, with the piston ends connected to the shaft by means of sealed needle bearings, eliminating the ned for oil. The mass flow rates produced by the compressor are by over 100 percent higher compared to the original Amfridge unit. Test results show that the compressor can meet the Spacelab refrigerator/freezer requirements.

  1. Stiffness and Damping Coefficient Estimation of Compliant Surface Gas Bearings for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    Della-Corte, Christopher

    2012-01-01

    Foil gas bearings are a key technology in many commercial and emerging oilfree turbomachinery systems. These bearings are nonlinear and have been difficult to analytically model in terms of performance characteristics such as load capacity, power loss, stiffness, and damping. Previous investigations led to an empirically derived method to estimate load capacity. This method has been a valuable tool in system development. The current work extends this tool concept to include rules for stiffness and damping coefficient estimation. It is expected that these rules will further accelerate the development and deployment of advanced oil-free machines operating on foil gas bearings.

  2. 75 FR 24502 - Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures; Reopening of Comment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-05

    ...Notice No. 10-09] RIN 2120-AJ52 Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures; Reopening of...793) Notice No. 09-12, entitled ``Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures'' that...

  3. 14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Hull type rotorcraft: Water-based and amphibian. 29.519 Section 29.519 Aeronautics and Space ...Loads § 29.519 Hull type rotorcraft: Water-based and amphibian. (a) General. For hull type...

  4. 14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Hull type rotorcraft: Water-based and amphibian. 29.519 Section 29.519 Aeronautics and Space ...Loads § 29.519 Hull type rotorcraft: Water-based and amphibian. (a) General. For hull type...

  5. 14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Hull type rotorcraft: Water-based and amphibian. 29.519 Section 29.519 Aeronautics and Space ...Loads § 29.519 Hull type rotorcraft: Water-based and amphibian. (a) General. For hull type...

  6. 14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Hull type rotorcraft: Water-based and amphibian. 29.519 Section 29.519 Aeronautics and Space ...Loads § 29.519 Hull type rotorcraft: Water-based and amphibian. (a) General. For hull type...

  7. 14 CFR 29.519 - Hull type rotorcraft: Water-based and amphibian.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Hull type rotorcraft: Water-based and amphibian. 29.519 Section 29.519 Aeronautics and Space ...Loads § 29.519 Hull type rotorcraft: Water-based and amphibian. (a) General. For hull type...

  8. 14 CFR 133.47 - Rotorcraft-load combination flight manual.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...peculiarities discovered when operating particular rotorcraft-load combinations; (2) Precautionary advice regarding static electricity discharges for Class B, Class C, and Class D rotorcraft-load combinations; and (3) Any other...

  9. 14 CFR 133.47 - Rotorcraft-load combination flight manual.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...peculiarities discovered when operating particular rotorcraft-load combinations; (2) Precautionary advice regarding static electricity discharges for Class B, Class C, and Class D rotorcraft-load combinations; and (3) Any other...

  10. 14 CFR 133.47 - Rotorcraft-load combination flight manual.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...peculiarities discovered when operating particular rotorcraft-load combinations; (2) Precautionary advice regarding static electricity discharges for Class B, Class C, and Class D rotorcraft-load combinations; and (3) Any other...

  11. 14 CFR 133.47 - Rotorcraft-load combination flight manual.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...peculiarities discovered when operating particular rotorcraft-load combinations; (2) Precautionary advice regarding static electricity discharges for Class B, Class C, and Class D rotorcraft-load combinations; and (3) Any other...

  12. 14 CFR 133.47 - Rotorcraft-load combination flight manual.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...peculiarities discovered when operating particular rotorcraft-load combinations; (2) Precautionary advice regarding static electricity discharges for Class B, Class C, and Class D rotorcraft-load combinations; and (3) Any other...

  13. Mechanisms and actuators for rotorcraft blade morphing

    NASA Astrophysics Data System (ADS)

    Vocke, Robert D., III

    The idea of improved fight performance through changes in the control surfaces dates back to the advent of aviation with the Wright brothers' pioneering work on "wing warping," but it was not until the recent progress in material and actuator development that such control surfaces seemed practical for modern aircraft. This has opened the door to a new class of aircraft that have the ability to change shape or morph, which are being investigated due to the potential to have a single platform serve multiple mission objectives, as well as improve performance characteristics. While the majority of existing research for morphing aircraft has focused on fixedwing aircraft, rotary-wing aircraft have begun to receive more attention. The purpose of this body of work is to investigate the current state of morphing actuation technology for rotorcraft and improve upon it. Specifically, this work looks at two types of morphing: Pneumatic Artificial Muscle (PAM) actuated trailing edge flaps and conformal variable diameter morphing. First, active camber changes through the use of PAM powered trailing edge flaps were investigated due to the potential for reductions in power requirements and vibration/noise levels. A PAM based antagonistic actuation system was developed utilizing a novel combination of mechanism geometry and PAM bias contraction optimization to overcome the natural extension stiffening characteristics of PAMs. In open-loop bench-top testing against a "worst-case" constant torsional loading, the system demonstrated actuation authority suitable for both primary control and vibration/noise reduction. Additionally, closed-loop test data indicated that the system was capable of tracking complex waveforms consistent with those needed for rotorcraft control. This system demonstrated performance on-par with the state of the art pneumatic trailing edge flap actuators, yet with a much smaller footprint and impact on the rotor-blade. The second morphing system developed in this work is a conformal variable diameter rotor system suitable for implementation on a modern tilt-rotor aircraft, which can reduce power requirements in both cruise and hover configurations. An initial prototype variable span airfoil was constructed using a silicone elastomer matrix composite skin and a plastic rapid prototyped morphing substructure. Benchtop and wind tunnel tests verified the ability of this system to increase active wing area by 100%. The prototype technology was then matured for use in the harsh rotor blade environment, with a much stiffer polyurethane skin and a titanium substructure. Coupon testing verified the efficacy of this approach, and a final conceptual design was completed using the stiffness-tuning characteristics of the morphing substructure to create a self-actuating morphing blade tip.

  14. Electric vehicle propulsion alternatives

    NASA Technical Reports Server (NTRS)

    Secunde, R. R.; Schuh, R. M.; Beach, R. F.

    1983-01-01

    Propulsion technology development for electric vehicles is summarized. Analytical studies, technology evaluation, and the development of technology for motors, controllers, transmissions, and complete propulsion systems are included.

  15. Rotorcraft-based emergency medical services in the Caribbean Basin

    NASA Technical Reports Server (NTRS)

    Smith, R. W.; Alton, L. R.

    1987-01-01

    There is a pressing need for improved health care in general and emergency health care in particular throughout the Caribbean Basin. The importance of rotorcraft as an integral part of the needed system of emergency medical care in the region was investigated. Many of the larger countries in the region currently have the needed infrastructure to implement a national system of rotorcraft-based emergency medical centers within their borders. By helping to establish a system of rotorcraft based health care centers in strategic locations in the Lesser Antilles, the U.S. can assist the islands of the region by demonstrating the concept and establishing a potential training site for the other larger countries of the region. There is sufficient demand for rotorcraft based emergency health care within the Lesser Antilles to locate one center on the island of Puerto Rico and another one of the southern-most islands. With the use of fixed wing aircraft or long range helicopters, the two rotorcraft based centers could provide the region with rapid and efficient emergency health care. The superior speed and range of the XV-15 Tilt Rotor aircraft make it an attractive possibility for emergency transport and rescue in this region.

  16. Cost Analysis for Large Civil Transport Rotorcraft

    NASA Technical Reports Server (NTRS)

    Coy, John J.

    2006-01-01

    This paper presents cost analysis of purchase price and DOC+I (direct operating cost plus interest) that supports NASA s study of three advanced rotorcraft concepts that could enter commercial transport service within 10 to 15 years. The components of DOC+I are maintenance, flight crew, fuel, depreciation, insurance, and finance. The cost analysis aims at VTOL (vertical takeoff and landing) and CTOL (conventional takeoff and landing) aircraft suitable for regional transport service. The resulting spreadsheet-implemented cost models are semi-empirical and based on Department of Transportation and Army data from actual operations of such aircraft. This paper describes a rationale for selecting cost tech factors without which VTOL is more costly than CTOL by a factor of 10 for maintenance cost and a factor of two for purchase price. The three VTOL designs selected for cost comparisons meet the mission requirement to fly 1,200 nautical miles at 350 knots and 30,000 ft carrying 120 passengers. The lowest cost VTOL design is a large civil tilt rotor (LCTR) aircraft. With cost tech factors applied, the LCTR is reasonably competitive with the Boeing 737-700 when operated in economy regional service following the business model of the selected baseline operation, that of Southwest Airlines.

  17. Evaluation of Scaling Methods for Rotorcraft Icing

    NASA Technical Reports Server (NTRS)

    Tsao, Jen-Ching; Kreeger, Richard E.

    2010-01-01

    This paper reports result of an experimental study in the NASA Glenn Icing Research Tunnel (IRT) to evaluate how well the current recommended scaling methods developed for fixed-wing unprotected surface icing applications might apply to representative rotor blades at finite angle of attack. Unlike the fixed-wing case, there is no single scaling method that has been systematically developed and evaluated for rotorcraft icing applications. In the present study, scaling was based on the modified Ruff method with scale velocity determined by maintaining constant Weber number. Models were unswept NACA 0012 wing sections. The reference model had a chord of 91.4 cm and scale model had a chord of 35.6 cm. Reference tests were conducted with velocities of 76 and 100 kt (39 and 52 m/s), droplet MVDs of 150 and 195 fun, and with stagnation-point freezing fractions of 0.3 and 0.5 at angle of attack of 0deg and 5deg. It was shown that good ice shape scaling was achieved for NACA 0012 airfoils with angle of attack lip to 5deg.

  18. Sikorsky Aircraft Advanced Rotorcraft Transmission (ART) program

    NASA Technical Reports Server (NTRS)

    Kish, Jules G.

    1993-01-01

    The objectives of the Advanced Rotorcraft Transmission program were to achieve a 25 percent weight reduction, a 10 dB noise reduction, and a 5,000 hour mean time between removals (MTBR). A three engine Army Cargo Aircraft (ACA) of 85,000 pounds gross weight was used as the baseline. Preliminary designs were conducted of split path and split torque transmissions to evaluate weight, reliability, and noise. A split path gearbox was determined to be 23 percent lighter, greater than 10 dB quieter, and almost four times more reliable than the baseline two stage planetary design. Detail design studies were conducted of the chosen split path configuration, and drawings were produced of a 1/2 size gearbox consisting of a single engine path of the split path section. Fabrication and testing was then conducted on the 1/2 size gearbox. The 1/2 size gearbox testing proved that the concept of the split path gearbox with high reduction ratio double helical output gear was sound. The improvements were attributed to extensive use of composites, spring clutches, advanced high hot hardness gear steels, the split path configuration itself, high reduction ratio, double helical gearing on the output stage, elastomeric load sharing devices, and elimination of accessory drives.

  19. Rotorcraft handling-qualities design criteria development

    NASA Technical Reports Server (NTRS)

    Aiken, Edwin W.; Lebacqz, J. Victor; Chen, Robert T. N.; Key, David L.

    1988-01-01

    Joint NASA/Army efforts at the Ames Research Center to develop rotorcraft handling-qualities design criteria began in earnest in 1975. Notable results were the UH-1H VSTOLAND variable stability helicopter, the VFA-2 camera-and-terrain-board simulator visual system, and the generic helicopter real-time mathematical model, ARMCOP. An initial series of handling-qualities studies was conducted to assess the effects of rotor design parameters, interaxis coupling, and various levels of stability and control augmentation. The ability to conduct in-flight handling-qualities research was enhanced by the development of the NASA/Army CH-47 variable-stability helicopter. Research programs conducted using this vehicle include vertical-response investigations, hover augmentation systems, and the effects of control-force characteristics. The handling-qualities data base was judged to be sufficient to allow an update of the military helicopter handling-qualities specification, MIL-H-8501. These efforts, including not only the in-house experimental work but also contracted research and collaborative programs performed under the auspices of various international agreements. The report concludes by reviewing the topics that are currently most in need of work, and the plans for addressing these topics.

  20. Airfoil Dynamic Stall and Rotorcraft Maneuverability

    NASA Technical Reports Server (NTRS)

    Bousman, William G.

    2000-01-01

    The loading of an airfoil during dynamic stall is examined in terms of the augmented lift and the associated penalties in pitching moment and drag. It is shown that once stall occurs and a leading-edge vortex is shed from the airfoil there is a unique relationship between the augmented lift, the negative pitching moment, and the increase in drag. This relationship, referred to here as the dynamic stall function, shows limited sensitivity to effects such as the airfoil section profile and Mach number, and appears to be independent of such parameters as Reynolds number, reduced frequency, and blade sweep. For single-element airfoils there is little that can be done to improve rotorcraft maneuverability except to provide good static C(l(max)) characteristics and the chord or blade number that is required to provide the necessary rotor thrust. However, multi-element airfoils or airfoils with variable geometry features can provide augmented lift in some cases that exceeds that available from a single-element airfoil. The dynamic stall function is shown to be a useful tool for the evaluation of both measured and calculated dynamic stall characteristics of single element, multi-element, and variable geometry airfoils.

  1. Large rotorcraft transmission technology development program

    NASA Technical Reports Server (NTRS)

    Mack, J. C.

    1983-01-01

    Testing of a U.S. Army XCH-62 HLH aft rotor transmission under NASA Contract NAS 3-22143 was successfully completed. This test establishes the feasibility of large, high power rotorcraft transmissions as well as demonstrating the resolution of deficiencies identified during the HLH advanced technology programs and reported by USAAMRDLTR-77-38. Over 100 hours of testing was conducted. At the 100% design power rating of 10,620 horsepower, the power transferred through a single spiral bevel gear mesh is more than twice that of current helicopter bevel gearing. In the original design of these gears, industry-wide design methods were employed and failures were experienced which identified problem areas unique to gear size. To remedy this technology shortfall, a program was developed to predict gear stresses using finite element analysis for complete and accurate representation of the gear tooth and supporting structure. To validate the finite element methodology gear strain data from the existing U.S. Army HLH aft transmission was acquired, and existing data from smaller gears were made available.

  2. Synthetic vision for rotorcraft: low level flight

    NASA Astrophysics Data System (ADS)

    Szoboszlay, Zoltan; Jennings, Chad; Tiana, Carlo

    2006-05-01

    Two topics are discussed in this paper. The first is the Integrated Multi-sensor Synthetic Imagery System (IMSIS), being developed under an Army SBIR contract. The system updates on-board, pre-stored, terrain elevation data with 3D terrain elevation sensor data (such as radar). The system also merges 2D image contrast sensor data (such as infrared imagery) with the updated 3D terrain elevation data to render a synthetic image of the terrain on the rotorcraft pilot's display. The second topic is the testing of a new flight path marker, to show the pilot the predicted location of the aircraft with respect to the synthetic terrain (at 100m distance), as well as the predicted height above the terrain, the desired height above the terrain, and the point on the terrain the aircraft is expected to fly over. The Altitude and ground Track Predicting Flight Path Marker (ATP-FPM) symbol takes advantage of knowledge of terrain elevations ahead of the aircraft from a synthetic vision system, such as IMSIS. In simulation, the maximum low altitude error and maximum ground track error were both reduced by a factor of 2 with the ATP-FPM compared to the traditional instantaneous flight path marker. Pilot-to-pilot variations in performance were reduced and workload decreased with the ATP-FPM.

  3. Delamination durability of composite materials for rotorcraft

    NASA Technical Reports Server (NTRS)

    Obrien, T. Kevin

    1988-01-01

    Delamination is the most commonly observed failure mode in composite rotorcraft dynamic components. Although delamination may not cause immediate failure of the composite part, it often precipitates component repair or replacement, which inhibits fleet readiness, and results in increased life cycle costs. A fracture mechanics approach for analyzing, characterizing, and designing against delamination will be outlined. Examples of delamination problems will be illustrated where the strain energy release rate associated with delamination growth was found to be a useful generic parameter, independent of thickness, layup, and delamination source, for characterizing delamination failure. Several analysis techniques for calculating strain energy release rates for delamination from a variety of sources will be outlined. Current efforts to develop ASTM standard test methods for measuring interlaminar fracture toughness and developing delamination failure criteria will be reviewed. A technique for quantifying delamination durability due to cyclic loading will be presented. The use of this technique for predicting fatigue life of composite laminates and developing a fatigue design philosophy for composite structural components will be reviewed.

  4. Technology needs for high speed rotorcraft (2)

    NASA Technical Reports Server (NTRS)

    Scott, Mark W.

    1991-01-01

    An analytical study was conducted to identify rotorcraft concepts best capable of combining a cruise speed of 350 to 450 knots with helicopter-like low speed attributes, and to define the technology advancements needed to make them viable by the year 2000. A systematic approach was used to compare the relative attributes and mission gross weights for a wide range of concepts, resulting in a downselect to the most promising concept/mission pairs. For transport missions, tilt-wing and variable diameter tilt-rotor (VDTR) concepts were found to be superior. For a military scout/attack role, the VDTR was best, although a shrouded rotor concept could provide a highly agile, low observable alternative if its weight empty fraction could be reduced. A design speed of 375 to 425 knots was found to be the maximum desirable for transport missions, with higher speed producing rapidly diminishing benefits in productivity. The key technologies that require advancement to make the tilt-wing and VDTR concepts viable are in the areas of wing and proprotor aerodynamics, efficient structural design, flight controls, refinement of the geared flap pitch control system, expansion of the speed/descent envelope, and the structural and aerodynamic tradeoffs of wing thickness and forward sweep. For the shrouded rotor, weight reduction is essential, particularly with respect to the mechanism for covering the rotor in cruise.

  5. NASA/HAA Advanced Rotorcraft Technology and Tilt Rotor Workshops. Volume 1: Executive Summary

    NASA Technical Reports Server (NTRS)

    1980-01-01

    This presentation provides an overview of the NASA Rotorcraft Program as an introduction to the technical sessions of the Advanced Rotorcraft Technology Workshop. It deals with the basis for NASA's increasing emphasis on rotorcraft technology, NASA's research capabilities, recent program planning efforts, highlights of its 10-year plan and future directions and opportunities.

  6. NASA/Army Rotorcraft Technology. Volume 3: Systems Integration, Research Aircraft, and Industry

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This is part 3 of the conference proceedings on rotorcraft technology. This volume is divided into areas on systems integration, research aircraft, and industry. Representative titles from each area are: system analysis in rotorcraft design, the past decade; rotorcraft flight research with emphasis on rotor systems; and an overview of key technology thrusts at Bell Helicopter Textron.

  7. An Oil-Free Thrust Foil Bearing Facility Design, Calibration, and Operation

    NASA Technical Reports Server (NTRS)

    Bauman, Steve

    2005-01-01

    New testing capabilities are needed in order to foster thrust foil air bearing technology development and aid its transition into future Oil-Free gas turbines. This paper describes a new test apparatus capable of testing thrust foil air bearings up to 100 mm in diameter at speeds to 80,000 rpm and temperatures to 650 C (1200 F). Measured parameters include bearing torque, load capacity, and bearing temperatures. This data will be used for design performance evaluations and for validation of foil bearing models. Preliminary test results demonstrate that the rig is capable of testing thrust foil air bearings under a wide range of conditions which are anticipated in future Oil-Free gas turbines. Torque as a function of speed and temperature corroborates results expected from rudimentary performance models. A number of bearings were intentionally failed with no resultant damage whatsoever to the test rig. Several test conditions (specific speeds and loads) revealed undesirable axial shaft vibrations which have been attributed to the magnetic bearing control system and are under study. Based upon these preliminary results, this test rig will be a valuable tool for thrust foil bearing research, parametric studies and technology development.

  8. Load Capacity Estimation of Foil Air Journal Bearings for Oil-Free Turbomachinery Applications

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher; Valco, Mark J.

    2000-01-01

    This paper introduces a simple "Rule of Thumb" (ROT) method to estimate the load capacity of foil air journal bearings, which are self-acting compliant-surface hydrodynamic bearings being considered for Oil-Free turbo-machinery applications such as gas turbine engines. The ROT is based on first principles and data available in the literature and it relates bearing load capacity to the bearing size and speed through an empirically based load capacity coefficient, D. It is shown that load capacity is a linear function of bearing surface velocity and bearing projected area. Furthermore, it was found that the load capacity coefficient, D, is related to the design features of the bearing compliant members and operating conditions (speed and ambient temperature). Early bearing designs with basic or "first generation" compliant support elements have relatively low load capacity. More advanced bearings, in which the compliance of the support structure is tailored, have load capacities up to five times those of simpler designs. The ROT enables simplified load capacity estimation for foil air journal bearings and can guide development of new Oil-Free turbomachinery systems.

  9. Requirements for Next Generation Comprehensive Analysis of Rotorcraft

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Data, Anubhav

    2008-01-01

    The unique demands of rotorcraft aeromechanics analysis have led to the development of software tools that are described as comprehensive analyses. The next generation of rotorcraft comprehensive analyses will be driven and enabled by the tremendous capabilities of high performance computing, particularly modular and scaleable software executed on multiple cores. Development of a comprehensive analysis based on high performance computing both demands and permits a new analysis architecture. This paper describes a vision of the requirements for this next generation of comprehensive analyses of rotorcraft. The requirements are described and substantiated for what must be included and justification provided for what should be excluded. With this guide, a path to the next generation code can be found.

  10. Accomplishments at NASA Langley Research Center in rotorcraft aerodynamics technology

    NASA Technical Reports Server (NTRS)

    Wilson, John C.

    1988-01-01

    In recent years, the development of aerodynamic technology for rotorcraft has continued successfully at NASA LaRC. Though the NASA Langley Research Center is not the lead NASA center in this area, the activity was continued due to facilities and individual capabilities which are recognized as contributing to helicopter research needs of industry and government. Noteworthy accomplishments which contribute to advancing the state of rotorcraft technology in the areas of rotor design, airfoil research, rotor aerodynamics, and rotor/fuselage interaction aerodynamics are described. Rotor designs were defined for current helicopters and evaluated in wind tunnel testing. These designs have incorporated advanced airfoils defined analytically and also proven in wind tunnel tests. A laser velocimetry system has become a productive tool for experimental definition of rotor inflow/wake and is providing data for rotorcraft aerodynamic code validation.

  11. Preliminary Sizing of 120-Passenger Advanced Civil Rotorcraft Concepts

    NASA Technical Reports Server (NTRS)

    vanAken, Johannes M.; Sinsay, Jeffrey D.

    2006-01-01

    The results of a preliminary sizing study of advanced civil rotorcraft concepts that are capable of carrying 120 passengers over a range of 1,200 nautical miles are presented. The cruise altitude of these rotorcraft is 30,000 ft and the cruise velocity is 350 knots. The mission requires a hover capability, creating a runway independent solution, which might aid in reducing strain on the existing airport infrastructure. Concepts studied are a tiltrotor, a tandem rotor compound, and an advancing blade concept. The first objective of the study is to determine the relative merits of these designs in terms of mission gross weight, engine size, fuel weight, aircraft purchase price, and direct operating cost. The second objective is to identify the enabling technology for these advanced heavy lift civil rotorcraft.

  12. Aircraft System Analysis of Technology Benefits to Civil Transport Rotorcraft

    NASA Technical Reports Server (NTRS)

    Wilkerson, Joseph B.; Smith, Roger L.

    2008-01-01

    An aircraft systems analysis was conducted to evaluate the net benefits of advanced technologies on two conceptual civil transport rotorcraft, to quantify the potential of future civil rotorcraft to become operationally viable and economically competitive, with the ultimate goal of alleviating congestion in our airways, runways and terminals. These questions are three of many that must be resolved for the successful introduction of civil transport rotorcraft: 1) Can civil transport rotorcraft actually relieve current airport congestion and improve overall air traffic and passenger throughput at busy hub airports? What is that operational scenario? 2) Can advanced technology make future civil rotorcraft economically competitive in scheduled passenger transport? What are those enabling technologies? 3) What level of investment is necessary to mature the key enabling technologies? This study addresses the first two questions, and several others, by applying a systems analysis approach to a broad spectrum of potential advanced technologies at a conceptual level of design. The method was to identify those advanced technologies that showed the most promise and to quantify their benefits to the design, development, production, and operation of future civil rotorcraft. Adjustments are made to sizing data by subject matter experts to reflect the introduction of new technologies that offer improved performance, reduced weight, reduced maintenance, or reduced cost. This study used projected benefits from new, advanced technologies, generally based on research results, analysis, or small-scale test data. The technologies are identified, categorized and quantified in the report. The net benefit of selected advanced technologies is quantified for two civil transport rotorcraft concepts, a Single Main Rotor Compound (SMRC) helicopter designed for 250 ktas cruise airspeed and a Civil Tilt Rotor (CTR) designed for 350 ktas cruise airspeed. A baseline design of each concept was sized for a representative civil passenger transport mission, using current technology. Individual advanced technologies are quantified and applied to resize the aircraft, thereby quantifying the net benefit of that technology to the rotorcraft. Estimates of development cost, production cost and operating and support costs are made with a commercial cost estimating program, calibrated to Boeing products with adjustments for future civil production processes. A cost metric of cash direct operating cost per available seat-mile (DOC ASM) is used to compare the cost benefit of the technologies. The same metric is used to compare results with turboprop operating costs. Reduced engine SFC was the most advantageous advanced technology for both rotorcraft concepts. Structural weight reduction was the second most beneficial technology, followed by advanced drive systems and then by technology for rotorcraft performance. Most of the technologies evaluated in this report should apply similarly to conventional helicopters. The implicit assumption is that resources will become available to mature the technologies for fullscale production aircraft. That assumption is certainly the weak link in any forecast of future possibilities. The analysis serves the purpose of identifying which technologies offer the most potential benefit, and thus the ones that should receive the highest priority for continued development. This study directly addressed the following NASA Subsonic Rotary Wing (SRW) subtopics: SR W.4.8.I.J Establish capability for rotorcraft system analysis and SRW. 4.8.I.4 Conduct limited technology benefit assessment on baseline rotorcraft configurations.

  13. Solar Thermal Propulsion Concept

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Harnessing the Sun's energy through Solar Thermal Propulsion will propel vehicles through space by significantly reducing weight, complexity, and cost while boosting performance over current conventional upper stages. Another solar powered system, solar electric propulsion, demonstrates ion propulsion is suitable for long duration missions. Pictured is an artist's concept of space flight using solar thermal propulsion.

  14. Electric propulsion, circa 2000

    NASA Technical Reports Server (NTRS)

    Hudson, W. R.; Finke, R. C.

    1980-01-01

    This paper discusses the future of electric propulsion, circa 2000. Starting with the first generation Solar Electric Propulsion (SEP) technology as the first step toward the next century's advanced propulsion systems, the current status and future trends of other systems such as the magnetoplasmadynamic accelerator, the mass driver, the laser propulsion system, and the rail gun are described.

  15. Computer vision techniques for rotorcraft low altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar

    1990-01-01

    Rotorcraft operating in high-threat environments fly close to the earth's surface to utilize surrounding terrain, vegetation, or manmade objects to minimize the risk of being detected by an enemy. Increasing levels of concealment are achieved by adopting different tactics during low-altitude flight. Rotorcraft employ three tactics during low-altitude flight: low-level, contour, and nap-of-the-earth (NOE). The key feature distinguishing the NOE mode from the other two modes is that the whole rotorcraft, including the main rotor, is below tree-top whenever possible. This leads to the use of lateral maneuvers for avoiding obstacles, which in fact constitutes the means for concealment. The piloting of the rotorcraft is at best a very demanding task and the pilot will need help from onboard automation tools in order to devote more time to mission-related activities. The development of an automation tool which has the potential to detect obstacles in the rotorcraft flight path, warn the crew, and interact with the guidance system to avoid detected obstacles, presents challenging problems. Research is described which applies techniques from computer vision to automation of rotorcraft navigtion. The effort emphasizes the development of a methodology for detecting the ranges to obstacles in the region of interest based on the maximum utilization of passive sensors. The range map derived from the obstacle-detection approach can be used as obstacle data for the obstacle avoidance in an automatic guidance system and as advisory display to the pilot. The lack of suitable flight imagery data presents a problem in the verification of concepts for obstacle detection. This problem is being addressed by the development of an adequate flight database and by preprocessing of currently available flight imagery. The presentation concludes with some comments on future work and how research in this area relates to the guidance of other autonomous vehicles.

  16. Some recent applications of Navier-Stokes codes to rotorcraft

    NASA Technical Reports Server (NTRS)

    Mccroskey, W. J.

    1992-01-01

    Many operational limitations of helicopters and other rotary-wing aircraft are due to nonlinear aerodynamic phenomena incuding unsteady, three-dimensional transonic and separated flow near the surfaces and highly vortical flow in the wakes of rotating blades. Modern computational fluid dynamics (CFD) technology offers new tools to study and simulate these complex flows. However, existing Euler and Navier-Stokes codes have to be modified significantly for rotorcraft applications, and the enormous computational requirements presently limit their use in routine design applications. Nevertheless, the Euler/Navier-Stokes technology is progressing in anticipation of future supercomputers that will enable meaningful calculations to be made for complete rotorcraft configurations.

  17. Low-Altitude Operation of Unmanned Rotorcraft

    NASA Astrophysics Data System (ADS)

    Scherer, Sebastian

    Currently deployed unmanned rotorcraft rely on preplanned missions or teleoperation and do not actively incorporate information about obstacles, landing sites, wind, position uncertainty, and other aerial vehicles during online motion planning. Prior work has successfully addressed some tasks such as obstacle avoidance at slow speeds, or landing at known to be good locations. However, to enable autonomous missions in cluttered environments, the vehicle has to react quickly to previously unknown obstacles, respond to changing environmental conditions, and find unknown landing sites. We consider the problem of enabling autonomous operation at low-altitude with contributions to four problems. First we address the problem of fast obstacle avoidance for a small aerial vehicle and present results from over a 1000 rims at speeds up to 10 m/s. Fast response is achieved through a reactive algorithm whose response is learned based on observing a pilot. Second, we show an algorithm to update the obstacle cost expansion for path planning quickly and demonstrate it on a micro aerial vehicle, and an autonomous helicopter avoiding obstacles. Next, we examine the mission of finding a place to land near a ground goal. Good landing sites need to be detected and found and the final touch down goal is unknown. To detect the landing sites we convey a model based algorithm for landing sites that incorporates many helicopter relevant constraints such as landing sites, approach, abort, and ground paths in 3D range data. The landing site evaluation algorithm uses a patch-based coarse evaluation for slope and roughness, and a fine evaluation that fits a 3D model of the helicopter and landing gear to calculate a goodness measure. The data are evaluated in real-time to enable the helicopter to decide on a place to land. We show results from urban, vegetated, and desert environments, and demonstrate the first autonomous helicopter that selects its own landing sites. We present a generalized planning framework that enables reaching a goal point, searching for unknown landing sites, and approaching a landing zone. In the framework, sub-objective functions, constraints, and a state machine define the mission and behavior of an UAV. As the vehicle gathers information by moving through the environment, the objective functions account for this new information. The operator in this framework can directly specify his intent as an objective function that defines the mission rather than giving a sequence of pre-specified goal points. This allows the robot to react to new information received and adjust its path accordingly. The objective is used in a combined coarse planning and trajectory optimization algorithm to determine the best patch the robot should take. We show simulated results for several different missions and in particular focus on active landing zone search. We presented several effective approaches for perception and action for low-altitude flight and demonstrated their effectiveness in field experiments on three autonomous aerial vehicles: a 1m quadrocopter, a 36m helicopter, and a hill-size helicopter. These techniques permit rotorcraft to operate where they have their greatest advantage: In unstructured, unknown environments at low-altitude.

  18. Space propulsion

    NASA Astrophysics Data System (ADS)

    Kazaroff, John M.

    1993-02-01

    Lewis Research Center is developing broad-based new technologies for space chemical engines to satisfy long-term needs of ETO launch vehicles and other vehicles operating in and beyond Earth orbit. Specific objectives are focused on high performance LO2/LH2 engines providing moderate thrusts of 7,5-200 klb. This effort encompasses research related to design analysis and manufacturing processes needed to apply advanced materials to subcomponents, components, and subsystems of space-based systems and related ground-support equipment. High-performance space-based chemical engines face a number of technical challenges. Liquid hydrogen turbopump impellers are often so large that they cannot be machined from a single piece, yet high stress at the vane/shroud interface makes bonding extremely difficult. Tolerances on fillets are critical on large impellers. Advanced materials and fabricating techniques are needed to address these and other issues of interest. Turbopump bearings are needed which can provide reliable, long life operation at high speed and high load with low friction losses. Hydrostatic bearings provide good performance, but transients during pump starts and stops may be an issue because no pressurized fluid is available unless a separate bearing pressurization system is included. Durable materials and/or coatings are needed that can demonstrate low wear in the harsh LO2/LH2 environment. Advanced materials are also needed to improve the lifetime, reliability and performance of other propulsion system elements such as seals and chambers.

  19. A New High-Speed Oil-Free Turbine Engine Rotordynamic Simulator Test Rig

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2007-01-01

    A new test rig has been developed for simulating high-speed turbomachinery rotor systems using Oil-Free foil air bearing technology. Foil air bearings have been used in turbomachinery, primarily air cycle machines, for the past four decades to eliminate the need for oil lubrication. The goal of applying this bearing technology to other classes of turbomachinery has prompted the fabrication of this test rig. The facility gives bearing designers the capability to test potential bearing designs with shafts that simulate the rotating components of a target machine without the high cost of building "make-and-break" hardware. The data collected from this rig can be used to make design changes to the shaft and bearings in subsequent design iterations. This paper describes the new test rig and demonstrates its capabilities through the initial run with a simulated shaft system.

  20. Evaporation-based microfluidic production of oil-free cell-containing hydrogel particles.

    PubMed

    Fan, Rong; Naqvi, Kubra; Patel, Krishna; Sun, Jun; Wan, Jiandi

    2015-09-01

    We demonstrate an evaporation-based microfluidic strategy to produce oil-free cell containing hydrogel particles. Perfluoro-n-pentane, which is used as the continuous oil phase to generate cell-containing hydrogel (Extracel) particles, is removed at an elevated temperature. Human colon cancer cells (HCT116) encapsulated in the hydrogel particles show higher viability than cells encapsulated in particles that are produced via a non-evaporative oil phase. In addition, single HCT116 cells can be cultured for a week in such particles and respond to inflammatory stimuli, highlighting the potential applications of the developed strategy for 3D cell culture, drug testing, and cell-based drug delivery. PMID:25825624

  1. Design and Implement of a Rotorcraft UAV Testbed

    Microsoft Academic Search

    Juntong Qi; Xingang Zhao; Zhe Jiang; Jianda Han

    2006-01-01

    This paper describes recent research on the design and implement of a small-scaled rotorcraft unmanned aerial vehicle (RUAV) system. This platform is going to be used as a testbed for experimentally evaluating advanced control methodologies dedicated on improving the maneuverability, reliability as well as autonomy of RUAV. Sensors and controller are implemented onboard. The full system has been tested successfully

  2. Incorporating Handling Qualities Analysis into Rotorcraft Conceptual Design

    NASA Technical Reports Server (NTRS)

    Lawrence, Ben

    2014-01-01

    This paper describes the initial development of a framework to incorporate handling qualities analyses into a rotorcraft conceptual design process. In particular, the paper describes how rotorcraft conceptual design level data can be used to generate flight dynamics models for handling qualities analyses. Also, methods are described that couple a basic stability augmentation system to the rotorcraft flight dynamics model to extend analysis to beyond that of the bare airframe. A methodology for calculating the handling qualities characteristics of the flight dynamics models and for comparing the results to ADS-33E criteria is described. Preliminary results from the application of the handling qualities analysis for variations in key rotorcraft design parameters of main rotor radius, blade chord, hub stiffness and flap moment of inertia are shown. Varying relationships, with counteracting trends for different handling qualities criteria and different flight speeds are exhibited, with the action of the control system playing a complex part in the outcomes. Overall, the paper demonstrates how a broad array of technical issues across flight dynamics stability and control, simulation and modeling, control law design and handling qualities testing and evaluation had to be confronted to implement even a moderately comprehensive handling qualities analysis of relatively low fidelity models. A key outstanding issue is to how to 'close the loop' with an overall design process, and options for the exploration of how to feedback handling qualities results to a conceptual design process are proposed for future work.

  3. Concept development of automatic guidance for rotorcraft obstacle avoidance

    NASA Technical Reports Server (NTRS)

    Cheng, Victor H. L.

    1990-01-01

    The automatic guidance of rotorcraft for obstacle avoidance in nap-of-the-earth flight is studied. A hierarchical breakdown of the guidance components is used to identify the functional requirements. These requirements and anticipated sensor capabilities lead to a preliminary guidance concept, which has been evaluated via computer simulations.

  4. Minimum-exposure near-terrain flight trajectories for rotorcraft

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Cheng, V. H. L.

    1992-01-01

    The paper presents methodologies for constructing optimal trajectories for rotorcraft executing nap-of-the-earth flight over known terrain. Unlike the standard techniques, the present approaches require only a one-dimensional numerical search for determining optimal trajectories. Numerical algorithms are developed using two kinematic vehicle models in conjunction with optimal control theory.

  5. Topological optimization of rotorcraft subfloor structures for crashworthiness considerations

    Microsoft Academic Search

    P. Hajela; E. Lee

    1997-01-01

    The present paper discusses significant design issues in the sizing of rotorcraft structures for requirements of enhanced crash performance. The focus of the study is on topological design of the subfloor structure, defined as a crush zone under a more rigid floor structure. The topological design problem includes both an appropriate selection of an energy absorbing material (tailored load-deflection curve),

  6. General Rotorcraft Aeromechanical Stability Program (GRASP): Theory manual

    NASA Technical Reports Server (NTRS)

    Hodges, Dewey H.; Hopkins, A. Stewart; Kunz, Donald L.; Hinnant, Howard E.

    1990-01-01

    The general rotorcraft aeromechanical stability program (GRASP) was developed to calculate aeroelastic stability for rotorcraft in hovering flight, vertical flight, and ground contact conditions. GRASP is described in terms of its capabilities and its philosophy of modeling. The equations of motion that govern the physical system are described, as well as the analytical approximations used to derive them. The equations include the kinematical equation, the element equations, and the constraint equations. In addition, the solution procedures used by GRASP are described. GRASP is capable of treating the nonlinear static and linearized dynamic behavior of structures represented by arbitrary collections of rigid-body and beam elements. These elements may be connected in an arbitrary fashion, and are permitted to have large relative motions. The main limitation of this analysis is that periodic coefficient effects are not treated, restricting rotorcraft flight conditions to hover, axial flight, and ground contact. Instead of following the methods employed in other rotorcraft programs. GRASP is designed to be a hybrid of the finite-element method and the multibody methods used in spacecraft analysis. GRASP differs from traditional finite-element programs by allowing multiple levels of substructure in which the substructures can move and/or rotate relative to others with no small-angle approximations. This capability facilitates the modeling of rotorcraft structures, including the rotating/nonrotating interface and the details of the blade/root kinematics for various types. GRASP differs from traditional multibody programs by considering aeroelastic effects, including inflow dynamics (simple unsteady aerodynamics) and nonlinear aerodynamic coefficients.

  7. Adverse rotorcraft pilot couplings—Past, present and future challenges

    NASA Astrophysics Data System (ADS)

    Pavel, Marilena D.; Jump, Michael; Dang-Vu, Binh; Masarati, Pierangelo; Gennaretti, Massimo; Ionita, Achim; Zaichik, Larisa; Smaili, Hafid; Quaranta, Giuseppe; Yilmaz, Deniz; Jones, Michael; Serafini, Jacopo; Malecki, Jacek

    2013-10-01

    Fixed and rotary wing pilots alike are familiar with potential instabilities or with annoying limit cycle oscillations that arise from the effort of controlling aircraft with high response actuation systems. Understanding, predicting and suppressing these inadvertent and sustained aircraft oscillations, known as aircraft (rotorcraft)-pilot couplings (A/RPCs) is a challenging problem for the designers. The goal of the present paper is to give an overview on the state-of-the-art in RPC problem, underlining the future challenges in this field. It is shown that, exactly as in the case of fixed wing APCs, RPCs existed from the beginning of rotorcraft development and that the problem of eliminating them is not yet solved: the current rotorcraft modelling for RPC analysis is rather limited to the particular case analysed and there is a lack of quantitative pilot behavioural models to analyse RPCs. The paper underlines the importance of involuntary pilot control actions, generally attributed to biodynamic couplings in predicting RPCs in rotorcraft. It is also shown that recent experiences demonstrate that modern rotorcraft seem to embed tendencies predisposing the flight control system FCS system towards dangerous RPCs. As the level of automation is likely to increase in future designs, extending to smaller aircraft and to different kinds of operation, the consequences of the pilot ‘fighting’ the FCS system and inducing A/RPCs needs to be eradicated. In Europe, the ARISTOTEL project (2010-2013) has been launched with the aim of understanding and predicting modern aircraft's susceptibility to A/RPC. The present paper gives an overview of future challenges to be solved for RPC-free design and some new solutions herein.

  8. Electrodynamic Tether Propulsion System

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This picture is an artist's concept of an orbiting vehicle using the Electrodynamic Tethers Propulsion System. Relatively short electrodynamic tethers can use solar power to push against a planetary magnetic field to achieve propulsion without the expenditure of propellant.

  9. OTV Propulsion Issues

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The statistical technology needs of aero-assist maneuvering, propulsion, and usage of cryogenic fluids were presented. Industry panels discussed the servicing of reusable space based vehicles and propulsion-vehicle interation.

  10. Propulsion Systems Panel deliberations

    Microsoft Academic Search

    Carmelo J. Bianca; Robert Miner; Lawrence M. Johnston; R. Bruce; Daniel P. Dennies; W. Dickenson; Robert Dreshfield; Walt Karakulko; Mike McGaw; Paul M. Munafo

    1993-01-01

    The Propulsion Systems Panel was established because of the specialized nature of many of the materials and structures technology issues related to propulsion systems. This panel was co-chaired by Carmelo Bianca, MSFC, and Bob Miner, LeRC. Because of the diverse range of missions anticipated for the Space Transportation program, three distinct propulsion system types were identified in the workshop planning

  11. New Concepts and Perspectives on Micro-Rotorcraft and Small Autonomous Rotary-Wing Vehicles

    NASA Technical Reports Server (NTRS)

    Young, Larry A.; Aiken, E. W.; Johnson, J. L.; Demblewski, R.; Andrews, J.; Aiken, Irwin W. (Technical Monitor)

    2001-01-01

    A key part of the strategic vision for rotorcraft research as identified by senior technologists within the Army/NASA Rotorcraft Division at NASA Ames Research Center is the development and use of small autonomous rotorcraft. Small autonomous rotorcraft are defined for the purposes of this paper to be a class of vehicles that range in size from rotary-wing micro air vehicles (MAVs) to larger, more conventionally sized, rotorcraft uninhabited aerial vehicles (UAVs) - i.e. vehicle gross weights ranging from hundreds of grams to thousands of kilograms. The development of small autonomous rotorcraft represents both a technology challenge and a potential new vehicle class that will have substantial societal impact for: national security, personal transport, planetary science, and public service.

  12. Solar Thermal Propulsion

    NASA Technical Reports Server (NTRS)

    Gerrish, Harold P., Jr.

    2003-01-01

    This paper presents viewgraphs on Solar Thermal Propulsion (STP). Some of the topics include: 1) Ways to use Solar Energy for Propulsion; 2) Solar (fusion) Energy; 3) Operation in Orbit; 4) Propulsion Concepts; 5) Critical Equations; 6) Power Efficiency; 7) Major STP Projects; 8) Types of STP Engines; 9) Solar Thermal Propulsion Direct Gain Assembly; 10) Specific Impulse; 11) Thrust; 12) Temperature Distribution; 13) Pressure Loss; 14) Transient Startup; 15) Axial Heat Input; 16) Direct Gain Engine Design; 17) Direct Gain Engine Fabrication; 18) Solar Thermal Propulsion Direct Gain Components; 19) Solar Thermal Test Facility; and 20) Checkout Results.

  13. Identification of propulsion systems

    NASA Technical Reports Server (NTRS)

    Merrill, Walter; Guo, Ten-Huei; Duyar, Ahmet

    1991-01-01

    This paper presents a tutorial on the use of model identification techniques for the identification of propulsion system models. These models are important for control design, simulation, parameter estimation, and fault detection. Propulsion system identification is defined in the context of the classical description of identification as a four step process that is unique because of special considerations of data and error sources. Propulsion system models are described along with the dependence of system operation on the environment. Propulsion system simulation approaches are discussed as well as approaches to propulsion system identification with examples for both air breathing and rocket systems.

  14. Efficient assembly of finite-element subsystems with large relative rotations. [for rotorcraft dynamic characteristics

    NASA Technical Reports Server (NTRS)

    Fuh, Jon-Shen; Panda, Brahmananda; Peters, David A.

    1988-01-01

    A finite element approach is presented for the modeling of rotorcraft undergoing elastic deformation in addition to large rigid body motion with respect to inertial space, with particular attention given to the coupling of the rotor and fuselage subsystems subject to large relative rotations. The component synthesis technique used here allows the coupling of rotors to the fuselage for different rotorcraft configurations. The formulation is general and applicable to any rotorcraft vibration, aeroelasticity, and dynamics problem.

  15. Mars Rotorcraft: Possibilities, Limitations, and Implications For Human/Robotic Exploration

    NASA Technical Reports Server (NTRS)

    Young, Larry A.; Aiken, Edwin; Lee, Pascal; Briggs, Geoffrey

    2005-01-01

    Several research investigations have examined the challenges and opportunities in the use of small robotic rotorcraft for the exploration of Mars. To date, only vehicles smaller than 150 kg have been studied. This paper proposes to examine the question of maximum Mars rotorcraft size, range, and payload/cargo capacity. Implications for the issue of whether or not (from an extreme design standpoint) a manned Mars rotorcraft is viable are also discussed.

  16. Oil-Free Rotor Support Technologies for Long Life, Closed Cycle Brayton Turbines

    NASA Technical Reports Server (NTRS)

    Lucero, John M.; DellaCorte, Christopher

    2004-01-01

    The goal of this study is to provide technological support to ensure successful life and operation of a 50-300 kW dynamic power conversion system specifically with response to the rotor support system. By utilizing technical expertise in tribology, bearings, rotordynamic, solid lubricant coatings and extensive test facilities, valuable input for mission success is provided. A discussion of the history of closed cycle Brayton turboalternators (TA) will be included. This includes the 2 kW Mini-Brayton Rotating Unit (Mini-BRU), the 10kW Brayton Rotating Unit (BRU) and the 125 kW turboalternator-compressor (TAC) designed in mid 1970's. Also included is the development of air-cycle machines and terrestrial oil-free gas turbine power systems in the form of microturbines, specifically Capstone microturbines. A short discussion of the self-acting compliant surface hydrodynamic fluid film bearings, or foil bearings, will follow, including a short history of the load capacity advances, the NASA coatings advancements as well as design model advances. Successes in terrestrial based machines will be noted and NASA tribology and bearing research test facilities will be described. Finally, implementation of a four step integration process will be included in the discussion.

  17. Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Lukaszewicz, V.; Valco, M. J.; Radil, K. C.; Heshmat, H.

    2000-01-01

    The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304 is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.

  18. Performance and Durability of High Temperature Foil Air Bearing for Oil-Free Turbomachinery

    NASA Technical Reports Server (NTRS)

    DellaCorte, C.; Valco, M. J.; Radil, K. C.; Heshmat, H.

    1999-01-01

    The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304, is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.

  19. Functional evaluation and characterization of a newly developed silicone oil-free prefillable syringe system.

    PubMed

    Yoshino, Keisuke; Nakamura, Koji; Yamashita, Arisa; Abe, Yoshihiko; Iwasaki, Kazuhiro; Kanazawa, Yukie; Funatsu, Kaori; Yoshimoto, Tsuyoshi; Suzuki, Shigeru

    2014-05-01

    The functionality of a newly developed silicone oil-free (SOF) syringe system, of which the plunger stopper is coated by a novel coating technology (i-coating™), was assessed. By scanning electron microscopy observations and other analysis, it was confirmed that the plunger stopper surface was uniformly covered with the designed chemical composition. A microflow imaging analysis showed that the SOF system drastically reduced both silicone oil (SO) doplets and oil-induced aggregations in a model protein formulation, whereas a large number of subvisible particles and protein aggregations were formed when a SO system was used. Satisfactory container closure integrity (CCI) was confirmed by means of dye and microorganism penetration studies. Furthermore, no significant difference between the break loose and gliding forces was observed in the former, and stability studies revealed that the SOF system could perfectly show the aging independence in break loose force observed in the SO system. The results suggest that the introduced novel SOF system has a great potential and represents an alternative that can achieve very low subvisible particles, secure CCI, and the absence of a break loose force. In particular, no risk of SO-induced aggregation can bring additional value in the highly sensitive biotech drug market. PMID:24643749

  20. Technology needs for high speed rotorcraft (3)

    NASA Technical Reports Server (NTRS)

    Detore, Jack; Conway, Scott

    1991-01-01

    The spectrum of vertical takeoff and landing (VTOL) type aircraft is examined to determine which aircraft are most likely to achieve high subsonic cruise speeds and have hover qualities similar to a helicopter. Two civil mission profiles are considered: a 600-n.mi. mission for a 15- and a 30-passenger payload. Applying current technology, only the 15- and 30-passenger tiltfold aircraft are capable of attaining the 450-knot design goal. The two tiltfold aircraft at 450 knots and a 30-passenger tiltrotor at 375 knots were further developed for the Task II technology analysis. A program called High-Speed Total Envelope Proprotor (HI-STEP) is recommended to meet several of these issues based on the tiltrotor concept. A program called Tiltfold System (TFS) is recommended based on the tiltrotor concept. A task is identified to resolve the best design speed from productivity and demand considerations based on the technology that emerges from the recommended programs. HI-STEP's goals are to investigate propulsive efficiency, maneuver loads, and aeroelastic stability. Programs currently in progress that may meet the other technology needs include the Integrated High Performance Turbine Engine Technology (IHPTET) (NASA Lewis) and the Advanced Structural Concepts Program funded through NASA Langley.

  1. Advanced Rotorcraft Transmission (ART) program-Boeing helicopters status report

    NASA Technical Reports Server (NTRS)

    Lenski, Joseph W., Jr.; Valco, Mark J.

    1991-01-01

    The Advanced Rotorcraft Transmission (ART) program is structured to incorporate key emerging material and component technologies into an advanced rotorcraft transmission with the intention of making significant improvements in the state of the art (SOA). Specific objectives of ART are: (1) Reduce transmission weight by 25 pct.; (2) Reduce transmission noise by 10 dB; and (3) Improve transmission life and reliability, while extending Mean Time Between Removal to 5000 hr. Boeing selected a transmission sized for the Tactical Tilt Rotor (TTR) aircraft which meets the Future Air Attack Vehicle (FAVV) requirements. Component development testing will be conducted to evaluate the high risk concepts prior to finalizing the advanced transmission configuration. The results of tradeoff studies and development test which were completed are summarized.

  2. Image-based ranging and guidance for rotorcraft

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.

    1991-01-01

    This report documents the research carried out under NASA Cooperative Agreement No. NCC2-575 during the period Oct. 1988 - Dec. 1991. Primary emphasis of this effort was on the development of vision based navigation methods for rotorcraft nap-of-the-earth flight regime. A family of field-based ranging algorithms were developed during this research period. These ranging schemes are capable of handling both stereo and motion image sequences, and permits both translational and rotational camera motion. The algorithms require minimal computational effort and appear to be implementable in real time. A series of papers were presented on these ranging schemes, some of which are included in this report. A small part of the research effort was expended on synthesizing a rotorcraft guidance law that directly uses the vision-based ranging data. This work is discussed in the last section.

  3. Application of Climate Impact Metrics to Rotorcraft Design

    NASA Technical Reports Server (NTRS)

    Russell, Carl; Johnson, Wayne

    2013-01-01

    Multiple metrics are applied to the design of large civil rotorcraft, integrating minimum cost and minimum environmental impact. The design mission is passenger transport with similar range and capacity to a regional jet. Separate aircraft designs are generated for minimum empty weight, fuel burn, and environmental impact. A metric specifically developed for the design of aircraft is employed to evaluate emissions. The designs are generated using the NDARC rotorcraft sizing code, and rotor analysis is performed with the CAMRAD II aeromechanics code. Design and mission parameters such as wing loading, disk loading, and cruise altitude are varied to minimize both cost and environmental impact metrics. This paper presents the results of these parametric sweeps as well as the final aircraft designs.

  4. Measurement of Rotorcraft Blade Deformation using Projection Moire Interferometry

    NASA Technical Reports Server (NTRS)

    Fleming, Gary A.; Gorton, Susan Althoff

    1998-01-01

    Projection Moire Interferometry (PMI) has been used to obtain near instantaneous, quantitative blade deformation measurements of a generic rotorcraft model at several test conditions. These laser-based measurements provide quantitative, whole field, dynamic blade deformation profiles conditionally sampled as a function of rotor azimuth. The instantaneous nature of the measurements permits computation of the mean and unsteady blade deformation, blade bending, and twist. The PMI method is presented, and the image processing steps required to obtain quantitative deformation profiles from PMI interferograms are described. Experimental results are provided which show blade bending, twist, and unsteady motion. This initial proof-of-concept test has demonstrated the capability of PMI to acquire accurate, full field rotorcraft blade deformation data.

  5. Impact of pilots' biodynamic feedthrough on rotorcraft by robust stability

    NASA Astrophysics Data System (ADS)

    Quaranta, Giuseppe; Masarati, Pierangelo; Venrooij, Joost

    2013-09-01

    The coupling of rotorcraft dynamics with the dynamics of one of the main systems devoted to its control, the pilot, may lead to several peculiar phenomena, known as Rotorcraft-Pilot Couplings (RPCs), all characterized by an abnormal behavior that may jeopardize flight safety. Among these phenomena, there is a special class of couplings which is dominated by the biodynamic behavior of the pilot's limbs that close the loop between the vibrations and the control inceptors in the cockpit. Leveraging robust stability analysis, the inherently uncertain pilot biodynamics can be treated as the uncertain portion of a feedback system, making analytical, numerical or graphical determination of proneness to RPC possible by comparing robust stability margins of helicopter models with experimental Biodynamic Feedthrough (BDFT) data. The application of the proposed approach to collective bounce is exemplified using simple analytical helicopter and pilot models. The approach is also applied to detailed helicopter models and experimental BDFT measurement data.

  6. Structures technology for a new generation of rotorcraft

    NASA Technical Reports Server (NTRS)

    Bartlett, Felton D., Jr.

    1989-01-01

    This paper presents an overview of structures research at the U. S. Army Aerostructures Directorate. The objectives of this research are to investigate, explore, and demonstrate emerging technologies that will provide lighter, safer, more survivable, and more cost-effective structures for rotorcraft in the 1990s and beyond. The emphasis of today's R&D is to contribute proven structures technology to the U. S. rotorcraft industry and Army aviation that directly impacts tomorrow's fleet readiness and mission capabilities. The primary contributor toward meeting these challenges is the development of high-strength and durable composites to minimize structural weight while maximizing cost effectiveness. Special aviation issues such as delamination of dynamic components, impact damage to thin skins, crashworthiness, and affordable manufacturing need to be resolved before the full potential of composites technology can be realized. To that end, this paper highlights research into composites structural integrity, crashworthiness, and materials applications which addresses these issues.

  7. Blade vortex interaction noise reduction techniques for a rotorcraft

    NASA Technical Reports Server (NTRS)

    Charles, Bruce D. (Inventor); Hassan, Ahmed A. (Inventor); Tadghighi, Hormoz (Inventor); JanakiRam, Ram D. (Inventor); Sankar, Lakshmi N. (Inventor)

    1996-01-01

    An active control device for reducing blade-vortex interactions (BVI) noise generated by a rotorcraft, such as a helicopter, comprises a trailing edge flap located near the tip of each of the rotorcraft's rotor blades. The flap may be actuated in any conventional way, and is scheduled to be actuated to a deflected position during rotation of the rotor blade through predetermined regions of the rotor azimuth, and is further scheduled to be actuated to a retracted position through the remaining regions of the rotor azimuth. Through the careful azimuth-dependent deployment and retraction of the flap over the rotor disk, blade tip vortices which are the primary source for BVI noise are (a) made weaker and (b) pushed farther away from the rotor disk (that is, larger blade-vortex separation distances are achieved).

  8. An Analysis of U.S. Civil Rotorcraft Accidents by Cost and Injury (1990-1996)

    NASA Technical Reports Server (NTRS)

    Iseler, Laura; DeMaio, Joe; Rutkowski, Michael (Technical Monitor)

    2002-01-01

    A study of rotorcraft accidents was conducted to identify safety issues and research areas that might lead to a reduction in rotorcraft accidents and fatalities. The primary source of data was summaries of National Transportation Safety Board (NTSB) accident reports. From 1990 to 1996, the NTSB documented 1396 civil rotorcraft accidents in the United States in which 491 people were killed. The rotorcraft data were compared to airline and general aviation data to determine the relative safety of rotorcraft compared to other segments of the aviation industry. In depth analysis of the rotorcraft data addressed demographics, mission, and operational factors. Rotorcraft were found to have an accident rate about ten times that of commercial airliners and about the same as that of general aviation. The likelihood that an accident would be fatal was about equal for all three classes of operation. The most dramatic division in rotorcraft accidents is between flights flown by private pilots versus professional pilots. Private pilots, flying low cost aircraft in benign environments, have accidents that are due, in large part, to their own errors. Professional pilots, in contrast, are more likely to have accidents that are a result of exacting missions or use of specialized equipment. For both groups judgement error is more likely to lead to a fatal accident than are other types of causes. Several approaches to improving the rotorcraft accident rate are recommended. These mostly address improvement in the training of new pilots and improving the safety awareness of private pilots.

  9. Behavioral representation of military tactics for single-vehicle autonomous rotorcraft via statecharts

    E-print Network

    Hickie, Mark M

    2005-01-01

    Over the past several years, aerospace companies have developed unmanned helicopters suitable for integration into military operations as reconnaissance platforms. These rotorcraft, however, require ground-based human ...

  10. Smart Rotorcraft Field Assistants for Terrestrial and Planetary Science

    NASA Technical Reports Server (NTRS)

    Young, Larry A.; Aiken, Edwin W.; Briggs, Geoffrey A.

    2004-01-01

    Field science in extreme terrestrial environments is often difficult and sometimes dangerous. Field seasons are also often short in duration. Robotic field assistants, particularly small highly mobile rotary-wing platforms, have the potential to significantly augment a field season's scientific return on investment for geology and astrobiology researchers by providing an entirely new suite of sophisticated field tools. Robotic rotorcraft and other vertical lift planetary aerial vehicle also hold promise for supporting planetary science missions.

  11. The ServoHeli-20 Rotorcraft UAV Project

    Microsoft Academic Search

    Juntong Qi; Dalei Song; Lei Dai; Jianda Han

    2008-01-01

    This paper describes research on the design, implement and testing of a small-scaled rotorcraft unmanned aerial vehicle (RUAV) system - ServoHeli-20. A turbine-powered UAV weighted less than 10 kg was designed, and its major components tested by a group of undergraduate students at Shenyang Institute of Automation, Chinese Academy of Sciences in Shenyang, China. The aircraft was designed to reach

  12. Improved finite-element methods for rotorcraft structures

    NASA Technical Reports Server (NTRS)

    Hinnant, Howard E.

    1991-01-01

    An overview of the research directed at improving finite-element methods for rotorcraft airframes is presented. The development of a modification to the finite element method which eliminates interelement discontinuities is covered. The following subject areas are discussed: geometric entities, interelement continuity, dependent rotational degrees of freedom, and adaptive numerical integration. This new methodology is being implemented as an anisotropic, curvilinear, p-version, beam, shell, and brick finite element program.

  13. Contributions to the Characterization and Mitigation of Rotorcraft Brownout

    NASA Astrophysics Data System (ADS)

    Tritschler, John Kirwin

    Rotorcraft brownout, the condition in which the flow field of a rotorcraft mobilizes sediment from the ground to generate a cloud that obscures the pilot's field of view, continues to be a significant hazard to civil and military rotorcraft operations. This dissertation presents methodologies for: (i) the systematic mitigation of rotorcraft brownout through operational and design strategies and (ii) the quantitative characterization of the visual degradation caused by a brownout cloud. In Part I of the dissertation, brownout mitigation strategies are developed through simulation-based brownout studies that are mathematically formulated within a numerical optimization framework. Two optimization studies are presented. The first study involves the determination of approach-to-landing maneuvers that result in reduced brownout severity. The second study presents a potential methodology for the design of helicopter rotors with improved brownout characteristics. The results of both studies indicate that the fundamental mechanisms underlying brownout mitigation are aerodynamic in nature, and the evolution of a ground vortex ahead of the rotor disk is seen to be a key element in the development of a brownout cloud. In Part II of the dissertation, brownout cloud characterizations are based upon the Modulation Transfer Function (MTF), a metric commonly used in the optics community for the characterization of imaging systems. The use of the MTF in experimentation is examined first, and the application of MTF calculation and interpretation methods to actual flight test data is described. The potential for predicting the MTF from numerical simulations is examined second, and an initial methodology is presented for the prediction of the MTF of a brownout cloud. Results from the experimental and analytical studies rigorously quantify the intuitively-known facts that the visual degradation caused by brownout is a space and time-dependent phenomenon, and that high spatial frequency features, i.e., fine-grained detail, are obscured before low spatial frequency features, i.e., large objects. As such, the MTF is a metric that is amenable to Handling Qualities (HQ) analyses.

  14. High Efficiency Centrifugal Compressor for Rotorcraft Applications

    NASA Technical Reports Server (NTRS)

    Medic, Gorazd; Sharma, Om P.; Jongwook, Joo; Hardin, Larry W.; McCormick, Duane C.; Cousins, William T.; Lurie, Elizabeth A.; Shabbir, Aamir; Holley, Brian M.; Van Slooten, Paul R.

    2014-01-01

    The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were measured at design flow rate and speed. The measured efficiency and stall margin were lower than pre-test CFD predictions by 2.4 percentage points (pt) and 4.5 pt, respectively. Initial impressions from the experimental data indicated that the loss in the efficiency and stall margin can be attributed to a design shortfall in the impeller. However, detailed investigation of experimental data and post-test CFD simulations of higher fidelity than pre-test CFD, and in particular the unsteady CFD simulations and the assessment with a wider range of turbulence models, have indicated that the loss in efficiency is most likely due to the impact of unfavorable unsteady impeller/diffuser interactions induced by diffuser vanes, an impeller/diffuser corrected flow-rate mismatch (and associated incidence levels), and, potentially, flow separation in the radial-to-axial bend. An experimental program with a vaneless diffuser is recommended to evaluate this observation. A subsequent redesign of the diffuser (and the radial-to-axial bend) is also recommended. The diffuser needs to be redesigned to eliminate the mismatching of the impeller and the diffuser, targeting a slightly higher flow capacity. Furthermore, diffuser vanes need to be adjusted to align the incidence angles, to optimize the splitter vane location (both radially and circumferentially), and to minimize the unsteady interactions with the impeller. The radial-to-axial bend needs to be redesigned to eliminate, or at least minimize, the flow separation at the inner wall, and its impact on the flow in the diffuser upstream. Lessons were also learned in terms of CFD methodology and the importance of unsteady CFD simulations for centrifugal compressors was highlighted. Inconsistencies in the implementation of a widely used two-equation turbulence model were identified and corrections are recommended. It was also observed that unsteady simulations for centrifugal compressors require significantly longer integration times than what is current practice in industry.

  15. Airworthiness Qualification Criteria for Rotorcraft with External Sling Loads

    NASA Technical Reports Server (NTRS)

    Key, David L.

    2002-01-01

    This report presents the results of a study to develop airworthiness requirements for rotorcraft with external sling loads. The report starts with a review of the various phenomena that limit external sling load operations. Specifically discussed are the rotorcraft-load aeroservoelastic stability, load-on handling qualities, effects of automatic flight control system failure, load suspension system failure, and load stability at speed. Based on past experience and treatment of these phenomena, criteria are proposed to form a package for airworthiness qualification. The desired end objective is a set of operational flight envelopes for the rotorcraft with intended loads that can be provided to the user to guide operations in the field. The specific criteria proposed are parts of ADS-33E-PRF; MIL-F-9490D, and MIL-STD-913A all applied in the context of external sling loads. The study was performed for the Directorate of Engineering, U.S. Army Aviation and Missile Command (AMCOM), as part of the contract monitored by the Aerothermodynamics Directorate, U.S. Army AMCOM.

  16. Rotorcraft fatigue life-prediction: Past, present, and future

    NASA Astrophysics Data System (ADS)

    Everett, Richard A., Jr.; Elber, W.

    1994-03-01

    In this paper the methods used for calculating the fatigue life of metallic dynamic components in rotorcraft is reviewed. In the past, rotorcraft fatigue design has combined constant amplitude tests of full-scale parts with flight loads and usage data in a conservative manner to provide 'safe life' component replacement times. This is in contrast to other industries, such as the automobile industry, where spectrum loading in fatigue testing is a part of the design procedure. Traditionally, the linear cumulative damage rule has been used in a deterministic manner using a conservative value for fatigue strength based on a one in a thousand probability of failure. Conservatism on load and usage are also often employed. This procedure will be discussed along with the current U.S. Army fatigue life specification for new rotorcraft which is the so-called 'six nines' reliability requirement. In order to achieve the six nines reliability requirement the exploration and adoption of new approaches in design and fleet management may also be necessary if this requirement is to be met with a minimum impact on structural weight. To this end a fracture mechanics approach to fatigue life design may be required in order to provide a more accurate estimate of damage progression. Also reviewed in this paper is a fracture mechanics approach for calculating total fatigue life which is based on a crack-closure small crack considerations.

  17. Robust crossfeed design for hovering rotorcraft. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Catapang, David R.

    1993-01-01

    Control law design for rotorcraft fly-by-wire systems normally attempts to decouple angular responses using fixed-gain crossfeeds. This approach can lead to poor decoupling over the frequency range of pilot inputs and increase the load on the feedback loops. In order to improve the decoupling performance, dynamic crossfeeds may be adopted. Moreover, because of the large changes that occur in rotorcraft dynamics due to small changes about the nominal design condition, especially for near-hovering flight, the crossfeed design must be 'robust.' A new low-order matching method is presented here to design robost crossfeed compensators for multi-input, multi-output (MIMO) systems. The technique identifies degrees-of-freedom that can be decoupled using crossfeeds, given an anticipated set of parameter variations for the range of flight conditions of concern. Cross-coupling is then reduced for degrees-of-freedom that can use crossfeed compensation by minimizing off-axis response magnitude average and variance. Results are presented for the analysis of pitch, roll, yaw, and heave coupling of the UH-60 Black Hawk helicopter in near-hovering flight. Robust crossfeeds are designed that show significant improvement in decoupling performance and robustness over nominal, single design point, compensators. The design method and results are presented in an easily-used graphical format that lends significant physical insight to the design procedure. This plant pre-compensation technique is an appropriate preliminary step to the design of robust feedback control laws for rotorcraft.

  18. NDARC - NASA Design and Analysis of Rotorcraft Validation and Demonstration

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2010-01-01

    Validation and demonstration results from the development of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are presented. The principal tasks of NDARC are to design a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft chosen as NDARC development test cases are the UH-60A single main-rotor and tail-rotor helicopter, the CH-47D tandem helicopter, the XH-59A coaxial lift-offset helicopter, and the XV-15 tiltrotor. These aircraft were selected because flight performance data, a weight statement, detailed geometry information, and a correlated comprehensive analysis model are available for each. Validation consists of developing the NDARC models for these aircraft by using geometry and weight information, airframe wind tunnel test data, engine decks, rotor performance tests, and comprehensive analysis results; and then comparing the NDARC results for aircraft and component performance with flight test data. Based on the calibrated models, the capability of the code to size rotorcraft is explored.

  19. Automated Design of Noise-Minimal, Safe Rotorcraft Trajectories

    NASA Technical Reports Server (NTRS)

    Morris, Robert A.; Venable, K. Brent; Lindsay, James

    2012-01-01

    NASA and the international community are investing in the development of a commercial transportation infrastructure that includes the increased use of rotorcraft, specifically helicopters and aircraft such as a 40-passenger civil tilt rotors. Rotorcraft have a number of advantages over fixed wing aircraft, primarily in not requiring direct access to the primary fixed wing runways. As such they can operate at an airport without directly interfering with major air carrier and commuter aircraft operations. However, there is significant concern over the impact of noise on the communities surrounding the transportation facilities. In this paper we propose to address the rotorcraft noise problem by exploiting powerful search techniques coming from artificial intelligence, coupled with simulation and field tests, to design trajectories that are expected to improve on the amount of ground noise generated. This paper investigates the use of simulation based on predictive physical models to facilitate the search for low-noise trajectories using a class of automated search algorithms called local search. A novel feature of this approach is the ability to incorporate constraints into the problem formulation that addresses passenger safety and comfort.

  20. Structural Dynamics Verification of Rotorcraft Comprehensive Analysis System (RCAS)

    SciTech Connect

    Bir, G. S.

    2005-02-01

    The Rotorcraft Comprehensive Analysis System (RCAS) was acquired and evaluated as part of an ongoing effort by the U.S Department of Energy (DOE) and the National Renewable Energy Laboratory (NREL) to provide state-of-the-art wind turbine modeling and analysis technology for Government and industry. RCAS is an interdisciplinary tool offering aeroelastic modeling and analysis options not supported by current codes. RCAS was developed during a 4-year joint effort among the U.S. Army's Aeroflightdynamics Directorate, Advanced Rotorcraft Technology Inc., and the helicopter industry. The code draws heavily from its predecessor 2GCHAS (Second Generation Comprehensive Helicopter Analysis System), which required an additional 14 years to develop. Though developed for the rotorcraft industry, its general-purpose features allow it to model or analyze a general dynamic system. Its key feature is a specialized finite element that can model spinning flexible parts. The code, therefore, appears particularly suited for wind turbines whose dynamics is dominated by massive flexible spinning rotors. In addition to the simulation capability of the existing codes, RCAS [1-3] offers a range of unique capabilities, including aeroelastic stability analysis, trim, state-space modeling, operating modes, modal reduction, multi-blade coordinate transformation, periodic-system-specific analysis, choice of aerodynamic models, and a controls design/implementation graphical interface.

  1. Rotorcraft fatigue life-prediction: Past, present, and future

    NASA Technical Reports Server (NTRS)

    Everett, Richard A., Jr.; Elber, W.

    1994-01-01

    In this paper the methods used for calculating the fatigue life of metallic dynamic components in rotorcraft is reviewed. In the past, rotorcraft fatigue design has combined constant amplitude tests of full-scale parts with flight loads and usage data in a conservative manner to provide 'safe life' component replacement times. This is in contrast to other industries, such as the automobile industry, where spectrum loading in fatigue testing is a part of the design procedure. Traditionally, the linear cumulative damage rule has been used in a deterministic manner using a conservative value for fatigue strength based on a one in a thousand probability of failure. Conservatism on load and usage are also often employed. This procedure will be discussed along with the current U.S. Army fatigue life specification for new rotorcraft which is the so-called 'six nines' reliability requirement. In order to achieve the six nines reliability requirement the exploration and adoption of new approaches in design and fleet management may also be necessary if this requirement is to be met with a minimum impact on structural weight. To this end a fracture mechanics approach to fatigue life design may be required in order to provide a more accurate estimate of damage progression. Also reviewed in this paper is a fracture mechanics approach for calculating total fatigue life which is based on a crack-closure small crack considerations.

  2. Research Capabilities for Oil-Free Turbomachinery Expanded by New Rotordynamic Simulator Facility

    NASA Technical Reports Server (NTRS)

    Howard, Samuel A.

    2004-01-01

    A new test rig has been developed for simulating high-speed turbomachinery shafting using Oil-Free foil air bearing technology. Foil air journal bearings are self-acting hydrodynamic bearings with a flexible inner sleeve surface using air as the lubricant. These bearings have been used in turbomachinery, primarily air cycle machines, for the past four decades to eliminate the need for oil lubrication. More recently, interest has been growing in applying foil bearings to aircraft gas turbine engines. They offer potential improvements in efficiency and power density, decreased maintenance costs, and other secondary benefits. The goal of applying foil air bearings to aircraft gas turbine engines prompted the fabrication of this test rig. The facility enables bearing designers to test potential bearing designs with shafts that simulate the rotating components of a target engine without the high cost of building actual flight hardware. The data collected from this rig can be used to make changes to the shaft and bearings in subsequent design iterations. The rest of this article describes the new test rig and demonstrates some of its capabilities with an initial simulated shaft system. The test rig has two support structures, each housing a foil air journal bearing. The structures are designed to accept any size foil journal bearing smaller than 63 mm (2.5 in.) in diameter. The bearing support structures are mounted to a 91- by 152-cm (3- by 5-ft) table and can be separated by as much as 122 cm (4 ft) and as little as 20 cm (8 in.) to accommodate a wide range of shaft sizes. In the initial configuration, a 9.5-cm (3.75-in.) impulse air turbine drives the test shaft. The impulse turbine, as well as virtually any number of "dummy" compressor and turbine disks, can be mounted on the shaft inboard or outboard of the bearings. This flexibility allows researchers to simulate various engine shaft configurations. The bearing support structures include a unique bearing mounting fixture that rotates to accommodate a laserbased alignment system. This can measure the misalignment of the bearing centers in each of 2 translational degrees of freedom and 2 rotational degrees of freedom. In the initial configuration, with roughly a 30.5-cm- (12-in.-) long shaft, two simulated aerocomponent disks, and two 50.8-cm (2-in.) foil journal bearings, the rig can operate at 65,000 rpm at room temperature. The test facility can measure shaft displacements in both the vertical and horizontal directions at each bearing location. Horizontal and vertical structural vibrations are monitored using accelerometers mounted on the bearing support structures. This information is used to determine system rotordynamic response, including critical speeds, mode shapes, orbit size and shape, and potentially the onset of instabilities. Bearing torque can be monitored as well to predict the power loss in the foil bearings. All of this information is fed back and forth between NASA and the foil bearing designers in an iterative fashion to converge on a final bearing and shaft design for a given engine application. In addition to its application development capabilities, the test rig offers several unique capabilities for basic bearing research. Using the laser alignment system mentioned earlier, the facility will be used to map foil air journal bearing performance. A known misalignment of increasing severity will be induced to determine the sensitivity of foil bearings to misalignment. Other future plans include oil-free integral starter generator testing and development, and dynamic load testing of foil journal bearings.

  3. Advanced space propulsion concepts

    NASA Technical Reports Server (NTRS)

    Lapointe, Michael R.

    1993-01-01

    The NASA Lewis Research Center has been actively involved in the evaluation and development of advanced spacecraft propulsion. Recent program elements have included high energy density propellants, electrode less plasma thruster concepts, and low power laser propulsion technology. A robust advanced technology program is necessary to develop new, cost-effective methods of spacecraft propulsion, and to continue to push the boundaries of human knowledge and technology.

  4. Electric propulsion system technology

    Microsoft Academic Search

    John R. Brophy; Charles E. Garner; Keith D. Goodfellow; Thomas J. Pivirotto; James E. Polk

    1992-01-01

    The work performed in fiscal year (FY) 1991 under the Propulsion Technology Program RTOP (Research and Technology Objectives and Plans) No. (55) 506-42-31 for Low-Thrust Primary and Auxiliary Propulsion technology development is described. The objectives of this work fall under two broad categories. The first of these deals with the development of ion engines for primary propulsion in support of

  5. Space propulsion technology overview

    Microsoft Academic Search

    J. J. Pelouch Jr.

    1979-01-01

    Chemical and electric propulsion technologies for operations beyond the shuttle's orbit with focus on future mission needs and economic effectiveness is discussed. The adequacy of the existing propulsion state-of-the-art, barriers to its utilization, benefit of technology advances, and the prognosis for advancement are the themes of the discussion. Low-thrust propulsion for large space systems is cited as a new technology

  6. Overview of electric propulsion

    NASA Astrophysics Data System (ADS)

    Dani?ko, Dariusz

    2014-11-01

    Space Electric Rocket Test (SERT 1) was the first experiment in which electric propulsion device was sent into space. The present year marks the 50th anniversary of that particular mission that opened the door for the application of electric propulsion on board spacecrafts. We present an overview of existing electric propulsion technology along with the description of the most successful missions that followed the success of the SERT 1mission.

  7. Field resonance propulsion concept

    NASA Technical Reports Server (NTRS)

    Holt, A. C.

    1979-01-01

    A propulsion concept was developed based on a proposed resonance between coherent, pulsed electromagnetic wave forms, and gravitational wave forms (or space-time metrics). Using this concept a spacecraft propulsion system potentially capable of galactic and intergalactic travel without prohibitive travel times was designed. The propulsion system utilizes recent research associated with magnetic field line merging, hydromagnetic wave effects, free-electron lasers, laser generation of megagauss fields, and special structural and containment metals. The research required to determine potential, field resonance characteristics and to evaluate various aspects of the spacecraft propulsion design is described.

  8. The role of the research simulator in the systems development of rotorcraft

    NASA Technical Reports Server (NTRS)

    Statler, I. C.; Deel, A.

    1981-01-01

    The potential application of the research simulator to future rotorcraft systems design, development, product improvement evaluations, and safety analysis is examined. Current simulation capabilities for fixed-wing aircraft are reviewed and the requirements of a rotorcraft simulator are defined. The visual system components, vertical motion simulator, cab, and computation system for a research simulator under development are described.

  9. Solid Rocket Propulsion Technology

    Microsoft Academic Search

    A. Davenas

    1992-01-01

    This book, a translation of the French title Technologie des Propergols Solides, offers otherwise unavailable information on the subject of solid propellants and their use in rocket propulsion. The fundamentals of rocket propulsion are developed in chapter one and detailed descriptions of concepts are covered in the following chapters. Specific design methods and the theoretical physics underlying them are presented,

  10. Nuclear thermal propulsion

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.

    1991-01-01

    This document is presented in viewgraph form, and the topics covered include the following: (1) the direct fission-thermal propulsion process; (2) mission applications of direct fission-thermal propulsion; (3) nuclear engines for rocket vehicles; (4) manned mars landers; and (5) particle bed reactor design.

  11. Advanced Chemical Propulsion

    NASA Technical Reports Server (NTRS)

    Alexander, Leslie, Jr.

    2006-01-01

    Advanced Chemical Propulsion (ACP) provides near-term incremental improvements in propulsion system performance and/or cost. It is an evolutionary approach to technology development that produces useful products along the way to meet increasingly more demanding mission requirements while focusing on improving payload mass fraction to yield greater science capability. Current activities are focused on two areas: chemical propulsion component, subsystem, and manufacturing technologies that offer measurable system level benefits; and the evaluation of high-energy storable propellants with enhanced performance for in-space application. To prioritize candidate propulsion technology alternatives, a variety of propulsion/mission analyses and trades have been conducted for SMD missions to yield sufficient data for investment planning. They include: the Advanced Chemical Propulsion Assessment; an Advanced Chemical Propulsion System Model; a LOx-LH2 small pumps conceptual design; a space storables propellant study; a spacecraft cryogenic propulsion study; an advanced pressurization and mixture ratio control study; and a pump-fed vs. pressure-fed study.

  12. Nuclear Pulse Propulsion

    Microsoft Academic Search

    J. C. Nance

    1965-01-01

    A general technical description and programmatic review of nuclear pulse propulsion activities over the last decade is presented. Major problem areas are reviewed together with the status of current research efforts. Sufficient technical information is now available to predict achievable propulsion systems performance with a rather high degree of confidence based on current materials and nuclear technology. Expected performance is

  13. Electric Propulsion Apparatus

    NASA Technical Reports Server (NTRS)

    Patterson, Michael J. (Inventor)

    2013-01-01

    An electric propulsion machine includes an ion thruster having an annular discharge chamber housing an anode having a large surface area. The ion thruster includes flat annular ion optics with a small span to gap ratio. Optionally, a second electric propulsion thruster may be disposed in a cylindrical space disposed within an interior of the annulus.

  14. Ion propulsion for spacecraft

    NASA Technical Reports Server (NTRS)

    Kerslake, W. R.

    1977-01-01

    The theory of the ion-thruster propulsion system is discussed along with the Space Electric Rocket Test 1 and 2. The use of electric propulsion for stationkeeping and attitude control functions of geosynchronous satellites is described, and a comparison of thruster systems is presented.

  15. Overview of Lightweight Structures for Rotorcraft Engines and Drivetrains

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.

    2011-01-01

    This is an overview presentation of research being performed in the Advanced Materials Task within the NASA Subsonic Rotary Wing Project. This research is focused on technology areas that address both national goals and project goals for advanced rotorcraft. Specific technology areas discussed are: (1) high temperature materials for advanced turbines in turboshaft engines; (2) polymer matrix composites for lightweight drive system components; (3) lightweight structure approaches for noise and vibration control; and (4) an advanced metal alloy for lighter weight bearings and more reliable mechanical components. An overview of the technology in each area is discussed, and recent accomplishments are presented.

  16. Introduction of the M-85 high-speed rotorcraft concept

    NASA Technical Reports Server (NTRS)

    Stroub, Robert H.

    1991-01-01

    As a result of studying possible requirements for high-speed rotorcraft and studying many high-speed concepts, a new high-speed rotorcraft concept, designated as M-85, was derived. The M-85 is a helicopter that is reconfigured to a fixed-wing aircraft for high-speed cruise. The concept was derived as an approach to enable smooth, stable conversion between fixed-wing and rotary-wing while retaining hover and low-speed flight characteristics of a low disk loading helicopter. The name, M-85, reflects the high-speed goals of 0.85 Mach number at high altitude. For a high-speed rotorcraft, it is expected that a viable concept must be a cruise-efficient, fixed-wing aircraft so it may be attractive for a multiplicity of missions. It is also expected that a viable high-speed rotorcraft concept must be cruise efficient first and secondly, efficient in hover. What makes the M-85 unique is the large circular hub fairing that is large enough to support the aircraft during conversion between rotary-wind and fixed-wing modes. With the aircraft supported by this hub fairing, the rotor blades can be unloaded during the 100 percent change in rotor rpm. With the blades unloaded, the potential for vibratory loads would be lessened. In cruise, the large circular hub fairing would be part of the lifting system with additional lifting panels deployed for better cruise efficiency. In hover, the circular hub fairing would slightly reduce lift potential and/or decrease hover efficiency of the rotor system. The M-85 concept is described and estimated forward flight performance characteristics are presented in terms of thrust requirements and L/D with airspeed. The forward flight performance characteristics reflect recent completed wind tunnel tests of the wing concept. Also presented is a control system technique that is critical to achieving low oscillatory loads in rotary-wing mode. Hover characteristics, C(sub p) versus C(sub T) from test data, is discussed. Other techniques pertinent to the M-85 concept such as passively controlling inplane vibration during starting and stopping of the rotor system, aircraft control system, and rotor drive technologies are discussed.

  17. Flight simulator fidelity assessment in a rotorcraft lateral translation maneuver

    NASA Technical Reports Server (NTRS)

    Hess, R. A.; Malsbury, T.; Atencio, A., Jr.

    1992-01-01

    A model-based methodology for assessing flight simulator fidelity in closed-loop fashion is exercised in analyzing a rotorcraft low-altitude maneuver for which flight test and simulation results were available. The addition of a handling qualities sensitivity function to a previously developed model-based assessment criteria allows an analytical comparison of both performance and handling qualities between simulation and flight test. Model predictions regarding the existence of simulator fidelity problems are corroborated by experiment. The modeling approach is used to assess analytically the effects of modifying simulator characteristics on simulator fidelity.

  18. Vision-based recursive estimation of rotorcraft obstacle locations

    NASA Technical Reports Server (NTRS)

    Leblanc, D. J.; Mcclamroch, N. H.

    1992-01-01

    The authors address vision-based passive ranging during nap-of-the-earth (NOE) rotorcraft flight. They consider the problem of estimating the relative location of identifiable features on nearby obstacles, assuming a sequence of noisy camera images and imperfect measurements of the camera's translation and rotation. An iterated extended Kalman filter is used to provide recursive range estimation. The correspondence problem is simplified by predicting and tracking each feature's image within the Kalman filter framework. Simulation results are presented which show convergent estimates and generally successful feature point tracking. Estimation performance degrades for features near the optical axis and for accelerating motions. Image tracking is also sensitive to angular rate.

  19. Considerations for automated nap-of-the-earth rotorcraft flight

    NASA Technical Reports Server (NTRS)

    Cheng, Victor H. L.; Sridhar, Banavar

    1988-01-01

    The authors consider nap-of-the-earth (NOE) rotorcraft flight as one of the applications in which obstacle avoidance plays a key role, and investigate the prospects of automating the guidance functions of NOE flight. Based on a proposed structure for the guidance functions, obstacle detection and obstacle avoidance are identified as the two critical components requiring substantial advancement before an automating guidance system can be realized. The major sources of difficulties in developing these two components are discussed, including sensor requirements for which a systematic analysis is provided.

  20. Efficiency of Fish Propulsion

    E-print Network

    Maertens, A P; Yue, D K P

    2014-01-01

    It is shown that the system efficiency of a self-propelled flexible body is ill-defined unless one considers the concept of quasi-propulsive efficiency, defined as the ratio of the power needed to tow a body in rigid-straight condition over the power it needs for self-propulsion, both measured for the same speed. Through examples we show that the quasi-propulsive efficiency is the only rational non-dimensional metric of the propulsive fitness of fish and fish-like mechanisms. Using two-dimensional viscous simulations and the concept of quasi-propulsive efficiency, we discuss the efficiency two-dimensional undulating foils. We show that low efficiencies, due to adverse body-propulsor hydrodynamic interactions, cannot be accounted for by the increase in friction drag.

  1. Acoustic Predictions of Manned and Unmanned Rotorcraft Using the Comprehensive Analytical Rotorcraft Model for Acoustics (CARMA) Code System

    NASA Technical Reports Server (NTRS)

    Boyd, D. Douglas, Jr.; Burley, Casey L.; Conner, David A.

    2005-01-01

    The Comprehensive Analytical Rotorcraft Model for Acoustics (CARMA) is being developed under the Quiet Aircraft Technology Project within the NASA Vehicle Systems Program. The purpose of CARMA is to provide analysis tools for the design and evaluation of efficient low-noise rotorcraft, as well as support the development of safe, low-noise flight operations. The baseline prediction system of CARMA is presented and current capabilities are illustrated for a model rotor in a wind tunnel, a rotorcraft in flight and for a notional coaxial rotor configuration; however, a complete validation of the CARMA system capabilities with respect to a variety of measured databases is beyond the scope of this work. For the model rotor illustration, predicted rotor airloads and acoustics for a BO-105 model rotor are compared to test data from HART-II. For the flight illustration, acoustic data from an MD-520N helicopter flight test, which was conducted at Eglin Air Force Base in September 2003, are compared with CARMA full vehicle flight predictions. Predicted acoustic metrics at three microphone locations are compared for limited level flight and descent conditions. Initial acoustic predictions using CARMA for a notional coaxial rotor system are made. The effect of increasing the vertical separation between the rotors on the predicted airloads and acoustic results are shown for both aerodynamically non-interacting and aerodynamically interacting rotors. The sensitivity of including the aerodynamic interaction effects of each rotor on the other, especially when the rotors are in close proximity to one another is initially examined. The predicted coaxial rotor noise is compared to that of a conventional single rotor system of equal thrust, where both are of reasonable size for an unmanned aerial vehicle (UAV).

  2. Advanced Propulsion Research Interest in Materials for Propulsion

    NASA Technical Reports Server (NTRS)

    Cole, John

    2003-01-01

    This viewgraph presentation provides an overview of material science and technology in the area of propulsion energetics. The authors note that conventional propulsion systems are near peak performance and further refinements in manufacturing, engineering design and materials will only provide incremental increases in performance. Energetic propulsion technologies could potential solve the problems of energy storage density and energy-to-thrust conversion efficiency. Topics considered include: the limits of thermal propulsion systems, the need for energetic propulsion research, emerging energetic propulsion technologies, materials research needed for advanced propulsion, and potential research opportunities.

  3. Distributed Propulsion Vehicles

    NASA Technical Reports Server (NTRS)

    Kim, Hyun Dae

    2010-01-01

    Since the introduction of large jet-powered transport aircraft, the majority of these vehicles have been designed by placing thrust-generating engines either under the wings or on the fuselage to minimize aerodynamic interactions on the vehicle operation. However, advances in computational and experimental tools along with new technologies in materials, structures, and aircraft controls, etc. are enabling a high degree of integration of the airframe and propulsion system in aircraft design. The National Aeronautics and Space Administration (NASA) has been investigating a number of revolutionary distributed propulsion vehicle concepts to increase aircraft performance. The concept of distributed propulsion is to fully integrate a propulsion system within an airframe such that the aircraft takes full synergistic benefits of coupling of airframe aerodynamics and the propulsion thrust stream by distributing thrust using many propulsors on the airframe. Some of the concepts are based on the use of distributed jet flaps, distributed small multiple engines, gas-driven multi-fans, mechanically driven multifans, cross-flow fans, and electric fans driven by turboelectric generators. This paper describes some early concepts of the distributed propulsion vehicles and the current turboelectric distributed propulsion (TeDP) vehicle concepts being studied under the NASA s Subsonic Fixed Wing (SFW) Project to drastically reduce aircraft-related fuel burn, emissions, and noise by the year 2030 to 2035.

  4. Foil Bearing Starting Considerations and Requirements for Rotorcraft Engine Applications

    NASA Technical Reports Server (NTRS)

    Radil, Kevin C.; DellaCorte, Christopher

    2009-01-01

    Foil gas bearings under development for rotorcraft-sized, hot core engine applications have been susceptible to damage from the slow acceleration and rates typically encountered during the pre-ignition stage in conventional engines. Recent laboratory failures have been assumed to be directly linked to operating foil bearings below their lift-off speed while following conventional startup procedures for the engines. In each instance, the continuous sliding contact between the foils and shaft was believed to thermally overload the bearing and cause the engines to fail. These failures highlight the need to characterize required acceleration rates and minimum operating speeds for these applications. In this report, startup experiments were conducted with a large, rotorcraft engine sized foil bearing under moderate load and acceleration rates to identify the proper start procedures needed to avoid bearing failure. The results showed that a bearing under a 39.4 kPa static load can withstand a modest acceleration rate of 500 rpm/s and excessive loitering below the bearing lift-off speed provided an adequate solid lubricant is present.

  5. Free Flight Rotorcraft Flight Test Vehicle Technology Development

    NASA Technical Reports Server (NTRS)

    Hodges, W. Todd; Walker, Gregory W.

    1994-01-01

    A rotary wing, unmanned air vehicle (UAV) is being developed as a research tool at the NASA Langley Research Center by the U.S. Army and NASA. This development program is intended to provide the rotorcraft research community an intermediate step between rotorcraft wind tunnel testing and full scale manned flight testing. The technologies under development for this vehicle are: adaptive electronic flight control systems incorporating artificial intelligence (AI) techniques, small-light weight sophisticated sensors, advanced telepresence-telerobotics systems and rotary wing UAV operational procedures. This paper briefly describes the system's requirements and the techniques used to integrate the various technologies to meet these requirements. The paper also discusses the status of the development effort. In addition to the original aeromechanics research mission, the technology development effort has generated a great deal of interest in the UAV community for related spin-off applications, as briefly described at the end of the paper. In some cases the technologies under development in the free flight program are critical to the ability to perform some applications.

  6. A Higher Harmonic Optimal Controller to Optimise Rotorcraft Aeromechanical Behaviour

    NASA Technical Reports Server (NTRS)

    Leyland, Jane Anne

    1996-01-01

    Three methods to optimize rotorcraft aeromechanical behavior for those cases where the rotorcraft plant can be adequately represented by a linear model system matrix were identified and implemented in a stand-alone code. These methods determine the optimal control vector which minimizes the vibration metric subject to constraints at discrete time points, and differ from the commonly used non-optimal constraint penalty methods such as those employed by conventional controllers in that the constraints are handled as actual constraints to an optimization problem rather than as just additional terms in the performance index. The first method is to use a Non-linear Programming algorithm to solve the problem directly. The second method is to solve the full set of non-linear equations which define the necessary conditions for optimality. The third method is to solve each of the possible reduced sets of equations defining the necessary conditions for optimality when the constraints are pre-selected to be either active or inactive, and then to simply select the best solution. The effects of maneuvers and aeroelasticity on the systems matrix are modelled by using a pseudo-random pseudo-row-dependency scheme to define the systems matrix. Cases run to date indicate that the first method of solution is reliable, robust, and easiest to use, and that it was superior to the conventional controllers which were considered.

  7. A comparison of fatigue life prediction methodologies for rotorcraft

    NASA Technical Reports Server (NTRS)

    Everett, R. A., Jr.

    1990-01-01

    Because of the current U.S. Army requirement that all new rotorcraft be designed to a 'six nines' reliability on fatigue life, this study was undertaken to assess the accuracy of the current safe life philosophy using the nominal stress Palmgrem-Miner linear cumulative damage rule to predict the fatigue life of rotorcraft dynamic components. It has been shown that this methodology can predict fatigue lives that differ from test lives by more than two orders of magnitude. A further objective of this work was to compare the accuracy of this methodology to another safe life method called the local strain approach as well as to a method which predicts fatigue life based solely on crack growth data. Spectrum fatigue tests were run on notched (k(sub t) = 3.2) specimens made of 4340 steel using the Felix/28 tests fairly well, being slightly on the unconservative side of the test data. The crack growth method, which is based on 'small crack' crack growth data and a crack-closure model, also predicted the fatigue lives very well with the predicted lives being slightly longer that the mean test lives but within the experimental scatter band. The crack growth model was also able to predict the change in test lives produced by the rainflow reconstructed spectra.

  8. Nuclear Cryogenic Propulsion Stage

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

    2012-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced NEP.

  9. Advanced Space Propulsion

    NASA Technical Reports Server (NTRS)

    Frisbee, Robert H.

    1996-01-01

    This presentation describes a number of advanced space propulsion technologies with the potential for meeting the need for dramatic reductions in the cost of access to space, and the need for new propulsion capabilities to enable bold new space exploration (and, ultimately, space exploitation) missions of the 21st century. For example, current Earth-to-orbit (e.g., low Earth orbit, LEO) launch costs are extremely high (ca. $10,000/kg); a factor 25 reduction (to ca. $400/kg) will be needed to produce the dramatic increases in space activities in both the civilian and government sectors identified in the Commercial Space Transportation Study (CSTS). Similarly, in the area of space exploration, all of the relatively 'easy' missions (e.g., robotic flybys, inner solar system orbiters and landers; and piloted short-duration Lunar missions) have been done. Ambitious missions of the next century (e.g., robotic outer-planet orbiters/probes, landers, rovers, sample returns; and piloted long-duration Lunar and Mars missions) will require major improvements in propulsion capability. In some cases, advanced propulsion can enable a mission by making it faster or more affordable, and in some cases, by directly enabling the mission (e.g., interstellar missions). As a general rule, advanced propulsion systems are attractive because of their low operating costs (e.g., higher specific impulse, ISD) and typically show the most benefit for relatively 'big' missions (i.e., missions with large payloads or AV, or a large overall mission model). In part, this is due to the intrinsic size of the advanced systems as compared to state-of-the-art (SOTA) chemical propulsion systems. Also, advanced systems often have a large 'infrastructure' cost, either in the form of initial R&D costs or in facilities hardware costs (e.g., laser or microwave transmission ground stations for beamed energy propulsion). These costs must then be amortized over a large mission to be cost-competitive with a SOTA system with a low initial development and infrastructure cost and a high operating cost. Note however that this has resulted in a 'Catch 22' standoff between the need for large initial investment that is amortized over many launches to reduce costs, and the limited number of launches possible at today's launch costs. Some examples of missions enabled (either in cost or capability) by advanced propulsion include long-life station-keeping or micro-spacecraft applications using electric propulsion or BMDO-derived micro-thrusters, low-cost orbit raising (LEO to GEO or Lunar orbit) using electric propulsion, robotic planetary missions using aerobraking or electric propulsion, piloted Mars missions using aerobraking and/or propellant production from Martian resources, very fast (100-day round-trip) piloted Mars missions using fission or fusion propulsion, and, finally, interstellar missions using fusion, antimatter, or beamed energy. The NASA Advanced Propulsion Technology program at the Jet Propulsion Laboratory (JPL) is aimed at assessing the feasibility of a range of near-term to far term advanced propulsion technologies that have the potential to reduce costs and/or enable future space activities. The program includes cooperative modeling and research activities between JPL and various universities and industry; and directly supported independent research at universities and industry. The cooperative program consists of mission studies, research and development of ion engine technology using C60 (Buckminsterfullerene) propellant, and research and development of lithium-propellant Lorentz-force accelerator (LFA) engine technology. The university/industry-supported research includes modeling and proof-of-concept experiments in advanced, high-lsp, long-life electric propulsion, and in fusion propulsion.

  10. Physics and Process Modeling (PPM) and Other Propulsion R and T. Volume 1; Materials Processing, Characterization, and Modeling; Lifting Models

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This CP contains the extended abstracts and presentation figures of 36 papers presented at the PPM and Other Propulsion R&T Conference. The focus of the research described in these presentations is on materials and structures technologies that are parts of the various projects within the NASA Aeronautics Propulsion Systems Research and Technology Base Program. These projects include Physics and Process Modeling; Smart, Green Engine; Fast, Quiet Engine; High Temperature Engine Materials Program; and Hybrid Hyperspeed Propulsion. Also presented were research results from the Rotorcraft Systems Program and work supported by the NASA Lewis Director's Discretionary Fund. Authors from NASA Lewis Research Center, industry, and universities conducted research in the following areas: material processing, material characterization, modeling, life, applied life models, design techniques, vibration control, mechanical components, and tribology. Key issues, research accomplishments, and future directions are summarized in this publication.

  11. Current Research Activities in Drive System Technology in Support of the NASA Rotorcraft Program

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Zakrajsek, James J.

    2006-01-01

    Drive system technology is a key area for improving rotorcraft performance, noise/vibration reduction, and reducing operational and manufacturing costs. An overview of current research areas that support the NASA Rotorcraft Program will be provided. Work in drive system technology is mainly focused within three research areas: advanced components, thermal behavior/emergency lubrication system operation, and diagnostics/prognostics (also known as Health and Usage Monitoring Systems (HUMS)). Current research activities in each of these activities will be presented. Also, an overview of the conceptual drive system requirements and possible arrangements for the Heavy Lift Rotorcraft program will be reviewed.

  12. Solar Thermal Rocket Propulsion

    NASA Technical Reports Server (NTRS)

    Sercel, J. C.

    1986-01-01

    Paper analyzes potential of solar thermal rockets as means of propulsion for planetary spacecraft. Solar thermal rocket uses concentrated Sunlight to heat working fluid expelled through nozzle to produce thrust.

  13. Viscous Marangoni propulsion

    E-print Network

    Eric Lauga; Anthony M. J. Davis

    2012-12-05

    Marangoni propulsion is a form of locomotion wherein an asymmetric release of surfactant by a body located at the surface of a liquid leads to its directed motion. We present in this paper a mathematical model for Marangoni propulsion in the viscous regime. We consider the case of a thin rigid circular disk placed at the surface of a viscous fluid and whose perimeter has a prescribed concentration of an insoluble surfactant, to which the rest of its surface is impenetrable. Assuming a linearized equation of state between surface tension and surfactant concentration, we derive analytically the surfactant, velocity and pressure fields in the asymptotic limit of low Capillary, Peclet and Reynolds numbers. We then exploit these results to calculate the Marangoni propulsion speed of the disk. Neglecting the stress contribution from Marangoni flows is seen to over-predict the propulsion speed by 50%.

  14. Space propulsion technology overview

    NASA Technical Reports Server (NTRS)

    Pelouch, J. J., Jr.

    1979-01-01

    Chemical and electric propulsion technologies for operations beyond the shuttle's orbit with focus on future mission needs and economic effectiveness is discussed. The adequacy of the existing propulsion state-of-the-art, barriers to its utilization, benefit of technology advances, and the prognosis for advancement are the themes of the discussion. Low-thrust propulsion for large space systems is cited as a new technology with particularly high benefit. It is concluded that the shuttle's presence for at least two decades is a legitimate basis for new propulsion technology, but that this technology must be predicted on an awareness of mission requirements, economic factors, influences of other technologies, and real constraints on its utilization.

  15. Space and transatmospheric propulsion technology

    Microsoft Academic Search

    Charles Merkle; Maynard L. Stangeland; James R. Brown; John P. McCarty; Louis A. Povinelli; G. Burton Northam; Edward E. Zukoski

    1994-01-01

    This report focuses primarily on Japan's programs in liquid rocket propulsion and propulsion for spaceplane and related transatmospheric areas. It refers briefly to Japan's solid rocket programs and to new supersonic air-breathing propulsion efforts. The panel observed that the Japanese had a carefully thought-out plan, a broad-based program, and an ambitious but achievable schedule for propulsion activity. Japan's overall propulsion

  16. Advanced propulsion concepts

    NASA Technical Reports Server (NTRS)

    Frisbee, Robert H.

    1991-01-01

    A variety of Advanced Propulsion Concepts (APC) is discussed. The focus is on those concepts that are sufficiently near-term that they could be developed for the Space Exploration Initiative. High-power (multi-megawatt) electric propulsion, solar sails, tethers, and extraterrestrial resource utilization concepts are discussed. A summary of these concepts and some general conclusions on their technology development needs are presented.

  17. Fusion propulsion systems

    Microsoft Academic Search

    V. E. Haloulakos

    1989-01-01

    The results of a US Air Force Astronautics Laboratory (AFAL)-sponsored study of fusion propulsion are summarized. The study explored the potential of fusion propulsion for Air Force missions. Fusion fuels and existing confinement concepts were evaluated according to elaborate criteria. Two fuels, deuterium-tritium and deuterium-helium 3 (D-3He), were considered worthy of further consideration. D-3He was selected as the most attractive

  18. Solar Thermal Propulsion Test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. This image, taken during the test, depicts the light being concentrated into the focal point inside the vacuum chamber. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

  19. Active vibration and noise alleviation in rotorcraft using microflaps

    NASA Astrophysics Data System (ADS)

    Padthe, Ashwani Kumar

    This work presents a comprehensive analysis of active Gurney flaps, or microflaps, for on blade control of noise and vibration in rotorcraft. The initial portion of the work considered the two-dimensional unsteady aerodynamic characteristics of three different oscillating microflap configurations using a compressible computational fluid dynamics (CFD) flow solver. Among these the configuration most suitable for rotorcraft applications was chosen. An unsteady reduced order aerodynamic model (ROM) was developed for the microflap using the Rational Function Approximation approach and CFD based oscillatory aerodynamic load data. The resulting ROM is a state-space, time-domain model that accounts for unsteadiness, compressibility and time-varying freestream effects. The ROM was validated against direct CFD calculations for a wide range of flow conditions showing excellent agreement. Subsequently, the ROM was then incorporated into a comprehensive rotorcraft simulation code featuring a free-wake model, an acoustic prediction tool, and fully coupled flap-lag-torsional blade dynamics. The higher harmonic control (HHC) algorithm was used to simulate closed-loop active control with a 1.5% chord microflap on a hingeless rotor configuration resembling the MBB BO-105. Three span-wise configurations, single, dual, and a five-microflap configuration were considered. Results indicate that the microflap can achieve reductions ranging from 3-6 dB in the blade-vortex interaction (BVI) noise. Vibration reduction ranging from 70-90% was also demonstrated at both low-speed and high-speed flight conditions. It was also found that reduction in BVI noise results in an increase in vibrations and vice versa, a trend also noted in previous active control studies employing HHC and conventional partial span trailing-edge flaps. Next, simultaneous BVI noise and vibration reduction was studied. A reduction of 2-3 dB in the advancing and retreating side noise combined with a 55% reduction in the vibratory loads was achieved using the five-microflap configuration. The 1.5% chord microflap was also compared to a 20% chord plain trailing-edge flap showing similar effectiveness in reducing vibration and noise. Finally, a new approach for dealing with actuator saturation in the HHC algorithm was developed using nonlinear constrained optimization techniques. The optimization approach takes less computational time compared to the previous approaches while yielding better performance in the case of multiple control surfaces.

  20. Fusion for Space Propulsion

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Schmidt, George R.; Santarius, John F.; Turchi, Peter J.; Siemon, Richard E.; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    The need for fusion propulsion for interplanetary flights is discussed. For a propulsion system, there are three important system attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For efficient and affordable human exploration of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion obviously cannot meet the requirement in propellant exhaust velocity. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the fission energy to heat a low atomic weight propellant produces propellant velocity of the order of 10 kinds. Alternatively the fission energy can be converted into electricity that is used to accelerate particles to high exhaust velocity. However, the necessary power conversion and conditioning equipment greatly increases the mass of the propulsion system. Fundamental considerations in waste heat rejection and power conditioning in a fission electric propulsion system place a limit on its jet specific power to the order of about 0.2 kW/kg. If fusion can be developed for propulsion, it appears to have the best of all worlds - it can provide the largest absolute amount of energy, the propellant exhaust velocity (> 100 km/s), and the high specific jet power (> 10 kW/kg). An intermediate step towards fusion propulsion might be a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. There are similarities as well as differences between applying fusion to propulsion and to terrestrial electrical power generation. The similarities are the underlying plasma and fusion physics, the enabling component technologies, the computational and the diagnostics capabilities. These physics and engineering capabilities have been demonstrated for a fusion reactor gain (Q) of the order of unity (TFTR: 0.25, JET: 0.65, JT-60: Q(sub eq) approx. 1.25). These technological advances made it compelling for considering fusion for propulsion.

  1. 75 FR 793 - Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-06

    ...RIN 2120-AJ52 Damage Tolerance and Fatigue Evaluation of Composite Rotorcraft Structures...amendment would require evaluation of fatigue and residual static strength of composite...using a damage tolerance evaluation, or a fatigue evaluation, if the applicant...

  2. 77 FR 4890 - Damage Tolerance and Fatigue Evaluation for Composite Rotorcraft Structures, and Damage Tolerance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    ...2120-AJ51 Damage Tolerance and Fatigue Evaluation for Composite Rotorcraft Structures, and Damage Tolerance and Fatigue Evaluation for Metallic Structures...final rules, ``Damage Tolerance and Fatigue Evaluation for Composite...

  3. adlp98052001.pdf Whole-Field Velocity Measurement for Rotorcraft Aerodynamic Interactions*

    E-print Network

    adlp98052001.pdf Whole-Field Velocity Measurement for Rotorcraft Aerodynamic Interactions* Reddy, U in the tailrotor flowfield of a helicopter model, in the 14' x 22' Subsonic tunnel at Langley Research Center

  4. Preliminary design capability enhancement via development of rotorcraft operating economics model

    E-print Network

    Giansiracusa, Michael P

    2010-01-01

    The purpose of this thesis is to develop a means of predicting direct operating cost (DOC) for new commercial rotorcraft early in the design process. This project leverages historical efforts to model operating costs in ...

  5. Proceedings of the Monterey Conference on Planning for Rotorcraft and Commuter Air Transportation

    NASA Technical Reports Server (NTRS)

    Stockwell, W. L.

    1983-01-01

    Planning and technological issues involved in rotorcraft and commuter fixed-wing air transportation are discussed. Subject areas include the future community environment, aircraft technology, community transportation planning, and regulatory perspectives.

  6. General Rotorcraft Aeromechanical Stability Program (GRASP) version 1.03: User's manual

    NASA Technical Reports Server (NTRS)

    Hopkins, A. Stewart; Kunz, Donald L.

    1988-01-01

    The Rotorcraft Dynamics Division, Aeroflightdynamics Directorate, U.S. Army Aviation Research and Technology Activity has developed the General Rotorcraft Aeromechanical Stability Program (GRASP) to perform calculations that will assess the stability of rotorcraft in hovering flight and ground contact conditions. The program is designed to be state-of-the-art, hybrid, finite-element/multibody code that can be applied to all existing and future helicopter configurations. While GRASP was specifically designed to solve rotorcraft stability problems, its innovative structure and formulation allow for application to a wide range of structures. This manual describes the preparation of the input file required by Version 1.03 of GRASP, the procedures used to invoke GRASP on the NASA Ames Research Center CRAY X-MP 48 computer, and the interpretation of the output produced by GRASP. The parameters used by the input file are defined, and summaries of the input file and the job control language are included.

  7. A comparative analysis of technological learning systems in emerging rotorcraft companies

    E-print Network

    Gan, Thiam Soon

    2011-01-01

    The aim of this research is to understand how emerging rotorcraft companies in various countries accomplished technological learning over the last sixty years. Owing to its unique products and growing market demand, ...

  8. NASA/HAA Advanced Rotorcraft Technology and Tilt Rotor Workshop. Volume 6: Vehicle Configuration Session

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Five high speed rotorcraft configurations are considered: the high speed helicopter, compound helicopter, ABC, tilt rotor and the X wing. The technology requirements and the recommended actions are discussed.

  9. --------Original Message --------Subject: [robo-ms] Fwd: Software Engineer for Rotorcraft Robotics and Simulation

    E-print Network

    Plotkin, Joshua B.

    > * Structured software methodologies (e.g., iterative, spiral, agile, Scrum, RUP, etc.). > * Object oriented-------- Original Message -------- Subject: [robo-ms] Fwd: Software Engineer for Rotorcraft: Vijay Kumar > Cc: Kostas Daniilidis > Subject: Software

  10. Development of autonomous magnetometer rotorcraft for wide area assessment

    SciTech Connect

    Roelof Versteeg; Matt Anderson; Les Beard; Eric Corban; Darryl Curley; Jeff Gamey; Ross Johnson; Dwight Junkin; Mark McKay; Jared Salzmann; Mikhail Tchernychev; Suraj Unnikrishnan; Scott Vinson

    2010-04-01

    Large areas across the United States are potentially contaminated with UXO, with some ranges encompassing tens to hundreds of thousands of acres. Technologies are needed which will allow for cost effective wide area scanning with 1) near 100 % coverage and 2) near 100 % detection of subsurface ordnance or features indicative of subsurface ordnance. The current approach to wide area assessment is a multi-level one, in which medium - altitude fixed wing optical imaging is used for an initial site assessment. This assessment is followed with low altitude manned helicopter based magnetometry. Subsequent to this wide area assessment targeted surface investigations are performed using either towed geophysical sensor arrays or man portable sensors. In order to be an effective tool for small UXO detection, the sensing altitude for magnetic site investigations needs to be on the order of 1 – 3 meters. These altitude requirements mean that manned helicopter surveys will generally only be feasible in large, open and relatively flat terrains. While such surveys are effective in mapping large areas relatively fast there are substantial mobilization/demobilization, staffing and equipment costs associated with these surveys (resulting in costs of approximately $100-$150/acre). In addition, due to the low altitude there are substantial risks to pilots and equipment. Surface towed arrays provide high resolution maps but have other limitations, e.g. in their ability to navigate rough terrain effectively. There is thus a need for other systems which can be used for effective data collection. An UAV (Unmanned Aerial Vehicle) magnetometer platform is an obvious alternative. The motivation behind such a system is that it reduces risk to operators, is lower in initial and Operational and Maintenance (O&M) costs (and can thus potentially be applied to smaller sites) and has the potential of being more effective in terms of detection and possibly characterization (through the use of dynamic acquisition, i.e. survey mission inflight reprioritization). We describe and report on a one year effort with as primary goal to provide a recommendation to SERDP for a path forward in the implementation of one or more autonomous unmanned magnetometer rotorcraft platforms. This recommendation (which is provided in chapter 6) is based on the following three elements a) An assessment on the applicability of autonomous rotorcraft magnetometer systems to the current DoD site inventory, and an initial assessment of which type(s) of autonomous unmanned magnetometer rotorcraft platforms (in terms of performance characteristics such as payload, altitude, obstacle avoidance, production rate and flight time) would be most relevant to this inventory (chapter 3); b) An evaluation of the feasibility of assembling such platforms from commercial components (unmanned rotorcraft, control systems and sensors – both magnetometer sensors and supporting sensors). This evaluation included several highly successful field tests (chapter 4 and 5); c) A recommendation of the path forward, which includes a detailed outline of the efforts required in the design, assembly and testing of different modular platforms (chapter 6)

  11. Computer vision techniques for rotorcraft low-altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Cheng, Victor H. L.

    1988-01-01

    A description is given of research that applies techniques from computer vision to automation of rotorcraft navigation. The effort emphasizes the development of a methodology for detecting the ranges to obstacles in the region of interest based on the maximum utilization of passive sensors. The range map derived from the obstacle detection approach can be used as obstacle data for the obstacle avoidance in an automataic guidance system and as advisory display to the pilot. The lack of suitable flight imagery data, however, presents a problem in the verification of concepts for obstacle detection. This problem is being addressed by the development of an adequate flight database and by preprocessing of currently available flight imagery. Some comments are made on future work and how research in this area relates to the guidance of other autonomous vehicles.

  12. Vision based techniques for rotorcraft low altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Suorsa, Ray; Smith, Philip

    1991-01-01

    An overview of research in obstacle detection at NASA Ames Research Center is presented. The research applies techniques from computer vision to automation of rotorcraft navigation. The development of a methodology for detecting the range to obstacles based on the maximum utilization of passive sensors is emphasized. The development of a flight and image data base for verification of vision-based algorithms, and a passive ranging methodology tailored to the needs of helicopter flight are discussed. Preliminary results indicate that it is possible to obtain adequate range estimates except at regions close to the FOE. Closer to the FOE, the error in range increases since the magnitude of the disparity gets smaller, resulting in a low SNR.

  13. Computational Analysis of a Prototype Martian Rotorcraft Experiment

    NASA Technical Reports Server (NTRS)

    Corfeld, Kelly J.; Strawn, Roger C.; Long, Lyle N.

    2001-01-01

    This paper presents Reynolds-averaged Navier-Stokes calculations for a prototype Martian rotorcraft. The computations are intended for comparison with an ongoing Mars rotor hover test at NASA Ames Research Center. These computational simulations present a new and challenging problem, since rotors that operate on Mars will experience a unique low Reynolds number and high Mach number environment. Computed results for the 3-D rotor differ substantially from 2-D sectional computations in that the 3-D results exhibit a stall delay phenomenon caused by rotational forces along the blade span. Computational results have yet to be compared to experimental data, but computed performance predictions match the experimental design goals fairly well. In addition, the computed results provide a high level of detail in the rotor wake and blade surface aerodynamics. These details provide an important supplement to the expected experimental performance data.

  14. Passive range estimation for rotorcraft low-altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, B.; Suorsa, R.; Hussien, B.

    1993-01-01

    The automation of rotorcraft low-altitude flight presents challenging problems in control, computer vision and image understanding. A critical element in this problem is the ability to detect and locate obstacles, using on-board sensors, and modify the nominal trajectory. This requirement is also necessary for the safe landing of an autonomous lander on Mars. This paper examines some of the issues in the location of objects using a sequence of images from a passive sensor, and describes a Kalman filter approach to estimate the range to obstacles. The Kalman filter is also used to track features in the images leading to a significant reduction of search effort in the feature extraction step of the algorithm. The method can compute range for both straight line and curvilinear motion of the sensor. A laboratory experiment was designed to acquire a sequence of images along with sensor motion parameters under conditions similar to helicopter flight. Range estimation results using this imagery are presented.

  15. Passive range estimation for rotorcraft low-altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, B.; Suorsa, R.; Hussien, B.

    1991-01-01

    The automation of rotorcraft low-altitude flight presents challenging problems in control, computer vision and image understanding. A critical element in this problem is the ability to detect and locate obstacles, using on-board sensors, and modify the nominal trajectory. This requirement is also necessary for the safe landing of an autonomous lander on Mars. This paper examines some of the issues in the location of objects using a sequence of images from a passive sensor, and describes a Kalman filter approach to estimate the range to obstacles. The Kalman filter is also used to track features in the images leading to a significant reduction of search effort in the feature extraction step of the algorithm. The method can compute range for both straight line and curvilinear motion of the sensor. A laboratory experiment was designed to acquire a sequence of images along with sensor motion parameters under conditions similar to helicopter flight. Range estimation results using this imagery are presented.

  16. In-flight performance optimization for rotorcraft with redundant controls

    NASA Astrophysics Data System (ADS)

    Ozdemir, Gurbuz Taha

    A conventional helicopter has limits on performance at high speeds because of the limitations of main rotor, such as compressibility issues on advancing side or stall issues on retreating side. Auxiliary lift and thrust components have been suggested to improve performance of the helicopter substantially by reducing the loading on the main rotor. Such a configuration is called the compound rotorcraft. Rotor speed can also be varied to improve helicopter performance. In addition to improved performance, compound rotorcraft and variable RPM can provide a much larger degree of control redundancy. This additional redundancy gives the opportunity to further enhance performance and handling qualities. A flight control system is designed to perform in-flight optimization of redundant control effectors on a compound rotorcraft in order to minimize power required and extend range. This "Fly to Optimal" (FTO) control law is tested in simulation using the GENHEL model. A model of the UH-60, a compound version of the UH-60A with lifting wing and vectored thrust ducted propeller (VTDP), and a generic compound version of the UH-60A with lifting wing and propeller were developed and tested in simulation. A model following dynamic inversion controller is implemented for inner loop control of roll, pitch, yaw, heave, and rotor RPM. An outer loop controller regulates airspeed and flight path during optimization. A Golden Section search method was used to find optimal rotor RPM on a conventional helicopter, where the single redundant control effector is rotor RPM. The FTO builds off of the Adaptive Performance Optimization (APO) method of Gilyard by performing low frequency sweeps on a redundant control for a fixed wing aircraft. A method based on the APO method was used to optimize trim on a compound rotorcraft with several redundant control effectors. The controller can be used to optimize rotor RPM and compound control effectors through flight test or simulations in order to establish a schedule. The method has been expanded to search a two-dimensional control space. Simulation results demonstrate the ability to maximize range by optimizing stabilator deflection and an airspeed set point. Another set of results minimize power required in high speed flight by optimizing collective pitch and stabilator deflection. Results show that the control laws effectively hold the flight condition while the FTO method is effective at improving performance. Optimizations show there can be issues when the control laws regulating altitude push the collective control towards it limits. So a modification was made to the control law to regulate airspeed and altitude using propeller pitch and angle of attack while the collective is held fixed or used as an optimization variable. A dynamic trim limit avoidance algorithm is applied to avoid control saturation in other axes during optimization maneuvers. Range and power optimization FTO simulations are compared with comprehensive sweeps of trim solutions and FTO optimization shown to be effective and reliable in reaching an optimal when optimizing up to two redundant controls. Use of redundant controls is shown to be beneficial for improving performance. The search method takes almost 25 minutes of simulated flight for optimization to be complete. The optimization maneuver itself can sometimes drive the power required to high values, so a power limit is imposed to restrict the search to avoid conditions where power is more than5% higher than that of the initial trim state. With this modification, the time the optimization maneuver takes to complete is reduced down to 21 minutes without any significant change in the optimal power value.

  17. Design of Quiet Rotorcraft Approach Trajectories: Verification Phase

    NASA Technical Reports Server (NTRS)

    Padula, Sharon L.

    2010-01-01

    Flight testing that is planned for October 2010 will provide an opportunity to evaluate rotorcraft trajectory optimization techniques. The flight test will involve a fully instrumented MD-902 helicopter, which will be flown over an array of microphones. In this work, the helicopter approach trajectory is optimized via a multiobjective genetic algorithm to improve community noise, passenger comfort, and pilot acceptance. Previously developed optimization strategies are modified to accommodate new helicopter data and to increase pilot acceptance. This paper describes the MD-902 trajectory optimization plus general optimization strategies and modifications that are needed to reduce the uncertainty in noise predictions. The constraints that are imposed by the flight test conditions and characteristics of the MD-902 helicopter limit the testing possibilities. However, the insights that will be gained through this research will prove highly valuable.

  18. Technologies for automating rotorcraft nap-of-the-earth flight

    NASA Technical Reports Server (NTRS)

    Cheng, Victor H. L.; Sridhar, Banavar

    1992-01-01

    This paper discusses the technologies required for automating rotorcraft nap-of-the-earth flight, where the use of natural obstacles for masking from the enemy is intentional and the danger of undesirable obstacles such as enemy traps is real. Specifically, the automatic guidance structure is modeled by three decision-making levels: the far-field mission planning and the mid-field terrain-masking trajectory shaping are both driven by prestored terrain data, whereas the nearfield obstacle detection/avoidance is driven by real-time on-board sensor data. This paper summarizes the far-field and mid-field accomplishments, and reports on the status of the more-recent efforts in obstacle detection and avoidance development. Obstacle detection is based primarily on passive imaging sensors for the desirable properties of covertness and wide field of view, although active sensors are included in the structure to provide the much needed high resolution for thin-wire detection.

  19. Computational Analysis of a Prototype Martian Rotorcraft Experiment

    NASA Technical Reports Server (NTRS)

    Corfeld, Kelly J.; Strawn, Roger C.; Long, Lyle N.

    2002-01-01

    This paper presents Reynolds-averaged Navier-Stokes calculations for a prototype Martian rotorcraft. The computations are intended for comparison with an ongoing Mars rotor hover test at NASA Ames Research Center. These computational simulations present a new and challenging problem, since rotors that operate on Mars will experience a unique low Reynolds number and high Mach number environment. Computed results for the 3-D rotor differ substantially from 2-D sectional computations in that the 3-D results exhibit a stall delay phenomenon caused by rotational forces along the blade span. Computational results have yet to be compared to experimental data, but computed performance predictions match the experimental design goals fairly well. In addition, the computed results provide a high level of detail in the rotor wake and blade surface aerodynamics. These details provide an important supplement to the expected experimental performance data.

  20. Evaluation of Gear Condition Indicator Performance on Rotorcraft Fleet

    NASA Technical Reports Server (NTRS)

    Antolick, Lance J.; Branning, Jeremy S.; Wade, Daniel R.; Dempsey, Paula J.

    2010-01-01

    The U.S. Army is currently expanding its fleet of Health Usage Monitoring Systems (HUMS) equipped aircraft at significant rates, to now include over 1,000 rotorcraft. Two different on-board HUMS, the Honeywell Modern Signal Processing Unit (MSPU) and the Goodrich Integrated Vehicle Health Management System (IVHMS), are collecting vibration health data on aircraft that include the Apache, Blackhawk, Chinook, and Kiowa Warrior. The objective of this paper is to recommend the most effective gear condition indicators for fleet use based on both a theoretical foundation and field data. Gear diagnostics with better performance will be recommended based on both a theoretical foundation and results of in-fleet use. In order to evaluate the gear condition indicator performance on rotorcraft fleets, results of more than five years of health monitoring for gear faults in the entire HUMS equipped Army helicopter fleet will be presented. More than ten examples of gear faults indicated by the gear CI have been compiled and each reviewed for accuracy. False alarms indications will also be discussed. Performance data from test rigs and seeded fault tests will also be presented. The results of the fleet analysis will be discussed, and a performance metric assigned to each of the competing algorithms. Gear fault diagnostic algorithms that are compliant with ADS-79A will be recommended for future use and development. The performance of gear algorithms used in the commercial units and the effectiveness of the gear CI as a fault identifier will be assessed using the criteria outlined in the standards in ADS-79A-HDBK, an Army handbook that outlines the conversion from Reliability Centered Maintenance to the On-Condition status of Condition Based Maintenance.

  1. Gravitational Wave Propulsion

    NASA Astrophysics Data System (ADS)

    Fontana, Giorgio

    2005-02-01

    There is only one experimental proof that gravitational waves exist. With such a limitation, it may seem premature to suggest the possibility that gravitational waves can became a preferred space propulsion technique. The present understanding of the problem indicates that this is not the case. The emission of gravitational waves from astrophysical sources has been confirmed by observation, the respective detection at large distance from the source is difficult and actually we have no confirmation of a successful detection. Therefore the required preliminary discovery has been already made. This opinion is enforced by many different proposals for building the required powerful gravitational wave generators that have recently appeared in the literature and discussed at conferences. It is no longer reasonable to wait for additional confirmation of the existence of gravitational waves to start a program for building generators and testing their possible application to space travel. A vast literature shows that gravitational waves can be employed for space propulsion. Gravitational wave rockets have been proposed, non-linearity of Einstein equations allows the conversion of gravitational waves to a static gravitational field and ``artificial gravity assist'' may become a new way of travelling in space-time. Different approaches to gravitational wave propulsion are reviewed and compared. Gravitational wave propulsion is also compared to traditional rocket propulsion and an undeniable advantage can be demonstrated in terms of efficiency and performance. Testing the predictions will require gravitational wave generators with high power and wavelength short enough for producing high energy densities. Detectors designed for the specific application must be developed, taking into account that non-linearity effects are expected. The study and development of Gravitational wave propulsion is a very challenging endeavor, involving the most complex theories, sophisticated materials and testing techniques ever conceived by science. The development of Gravitational wave propulsion appears to be within the reach of a large national or a worldwide research program.

  2. Ion propulsion for communications satellites

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.

    1984-01-01

    In a recent study of potential applications for electric propulsion, it was determined that ion propulsion can provide North-South stationkeeping (NSSK) for communication satellites in geosynchronous orbit with appreciably less mass than chemical propulsion. While this finding is not new, the margin of benefit over advanced chemical propulsion technology depends strongly on the ion propulsion system specifications. Full advantage must be taken of the under-utilized stored energy available from the communication satellite's batteries. This paper describes a methodology for evaluating the benefits obtained in using ion propulsion for NSSK, both in terms of the mass reduction and its economic value.

  3. Propulsion IVHM Technology Experiment

    NASA Technical Reports Server (NTRS)

    Chicatelli, Amy K.; Maul, William A.; Fulton, Christopher E.

    2006-01-01

    The Propulsion IVHM Technology Experiment (PITEX) successfully demonstrated real-time fault detection and isolation of a virtual reusable launch vehicle (RLV) main propulsion system (MPS). Specifically, the PITEX research project developed and applied a model-based diagnostic system for the MPS of the X-34 RLV, a space-launch technology demonstrator. The demonstration was simulation-based using detailed models of the propulsion subsystem to generate nominal and failure scenarios during captive carry, which is the most safety-critical portion of the X-34 flight. Since no system-level testing of the X-34 Main Propulsion System (MPS) was performed, these simulated data were used to verify and validate the software system. Advanced diagnostic and signal processing algorithms were developed and tested in real time on flight-like hardware. In an attempt to expose potential performance problems, the PITEX diagnostic system was subjected to numerous realistic effects in the simulated data including noise, sensor resolution, command/valve talkback information, and nominal build variations. In all cases, the PITEX system performed as required. The research demonstrated potential benefits of model-based diagnostics, defined performance metrics required to evaluate the diagnostic system, and studied the impact of real-world challenges encountered when monitoring propulsion subsystems.

  4. Nuclear-electric propulsion - Manned Mars propulsion options

    NASA Technical Reports Server (NTRS)

    Palaszewski, Bryan; Brophy, John; King, David

    1989-01-01

    Nuclear-electric propulsion can significantly reduce the launch mass for manned Mars missions. By using high-specific-impulse (lsp) electric propulsion systems with advanced nuclear reactors, the total mass-to-orbit for a series of manned Mars flight is reduced. Propulsion technologies required for the manned Mars mission are described. Multi-megawatt Ion and Magneto-Plasma-Dynamic (MPD) propulsion thrusters, Power-Processing Units and nuclear power source are needed. Xenon (Xe)-Ion and MPD thruster performance are detailed. Mission analyses for several Mars mission options are addressed. Both MPD and Ion propulsion were investigated. A four-megawatt propulsion system power level was assumed. Mass comparisons for all-chemical oxygen/hydrogen propulsion missions and combined chemical and nuclear-electric propulsion Mars fleets are included. With fleets of small nuclear-electric vehicles, short trip times to Mars are also enabled.

  5. Electric Propulsion Applications and Impacts

    NASA Technical Reports Server (NTRS)

    Curran, Frank M.; Wickenheiser, Timothy J.

    1996-01-01

    Most space missions require on-board propulsion systems and these systems are often dominant spacecraft mass drivers. Presently, on-board systems account for more than half the injected mass for commercial communications systems and even greater mass fractions for ambitious planetary missions. Anticipated trends toward the use of both smaller spacecraft and launch vehicles will likely increase pressure on the performance of on-board propulsion systems. The acceptance of arcjet thrusters for operational use on commercial communications satellites ushered in a new era in on-board propulsion and exponential growth of electric propulsion across a broad spectrum of missions is anticipated. NASA recognizes the benefits of advanced propulsion and NASA's Office of Space Access and Technology supports an aggressive On-Board Propulsion program, including a strong electric propulsion element, to assure the availability of high performance propulsion systems to meet the goals of the ambitious missions envisioned in the next two decades. The program scope ranges from fundamental research for future generation systems through specific insertion efforts aimed at near term technology transfer. The On-Board propulsion program is committed to carrying technologies to levels required for customer acceptance and emphasizes direct interactions with the user community and the development of commercial sources. This paper provides a discussion of anticipated missions, propulsion functions, and electric propulsion impacts followed by an overview of the electric propulsion element of the NASA On-Board Propulsion program.

  6. Space transportation propulsion USSR launcher technology, 1990

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Space transportation propulsion U.S.S.R. launcher technology is discussed. The following subject areas are covered: Energia background (launch vehicle summary, Soviet launcher family) and Energia propulsion characteristics (booster propulsion, core propulsion, and growth capability).

  7. Nuclear electric propulsion

    NASA Technical Reports Server (NTRS)

    Keaton, Paul W.; Tubb, David J.

    1986-01-01

    The feasibility is investigated of using nuclear electric propulsion (NEP) for slow freighter ships traveling from a 500 km low Earth orbit (LEO) to the Moon's orbit about the Earth, and on to Mars. NEP is also shown to be feasible for transporting people to Mars on long conjunction-class missions lasting about nine months one way, and on short sprint missions lasting four months one way. Generally, it was not attempted to optimize ion exhaust velocities, but rather suitable parameters to demonstrate NEP feasibility were chosen. Various combinations of missions are compared with chemical and nuclear thermal propulsion (NTR) systems. Typically, NEP and NTR can accomplish the same lifting task with similar mass in LEO. When compared to chemical propulsion, NEP was found to accomplish the same missions with 40% less mass in LEO. These findings are sufficiently encouraging as to merit further studies with optimum systems.

  8. Fusion for Space Propulsion

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

    2001-01-01

    There is little doubt that humans will attempt to explore and develop the solar system in this century. A large amount of energy will be required for accomplishing this. The need for fusion propulsion is discussed. For a propulsion system, there are three important thermodynamical attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For human exploration and development of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion can produce exhaust velocity up to about 5 km/s. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the energy to heat a hydrogen propellant increases the exhaust velocity by only a factor of about two. Alternatively the energy can be converted into electricity which is then used to accelerate particles to high exhaust velocity. The necessary power conversion and conditioning equipment, however, increases the mass of the propulsion system for the same jet power by more than two orders of magnitude over chemical system, thus greatly limits the thrust-to-weight ratio attainable. The principal advantage of the fission process is that its development is relatively mature and is available right now. If fusion can be developed, fusion appears to have the best of all worlds in terms of propulsion - it can provide the absolute amount, the propellant exhaust velocity, and the high specific jet power. An intermediate step towards pure fusion propulsion is a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. The technical issues related to fusion for space propulsion are discussed. The technical priorities for developing and applying fusion for propulsion are somewhat different from those for terrestrial electrical power generation. Thus fusion schemes that are initially attractive for electrical power generation might not necessarily be attractive also for propulsion and vice versa, though the underlying fusion science and engineering enjoy much overlap. Parallel efforts to develop these qualitatively differently fusion schemes for the two applications could benefit greatly from each other due to the synergy in the underlying physics and engineering. Pulsed approaches to fusion have not been explored to the same degree as steady-state or long-pulse approaches to fusion in the fusion power research program. The concerns early on were several. One was that the pulsed power components might not have the service lifetimes meeting the requirements of a practical power generating plant. Another was that, for many pulsed fusion schemes, it was not clear whether the destruction of hardware per pulse could be minimized or eliminated or recycled to such an extent as to make economical electrical power generation feasible, Significant development of the underlying pulsed power component technologies have occurred in the last two decades because of defense and other energy requirements. The state of development of the pulsed power technologies are sufficiently advanced now to make it compelling to visit or re-visit pulsed fusion approaches for application to propulsion where the cost of energy is not so demanding a factor as in the case of terrestrial power application. For propulsion application, the overall mass of the fusion system is the critical factor. Producing fusion reactions require extreme states of matter. Conceptually, these extreme states of matter are more readily realizable in the pulsed states, at least within appropriate bounds, than in the steady states. Significant saving in system mass may result in such systems. Magnetic fields are effective in confining plasma energy, whereas inertial compression is an effective way of heating and containing the plasma. Intensive research in developing magnetic energy containme

  9. Advanced rocket propulsion

    NASA Technical Reports Server (NTRS)

    Obrien, Charles J.

    1993-01-01

    Existing NASA research contracts are supporting development of advanced reinforced polymer and metal matrix composites for use in liquid rocket engines of the future. Advanced rocket propulsion concepts, such as modular platelet engines, dual-fuel dual-expander engines, and variable mixture ratio engines, require advanced materials and structures to reduce overall vehicle weight as well as address specific propulsion system problems related to elevated operating temperatures, new engine components, and unique operating processes. High performance propulsion systems with improved manufacturability and maintainability are needed for single stage to orbit vehicles and other high performance mission applications. One way to satisfy these needs is to develop a small engine which can be clustered in modules to provide required levels of total thrust. This approach should reduce development schedule and cost requirements by lowering hardware lead times and permitting the use of existing test facilities. Modular engines should also reduce operational costs associated with maintenance and parts inventories.

  10. Free radical propulsion concept

    NASA Technical Reports Server (NTRS)

    Hawkins, C. E.; Nakanishi, S.

    1981-01-01

    A free radical propulsion concept utilizing the recombination energy of dissociated low molecular weight gases to produce thrust was examined. The concept offered promise of a propulsion system operating at a theoretical impulse, with hydrogen, as high as 2200 seconds at high thrust to power ratio, thus filling the gas existing between chemical and electrostatic propulsion capabilities. Microwave energy used to dissociate a continuously flowing gas was transferred to the propellant via three body recombination for conversion to propellant kinetic energy. Power absorption by the microwave plasma discharge was in excess of 90 percent over a broad range of pressures. Gas temperatures inferred from gas dynamic equations showed much higher temperatures from microwave heating than from electrothermal heating. Spectroscopic analysis appeared to corroborate the inferred temperatures of one of the gases tested.

  11. In-Space Propulsion Electric Propulsion Technologies Mission Benefits

    Microsoft Academic Search

    John W. Dankanich

    2008-01-01

    The primary source of electric propulsion development within NASA is the In-Space Propulsion Technology (ISPT) Project at the NASA Glenn Research Center under the management of the Science Mission Directorate. The electric propulsion (EP) technology area's objective is to develop near and mid-term EP technology that enhances or enables mission capture while minimizing risk and cost to the end user.

  12. Propulsion controlled aircraft computer

    NASA Technical Reports Server (NTRS)

    Cogan, Bruce R. (Inventor)

    2010-01-01

    A low-cost, easily retrofit Propulsion Controlled Aircraft (PCA) system for use on a wide range of commercial and military aircraft consists of an propulsion controlled aircraft computer that reads in aircraft data including aircraft state, pilot commands and other related data, calculates aircraft throttle position for a given maneuver commanded by the pilot, and then displays both current and calculated throttle position on a cockpit display to show the pilot where to move throttles to achieve the commanded maneuver, or is automatically sent digitally to command the engines directly.

  13. Supersonic laser propulsion.

    PubMed

    Rezunkov, Yurii; Schmidt, Alexander

    2014-11-01

    To produce supersonic laser propulsion, a new technique based on the interaction of a laser-ablated jet with supersonic gas flow in a nozzle is proposed. It is shown that such parameters of the jet, such as gas-plasma pressure and temperature in the ablation region as well as the mass consumption rate of the ablated solid propellant, are characteristic in this respect. The results of numerical simulations of the supersonic laser propulsion are presented for two types of nozzle configuration. The feasibility to achieve the momentum coupling coefficient of C(m)?10(-3) N/W is shown. PMID:25402938

  14. Space Transportation Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing; Stewart, Mark E.; Suresh, Ambady; Owen, A. Karl

    2001-01-01

    This report outlines the Space Transportation Propulsion Systems for the NPSS (Numerical Propulsion System Simulation) program. Topics include: 1) a review of Engine/Inlet Coupling Work; 2) Background/Organization of Space Transportation Initiative; 3) Synergy between High Performance Computing and Communications Program (HPCCP) and Advanced Space Transportation Program (ASTP); 4) Status of Space Transportation Effort, including planned deliverables for FY01-FY06, FY00 accomplishments (HPCCP Funded) and FY01 Major Milestones (HPCCP and ASTP); and 5) a review current technical efforts, including a review of the Rocket-Based Combined-Cycle (RBCC), Scope of Work, RBCC Concept Aerodynamic Analysis and RBCC Concept Multidisciplinary Analysis.

  15. Focused technology: Nuclear propulsion

    NASA Technical Reports Server (NTRS)

    Miller, Thomas J.

    1991-01-01

    The topics presented are covered in viewgraph form and include: nuclear thermal propulsion (NTP), which challenges (1) high temperature fuel and materials, (2) hot hydrogen environment, (3) test facilities, (4) safety, (5) environmental impact compliance, and (6) concept development, and nuclear electric propulsion (NEP), which challenges (1) long operational lifetime, (2) high temperature reactors, turbines, and radiators, (3) high fuel burn-up reactor fuels, and designs, (4) efficient, high temperature power conditioning, (5) high efficiency, and long life thrusters, (6) safety, (7) environmental impact compliance, and (8) concept development.

  16. Nuclear thermal propulsion program overview

    NASA Technical Reports Server (NTRS)

    Bennett, Gary L.

    1991-01-01

    Nuclear thermal propulsion program is described. The following subject areas are covered: lunar and Mars missions; national space policy; international cooperation in space exploration; propulsion technology; nuclear rocket program; and budgeting.

  17. The NASA Electric Propulsion Program

    NASA Technical Reports Server (NTRS)

    Stone, James R.; Byers, David C.; King, David Q.

    1988-01-01

    The NASA OAST Propulsion, Power, and Energy Division supports an electric propulsion program aimed at providing benefits to a broad class of missions. Concepts which have the potential to enable or significantly benefit space exploration and exploitation are identified and advanced toward application in the near and far term. This paper summarizes recent program progress in mission/system analysis; in electrothermal, electrostatic, and electromagnetic propulsion technologies; and in propulsion/spacecraft integration.

  18. Electric propulsion: An evolutionary technology

    Microsoft Academic Search

    Francis M. Curran; James S. Sovey; Roger M. Myers

    1993-01-01

    The NASA Lewis Research Center (LeRC) conducts and directs an electric propulsion research and technology program aimed at providing high-performance electric propulsion system options for a broad range of near and far-term missions. This evolutionary program emphasizes the development of propulsion systems for three classes of missions: (1) near term auxiliary propulsion applications such as North-South Stationkeeping for next generation

  19. Propulsion units for high speed ships

    Microsoft Academic Search

    M. A. Mavlyudov; A. A. Rusetskiy; Y. M. Sadovnikov; E. A. Fisher

    1975-01-01

    Methods of designing propulsion systems for ships with hydrodynamic and aerodynamic support principles are examined along with the characteristic features of propulsion systems for high-speed ships and the problems of their structural composition. Emphasis is placed on the following propulsion systems: cavitating propellers; propulsion systems with angular power transmission; water-jet propulsion systems; and gas-water and air propulsion systems.

  20. Progress in Conceptual Design and Analysis of Advanced Rotorcraft

    NASA Technical Reports Server (NTRS)

    Yamauchi, Gloria K.

    2012-01-01

    This presentation will give information on Multi-Disciplinary Analysis and Technology Development, including it's objectives and how they will be met. In addition, it will also present recent highlights including the Lift-Offset Civil Design and it's study conclusions, as well as, the LCTR2 Propulsion Concept's study conclusions. Recent publications and future publications will also be discussed.

  1. SPE propulsion electrolyzer for NASA's integrated propulsion test article

    NASA Astrophysics Data System (ADS)

    1991-08-01

    Hamilton Standard has delivered a 3000 PSI SPE Propulsion Electrolyzer Stack and Special Test Fixture to the NASA Lyndon B. Johnson Space Center (JSC) Integrated Propulsion Test Article (IPTA) program in June 1990, per contract NAS9-18030. This prototype unit demonstrates the feasibility of SPE-high pressure water electrolysis for future space applications such as Space Station propulsion and Lunar/Mars energy storage. The SPE-Propulsion Electrolyzer has met or exceeded all IPTA program goals. It continues to function as the primary hydrogen and oxygen source for the IPTA test bed at the NASA/JSC Propulsion and Power Division Thermochemical Test Branch.

  2. SPE propulsion electrolyzer for NASA's integrated propulsion test article

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Hamilton Standard has delivered a 3000 PSI SPE Propulsion Electrolyzer Stack and Special Test Fixture to the NASA Lyndon B. Johnson Space Center (JSC) Integrated Propulsion Test Article (IPTA) program in June 1990, per contract NAS9-18030. This prototype unit demonstrates the feasibility of SPE-high pressure water electrolysis for future space applications such as Space Station propulsion and Lunar/Mars energy storage. The SPE-Propulsion Electrolyzer has met or exceeded all IPTA program goals. It continues to function as the primary hydrogen and oxygen source for the IPTA test bed at the NASA/JSC Propulsion and Power Division Thermochemical Test Branch.

  3. Turboprop Propulsion Mechanic.

    ERIC Educational Resources Information Center

    Chanute AFB Technical Training Center, IL.

    This instructional package consists of a plan of instruction, glossary, and student handouts and exercises for use in training Air Force personnel to become turboprop propulsion mechanics. Addressed in the individual lessons of the course are the following: common hand tools, hardware, measuring devices, and safety wiring; aircraft and engine…

  4. Solar Electric Propulsion

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael

    2006-01-01

    The Solar Electric Propulsion (SEP) technology area is tasked to develop near and mid-term SEP technology to improve or enable science mission capture while minimizing risk and cost to the end user. The solar electric propulsion investments are primarily driven by SMD cost-capped mission needs. The technology needs are determined partially through systems analysis tasks including the recent "Re-focus Studies" and "Standard Architecture Study." These systems analysis tasks transitioned the technology development to address the near term propulsion needs suitable for cost-capped open solicited missions such as Discovery and New Frontiers Class missions. Major SEP activities include NASA's Evolutionary Xenon Thruster (NEXT), implementing a Standard Architecture for NSTAR and NEXT EP systems, and developing a long life High Voltage Hall Accelerator (HiVHAC). Lower level investments include advanced feed system development and xenon recovery testing. Future plans include completion of ongoing ISP development activities and evaluating potential use of commercial electric propulsion systems for SMD applications. Examples of enhanced mission capability and technology readiness dates shall be discussed.

  5. General Aviation Propulsion

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Programs exploring and demonstrating new technologies in general aviation propulsion are considered. These programs are the quiet, clean, general aviation turbofan (QCGAT) program; the general aviation turbine engine (GATE) study program; the general aviation propeller technology program; and the advanced rotary, diesel, and reciprocating engine programs.

  6. Progress in colloid propulsion

    E-print Network

    López Urdiales, Jóse Mariano, 1977-

    2004-01-01

    In the early decades of the Space Age, a great deal of work was put into the development of the Colloid Thruster as an electric propulsion system for spacecraft. In spite of the effort by the end of the 70s the programs ...

  7. Jet Propulsion Laboratory Homepage

    NSDL National Science Digital Library

    The Jet Propulsion Laboratory's (JPL) homepage provides links to spacecraft and mission information, imagery, news articles, events, features, and public services. Users can access articles and imagery from the Mars Rover and Cassini missions, images from the Spitzer Space Telescope, and an El Nino/La Nina Watch.

  8. Rarefaction wave gun propulsion

    NASA Astrophysics Data System (ADS)

    Kathe, Eric Lee

    A new species of gun propulsion that dramatically reduces recoil momentum imparted to the gun is presented. First conceived by the author on 18 March 1999, the propulsion concept is explained, a methodology for the design of a reasonable apparatus for experimental validation using NATO standard 35mm TP anti-aircraft ammunition is developed, and the experimental results are presented. The firing results are juxtaposed by a simple interior ballistic model to place the experimental findings into a context within which they may better be understood. Rarefaction wave gun (RAVEN) propulsion is an original contribution to the field of armament engineering. No precedent is known, and no experimental results of such a gun have been published until now. Recoil reduction in excess of 50% was experimentally achieved without measured loss in projectile velocity. RAVEN achieves recoil reduction by means of a delayed venting of the breech of the gun chamber that directs the high enthalpy propellant gases through an expansion nozzle to generate forward thrust that abates the rearward momentum applied to the gun prior to venting. The novel feature of RAVEN, relative to prior recoilless rifles, is that sufficiently delayed venting results in a rarefaction wave that follows the projectile though the bore without catching it. Thus, the projectile exits the muzzle without any compromise to its propulsion performance relative to guns that maintain a sealed chamber.

  9. Application of Pressure-Sensitive Paint to Rotorcraft

    NASA Technical Reports Server (NTRS)

    Schairer, Edward T.; Hand, Lawrence A.; Bell, James H.; Mehta, Rabindra D.; Nixon, David (Technical Monitor)

    1998-01-01

    In this presentation, a plan to develop methods for applying pressure-sensitive paint to rotorcraft will be described. These methods are needed because flows over rotor blades are typically very complex and poorly understood and because conventional methods for measuring unsteady pressures on rotor blades (using unsteady pressure transducers provide grossly inadequate spatial resolution. Since PSP is a surface, rather than a point, measurement technique, it has the potential to significantly increase the spatial resolution )f pressure measurements on rotor blades. PSP techniques currently in use at Ames were developed for measuring steady pressures on rigid, complex airplane configurations in large, production wind tunnels. Applying PSP to rotorcraft requires a significant departure from these techniques. First and most importantly new, fast-responding and self-referencing pressure paints are required. The paints must be fast (98% response in 1-5 msec) to resolve flow unsteadiness; they must be self-referencing (or "binary") to account for changes in incident light intensity due to deflection of flexible rotors. Self-referencing paints have been used at Ames for some time; however, these paints have response times that are far too long for unsteady applications. Flash illumination is required to resolve flow unsteadiness and to minimize image blurring due to relative motion between the model and the camera. Current practice at Ames is to use continuous illumination Finally, "in situ" paint calibration versus measurements by pressure transducers, which is current Ames practice, is not practical because of the difficulty and expense of installing transducers in rotor blades. Instead, the paint must be calibrated "a priori" in a calibration chamber. A sequence of five experiments that systematically isolates and addresses the problems involved in making PSP measurements on rotor blades has been planned. These are: (1) measurements on a rigid rotor in hover; (2) measurements on a flexible rotor in hover; measurements of paint response time in a calibration apparatus; (4) measurements on a rigid, two-dimensional oscillating airfoil; and (5) measurements on a flexible rotor in forward flight. Experiments were recently conducted at Ames where PSP measurements were made on a rigid oscillating airfoil (experiment type 4) and on a flexible rotor in hover (experiment type 2). Preliminary results from these experiments will be discussed.

  10. Center for Advanced Space Propulsion

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Center for Advanced Space Propulsion (CASP) is part of the University of Tennessee-Calspan Center for Aerospace Research (CAR). It was formed in 1985 to take advantage of the extensive research faculty and staff of the University of Tennessee and Calspan Corporation. It is also one of sixteen NASA sponsored Centers established to facilitate the Commercial Development of Space. Based on investigators' qualifications in propulsion system development, and matching industries' strong intent, the Center focused its efforts in the following technical areas: advanced chemical propulsion, electric propulsion, AI/Expert systems, fluids management in microgravity, and propulsion materials processing. This annual report focuses its discussion in these technical areas.

  11. Electric propulsion for communications satellites

    NASA Technical Reports Server (NTRS)

    Free, B. A.; Guman, W. J.; Herron, B. G.; Zafran, S.

    1978-01-01

    Electric propulsion systems derive their low overall mass, relative to chemical propulsion systems, from an optimized mix of independently controlled power and mass flow rate. A significant reduction in mass can be secured by substituting electric propulsion for conventional hydrazine systems for all the major propulsion tasks of a communications satellite. Additional advantages for all electric propulsion maneuvers are precision location and higher pointing accuracy. Three auxiliary electric propulsion systems are now available for application on communications satellites: the electrically augmented hydrazine system, the Teflon pulsed plasma system, and the mercury ion thruster system. Primary electric propulsion will be available in the mid to late 1980s as a spin-off of NASA's program of interplanetary exploration.

  12. Model for Vortex Ring State Influence on Rotorcraft Flight Dynamics

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2005-01-01

    The influence of vortex ring state (VRS) on rotorcraft flight dynamics is investigated, specifically the vertical velocity drop of helicopters and the roll-off of tiltrotors encountering VRS. The available wind tunnel and flight test data for rotors in vortex ring state are reviewed. Test data for axial flow, non-axial flow, two rotors, unsteadiness, and vortex ring state boundaries are described and discussed. Based on the available measured data, a VRS model is developed. The VRS model is a parametric extension of momentum theory for calculation of the mean inflow of a rotor, hence suitable for simple calculations and real-time simulations. This inflow model is primarily defined in terms of the stability boundary of the aircraft motion. Calculations of helicopter response during VRS encounter were performed, and good correlation is shown with the vertical velocity drop measured in flight tests. Calculations of tiltrotor response during VRS encounter were performed, showing the roll-off behavior characteristic of tiltrotors. Hence it is possible, using a model of the mean inflow of an isolated rotor, to explain the basic behavior of both helicopters and tiltrotors in vortex ring state.

  13. Model for Vortex Ring State Influence on Rotorcraft Flight Dynamics

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne

    2004-01-01

    The influence of vortex ring state (VRS) on rotorcraft flight dynamics is investigated, specifically the vertical velocity drop of helicopters and the roll-off of tiltrotors encountering VRS. The available wind tunnel and flight test data for rotors in vortex ring state are reviewed. Test data for axial flow, nonaxial flow, two rotors, unsteadiness, and vortex ring state boundaries are described and discussed. Based on the available measured data, a VRS model is developed. The VRS model is a parametric extension of momentum theory for calculation of the mean inflow of a rotor, hence suitable for simple calculations and real-time simulations. This inflow model is primarily defined in terms of the stability boundary of the aircraft motion. Calculations of helicopter response during VRS encounter were performed, and good correlation is shown with the vertical velocity drop measured in flight tests. Calculations of tiltrotor response during VRS encounter were performed, showing the roll-off behavior characteristic of tiltrotors. Hence it is possible, using a model of the mean inflow of an isolated rotor, to explain the basic behavior of both helicopters and tiltrotors in vortex ring state.

  14. Embedded Data Acquisition Tools for Rotorcraft Diagnostic Sensors

    NASA Technical Reports Server (NTRS)

    Wagoner, Robert

    2014-01-01

    Rotorcraft drive trains must withstand enormous pressure while operating continuously in extreme temperature and vibration environments. Captive components, such as planetary and spiral bevel gears, see enormous strain but are not accessible to fixed instrumentation, such as a piezoelectric transducer. Thus, it is difficult to directly monitor components that are most susceptible to damage. This innovation is a self-contained data processing unit within a specialized fixture that installs directly inside the rotating pinion gear in the gearbox. From this location, it detects and transmits high-resolution prognostic data to a fixed transceiver. The sensor is based on microelectromechanical systems (MEMS) technology and uses innovative circuit designs to capture high-bandwidth data and transmit it wirelessly from inside an operational helicopter transmission. With Ridgetop's advanced MEMS-based sensor, researchers have, for the first time, been able to extract high-resolution acoustic signatures wirelessly from sensors within the transmission that would otherwise be muffled by background gear noises. Ridgetop's innovative instrument will help researchers perform dynamic analysis of gear interaction and develop improved designs for gear components. In addition, data from this instrument can be used to validate new algorithms that detect and predict faults based on external acoustic signatures, for prognostic purposes. The result of this work will be an improvement in safety, performance, and cost for future generations of rotating components.

  15. Rotorcraft airframe structural optimization for combined vibration and fatigue constraints

    NASA Technical Reports Server (NTRS)

    Sareen, Ashish K.; Schrage, Daniel P.; Murthy, T. S.

    1991-01-01

    This paper addresses the application of a formal optimization technique in rotorcraft airframe structural design studies to reduce the structural weight, to lower airframe vibrations, and to enhance fatigue life of the structure. Vibration and fatigue considerations in airframe design are described. An optimization methodology based on the use of a nonlinear programming technique to size airframe structural members subjected to constraints on weight, vibration response and fatigue stresses under dynamic loads, are described. The paper focuses on the development of necessary computational tools for airframe structural optimization and describes the sensitivity analysis procedure for these types of design constraints. Further, the paper describes the optimization procedure as implemented in a computer code called DYNOPT which is a unique operational combination of several newly developed Fortran codes as well as modification of existing codes consisting of the direct matrix abstraction modules of the MSC/NASTRAN Program and CONMIN optimizer. The application of the optimization procedure is demonstrated using an elastic-line model of the Bell AH-1G helicopter airframe structure and computational results are discussed.

  16. Micro electric propulsion feasibility

    NASA Technical Reports Server (NTRS)

    Aston, Graeme; Aston, Martha

    1992-01-01

    Miniature, 50 kg class, strategic satellites intended for extended deployment in space require an on-board propulsion capability to perform needed attitude control adjustments and drag compensation maneuvers. Even on such very small spacecraft, these orbit maintenance functions can be significant and result in a substantial propellant mass requirement. Development of advanced propulsion technology could reduce this propellant mass significantly, and thereby maximize the payload capability of these spacecraft. In addition, spacecraft maneuverability could be enhanced and/or multi-year mission lifetimes realized. These benefits cut spacecraft replacement costs, and reduce services needed to maintain the launch vehicles. For SDIO brilliant pebble spacecraft, a miniaturized hydrazine propulsion system provides both boost and divert thrust control. This type of propulsion system is highly integrated and is capable of delivering large thrust levels for short time periods. However, orbit maintenance functions such as drag make-up require only very small velocity corrections. Using the boost and/or divert thrusters for these small corrections exposes this highly integrated propulsion system to continuous on/off cycling and thereby increases the risk of system failure. Furthermore, since drag compensation velocity corrections would be orders of magnitude less than these thrusters were designed to deliver, their effective specific impulse would be expected to be lower when operated at very short pulse lengths. The net result of these effects would be a significant depletion of the on-board hydrazine propellant supply throughout the mission, and a reduced propulsion system reliability, both of which would degrade the interceptors usefulness. In addition to SDIO brilliant pebble spacecraft, comparably small spacecraft can be anticipated for other future strategic defense applications such as surveillance and communication. For such spacecraft, high capability and reliability, minimal detectability and low cost are requirements. All these miniature spacecraft share a common characteristic: because of their on-board electronic equipment they have, by design, solar order 50-100 W. In a relative sense, such spacecraft are power rich when compared to other larger spacecraft. This power rich situation is offset by very tight mass budgets, which make reductions in propellant mass requirements a key issue in meeting overall spacecraft minimum mass goals. In principle, power rich and propellant poor brilliant pebbles class spacecraft can benefit from using high specific impulse electric propulsion to reduce chemical propellant mass requirements. However, at power levels of order 50 W, arcjets cannot be made to function, ion thrusters are too complex and heavy and resistojets have too low a specific impulse. Recognizing these capability limitations in existing electric propulsion technology, the SDIO/IST sponsored the Phase I SBIR Micro Electric Propulsion (MEP) thruster study described in this report. The objective of this study was to examine the feasibility of developing a very simple, low mass and small volume, electric thruster for operation on hydrazine at less than 100 W of input power. The feasibility of developing such a MEP thruster was successfully demonstrated by EPL by the discovery of a novel plasma acceleration process. The sections in this report summarize the approach, test results and major accomplishments of this proof-of-concept program.

  17. Rotordynamic Feasibility of a Conceptual Variable-Speed Power Turbine Propulsion System for Large Civil Tilt-Rotor Applications

    NASA Technical Reports Server (NTRS)

    Howard, Samuel

    2012-01-01

    A variable-speed power turbine concept is analyzed for rotordynamic feasibility in a Large Civil Tilt-Rotor (LCTR) class engine. Implementation of a variable-speed power turbine in a rotorcraft engine would enable high efficiency propulsion at the high forward velocities anticipated of large tilt-rotor vehicles. Therefore, rotordynamics is a critical issue for this engine concept. A preliminary feasibility study is presented herein to address this concern and identify if variable-speed is possible in a conceptual engine sized for the LCTR. The analysis considers critical speed placement in the operating speed envelope, stability analysis up to the maximum anticipated operating speed, and potential unbalance response amplitudes to determine that a variable-speed power turbine is likely to be challenging, but not impossible to achieve in a tilt-rotor propulsion engine.

  18. Hybrid propulsion technology program

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Technology was identified which will enable application of hybrid propulsion to manned and unmanned space launch vehicles. Two design concepts are proposed. The first is a hybrid propulsion system using the classical method of regression (classical hybrid) resulting from the flow of oxidizer across a fuel grain surface. The second system uses a self-sustaining gas generator (gas generator hybrid) to produce a fuel rich exhaust that was mixed with oxidizer in a separate combustor. Both systems offer cost and reliability improvement over the existing solid rocket booster and proposed liquid boosters. The designs were evaluated using life cycle cost and reliability. The program consisted of: (1) identification and evaluation of candidate oxidizers and fuels; (2) preliminary evaluation of booster design concepts; (3) preparation of a detailed point design including life cycle costs and reliability analyses; (4) identification of those hybrid specific technologies needing improvement; and (5) preperation of a technology acquisition plan and large scale demonstration plan.

  19. Deuterium microbomb rocket propulsion

    E-print Network

    Friedwardt Winterberg

    2008-12-02

    Large scale manned space flight within the solar system is still confronted with the solution of two problems: 1. A propulsion system to transport large payloads with short transit times between different planetary orbits. 2. A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimegampere proton beam, drawn from the magnetically insulated spacecraft acting in the ultrahigh vacuum of space as a gigavolt capacitor. For the solution of the second problem, the ignition is done by argon ion lasers driven by high explosives, with the lasers destroyed in the fusion explosion and becoming part of the exhaust.

  20. Deuterium microbomb rocket propulsion

    E-print Network

    Winterberg, Friedwardt

    2008-01-01

    Large scale manned space flight within the solar system is still confronted with the solution of two problems: 1. A propulsion system to transport large payloads with short transit times between different planetary orbits. 2. A cost effective lifting of large payloads into earth orbit. For the solution of the first problem a deuterium fusion bomb propulsion system is proposed where a thermonuclear detonation wave is ignited in a small cylindrical assembly of deuterium with a gigavolt-multimegampere proton beam, drawn from the magnetically insulated spacecraft acting in the ultrahigh vacuum of space as a gigavolt capacitor. For the solution of the second problem, the ignition is done by argon ion lasers driven by high explosives, with the lasers destroyed in the fusion explosion and becoming part of the exhaust.

  1. Contributions of the Langley Transonic Dynamics Tunnel to Rotorcraft Technology and Development

    NASA Technical Reports Server (NTRS)

    Yeager, William T., Jr.; Kvaternik, Raymond G.

    2000-01-01

    A historical account of the contributions of the Langley Transonic Dynamics Tunnel (TDT) to rotorcraft technology and development tunnel's inception in 1960 is presented. The paper begins with a summary of the major characteristics of the TDT and a description of the unique capability offered by the TDT for testing aeroelastic models by virtue of its heavy gas test medium. This is followed by some remarks on the role played by scale models in the design and development of rotorcraft vehicles and review of the basic scaling relationships important for designing and building dynamic aeroelastic models of rotorcraft vehicles for testing in the TDT. Chronological accounts of helicopter and tiltrotor research conducted in the TDT are then described in separate sections. The discussions include a description of the various models employed, the specific objectives of the tests, and illustrative results.

  2. Zero/zero rotorcraft certification issues. Volume 2: Plenary session presentations

    NASA Technical Reports Server (NTRS)

    Adams, Richard J.

    1988-01-01

    This report analyzes the Zero/Zero Rotorcraft Certification Issues from the perspectives of manufacturers, operators, researchers and the FAA. The basic premise behind this analysis is that zero/zero, or at least extremely low visibility, rotorcraft operations are feasible today from both a technological and an operational standpoint. The questions and issues that need to be resolved are: What certification requirements do we need to ensure safety. Can we develop procedures which capitalize on the performance and maneuvering capabilities unique to rotorcraft. Will extremely low visibility operations be economically feasible. This is Volume 2 of three. It presents the operator perspectives (system needs), applicable technology and zero/zero concepts developed in the first 12 months of research of this project.

  3. Zero/zero rotorcraft certification issues. Volume 3: Working group results

    NASA Technical Reports Server (NTRS)

    Adams, Richard J.

    1988-01-01

    This report analyzes the Zero/Zero Rotorcraft Certification Issues from the perspectives of manufacturers, operators, researchers and the FAA. The basic premise behind this analysis is that zero/zero, or at least extremely low visibility, rotorcraft operations are feasible today from both a technological and an operational standpoint. The questions and issues that need to be resolved are: What certification requirements do we need to ensure safety. Can we develop procedures which capitalize on the performance and maneuvering capabilities unique to rotorcraft. Will extremely low visibility operations be economically feasible. This is Volume 3 of three. It provides the issue-by-issue deliberations of the experts involved in the Working Groups assigned to deal with them in the Issues Forum.

  4. A Historical Overview of Aeroelasticity Branch and Transonic Dynamics Tunnel Contributions to Rotorcraft Technology and Development

    NASA Technical Reports Server (NTRS)

    Yeager, William T., Jr.; Kvaternik, Raymond G.

    2001-01-01

    A historical account of the contributions of the Aeroelasticity Branch (AB) and the Langley Transonic Dynamics Tunnel (TDT) to rotorcraft technology and development since the tunnel's inception in 1960 is presented. The paper begins with a summary of the major characteristics of the TDT and a description of the unique capability offered by the TDT for testing aeroelastic models by virtue of its heavy gas test medium. This is followed by some remarks on the role played by scale models in the design and development of rotorcraft vehicles and a review of the basic scaling relationships important for designing and building dynamic aeroelastic models of rotorcraft vehicles for testing in the TDT. Chronological accounts of helicopter and tiltrotor research conducted in AB/TDT are then described in separate sections. Both experimental and analytical studies are reported and include a description of the various physical and mathematical models employed, the specific objectives of the investigations, and illustrative experimental and analytical results.

  5. Emerging Propulsion Technologies

    NASA Technical Reports Server (NTRS)

    Keys, Andrew S.

    2006-01-01

    The Emerging Propulsion Technologies (EPT) investment area is the newest area within the In-Space Propulsion Technology (ISPT) Project and strives to bridge technologies in the lower Technology Readiness Level (TRL) range (2 to 3) to the mid TRL range (4 to 6). A prioritization process, the Integrated In-Space Transportation Planning (IISTP), was developed and applied in FY01 to establish initial program priorities. The EPT investment area emerged for technologies that scored well in the IISTP but had a low technical maturity level. One particular technology, the Momentum-eXchange Electrodynamic-Reboost (MXER) tether, scored extraordinarily high and had broad applicability in the IISTP. However, its technical maturity was too low for ranking alongside technologies like the ion engine or aerocapture. Thus MXER tethers assumed top priority at EPT startup in FY03 with an aggressive schedule and adequate budget. It was originally envisioned that future technologies would enter the ISP portfolio through EPT, and EPT developed an EPT/ISP Entrance Process for future candidate ISP technologies. EPT has funded the following secondary, candidate ISP technologies at a low level: ultra-lightweight solar sails, general space/near-earth tether development, electrodynamic tether development, advanced electric propulsion, and in-space mechanism development. However, the scope of the ISPT program has focused over time to more closely match SMD needs and technology advancement successes. As a result, the funding for MXER and other EPT technologies is not currently available. Consequently, the MXER tether tasks and other EPT tasks were expected to phased out by November 2006. Presentation slides are presented which provide activity overviews for the aerocapture technology and emerging propulsion technology projects.

  6. Interstellar Propulsion Concepts Assessment

    NASA Technical Reports Server (NTRS)

    Forward, Robert L.

    2000-01-01

    NASA is investigating the feasibility of conducting extra-solar and interstellar missions over the next 10 to 50 years. An assessment of technologies supporting these near and far term objectives is required. To help meet these objectives the Principal Investigator assessed the feasibility of candidate propulsion systems for the proposed 'Interstellar Probe', a mission to send a spacecraft to the Heliopause at 250 AU and beyond.

  7. The MAP Propulsion Subsystem

    NASA Technical Reports Server (NTRS)

    Davis, Gary T.; Bauer, Frank H. (Technical Monitor)

    2002-01-01

    This paper describes the requirements, design, integration, test, performance, and lessons learned of NASA's Microwave Anisotropy Probe (MAP) propulsion subsystem. MAP was launched on a Delta-II launch vehicle from NASA's Kennedy Space Center on June 30, 2001. Due to instrument thermal stability requirements, the Earth-Sun L2 Lagrange point was selected for the mission orbit. The L2 trajectory incorporated phasing loops and a lunar gravity assist. The propulsion subsystem's requirements are to manage momentum, perform maneuvers during the phasing loops to set up the lunar swingby, and perform stationkeeping at L2 for 2 years. MAP's propulsion subsystem uses 8 thrusters which are located and oriented to provide attitude control and momentum management about all axes, and delta-V in any direction without exposing the instrument to the sun. The propellant tank holds 72 kg of hydrazine, which is expelled by unregulated blowdown pressurization. Thermal management is complex because no heater cycling is allowed at L2. Several technical challenges presented themselves during I and T, such as in-situ weld repairs and in-situ bending of thruster tubes to accommodate late changes in the observatory CG. On-orbit performance has been nominal, and all phasing loop, mid-course correction, and stationkeeping maneuvers have been successfully performed to date.

  8. Gas Wave Bearings: A Stable Alternative to Journal Bearings for High-Speed Oil-Free Machines

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin

    2005-01-01

    To run both smoothly and efficiently, high-speed machines need stable, low-friction bearings to support their rotors. In addition, an oil-free bearing system is a common requirement in today's designs. Therefore, self-acting gas film bearings are becoming the bearing of choice in high-performance rotating machinery, including that used in the machine tool industry. Although plain journal bearings carry more load and have superior lift and land characteristics, they suffer from instability problems. Since 1992, a new type of fluid film bearing, the wave bearing, has been under development at the NASA Lewis Research Center in Cleveland, Ohio, by Dr. Florin Dimofte, a Senior Research Associate of the University of Toledo. One unique characteristic of the waved journal bearing that gives it improved capabilities over conventional journal bearings is the low-amplitude waves of its inner diameter surface. The radial clearance is on the order of one thousandth of the shaft radius, and the wave amplitude is nominally up to one-half the clearance. This bearing concept offers a load capacity which is very close to that of a plain journal bearing, but it runs more stably at nominal speeds.

  9. Propulsion patterns and pushrim biomechanics in manual wheelchair propulsion

    Microsoft Academic Search

    Michael L. Boninger; Aaron L. Souza; Rory A. Cooper; Shirley G. Fitzgerald; Alicia M. Koontz; Brian T. Fay

    2002-01-01

    Boninger ML, Souza AL, Cooper RA, Fitzgerald SG, Koontz AM, Fay BT. Propulsion patterns and pushrim biomechanics in manual wheelchair propulsion. Arch Phys Med Rehabil 2002;83:718-23. Objectives: To classify stroke patterns of manual wheelchair users and to determine if different patterns of propulsion lead to different biomechanics. Design: Case series. Setting: Biomechanics laboratory. Participants: Thirty-eight individuals with paraplegia who use

  10. A comprehensive analytical model of rotorcraft aerodynamics and dynamics. Part 3: Program manual

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1980-01-01

    The computer program for a comprehensive analytical model of rotorcraft aerodynamics and dynamics is described. This analysis is designed to calculate rotor performance, loads, and noise; the helicopter vibration and gust response; the flight dynamics and handling qualities; and the system aeroelastic stability. The analysis is a combination of structural, inertial, and aerodynamic models that is applicable to a wide range of problems and a wide class of vehicles. The analysis is intended for use in the design, testing, and evaluation of rotors and rotorcraft and to be a basis for further development of rotary wing theories.

  11. Application of special-purpose digital computers to rotorcraft real-time simulation

    NASA Technical Reports Server (NTRS)

    Mackie, D. B.; Michelson, S.

    1978-01-01

    The use of an array processor as a computational element in rotorcraft real-time simulation is studied. A multilooping scheme was considered in which the rotor would loop over its calculations a number of time while the remainder of the model cycled once on a host computer. To prove that such a method would realistically simulate rotorcraft, a FORTRAN program was constructed to emulate a typical host-array processor computing configuration. The multilooping of an expanded rotor model, which included appropriate kinematic equations, resulted in an accurate and stable simulation.

  12. Research Applications and Capabilities of the NASA/Army Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL)

    NASA Technical Reports Server (NTRS)

    Aiken, Edwin W.; Jacobsen, Robert A.; Hindson, William S.

    1996-01-01

    The Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL) is a UH-60 Black Hawk helicopter that is being modified by NASA and the US Army for flight systems research. The principal systems that are being installed in the aircraft are a Helmet-Mounted Display (HMD) and associated imaging systems, and a programmable full-authority Research Flight Control System (RFCS). In addition, comprehensive instrumentation of both the rigid body of the helicopter and the rotor system is provided. This paper describes the design features of this modern rotorcraft in-flight simulation facility and their current state of development. A brief description of initial research applications is included.

  13. An Adaptive Altitude Information Fusion Method for Autonomous Landing Processes of Small Unmanned Aerial Rotorcraft

    PubMed Central

    Lei, Xusheng; Li, Jingjing

    2012-01-01

    This paper presents an adaptive information fusion method to improve the accuracy and reliability of the altitude measurement information for small unmanned aerial rotorcraft during the landing process. Focusing on the low measurement performance of sensors mounted on small unmanned aerial rotorcraft, a wavelet filter is applied as a pre-filter to attenuate the high frequency noises in the sensor output. Furthermore, to improve altitude information, an adaptive extended Kalman filter based on a maximum a posteriori criterion is proposed to estimate measurement noise covariance matrix in real time. Finally, the effectiveness of the proposed method is proved by static tests, hovering flight and autonomous landing flight tests. PMID:23201993

  14. Design and development of an active Gurney flap for rotorcraft

    NASA Astrophysics Data System (ADS)

    Freire Gómez, Jon; Booker, Julian D.; Mellor, Phil H.

    2013-03-01

    The EU's Green Rotorcraft programme will develop an Active Gurney Flap (AGF) for a full-scale helicopter main rotor blade as part of its `smart adaptive rotor blade' technology demonstrators. AGFs can be utilized to provide a localized and variable lift enhancement on the rotor, enabling a redistribution of loading on the rotor blade around the rotor azimuth. Further advantages include the possibility of using AGFs to allow a rotor speed reduction, which subsequently provides acoustic benefits. Designed to be integrable into a commercial helicopter blade, and thereby capable of withstanding real in-flight centrifugal loading, blade vibrations and aerodynamic loads, the demonstrator is expected to achieve a high technology readiness level (TRL). The AGF will be validated initially by a constant blade section 2D wind tunnel test and latterly by full blade 3D whirl tower testing. This paper presents the methodology adopted for the AGF concept topology selection, based on a series of both qualitative and quantitative performance criteria. Two different AGF candidate mechanisms are compared, both powered by a small commercial electromagnetic actuator. In both topologies, the link between the actuator and the control surface consists of two rotating torque bars, pivoting on flexure bearings. This provides the required reliability and precision, while making the design virtually frictionless. The engineering analysis presented suggests that both candidates would perform satisfactorily in a 2D wind tunnel test, but that equally, both have design constraints which limit their potential to be further taken into a whirl tower test under full scale centrifugal and inertial loads.

  15. The Nuclear Cryogenic Propulsion Stage

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen; Belvin, Anthony; Borowski, Stanley K.; Scott, John

    2014-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP). Nuclear propulsion can be affordable and viable compared to other propulsion systems and must overcome a biased public fear due to hyper-environmentalism and a false perception of radiation and explosion risk.

  16. NASA Breakthrough Propulsion Physics Program

    NASA Technical Reports Server (NTRS)

    Millis, Marc G.

    1998-01-01

    In 1996, NASA established the Breakthrough Propulsion Physics program to seek the ultimate breakthroughs in space transportation: propulsion that requires no propellant mass, propulsion that attains the maximum transit speeds physically possible, and breakthrough methods of energy production to power such devices. Topics of interest include experiments and theories regarding the coupling of gravity and electromagnetism, vacuum fluctuation energy, warp drives and worm-holes, and superluminal quantum effects. Because these propulsion goals are presumably far from fruition, a special emphasis is to identify affordable, near-term, and credible research that could make measurable progress toward these propulsion goals. The methods of the program and the results of the 1997 workshop are presented. This Breakthrough Propulsion Physics program, managed by Lewis Research Center, is one part of a comprehensive, long range Advanced Space Transportation Plan managed by Marshall Space Flight Center.

  17. Embedded Wing Propulsion Conceptual Study

    NASA Technical Reports Server (NTRS)

    Kim, Hyun D.; Saunders, John D.

    2003-01-01

    As a part of distributed propulsion work under NASA's Revolutionary Aeropropulsion Concepts or RAC project, a new propulsion-airframe integrated vehicle concept called Embedded Wing Propulsion (EWP) is developed and examined through system and computational fluid dynamics (CFD) studies. The idea behind the concept is to fully integrate a propulsion system within a wing structure so that the aircraft takes full benefits of coupling of wing aerodynamics and the propulsion thrust stream. The objective of this study is to assess the feasibility of the EWP concept applied to large transport aircraft such as the Blended-Wing-Body aircraft. In this paper, some of early analysis and current status of the study are presented. In addition, other current activities of distributed propulsion under the RAC project are briefly discussed.

  18. Heat transfer in aerospace propulsion

    NASA Technical Reports Server (NTRS)

    Simoneau, Robert J.; Hendricks, Robert C.; Gladden, Herbert J.

    1988-01-01

    Presented is an overview of heat transfer related research in support of aerospace propulsion, particularly as seen from the perspective of the NASA Lewis Research Center. Aerospace propulsion is defined to cover the full spectrum from conventional aircraft power plants through the Aerospace Plane to space propulsion. The conventional subsonic/supersonic aircraft arena, whether commercial or military, relies on the turbine engine. A key characteristic of turbine engines is that they involve fundamentally unsteady flows which must be properly treated. Space propulsion is characterized by very demanding performance requirements which frequently push systems to their limits and demand tailored designs. The hypersonic flight propulsion systems are subject to severe heat loads and the engine and airframe are truly one entity. The impact of the special demands of each of these aerospace propulsion systems on heat transfer is explored.

  19. 1995 JANNAF Propulsion Meeting. Volume 1

    NASA Technical Reports Server (NTRS)

    Eggleston, Debra S. (Editor)

    1995-01-01

    This volume is a collection of 36 unclassified/unlimited distribution papers which were presented at the 1995 Joint Army-Navy-NASA-Air Force (JANNAF) propulsion meeting. Specific subjects discussed include the integrated High Payoff Rocket Propulsion Technology initiative, hybrid propulsion, electric propulsion, the Minuteman 2/3 missile system, slag, aluminum in propellant compositions, electric propulsion, rocket nozzle design, and tactical missiles.

  20. A new marine propulsion system

    Microsoft Academic Search

    Wei-Shi Han; Tao Liu

    2003-01-01

    A new marine propulsion system is proposed. A small liquid sodium cooled reactor acts as prime mover; alkali-metal thermal-to-electric\\u000a conversion (AMTEC) cells are employed to convert the heat energy to electricity; superconducting magneto-hydrodynamic thruster\\u000a combined with spray-water thruster works as propulsion. The configuration and characteristics of this system are described.\\u000a Such a nuclear-powered propulsion system is not only free of

  1. Electrolysis Propulsion for Spacecraft Applications

    NASA Technical Reports Server (NTRS)

    deGroot, Wim A.; Arrington, Lynn A.; McElroy, James F.; Mitlitsky, Fred; Weisberg, Andrew H.; Carter, Preston H., II; Myers, Blake; Reed, Brian D.

    1997-01-01

    Electrolysis propulsion has been recognized over the last several decades as a viable option to meet many satellite and spacecraft propulsion requirements. This technology, however, was never used for in-space missions. In the same time frame, water based fuel cells have flown in a number of missions. These systems have many components similar to electrolysis propulsion systems. Recent advances in component technology include: lightweight tankage, water vapor feed electrolysis, fuel cell technology, and thrust chamber materials for propulsion. Taken together, these developments make propulsion and/or power using electrolysis/fuel cell technology very attractive as separate or integrated systems. A water electrolysis propulsion testbed was constructed and tested in a joint NASA/Hamilton Standard/Lawrence Livermore National Laboratories program to demonstrate these technology developments for propulsion. The results from these testbed experiments using a I-N thruster are presented. A concept to integrate a propulsion system and a fuel cell system into a unitized spacecraft propulsion and power system is outlined.

  2. Reactors for nuclear electric propulsion

    SciTech Connect

    Buden, D.; Angelo, J.A. Jr.

    1981-01-01

    Propulsion is the key to space exploitation and power is the key to propulsion. This paper examines the role of nuclear fission reactors as the primary power source for high specific impulse electric propulsion systems for space missions of the 1980s and 1990s. Particular mission applications include transfer to and a reusable orbital transfer vehicle from low-Earth orbit to geosynchronous orbit, outer planet exploration and reconnaissance missions, and as a versatile space tug supporting lunar resource development. Nuclear electric propulsion is examined as an indispensable component in space activities of the next two decades.

  3. 46 CFR 130.120 - Propulsion control.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Propulsion control. 130.120 Section 130...SYSTEMS Vessel Control § 130.120 Propulsion control. (a) Each vessel must have— (1) A propulsion-control system operable from the...

  4. 46 CFR 130.120 - Propulsion control.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Propulsion control. 130.120 Section 130...SYSTEMS Vessel Control § 130.120 Propulsion control. (a) Each vessel must have— (1) A propulsion-control system operable from the...

  5. 46 CFR 130.120 - Propulsion control.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Propulsion control. 130.120 Section 130...SYSTEMS Vessel Control § 130.120 Propulsion control. (a) Each vessel must have— (1) A propulsion-control system operable from the...

  6. 46 CFR 130.120 - Propulsion control.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Propulsion control. 130.120 Section 130...SYSTEMS Vessel Control § 130.120 Propulsion control. (a) Each vessel must have— (1) A propulsion-control system operable from the...

  7. Space propulsion technology and cryogenic fluid depot

    NASA Technical Reports Server (NTRS)

    Diehl, Larry A.

    1988-01-01

    Information on space propulsion and technology and the cryogenic fluid depot is given in viewgraph form. Information is given on orbit transfer, electric propulsion, spacecraft propulsion, and program objectives.

  8. Electromagnetic propulsion test facility

    NASA Technical Reports Server (NTRS)

    Gooder, S. T.

    1984-01-01

    A test facility for the exploration of electromagnetic propulsion concept is described. The facility is designed to accommodate electromagnetic rail accelerators of various lengths (1 to 10 meters) and to provide accelerating energies of up to 240 kiloJoules. This accelerating energy is supplied as a current pulse of hundreds of kiloAmps lasting as long as 1 millisecond. The design, installation, and operating characteristics of the pulsed energy system are discussed. The test chamber and its operation at pressures down to 1300 Pascals (10 mm of mercury) are described. Some aspects of safety (interlocking, personnel protection, and operating procedures) are included.

  9. F-15 propulsion system

    NASA Technical Reports Server (NTRS)

    Bushman, Mark; Nobbs, Steven G.

    1995-01-01

    A brief description of the NASA F-15 research aircraft propulsion system is given. The F-15 is powered by two PW1128 afterburning turbofan engines which are growth versions of the F100-PW-100 engine. The PW1128 is controlled by a full-authority digital electronic engine control (DEEC). The F-15 inlet is a two-dimensional, three-ramp, external compression design with partially cut back side plates. Each inlet is independently controlled by an electronic air inlet controller (EAIC).

  10. Injectable PEGylated fibrinogen cell-laden microparticles made with a continuous solvent- and oil-free preparation method.

    PubMed

    Oliveira, Mariana B; Kossover, Olga; Mano, João F; Seliktar, Dror

    2015-02-01

    A new methodology is reported for the continuous, solvent- and oil-free production of photopolymerizable microparticles containing encapsulated human dermal fibroblasts. A precursor solution of cells in photoreactive poly(ethylene glycol) (PEG)-fibrinogen (PF) polymer was transported through a transparent injector exposed to light irradiation before being atomized in a jet-in-air nozzle. Shear rheometry data revealed the crosslinking kinetics of the PF/cell solution, which was then used to determine the amount of irradiation required to partially polymerize the mixture just prior to atomization. The partially polymerized drops of PF/cells fell into a gelation bath for further crosslinking until fully polymerized hydrogel microparticles were formed. As the drops of solution exited the air-in-jet nozzle, their viscosity was designed to be sufficiently high so as to prevent rapid mixing and/or dilution in the gelation bath, but without undergoing complete gelation in the nozzle. Several parameters of this system were varied to control the size and polydispersity of the microparticles, including the cell density, the flow rate and the air pressure in the nozzle. The system was capable of producing cell-laden microparticles with an average diameter of between 88.1 to 347.1 ?m, and a dispersity of between 1.1 and 2.4, depending on the parameters chosen. Varying the precursor flow rate and/or cell density was beneficial in controlling the size and polydispersity of the microparticles; all microparticles exhibited very high cell viability, which was not affected by these parameters. In conclusion, this dropwise photopolymerization methodology for preparing cell-laden microparticles is an attractive alternative to existing techniques that use harsh solvents/oils and offer limited control over particle size and polydispersity. PMID:25462849

  11. Development of the Mesicopter: A Miniature Autonomous Rotorcraft Ilan Kroo, Peter Kunz

    E-print Network

    Stanford University

    and thus can fly with considerably less thrust than required by a rotorcraft in hover, for which the thrust required for flight increases with speed, and in some cases at this scale a hovering device requires less for hover is: P = T Vh / M = W (W / 2S)1/2 / M where: Vh is the induced velocity in hover and M is th

  12. Performance Evaluation of Vision-Based Navigation and Landing on a Rotorcraft Unmanned Aerial Vehicle

    Microsoft Academic Search

    David Hubbard; Bryan Morse; Colin Theodore; Mark Tischler; Timothy W. Mclain

    2007-01-01

    A rotorcraft UAV provides an ideal experimental platform for vision-based navigation. This paper describes the flight tests of the US Army PALACE project, which implements Moravec's pseudo-normalized correlation tracking algorithm. The tracker uses the movement of the landing site in the camera, a laser range, and the aircraft attitude from an IMU to estimate the relative motion of the UAV.

  13. Application of Wavelets Transform to Fault Detection in Rotorcraft UAV Sensor Failure

    Microsoft Academic Search

    Jun-tong Qi; Jian-da Han

    2007-01-01

    This paper describes a novel wavelet-based approach to the detection of abrupt fault of Rotorcraft Unmanned Aerial Vehicle (RUAV) sensor system. By use of wavelet transforms that accurately localize the characteristics of a signal both in the time and frequency domains, the occurring instants of abnormal status of a sensor in the output signal can be identified by the multi-scale

  14. UKF-based rotorcraft UAV Fault adaptive control for actuator failure

    Microsoft Academic Search

    Juntong Qi; Zhe Jiang; Xingang Zhao

    2007-01-01

    A new fault adaptive control methodology against the actuator failure is proposed in this paper. The actuator failure modeling are introduced to denote the actuator healthy level (AHL) and the Unscented Kalman Filter (UKF) is employed for on-line estimation of both the flight states and the AHL parameters of rotorcraft UAV (RUAV). The functionality of the approach has been illustrated

  15. Department of Mechanical Engineering Fall 2010 Exotic Blade Shapes in Rotorcraft Acoustics

    E-print Network

    Demirel, Melik C.

    Acoustics Overview The team was charged with developing a blade tip modification by which rotorcraft noise were conducted followed by acoustic testing. The results were validated by using two different acoustic data collection systems. Outcomes The team's serrated tip design achieved an audible reduction

  16. In-Flight Performance Optimization for Rotorcraft with Redundant Controls Gurbuz Taha Ozdemir

    E-print Network

    Maroncelli, Mark

    PENNSTATE _ In-Flight Performance Optimization for Rotorcraft with Redundant Controls Gurbuz Taha. This additional redundancy gives the opportunity to further enhance performance and handling qualities. A flight control system is designed to perform in-flight optimization of redundant control effectors on a compound

  17. Meso-scale Flight and Miniature Rotorcraft Development Ilan Kroo, Peter Kunz

    E-print Network

    Stanford University

    1 Meso-scale Flight and Miniature Rotorcraft Development Ilan Kroo, Peter Kunz Stanford University in aerodynamics, control, and manufacturing. Many interesting scaling issues arise as one shrinks a flight vehicle that would enable flight at even smaller scales. Such vehicles would have many unique capabilities including

  18. ADVANCED COMPOSITE MATERIALS TECHNOLOGY FOR ROTORCRAFT Andrew Makeev*, University of Texas at Arlington, Arlington, Texas, USA

    E-print Network

    Texas at Arlington, University of

    , USA Mark Chris, Bell Helicopter Textron, Fort Worth, TX, USA Peter Holemans and Gina Miller, Boeing Rotorcraft Systems, Ridley Park, PA, USA Don Spencer, Kaman Helicopters, Bloomfield, CT, USA Nicolas Patz and fatigue performance, is identified. The advanced materials technology is based on high weight content

  19. Evaluation of CFD to Determine Two-Dimensional Airfoil Characteristics for Rotorcraft Applications

    Microsoft Academic Search

    Marilyn J. Smith; Mark Potsdam; Tin-Chee Wong; James Baeder; Sujeet Phanse

    2004-01-01

    The efficient prediction of helicopter rotor performance, vibratory loads, and aeroelastic properties still relies heavily on the use of comprehensive analysis codes by the rotorcraft industry. These comprehensive codes utilize look-up tables to provide two-dimensional aerodynamic characteristics. Typically these tables are comprised of a combination of wind tunnel data, empirical data and numerical analyses. The potential to rely more heavily

  20. Evaluation of innovative concepts for semi-active and active rotorcraft control

    NASA Astrophysics Data System (ADS)

    Van Weddingen, Yannick

    2011-12-01

    Lead-lag dampers are present in most rotor systems to provide the desired level of damping for all flight conditions. These dampers are critical components of the rotor system, and the performance of semi-active Coulomb friction-based lead-lag dampers is examined for the UH-60 aircraft. The concept of adaptive damping, or "damping on demand," is discussed for both ground resonance and forward flight. The concept of selective damping is also assessed, and shown to face many challenges. In rotorcraft flight dynamics, optimized warping twist change is a potentially enabling technology to improve overall rotorcraft performance. Research efforts in recent years have led to the application of active materials for rotorcraft blade actuation. An innovative concept is proposed wherein the typically closed section blade is cut open to create a torsionally compliant structure that acts as its own amplification device; deformation of the blade is dynamically controlled by out-of-plane warping. Full-blade warping is shown to have the potential for great design flexibility. Recent advances in rotorcraft blade design have also focused on variable-camber airfoils, particularly concepts involving "truss-core" configurations. One promising concept is the use of hexagonal chiral lattice structures in continuously deformable helicopter blades. The static behavior of passive and active chiral networks using piezoelectric actuation strategies is investigated, including under typical aerodynamic load levels. The analysis is then extended to the dynamic response of active chiral networks in unsteady aerodynamic environments.

  1. An Overview of SBIR Phase 2 Airbreathing Propulsion Technologies

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.; Bitler, Dean W.

    2014-01-01

    Technological innovation is the overall focus of NASA's Small Business Innovation Research (SBIR) program. The program invests in the development of innovative concepts and technologies to help NASA's mission directorates address critical research and development needs for agency projects. This report highlights innovative SBIR Phase II projects from 2007-2012 specifically addressing areas in Airbreathing Propulsion which is one of six core competencies at NASA Glenn Research Center. There are twenty technologies featured with emphasis on a wide spectrum of applications such as with a Turbo-Brayton cryocooler for aircraft superconducting systems, braided composite rotorcraft structures, engine air brake, combustion control valve, flexible composite driveshaft, and much more. Each article in this booklet describes an innovation, technical objective, and highlights NASA commercial and industrial applications. This report serves as an opportunity for NASA personnel including engineers, researchers, and program managers to learn of NASA SBIR's capabilities that might be crosscutting into this technology area. As the result, it would cause collaborations and partnerships between the small companies and NASA Programs and Projects resulting in benefit to both SBIR companies and NASA.

  2. CAMRAD - A COMPREHENSIVE ANALYTICAL MODEL OF ROTORCRAFT AERODYNAMICS AND DYNAMICS

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1994-01-01

    The Comprehensive Analytical Model of Rotorcraft Aerodynamics, CAMRAD, program is designed to calculate rotor performance, loads, and noise; helicopter vibration and gust response; flight dynamics and handling qualities; and system aeroelastic stability. The analysis is a consistent combination of structural, inertial, and aerodynamic models applicable to a wide range of problems and a wide class of vehicles. The CAMRAD analysis can be applied to articulated, hingeless, gimballed, and teetering rotors with an arbitrary number of blades. The rotor degrees of freedom included are blade/flap bending, rigid pitch and elastic torsion, and optionally gimbal or teeter motion. General two-rotor aircrafts can be modeled. Single main-rotor and tandem helicopter and sideby-side tilting proprotor aircraft configurations can be considered. The case of a rotor or helicopter in a wind tunnel can also be modeled. The aircraft degrees of freedom included are the six rigid body motion, elastic airframe motions, and the rotor/engine speed perturbations. CAMRAD calculates the load and motion of helicopters and airframes in two stages. First the trim solution is obtained; then the flutter, flight dynamics, and/or transient behavior can be calculated. The trim operating conditions considered include level flight, steady climb or descent, and steady turns. The analysis of the rotor includes nonlinear inertial and aerodynamic models, applicable to large blade angles and a high inflow ratio, The rotor aerodynamic model is based on two-dimensional steady airfoil characteristics with corrections for three-dimensional and unsteady flow effects, including a dynamic stall model. In the flutter analysis, the matrices are constructed that describe the linear differential equations of motion, and the equations are analyzed. In the flight dynamics analysis, the stability derivatives are calculated and the matrices are constructed that describe the linear differential equations of motion. These equations are analyzed. In the transient analysis, the rigid body equations of motion are numerically integrated, for a prescribed transient gust or control input. The CAMRAD program product is available by license for a period of ten years to domestic U.S. licensees. The licensed program product includes the CAMRAD source code, command procedures, sample applications, and one set of supporting documentation. Copies of the documentation may be purchased separately at the price indicated below. CAMRAD is written in FORTRAN 77 for the DEC VAX under VMS 4.6 with a recommended core memory of 4.04 megabytes. The DISSPLA package is necessary for graphical output. CAMRAD was developed in 1980.

  3. Assessing Potential Propulsion Breakthroughs

    NASA Technical Reports Server (NTRS)

    Millis, Marc G.

    2005-01-01

    The term, propulsion breakthrough, refers to concepts like propellantless space drives and faster-than-light travel, the kind of breakthroughs that would make interstellar exploration practical. Although no such breakthroughs appear imminent, a variety of investigations into these goals have begun. From 1996 to 2002, NASA supported the Breakthrough Propulsion Physics Project to examine physics in the context of breakthrough spaceflight. Three facets of these assessments are now reported: (1) predicting benefits, (2) selecting research, and (3) recent technical progress. Predicting benefits is challenging since the breakthroughs are still only notional concepts, but kinetic energy can serve as a basis for comparison. In terms of kinetic energy, a hypothetical space drive could require many orders of magnitude less energy than a rocket for journeys to our nearest neighboring star. Assessing research options is challenging when the goals are beyond known physics and when the implications of success are profound. To mitigate the challenges, a selection process is described where: (a) research tasks are constrained to only address the immediate unknowns, curious effects or critical issues, (b) reliability of assertions is more important than their implications, and (c) reviewers judge credibility rather than feasibility. The recent findings of a number of tasks, some selected using this process, are discussed. Of the 14 tasks included, six reached null conclusions, four remain unresolved, and four have opportunities for sequels. A dominant theme with the sequels is research about the properties of space, inertial frames, and the quantum vacuum.

  4. Electromagnetic propulsion for spacecraft

    NASA Technical Reports Server (NTRS)

    Myers, Roger M.

    1993-01-01

    Three electromagnetic propulsion technologies, solid propellant pulsed plasma thrusters (PPT), magnetoplasmadynamic (MPD) thrusters, and pulsed inductive thrusters (PIT), were developed for application to auxiliary and primary spacecraft propulsion. Both the PPT and MPD thrusters were flown in space, though only PPT's were used on operational satellites. The performance of operational PPT's is quite poor, providing only approximately 8 percent efficiency at approximately 1000 s specific impulse. However, laboratory PPT's yielding 34 percent efficiency at 2000 s specific impulse were extensively tested, and peak performance levels of 53 percent efficiency at 5170 s specific impulse were demonstrated. MPD thrusters were flown as experiments on the Japanese MS-T4 spacecraft and the Space Shuttle and were qualified for a flight in 1994. The flight MPD thrusters were pulsed, with a peak performance of 22 percent efficiency at 2500 s specific impulse using ammonia propellant. Laboratory MPD thrusters were demonstrated with up to 70 percent efficiency and 700 s specific impulse using lithium propellant. While the PIT thruster has never been flown, recent performance measurements using ammonia and hydrazine propellants are extremely encouraging, reaching 50 percent efficiency for specific impulses between 4000 to 8000 s. The fundamental operating principles, performance measurements, and system level design for the three types of electromagnetic thrusters are reviewed, and available data on flight tests are discussed for the PPT and MPD thrusters.

  5. Assessing potential propulsion breakthroughs.

    PubMed

    Millis, Marc G

    2005-12-01

    The term, propulsion breakthrough, refers to concepts like propellantless space drives and faster-than-light travel, the kind of breakthroughs that would make interstellar exploration practical. Although no such breakthroughs appear imminent, a variety of investigations have begun. During 1996-2002 NASA supported the breakthrough propulsion physics project to examine physics in the context of breakthrough spaceflight. Three facets of these assessments are now reported: (1) predicting benefits, (2) selecting research, and (3) recent technical progress. Predicting benefits is challenging, since the breakthroughs are still only notional concepts, but energy can serve as a basis for comparison. A hypothetical space drive would require many orders of magnitude less energy than a rocket for journeys to our nearest neighboring star. Assessing research options is challenging when the goals are beyond known physics and when the implications of success are profound. To mitigate the challenges, a selection process is described where: (1) research tasks are constrained to only address the immediate unknowns, curious effects, or critical issues; (2) reliability of assertions is more important than their implications; and (3) reviewers judge credibility rather than feasibility. The recent findings of a number of tasks, some selected using this process, are discussed. Of the 14 tasks included, six reached null conclusions, four remain unresolved, and four have opportunities for sequels. A dominant theme with the sequels is research about the properties of space, inertial frames, and the quantum vacuum. PMID:16510425

  6. Integrated airframe propulsion control

    NASA Technical Reports Server (NTRS)

    Fennell, R. E.; Black, S. B.

    1982-01-01

    Perturbation equations which describe flight dynamics and engine operation about a given operating point are combined to form an integrated aircraft/propulsion system model. Included in the model are the dependence of aerodynamic coefficients upon atmospheric variables along with the dependence of engine variables upon flight condition and inlet performance. An off-design engine performance model is used to identify interaction parameters in the model. Inclusion of subsystem interaction effects introduces coupling between flight and propulsion variables. To analyze interaction effects on control, consideration is first given to control requirements for separate flight and engine models. For the separate airframe model, feedback control provides substantial improvement in short period damping. For the integrated system, feedback control compensates for the coupling present in the model and provides good overall system stability. However, this feedback control law involves many non-zero gains. Analysis of suboptimal control strategies indicates that performance of the closed loop integrated system can be maintained with a feedback matrix in which the number of non-zero gains is small relative to the number of components in the feedback matrix.

  7. The NASA Electric Propulsion Program

    NASA Technical Reports Server (NTRS)

    Byers, David C.; Wasel, Robert A.

    1987-01-01

    The NASA OAST Propulsion, Power and Energy Division supports electric propulsion for a broad class of missions. Concepts with potential to significantly benefit or enable space exploration and exploitation are identified and advanced toward applications in the near to far term. Recent program progress in mission/system analyses and in electrothermal, ion, and electromagnetic technologies are summarized.

  8. JET PROPULSION LABORATORY COVER: FROM

    E-print Network

    Waliser, Duane E.

    Laboratory Cahforrua Instltute ofTechnology Pasadena,~orrua .-. III #12;IINTRODUCTION Propulsion Laboratory4-00 -4-11 5/q'd.... JET PROPULSION LABORATORY 1991 Annual Report #12;COVER: FROM ~IODEST BEGIN TELECOMMUNICATIONS SYSTEMS ADVA N CED TECHNOLOGY APPLICATIONS PROJECTS INSTITUTIONAL ACTIVITIES #12;A descnptlon

  9. Jet Propulsion Laboratory Introduction 1

    E-print Network

    Waliser, Duane E.

    for the period January 1 through December 31, 1989. JET PROPULSION LABORATORY California Institute of TechnologyJPL Annual Report 1989 Jet Propulsion Laboratory #12;#12;CONTENTS Introduction 1 Director's Message 2 Flight Projects 5 Space and Earth Science 15 Advanced Technology 22 Telecommunications Systems 31

  10. Performance of flapping foil propulsion

    Microsoft Academic Search

    L. Schouveiler; F. S. Hover; M. S. Triantafyllou

    2005-01-01

    The performance of an aquatic propulsion system inspired from the thunniform swimming mode is experimentally studied. This consists of generating the propulsive force with a foil undergoing a harmonic flapping which is a combination of a heave translation and a pitch rotation. Experiments are performed at a fixed value of the Reynolds number and of the heave amplitude. The effects

  11. Exotic power and propulsion concepts

    NASA Technical Reports Server (NTRS)

    Forward, Robert L.

    1990-01-01

    The status of some exotic physical phenomena and unconventional spacecraft concepts that might produce breakthroughs in power and propulsion in the 21st Century are reviewed. The subjects covered include: electric, nuclear fission, nuclear fusion, antimatter, high energy density materials, metallic hydrogen, laser thermal, solar thermal, solar sail, magnetic sail, and tether propulsion.

  12. Advanced technologies for nuclear propulsion

    Microsoft Academic Search

    Benton Clark; Scott Geels; Brian Sutter; Rohan Zaveri; Robert Zubrin

    1992-01-01

    The Mission Requirements and Resources Allocation Model is presently used to examine nuclear propulsion alternatives on the basis of projected performance levels. All calculations are based on a complete vehicle design, including habitat subsystem masses, external services, propulsion system component performance, power subsystems, tankage factors, and the allocations for both propellant boiloff volumes and the accumulation of unusable residuals. Attention

  13. Gasdynamic Mirror Fusion Propulsion Experiment

    Microsoft Academic Search

    Bill Emrich

    2000-01-01

    A gasdynamic mirror (GDM) fusion propulsion experiment is currently being constructed at the NASA Marshall Space Flight Center (MSFC) to test the feasibility of this particular type of fusion device. Because of the open magnetic field line configuration of mirror fusion devices, they are particularly well suited for propulsion system applications since they allow for the easy ejection of thrust

  14. Analyses Of Underwater Magnetohydrodynamic Propulsion

    Microsoft Academic Search

    J. B. Gilbertt; T. F. Lint

    1990-01-01

    Sea water magnetohydrodynamic (MHD) propulsion for marine vehicles offers many unique features. There is no need for propellers, and therefore no noise associated that. Gear reduction system for the shafts is thus no longer needed. It offers maneuverbility by directional thrusts along with quietness. The theories of MHD pump jet propulsion are discussed in detail in this paper. A so-called

  15. PROPULSION SYSTEMS FOR HYPERSONIC FLIGHT

    Microsoft Academic Search

    François Falempin

    During last twenty years, a large effort has been undertaken in Europe, and particularly in France, to improve knowledge on hypersonic airbreathing propulsion, to acquire a first know-how for components design and to develop needed technologies. On this scientific and technology basis, two families of possible application can be imagined for high- speed airbreathing propulsion : reusable space launcher and

  16. Nuclear electric propulsion systems overview

    NASA Technical Reports Server (NTRS)

    Doherty, Michael P.

    1993-01-01

    The topics are presented in viewgraph form and include the following: nuclear propulsion background; schedule for the nuclear electric propulsion (NEP) project; NEP for the Space Exploration Initiative; NEP on-going systems tasks; 20KWe mission/system study; and agenda.

  17. Propulsion considerations for supersonic oblique flying wings

    E-print Network

    Shinagawa, Yuto

    2006-01-01

    Propulsion considerations unique to the supersonic oblique flying wing, including cycle selection, sizing, and integration were investigated via the development and interrogation of aerodynamic and propulsive synthesis ...

  18. The NASA Electric Propulsion Program

    NASA Technical Reports Server (NTRS)

    Callahan, Lisa Wood; Curran, Francis M.

    1996-01-01

    Nearly all space missions require on-board propulsion systems and these systems typically have a major impact on spacecraft mass and cost. Electric propulsion systems offer major performance advantages over conventional chemical systems for many mission functions and the NASA Office of Space Access and Technology (OSAT) supports an extensive effort to develop the technology for high-performance, on-board electric propulsion system options to enhance and enable near- and far-term US space missions. This program includes research and development efforts on electrothermal, electrostatic, and electromagnetic propulsion system technologies to cover a wide range of potential applications. To maximize expectations of technology transfer, the program emphasizes strong interaction with the user community through a variety of cooperative and contracted approaches. This paper provides an overview of the OSAT electric propulsion program with an emphasis on recent progress and future directions.

  19. Electric propulsion system technology

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Garner, Charles E.; Goodfellow, Keith D.; Pivirotto, Thomas J.; Polk, James E.

    1992-01-01

    The work performed in fiscal year (FY) 1991 under the Propulsion Technology Program RTOP (Research and Technology Objectives and Plans) No. (55) 506-42-31 for Low-Thrust Primary and Auxiliary Propulsion technology development is described. The objectives of this work fall under two broad categories. The first of these deals with the development of ion engines for primary propulsion in support of solar system exploration. The second with the advancement of steady-state magnetoplasmadynamic (MPD) thruster technology at 100 kW to multimegawatt input power levels. The major technology issues for ion propulsion are demonstration of adequate engine life at the 5 to 10 kW power level and scaling ion engines to power levels of tens to hundreds of kilowatts. Tests of a new technique in which the decelerator grid of a three-grid ion accelerator system is biased negative of neutralizer common potential in order to collect facility induced charge-exchange ions are described. These tests indicate that this SAND (Screen, Accelerator, Negative Decelerator) configuration may enable long duration ion engine endurance tests to be performed at vacuum chamber pressures an order of magnitude higher than previously possible. The corresponding reduction in pumping speed requirements enables endurance tests of 10 kW class ion engines to be performed within the resources of existing technology programs. The results of a successful 5,000-hr endurance of a xenon hollow cathode operating at an emission current of 25 A are described, as well as the initial tests of hollow cathodes operating on a mixture of argon and 3 percent nitrogen. Work performed on the development of carbon/carbon grids, a multi-orifice hollow cathode, and discharge chamber erosion reduction through the addition of nitrogen are also described. Critical applied-field MPD thruster technical issues remain to be resolved, including demonstration of reliable steady-state operation at input powers of hundreds to thousands of kilowatts, achievement of thruster efficiency and specific impulse levels required for missions of interest, and demonstration of adequate engine life at these input power, efficiency, and specific impulse levels. To address these issues we have designed, built, and tested a 100 kW class, radiation-cooled applied-field MPD thruster and a unique dual-beam thrust stand that enables separate measurements of the applied- and self-field thrust components. We have also initiated the development of cathode thermal and plasma sheath models that will eventually be used to guide the experimental program. In conjunction with the cathode modeling, a new cathode test facility is being constructed. This facility will support the study of cathode thermal behavior and erosion mechanisms, the diagnosis of the near-cathode plasma and the development and endurance testing of new, high-current cathode designs. To facilitate understanding of electrode surface phenomenon, we have implemented a telephoto technique to obtain photographs of the electrodes during engine operation. In order to reduce the background vacuum tank pressure during steady-state engine operation in order to obtain high fidelity anode thermal data, we have developed and are evaluating a gas-dynamic diffuser. A review of experience with alkali metal propellants for MPD thrusters led to the conclusion that alkali metals, particularly lithium, offer the potential for significant engine performance and lifetime improvements. These propellants are also condensible at room temperature, substantially reducing test facility pumping requirements. The most significant systems-level issue is the potential for spacecraft contamination. Subsequent experimental and theoretical efforts should be directed toward verifying the performance and lifetime gains and characterizing the thruster flow field to assess its impact on spacecraft surfaces. Consequently, we have begun the design and development of a new facility to study engine operation with alkali metal propellants.

  20. Magnetohydrodynamic Augmented Propulsion Experiment

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.

    2008-01-01

    Over the past several years, efforts have been under way to design and develop an operationally flexible research facility for investigating the use of cross-field MHD accelerators as a potential thrust augmentation device for thermal propulsion systems. The baseline configuration for this high-power experimental facility utilizes a 1.5-MWe multi-gas arc-heater as a thermal driver for a 2-MWe MHD accelerator, which resides in a large-bore 2-tesla electromagnet. A preliminary design study using NaK seeded nitrogen as the working fluid led to an externally diagonalized segmented MHD channel configuration based on an expendable heat-sink design concept. The current status report includes a review of engineering/design work and performance optimization analyses and summarizes component hardware fabrication and development efforts, preliminary testing results, and recent progress toward full-up assembly and testing

  1. Pulsed hydrojet propulsion

    SciTech Connect

    Bohachevsky, I.O.; Torrey, M.D.

    1985-01-01

    The pulsed hydrojet is a device in which the water ingested from the free stream is accelerated out of the exhaust pipe to produce thrust. In this report we describe and analyze a way of accelerating the stream of water with pockets of high pressure steam and gas generated inside the stream by an exothermal reaction of suitable propellant injected and dispersed in the water. The velocity increment that must be imparted to the water to produce a substantial thrust need not be very large because the density of the water is comparable to the average density of the accelerated body. Results of the numerical modeling of the proposed jet acceleration mechanism indicate that the hydrojet propulsion device is potentially capable of propelling underwater projectiles at speeds three to five times greater than those currently attainable. Several promising applications of the hydrojet thruster are discussed and evaluated.

  2. Propulsion by directional adhesion

    NASA Astrophysics Data System (ADS)

    Bush, John; Prakash, Manu

    2008-03-01

    The rough, hairy integument of water-walking arthropods is well known to be responsible for their water-repellency; we here consider its additional propulsive role. We demonstrate that the tilted flexible leg hairs of water-walking arthropods render the leg cuticle directionally anisotropic: contact lines advance most readily towards the leg tips. The dynamical role of the resulting unidirectional adhesion is explored, and yields new insight into the manner in which water-walking arthropods generate thrust, glide and leap from the free surface. We thus provide new rationale for the fundamental topological difference in the roughness on plants and insects, and suggest novel directions for biomimetic design of smart, hydrophobic surfaces.

  3. Space station propulsion

    NASA Technical Reports Server (NTRS)

    Jones, Robert E.; Morren, W. Earl; Sovey, James S.; Tacina, Robert R.

    1987-01-01

    Two propulsion systems have been selected for the space station: gaseous H/O rockets for high thrust applications and the multipropellant resistojets for low thrust needs. These two thruster systems integrate very well with the fluid systems on the space station, utilizing waste fluids as their source of propellant. The H/O rocket will be fueled by electrolyzed water and the resistojets will use waste gases collected from the environmental control system and the various laboratories. The results are presented of experimental efforts with H/O and resistojet thrusters to determine their performance and life capability, as well as results of studies to determine the availability of water and waste gases.

  4. NASA's Jet Propulsion Laboratory

    NSDL National Science Digital Library

    This rich and extensive site from the California Institutes of Technology's Jet Propulsion Laboratory leads users to a vast array of images, videos and resources related to aerospace exploration and technology. Of especial interest to educators will be the Images and Multimedia sections of the site. The images tab takes users to the Planetary Photojournal section which provides access to thousands of photographs of planets (as well as their satellites), asteroids, and comets. In the multimedia section users can view slideshows, listen to podcasts and watch videos which explore a range of topics from the rainbow colors of Saturn to NASA's Spitzer Space Telescope. Resources on the site are free to use and could be integrated into a variety of curriculum.

  5. Physics of magnetic propulsion

    NASA Astrophysics Data System (ADS)

    Pulatov, V.

    2005-01-01

    The flight of a magnetic vehicle is expected at the expense of the electrodynamic lift and thrust force of interaction with the natural magnetic field and with the eddy currents in ground or water at low altitudes. It would present in future an alternative to rocketry and aviation owing to the expected better efficiency, constant mass and pure ecology. The principles of the magnetic propulsion (Prog Aerospace Sci 2001;37:245-61) allow to substantiate the proposed application and variant of design of the magnetic flight vehicle, to clarify its advantageous properties and to determine the main problems to be solved for its creation. The reviewed questions of its theory show a number of its important advantages. One of them is the possible performance of aerospace and interplanetary flights by the same unit. The proposed calculation basis for the numerical estimations and corresponding numerical examples would allow to image this vehicle structural features and to compare variants.

  6. Solar Thermal Propulsion Test Facility

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. This photograph, taken at MSFC's Solar Thermal Propulsion Test Facility, shows a concentrator mirror, a combination of 144 mirrors forming this 18-ft diameter concentrator, and a vacuum chamber that houses the focal point. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-foot diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth-orbit, rapid travel throughout the solar system, and exploration of interstellar space.

  7. Pressure-Sensitive Paints Advance Rotorcraft Design Testing

    NASA Technical Reports Server (NTRS)

    2013-01-01

    The rotors of certain helicopters can spin at speeds as high as 500 revolutions per minute. As the blades slice through the air, they flex, moving into the wind and back out, experiencing pressure changes on the order of thousands of times a second and even higher. All of this makes acquiring a true understanding of rotorcraft aerodynamics a difficult task. A traditional means of acquiring aerodynamic data is to conduct wind tunnel tests using a vehicle model outfitted with pressure taps and other sensors. These sensors add significant costs to wind tunnel testing while only providing measurements at discrete locations on the model's surface. In addition, standard sensor solutions do not work for pulling data from a rotor in motion. "Typical static pressure instrumentation can't handle that," explains Neal Watkins, electronics engineer in Langley Research Center s Advanced Sensing and Optical Measurement Branch. "There are dynamic pressure taps, but your costs go up by a factor of five to ten if you use those. In addition, recovery of the pressure tap readings is accomplished through slip rings, which allow only a limited amount of sensors and can require significant maintenance throughout a typical rotor test." One alternative to sensor-based wind tunnel testing is pressure sensitive paint (PSP). A coating of a specialized paint containing luminescent material is applied to the model. When exposed to an LED or laser light source, the material glows. The glowing material tends to be reactive to oxygen, explains Watkins, which causes the glow to diminish. The more oxygen that is present (or the more air present, since oxygen exists in a fixed proportion in air), the less the painted surface glows. Imaged with a camera, the areas experiencing greater air pressure show up darker than areas of less pressure. "The paint allows for a global pressure map as opposed to specific points," says Watkins. With PSP, each pixel recorded by the camera becomes an optical pressure tap. "Instead of having 100 or 200 pressure taps, you can have in theory several million, up to whatever the resolution of your camera is." Watkins explains that typical wind tunnel testing requires two models: one with very little instrumentation, and a pressure model with a significant amount of sensors applied. "If you can make all of your measurements on one model with PSP, you've decreased your model costs by at least a factor of two and preferably your testing costs by about that much," he says. PSP technology has been around for almost 20 years, but a PSP solution for gathering instantaneous dynamic pressure data from surfaces moving at high speeds, such as rotor blades, was not available until a NASA partnership led to a game-changing innovation.

  8. Enabling Electric Propulsion for Flight

    NASA Technical Reports Server (NTRS)

    Ginn, Starr

    2014-01-01

    Description of current ARMD projects; Team Seedling project AFRC and LaRC 31ft distributed electric propulsion wing on truck bed up 75 miles per hour for coefficient of lift validation. Convergent Aeronautic Solutions project (new ARMD reorg), sub-project Convergent Electric Propulsion Technologies AFRC, LaRC and GRC, re-winging a 4 passenger Tecnam aircraft with a 31ft distributed electric propulsion wing. Advanced Air Transport Technologies (Fixed Wing), Hybrid Electric Research Theme, developing a series hybrid ironbird and flight sim to study integration and performance challenges in preparation for a 1-2 MW flight project.

  9. Advanced Space Fission Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.; Borowski, Stanley K.

    2010-01-01

    Fission has been considered for in-space propulsion since the 1940s. Nuclear Thermal Propulsion (NTP) systems underwent extensive development from 1955-1973, completing 20 full power ground tests and achieving specific impulses nearly twice that of the best chemical propulsion systems. Space fission power systems (which may eventually enable Nuclear Electric Propulsion) have been flown in space by both the United States and the Former Soviet Union. Fission is the most developed and understood of the nuclear propulsion options (e.g. fission, fusion, antimatter, etc.), and fission has enjoyed tremendous terrestrial success for nearly 7 decades. Current space nuclear research and technology efforts are focused on devising and developing first generation systems that are safe, reliable and affordable. For propulsion, the focus is on nuclear thermal rockets that build on technologies and systems developed and tested under the Rover/NERVA and related programs from the Apollo era. NTP Affordability is achieved through use of previously developed fuels and materials, modern analytical techniques and test strategies, and development of a small engine for ground and flight technology demonstration. Initial NTP systems will be capable of achieving an Isp of 900 s at a relatively high thrust-to-weight ratio. The development and use of first generation space fission power and propulsion systems will provide new, game changing capabilities for NASA. In addition, development and use of these systems will provide the foundation for developing extremely advanced power and propulsion systems capable of routinely and affordably accessing any point in the solar system. The energy density of fissile fuel (8 x 10(exp 13) Joules/kg) is more than adequate for enabling extensive exploration and utilization of the solar system. For space fission propulsion systems, the key is converting the virtually unlimited energy of fission into thrust at the desired specific impulse and thrust-to-weight ratio. This presentation will discuss potential space fission propulsion options ranging from first generation systems to highly advanced systems. Ongoing research that shows promise for enabling second generation NTP systems with Isp greater than 1000 s will be discussed, as will the potential for liquid, gas, or plasma core systems. Space fission propulsion systems could also be used in conjunction with simple (water-based) propellant depots to enable routine, affordable missions to various destinations (e.g. moon, Mars, asteroids) once in-space infrastructure is sufficiently developed. As fuel and material technologies advance, very high performance Nuclear Electric Propulsion (NEP) systems may also become viable. These systems could enable sophisticated science missions, highly efficient cargo delivery, and human missions to numerous destinations. Commonalities between NTP, fission power systems, and NEP will be discussed.

  10. MSFC Nuclear Propulsion Materials Development

    NASA Technical Reports Server (NTRS)

    Rogers, J. R.; Cook, B.

    2004-01-01

    Nuclear propulsion systems for spacecraft applications present numerous technical challenges for propulsion systems. They have been the focus of a recent NRA. Challenges inclue: a nuclear reactor subsystem to produce thermal energy; a power conversion subsystem to convert the thermal energy into electrical energy; a propulsion subsystem that utilizes Hall effect thrusters; thruster technologies and high temperature materials to support subsystems. The MSFC Electrostatic Levitation (ESL) Facility provides an ideal platform for the study of high temperature and reactive materials. An overview of the facility and its capabilities will be presented.

  11. Electric propulsion and interstellar flight

    SciTech Connect

    Matloff, G.L.

    1987-01-01

    Two general classes of interstellar space-flights are defined: endothermic and exothermic. Endothermic methods utilize power sources external to the vehicle and associated technology. Faster exothermic methods utilize on-board propulsive power sources or energy-beam technology. Various proposed endothermic electric propulsion methods are described. These include solar electric rockets, mass drivers, and ramjets. A review of previously suggested exothermic electric propulsion methods is presented. Following this review is a detailed discussion of possible near future application of the beamed-laser ramjet, mainly for ultimate relativistic travel. Electric/magnetic techniques offer an excellent possibility for decelerating an interstellar vehicle, regardless of the acceleration technique. 20 references.

  12. Nuclear thermal propulsion engine cost trade studies

    Microsoft Academic Search

    Robert K. Paschall; Rocketdyne Division

    1993-01-01

    The NASA transportation strategy for the Mars Exploration architecture includes the use of nuclear thermal propulsion as the primary propulsion system for Mars transits. It is anticipated that the outgrowth of the NERVA\\/ROVER programs will be a nuclear thermal propulsion (NTP) system capable of providing the propulsion for missions to Mars. The specific impulse (Isp) for such a system is

  13. Strategic Technology JET PROPULSION LABORATORY

    E-print Network

    Waliser, Duane E.

    Strategic Technology Directions JET PROPULSION LABORATORY National Aeronautics and Space Administration 2 0 0 9 #12;© 2009 California Institute of Technology. Government sponsorship acknowledged. #12;Strategic Technology Directions 2009 offers a distillation of technologies, their links to space missions

  14. Environmental benefits of chemical propulsion

    NASA Technical Reports Server (NTRS)

    Hayes, Joyce A.; Goldberg, Benjamin E.; Anderson, David M.

    1995-01-01

    This paper identifies the necessity of chemical propulsion to satellite usage and some of the benefits accrued through monitoring global resources and patterns, including the Global Climate Change Model (GCM). The paper also summarized how the satellite observations are used to affect national and international policies. Chemical propulsion, like all environmentally conscious industries, does provide limited, controlled pollutant sources through its manufacture and usage. However, chemical propulsion is the sole source which enables mankind to launch spacecraft and monitor the Earth. The information provided by remote sensing directly affects national and international policies designed to protect the environment and enhance the overall quality of life on Earth. The resultant of chemical propulsion is the capability to reduce overall pollutant emissions to the benefit of mankind.

  15. Trajectory correction propulsion for TOPS

    NASA Technical Reports Server (NTRS)

    Long, H. R.; Bjorklund, R. A.

    1972-01-01

    A blowdown-pressurized hydrazine propulsion system was selected to provide trajectory correction impulse for outer planet flyby spacecraft as the result of cost/mass/reliability tradeoff analyses. Present hydrazine component and system technology and component designs were evaluated for application to the Thermoelectric Outer Planet Spacecraft (TOPS); while general hydrazine technology was adequate, component design changes were deemed necessary for TOPS-type missions. A prototype hydrazine propulsion system was fabricated and fired nine times for a total of 1600 s to demonstrate the operation and performance of the TOPS propulsion configuration. A flight-weight trajectory correction propulsion subsystem (TCPS) was designed for the TOPS based on actual and estimated advanced components.

  16. Nuclear thermal propulsion technology overview

    NASA Technical Reports Server (NTRS)

    Stone, James R.

    1993-01-01

    Viewgraphs on nuclear thermal propulsion technology overview are presented. Topics covered include non-nuclear material; instrumentation, controls, and health monitoring; turbopumps; nozzle and extension; and exhaust plume characteristics.

  17. Vehicle Integrated Propulsion Research Tests

    NASA Technical Reports Server (NTRS)

    Lekki, John D.; Hunter, Gary W.; Simon, Don; Meredith, Roger; Wrbanek, John; Woike, Mark; Tokars, Roger; Guffanti, Marianne; Lyall, Eric

    2013-01-01

    Overview of the Vehicle Integrated Propulsion Research Tests in the Vehicle Systems Safety Technologies project. This overview covers highlights of the completed VIPR I and VIPR II tests and also covers plans for the VIPR III test.

  18. The Nuclear Cryogenic Propulsion Stage

    NASA Technical Reports Server (NTRS)

    Houts, Michael G.; Kim, Tony; Emrich, William J.; Hickman, Robert R.; Broadway, Jeramie W.; Gerrish, Harold P.; Doughty, Glen; Belvin, Anthony; Borowski, Stanley K.; Scott, John

    2014-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progres made under the NCPS project could help enable both advanced NTP and advanced Nuclear Electric Propulsion (NEP).

  19. Electric propulsion system technology

    NASA Technical Reports Server (NTRS)

    Brophy, John R.; Garner, Charles E.; Goodfellow, Keith D.

    1991-01-01

    The work performed on the Ion Propulsion System Technology Task in FY90 is described. The objectives of this work fall under two broad categories. The first of these deals with issues associated with the application of xenon ion thrusters for primary propulsion of planetary spacecraft, and the second with the investigation of technologies which will facilitate the development of larger, higher power ion thrusters to support more advanced mission applications. Most of the effort was devoted to investigation of the critical issues associated with the use of ion thrusters for planetary spacecraft. These issues may be succinctly referred to as life time, system integration, and throttling. Chief among these is the engine life time. If the engines do not have sufficient life to perform the missions of interest, then the other issues become unimportant. Ion engine life time was investigated through two experimental programs: an investigation into the reduction of ion engine internal sputter erosion through the addition of small quantities of nitrogen, and a long duration cathode life test. In addition, a literature review and analysis of accelerator grid erosion were performed. The nitrogen addition tests indicated that the addition of between 0.5 and 1.0 percent of nitrogen by mass to the xenon propellant results in a reduction in the sputter erosion of discharge chamber components by a factor of between 20 and 50, with negligible reduction in thruster performance. The long duration test of a 6.35-mm dia. xenon hollow cathode is still in progress, and has accumulated more than 4,000 hours of operation at an emission current of 25 A at the time of this writing. One of the major system integration issues concerns possible interactions of the ion thruster produced charge exchange plasma with the spacecraft. A computer model originally developed to describe the behavior of mercury ion thruster charge exchange plasmas was resurrected and modified for xenon propellant. This model enables one to calculate the flow direction and local density of the charge exchange plasma, and indicates the degree to which this plasma can flow upstream of the thruster exhaust plane. A continuing effort to investigate the most desirable throttling technique for noble gas ion thrusters concentrated this year on experimentally determining the fixed flow rate throttling range of a 30-cm dia. thruster with a two-grid accelerator system. These experiments demonstrated a throttling capability which covers a 2.8 to 1 variation in input power. This throttling range is 55 percent greater than expected, and is due to better accelerator system performance at low net-to-total voltage ratios than indicated in the literature. To facilitate the development of large, higher power ion thrusters several brief studies were performed. These include the development of a technique which simulates ion thruster operation without beam extraction, the development of an optical technique to measure ion thruster grid distortion due to thermal expansion, tests of a capacitance measurement technique to quantify the accelerator system grid separation, and the development of a segmented thruster geometry which enables near term development of ion thrusters at power levels greater than 100 kW. Finally, a paper detailing the benefits of electric propulsion for the Space Exploration Initiative was written.

  20. Emerging Propulsion Technologies

    NASA Astrophysics Data System (ADS)

    Bonometti, J. A.

    2004-11-01

    The Emerging Propulsion Technologies (EPT) technology area is a branch of the In-Space Program that serves as a bridge to bring high-risk/high-payoff technologies to a higher level of maturity. Emerging technologies are innovative and, if successfully developed, could result in revolutionary science capabilities for NASA science missions. EPT is also charged with the responsibility of assessing the technology readiness level (TRL) of technologies under consideration for inclusion in the ISP portfolio. One such technology is the Momentum-eXchange/Electrodynamic Reboost (MXER) tether concept, which is the current, primary investment of EPT. The MXER tether is a long, rotating cable placed in an elliptical Earth orbit, whose rapid rotation allows its tip to catch a payload in a low Earth orbit and throw that payload to a high-energy orbit. Electrodynamic tether propulsion is used to restore the orbital energy transferred by the MXER tether to the payload and reboost the tether's orbit. This technique uses solar power to drive electrical current collected from the Earth's ionosphere through the tether, resulting in a magnetic interaction with the terrestrial field. Since the Earth itself serves as the reaction mass, the thrust force is generated without propellant and allows the MXER facility to be repeatedly reused without re-supply. Essentially, the MXER facility is a 'propellantless' upper stage that could assist nearly every mission going beyond low Earth orbit. Payloads to interplanetary destinations could especially benefit from the boost provided by the MXER facility, resulting in launch vehicle cost reductions, increased payload fractions and more frequent mission opportunities. Synergistic tether technologies resulting from MXER development could include science sampling in the upper atmosphere, remote probes or attached formation flying, artificial gravity experiments with low Coriolis forces, and other science needs that use long, ultra-light strength or conducting cables in space. Tether development additionally embraces the science investigation of ionospheric physics, micrometeorite and space particulates in LEO and precise earth environment knowledge of gravity fields, solar flux, .thermal environments and magnetic fields.

  1. COGAS propulsion for LNG ships

    NASA Astrophysics Data System (ADS)

    Wiggins, Edwin G.

    2011-06-01

    Propulsion of liquefied natural gas (LNG) ships is undergoing significant change. The traditional steam plant is losing favor because of its low cycle efficiency. Medium-speed diesel-electric and slow-speed diesel-mechanical drive ships are in service, and more are being built. Another attractive alternative is combined gas and steam turbine (COGAS) drive. This approach offers significant advantages over steam and diesel propulsion. This paper presents the case for the COGAS cycle.

  2. Nuclear Propulsion in Space (1968)

    ScienceCinema

    None

    2014-06-17

    Project NERVA was an acronym for Nuclear Engine for Rocket Vehicle Application, a joint program of the U.S. Atomic Energy Commission and NASA managed by the Space Nuclear Propulsion Office (SNPO) at the Nuclear Rocket Development Station in Jackass Flats, Nevada U.S.A. Between 1959 and 1972, the Space Nuclear Propulsion Office oversaw 23 reactor tests, both the program and the office ended at the end of 1972.

  3. Hydromagnetics and future propulsion systems

    NASA Technical Reports Server (NTRS)

    Holt, A. C.

    1980-01-01

    Futuristic hydromagnetic propulsion systems for spacecraft are examined with emphasis on systems that use regular coherent patterns of magnetic and electric fields of very high strength to interact with the structure of space-time to effect a quick translation from one space-time point to another. A particular type of this system is discussed: namely, the field resonance propulsion concept which will utilize superconducting magnets and a configuration of tunable free-electron lasers.

  4. Nuclear Propulsion in Space (1968)

    SciTech Connect

    None

    2012-06-23

    Project NERVA was an acronym for Nuclear Engine for Rocket Vehicle Application, a joint program of the U.S. Atomic Energy Commission and NASA managed by the Space Nuclear Propulsion Office (SNPO) at the Nuclear Rocket Development Station in Jackass Flats, Nevada U.S.A. Between 1959 and 1972, the Space Nuclear Propulsion Office oversaw 23 reactor tests, both the program and the office ended at the end of 1972.

  5. Electric propulsion for small satellites

    NASA Astrophysics Data System (ADS)

    Keidar, Michael; Zhuang, Taisen; Shashurin, Alexey; Teel, George; Chiu, Dereck; Lukas, Joseph; Haque, Samudra; Brieda, Lubos

    2015-01-01

    Propulsion is required for satellite motion in outer space. The displacement of a satellite in space, orbit transfer and its attitude control are the task of space propulsion, which is carried out by rocket engines. Electric propulsion uses electric energy to energize or accelerate the propellant. The electric propulsion, which uses electrical energy to accelerate propellant in the form of plasma, is known as plasma propulsion. Plasma propulsion utilizes the electric energy to first, ionize the propellant and then, deliver energy to the resulting plasma leading to plasma acceleration. Many types of plasma thrusters have been developed over last 50 years. The variety of these devices can be divided into three main categories dependent on the mechanism of acceleration: (i) electrothermal, (ii) electrostatic and (iii) electromagnetic. Recent trends in space exploration associate with the paradigm shift towards small and efficient satellites, or micro- and nano-satellites. A particular example of microthruster considered in this paper is the micro-cathode arc thruster (µCAT). The µCAT is based on vacuum arc discharge. Thrust is produced when the arc discharge erodes some of the cathode at high velocity and is accelerated out the nozzle by a Lorentz force. The thrust amount is controlled by varying the frequency of pulses with demonstrated range to date of 1–50 Hz producing thrust ranging from 1 µN to 0.05 mN.

  6. Solar Thermal Propulsion Test Facility

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. Solar thermal propulsion works by acquiring and redirecting solar energy to heat a propellant. This photograph shows a fully assembled solar thermal engine placed inside the vacuum chamber at the test facility prior to testing. The 20- by 24-ft heliostat mirror (not shown in this photograph) has a dual-axis control that keeps a reflection of the sunlight on the 18-ft diameter concentrator mirror, which then focuses the sunlight to a 4-in focal point inside the vacuum chamber. The focal point has 10 kilowatts of intense solar power. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move theNation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth orbit, rapid travel throughout the solar system, and exploration of interstellar space.

  7. Space and transatmospheric propulsion technology

    NASA Technical Reports Server (NTRS)

    Merkle, Charles; Stangeland, Maynard L.; Brown, James R.; Mccarty, John P.; Povinelli, Louis A.; Northam, G. Burton; Zukoski, Edward E.

    1994-01-01

    This report focuses primarily on Japan's programs in liquid rocket propulsion and propulsion for spaceplane and related transatmospheric areas. It refers briefly to Japan's solid rocket programs and to new supersonic air-breathing propulsion efforts. The panel observed that the Japanese had a carefully thought-out plan, a broad-based program, and an ambitious but achievable schedule for propulsion activity. Japan's overall propulsion program is behind that of the United States at the time of this study, but the Japanese are gaining rapidly. The Japanese are at the forefront in such key areas as advanced materials, enjoying a high level of project continuity and funding. Japan's space program has been evolutionary in nature, while the U.S. program has emphasized revolutionary advances. Projects have typically been smaller in Japan than in the United States, focusing on incremental advances in technology, with an excellent record of applying proven technology to new projects. This evolutionary approach, coupled with an ability to take technology off the shelf from other countries, has resulted in relatively low development costs, rapid progress, and enhanced reliability. Clearly Japan is positioned to be a world leader in space and transatmospheric propulsion technology by the year 2000.

  8. Improving the Flight Path Marker Symbol on Rotorcraft Synthetic Vision Displays

    NASA Technical Reports Server (NTRS)

    Szoboszlay, Zoltan P.; Hardy, Gordon H.; Welsh, Terence M.

    2004-01-01

    Two potential improvements to the flight path marker symbol were evaluated on a panel-mounted, synthetic vision, primary flight display in a rotorcraft simulation. One concept took advantage of the fact that synthetic vision systems have terrain height information available ahead of the aircraft. For this first concept, predicted altitude and ground track information was added to the flight path marker. In the second concept, multiple copies of the flight path marker were displayed at 3, 4, and 5 second prediction times as compared to a single prediction time of 3 seconds. Objective and subjective data were collected for eight rotorcraft pilots. The first concept produced significant improvements in pilot attitude control, ground track control, workload ratings, and preference ratings. The second concept did not produce significant differences in the objective or subjective measures.

  9. Maneuvering Rotorcraft Noise Prediction: A New Code for a New Problem

    NASA Technical Reports Server (NTRS)

    Brentner, Kenneth S.; Bres, Guillaume A.; Perez, Guillaume; Jones, Henry E.

    2002-01-01

    This paper presents the unique aspects of the development of an entirely new maneuver noise prediction code called PSU-WOPWOP. The main focus of the code is the aeroacoustic aspects of the maneuver noise problem, when the aeromechanical input data are provided (namely aircraft and blade motion, blade airloads). The PSU-WOPWOP noise prediction capability was developed for rotors in steady and transient maneuvering flight. Featuring an object-oriented design, the code allows great flexibility for complex rotor configuration and motion (including multiple rotors and full aircraft motion). The relative locations and number of hinges, flexures, and body motions can be arbitrarily specified to match the any specific rotorcraft. An analysis of algorithm efficiency is performed for maneuver noise prediction along with a description of the tradeoffs made specifically for the maneuvering noise problem. Noise predictions for the main rotor of a rotorcraft in steady descent, transient (arrested) descent, hover and a mild "pop-up" maneuver are demonstrated.

  10. Development of advanced techniques for rotorcraft state estimation and parameter identification

    NASA Technical Reports Server (NTRS)

    Hall, W. E., Jr.; Bohn, J. G.; Vincent, J. H.

    1980-01-01

    An integrated methodology for rotorcraft system identification consists of rotorcraft mathematical modeling, three distinct data processing steps, and a technique for designing inputs to improve the identifiability of the data. These elements are as follows: (1) a Kalman filter smoother algorithm which estimates states and sensor errors from error corrupted data. Gust time histories and statistics may also be estimated; (2) a model structure estimation algorithm for isolating a model which adequately explains the data; (3) a maximum likelihood algorithm for estimating the parameters and estimates for the variance of these estimates; and (4) an input design algorithm, based on a maximum likelihood approach, which provides inputs to improve the accuracy of parameter estimates. Each step is discussed with examples to both flight and simulated data cases.

  11. Effects of side-stick controllers on rotorcraft handling qualities for terrain flight

    NASA Technical Reports Server (NTRS)

    Aiken, E. W.

    1985-01-01

    Pertinent fixed and rotary-wing feasibility studies and handling-qualities research programs are reviewed and the effects of certain controller characteristics on handling qualities for specific rotorcraft flight tasks are summarized. The effects of the controller force-deflection relationship and the number of controlled axes that are integrated in a single controller are examined. Simulation studies were conducted which provide a significant part of the available handling qualities data. The studies demonstrate the feasibility of using a single, properly designed, limited-displacement, multiaxis controller for certain relatively routine flight tasks in a two-crew rotorcraft with nominal levels of stability and control augmentation with a high degree of reliability are incorporated, separated three or two-axis controller configurations are required for acceptable handling qualities.

  12. Status of NASA/Army rotorcraft research and development piloted flight simulation

    NASA Technical Reports Server (NTRS)

    Condon, Gregory W.; Gossett, Terrence D.

    1988-01-01

    The status of the major NASA/Army capabilities in piloted rotorcraft flight simulation is reviewed. The requirements for research and development piloted simulation are addressed as well as the capabilities and technologies that are currently available or are being developed by NASA and the Army at Ames. The application of revolutionary advances (in visual scene, electronic cockpits, motion, and modelling of interactive mission environments and/or vehicle systems) to the NASA/Army facilities are also addressed. Particular attention is devoted to the major advances made in integrating these individual capabilities into fully integrated simulation environment that were or are being applied to new rotorcraft mission requirements. The specific simulators discussed are the Vertical Motion Simulator and the Crew Station Research and Development Facility.

  13. A robust direct-integration method for rotorcraft maneuver and periodic response

    NASA Technical Reports Server (NTRS)

    Panda, Brahmananda

    1992-01-01

    The Newmark-Beta method and the Newton-Raphson iteration scheme are combined to develop a direct-integration method for evaluating the maneuver and periodic-response expressions for rotorcraft. The method requires the generation of Jacobians and includes higher derivatives in the formulation of the geometric stiffness matrix to enhance the convergence of the system. The method leads to effective convergence with nonlinear structural dynamics and aerodynamic terms. Singularities in the matrices can be addressed with the method as they arise from a Lagrange multiplier approach for coupling equations with nonlinear constraints. The method is also shown to be general enough to handle singularities from quasisteady control-system models. The method is shown to be more general and robust than the similar 2GCHAS method for analyzing rotorcraft dynamics.

  14. Quantitative Feedback Theory (QFT) applied to the design of a rotorcraft flight control system

    NASA Technical Reports Server (NTRS)

    Hess, R. A.; Gorder, P. J.

    1992-01-01

    Quantitative Feedback Theory describes a frequency-domain technique for the design of multi-input, multi-output control systems which meet time or frequency domain performance criteria when specified uncertainty exists in the linear description of the vehicle dynamics. Quantitative Feedback Theory is applied to the design of the longitudinal flight control system for a linear uncertain model of the AH-64 rotorcraft. In this model, the uncertainty is assigned, and is assumed to be attributable to actual uncertainty in the dynamic model and to the changes in the vehicle aerodynamic characteristics which occur near hover. The model includes an approximation to the rotor and actuator dynamics. The design example indicates the manner in which handling qualities criteria may be incorporated into the design of realistic rotorcraft control systems in which significant uncertainty exists in the vehicle model.

  15. AHS National Specialists' Meeting on Rotorcraft Dynamics, Arlington, TX, Nov. 13, 14, 1989, Proceedings

    SciTech Connect

    Not Available

    1989-01-01

    Various papers on rotorcraft dynamics are presented. Individual topics addressed include: aeromechanical stability of helicopters, evolution and test history of the V-22 Aeroelastic Model Series, helicopter individual blade control through optimal output feedback, dynamic characteristics of composite beam structures, dynamic testing of thin-walled composite box beams in a vacuum chamber, fundamental dynamics issues for comprehensive rotorcraft analyses, and development of the second generation Comprehensive Helicopter Analysis System. Also considered are: experiences in NASTRAN airframe vibration predictions, application of CRFD program to total helicopter dynamics, vibration reduction on servoflap controlled rotor using HHC, V-22 MSC/NASTRAN airframe vibration analysis and correlation, responses of helicopter rotors to vibratory airloads, helicopter rotor load calculations, prediction and alleviation of V-22 rotor dynamic loads, free wake analysis of rotor configurations for reduced vibratory airloads.

  16. Asymmetrical Capacitors for Propulsion

    NASA Technical Reports Server (NTRS)

    Canning, Francis X.; Melcher, Cory; Winet, Edwin

    2004-01-01

    Asymmetrical Capacitor Thrusters have been proposed as a source of propulsion. For over eighty years, it has been known that a thrust results when a high voltage is placed across an asymmetrical capacitor, when that voltage causes a leakage current to flow. However, there is surprisingly little experimental or theoretical data explaining this effect. This paper reports on the results of tests of several Asymmetrical Capacitor Thrusters (ACTs). The thrust they produce has been measured for various voltages, polarities, and ground configurations and their radiation in the VHF range has been recorded. These tests were performed at atmospheric pressure and at various reduced pressures. A simple model for the thrust was developed. The model assumed the thrust was due to electrostatic forces on the leakage current flowing across the capacitor. It was further assumed that this current involves charged ions which undergo multiple collisions with air. These collisions transfer momentum. All of the measured data was consistent with this model. Many configurations were tested, and the results suggest general design principles for ACTs to be used for a variety of purposes.

  17. HIERARCHICAL CONTROL SYSTEM SYNTHESIS FOR ROTORCRAFT-BASED UNMANNED AERIAL VEHICLES

    Microsoft Academic Search

    David Hyunchul Shim; Hyoun Jin Kirn; Shankar Sastry

    This paper introduces the development of multiple number of Unmanned Arial Vehicle (UAV) system as a part of BErkeley AeRobot (BEAR) project, highlighting the recent achievements in the design and implementation of rotorcraft-based UAV (RUAV) control system. Based on the experimental flight data, linear system model valid near hover condition is found by applying time-domain numerical methods to experimental flight

  18. Control system design for rotorcraft-based unmanned aerial vehicles using time-domain system identification

    Microsoft Academic Search

    David Hyunchul Shim; Hyoun Jin Kim; Shankar Sastry

    2000-01-01

    This paper introduces the development of flight control system for rotorcraft-based unmanned aerial vehicle (RUAV). In this research, the linear time-invariant model valid for hover is sought. The system response data is acquired in carefully devised experiment procedure and then a linear time-invariant system model is obtained using the time-domain analysis method. The acquired model is used to design feedback

  19. An Adaptive Threshold Neural-Network Scheme for Rotorcraft UAV Sensor Failure Diagnosis

    Microsoft Academic Search

    Juntong Qi; Xingang Zhao; Zhe Jiang; Jianda Han

    2007-01-01

    This paper presents an adaptive threshold neural-network scheme for Rotorcraft Unmanned Aerial Vehicle (RUAV) sensor failure\\u000a diagnosis. The approach based on adaptive threshold has the advantages of better detection and identification ability compared\\u000a with traditional neural-network-based scheme. In this paper, the proposed scheme is demonstrated using the model of a RUAV\\u000a and the results show that the adaptive threshold neural-network

  20. Monotonous Trend Estimation of Deck Displacement for Automatic Landing of Rotorcraft UAVs

    Microsoft Academic Search

    Xilin Yang; Matthew Garratt; Hemanshu Roy Pota

    2011-01-01

    This paper presents a novel and practical procedure for estimating the mean deck height to assist in automatic landing operations\\u000a of a Rotorcraft Unmanned Aerial Vehicle (RUAV) in harsh sea environments. A modified Prony Analysis (PA) procedure is outlined\\u000a to deal with real-time observations of deck displacement, which involves developing an appropriate dynamic model to approach\\u000a real deck motion with

  1. Development of a Pressure Sensitive Paint System for Measuring Global Surface Pressures on Rotorcraft Blades

    Microsoft Academic Search

    A. N. Watkins; B. D. Leighty; W. E. Lipford; O. D. Wong; D. M. Oglesby; J. L. Ingram

    2007-01-01

    This paper describes the results from a proof of concept test to examine the feasibility of using pressure sensitive paint (PSP) to measure global surface pressures on rotorcraft blades in hover. The test was performed using the U.S. army 2-meter rotor test stand (2MRTS) and 15% scale swept rotor blades. Data were collected from five blades using both the intensity-and

  2. A robust rotorcraft flight control system design methodology utilizing quantitative feedback theory

    NASA Technical Reports Server (NTRS)

    Gorder, Peter James

    1993-01-01

    Rotorcraft flight control systems present design challenges which often exceed those associated with fixed-wing aircraft. First, large variations in the response characteristics of the rotorcraft result from the wide range of airspeeds of typical operation (hover to over 100 kts). Second, the assumption of vehicle rigidity often employed in the design of fixed-wing flight control systems is rarely justified in rotorcraft where rotor degrees of freedom can have a significant impact on the system performance and stability. This research was intended to develop a methodology for the design of robust rotorcraft flight control systems. Quantitative Feedback Theory (QFT) was chosen as the basis for the investigation. Quantitative Feedback Theory is a technique which accounts for variability in the dynamic response of the controlled element in the design robust control systems. It was developed to address a Multiple-Input Single-Output (MISO) design problem, and utilizes two degrees of freedom to satisfy the design criteria. Two techniques were examined for extending the QFT MISO technique to the design of a Multiple-Input-Multiple-Output (MIMO) flight control system (FCS) for a UH-60 Black Hawk Helicopter. In the first, a set of MISO systems, mathematically equivalent to the MIMO system, was determined. QFT was applied to each member of the set simultaneously. In the second, the same set of equivalent MISO systems were analyzed sequentially, with closed loop response information from each loop utilized in subsequent MISO designs. The results of each technique were compared, and the advantages of the second, termed Sequential Loop Closure, were clearly evident.

  3. Versatile simulation testbed for rotorcraft speech I/O system design

    NASA Technical Reports Server (NTRS)

    Simpson, Carol A.

    1986-01-01

    A versatile simulation testbed for the design of a rotorcraft speech I/O system is described in detail. The testbed will be used to evaluate alternative implementations of synthesized speech displays and speech recognition controls for the next generation of Army helicopters including the LHX. The message delivery logic is discussed as well as the message structure, the speech recognizer command structure and features, feedback from the recognizer, and random access to controls via speech command.

  4. Fully automatic guidance for rotorcraft nap-of-the-earth (NOE) flight following planned profiles

    NASA Technical Reports Server (NTRS)

    Gorder, Peter J.; Clement, Warren F.; Jewell, Wayne F.

    1989-01-01

    Developing a single-pilot, all-weather nap-of-the-earth (NOE) capability requires fully automatic NOE navigation and flight control. Innovative guidance and control concepts are being investigated in a fourfold research effort that will culminate in the real-time piloted simulation of promising alternatives for automatic guidance and control of rotorcraft in NOE operations, thereby providing a practical demonstration for evaluating pilot acceptance of the automated concepts.

  5. Controls design with crossfeeds for hovering rotorcraft using quantitative feedback theory

    NASA Technical Reports Server (NTRS)

    Tischler, Mark B.; Biezad, Daniel J.; Cheng, Rendy

    1996-01-01

    A multi-input, multi-output controls design with dynamic crossfeed pre-compensation is presented for rotorcraft in near-hovering flight using Quantitative Feedback Theory (QFT). The resulting closed-loop control system bandwidth allows the rotorcraft to be considered for use as an inflight simulator. The use of dynamic, robust crossfeeds prior to the QFT design reduces the magnitude of required feedback gain and results in performance that meets most handling qualities specifications relative to the decoupling of off-axis responses. Handling qualities are Level 1 for both low-gain tasks and high-gain tasks in the roll, pitch, and yaw axes except for the 10 deg/sec moderate-amplitude yaw command where the rotorcraft exhibits Level 2 handling qualities in the yaw axis caused by phase lag. The combined effect of the QFT feedback design following the implementation of low-order, dynamic crossfeed compensators successfully decouples ten of twelve off-axis channels. For the other two channels it was not possible to find a single, low-order crossfeed that was effective. This is an area to be investigated in future research.

  6. Overview of the NASA Subsonic Rotary Wing Aeronautics Research Program in Rotorcraft Crashworthiness

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fuchs, Yvonne T.; Kellas, Sotiris

    2008-01-01

    This paper provides an overview of rotorcraft crashworthiness research being conducted at NASA Langley Research Center under sponsorship of the Subsonic Rotary Wing (SRW) Aeronautics Program. The research is focused in two areas: development of an externally deployable energy attenuating concept and improved prediction of rotorcraft crashworthiness. The deployable energy absorber (DEA) is a composite honeycomb structure, with a unique flexible hinge design that allows the honeycomb to be packaged and remain flat until needed for deployment. The capabilities of the DEA have been demonstrated through component crush tests and vertical drop tests of a retrofitted fuselage section onto different surfaces or terrain. The research on improved prediction of rotorcraft crashworthiness is focused in several areas including simulating occupant responses and injury risk assessment, predicting multi-terrain impact, and utilizing probabilistic analysis methods. A final task is to perform a system-integrated simulation of a full-scale helicopter crash test onto a rigid surface. A brief description of each research task is provided along with a summary of recent accomplishments.

  7. Overview of the NASA Subsonic Rotary Wing Aeronautics Research Program in Rotorcraft Crashworthiness

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Kellas, Sotiris; Fuchs, Yvonne T.

    2009-01-01

    This paper provides an overview of rotorcraft crashworthiness research being conducted at NASA Langley Research Center under sponsorship of the Subsonic Rotary Wing (SRW) Aeronautics Program. The research is focused in two areas: development of an externally deployable energy attenuating concept and improved prediction of rotorcraft crashworthiness. The deployable energy absorber (DEA) is a composite honeycomb structure, with a unique flexible hinge design that allows the honeycomb to be packaged and remain flat until needed for deployment. The capabilities of the DEA have been demonstrated through component crush tests and vertical drop tests of a retrofitted fuselage section onto different surfaces or terrain. The research on improved prediction of rotorcraft crashworthiness is focused in several areas including simulating occupant responses and injury risk assessment, predicting multi-terrain impact, and utilizing probabilistic analysis methods. A final task is to perform a system-integrated simulation of a full-scale helicopter crash test onto a rigid surface. A brief description of each research task is provided along with a summary of recent accomplishments.

  8. Megawatt Electromagnetic Plasma Propulsion

    NASA Technical Reports Server (NTRS)

    Gilland, James; Lapointe, Michael; Mikellides, Pavlos

    2003-01-01

    The NASA Glenn Research Center program in megawatt level electric propulsion is centered on electromagnetic acceleration of quasi-neutral plasmas. Specific concepts currently being examined are the Magnetoplasmadynamic (MPD) thruster and the Pulsed Inductive Thruster (PIT). In the case of the MPD thruster, a multifaceted approach of experiments, computational modeling, and systems-level models of self field MPD thrusters is underway. The MPD thruster experimental research consists of a 1-10 MWe, 2 ms pulse-forming-network, a vacuum chamber with two 32 diffusion pumps, and voltage, current, mass flow rate, and thrust stand diagnostics. Current focus is on obtaining repeatable thrust measurements of a Princeton Benchmark type self field thruster operating at 0.5-1 gls of argon. Operation with hydrogen is the ultimate goal to realize the increased efficiency anticipated using the lighter gas. Computational modeling is done using the MACH2 MHD code, which can include real gas effects for propellants of interest to MPD operation. The MACH2 code has been benchmarked against other MPD thruster data, and has been used to create a point design for a 3000 second specific impulse (Isp) MPD thruster. This design is awaiting testing in the experimental facility. For the PIT, a computational investigation using MACH2 has been initiated, with experiments awaiting further funding. Although the calculated results have been found to be sensitive to the initial ionization assumptions, recent results have agreed well with experimental data. Finally, a systems level self-field MPD thruster model has been developed that allows for a mission planner or system designer to input Isp and power level into the model equations and obtain values for efficiency, mass flow rate, and input current and voltage. This model emphasizes algebraic simplicity to allow its incorporation into larger trajectory or system optimization codes. The systems level approach will be extended to the pulsed inductive thruster and other electrodeless thrusters at a future date.

  9. Magnetohydrodynamic sea water propulsion

    SciTech Connect

    Petrick, M.; Thomas, A.; Genens, L.; Libera, J.; Nietert, R.; Bouillard, J.; Pierson, E.; Hill, D.; Picologlou, B.; Ohlsson, O.; Kasprzyk, T.; Berry, G.

    1991-01-01

    An experimental and theoretical investigation of a large scale MHD propulsor has been undertaken whose objectives are to (1) investigate the transient and steady state performance of the thruster over operating parameter ranges that are compatible with achievement of high efficiency, (2) to quantify the principal loss mechanisms within the thruster and (3) to obtain preliminary hydroacoustic data. The performance of the thruster was first investigated theoretically with a 3-D code to quantify the loss mechanisms and identify experimental parameter ranges of interest. The loss mechanisms of interest are ohmic losses within the channel and those resulting from electrical currents at the entrance and exit of the thruster, and enhanced frictional losses. The analysis indicated that the relative importance of the loss mechanisms was a function of the thruster design and operating parameters. The experimental investigation of the large scale propulsor is being conducted on a sea water test facility that was designed to match the capabilities of a large 6-T superconducting magnet. The facility design was such that {approximately}90{degrees} of all losses occurred within the propulsion test train (inlet nozzle, propulsor and diffuser) thus facilitating isolation of the loss mechanisms. The test thruster itself is heavily instrumented to provide local measurements of velocity, pressure, and electric fields. The predicted overall thruster performance and value of the loss mechanisms will be compared with measured values. Comparisons will also be presented of the voltage gradients between electrodes, overall thruster efficiency, axial pressure gradients across the propulsor, change in velocity profiles, axial and vertical current distributions and exit distribution of the electrolytic gases.

  10. Magnetohydrodynamic sea water propulsion

    SciTech Connect

    Petrick, M.; Thomas, A.; Genens, L.; Libera, J.; Nietert, R.; Bouillard, J.; Pierson, E.; Hill, D.; Picologlou, B.; Ohlsson, O.; Kasprzyk, T.; Berry, G.

    1991-12-31

    An experimental and theoretical investigation of a large scale MHD propulsor has been undertaken whose objectives are to (1) investigate the transient and steady state performance of the thruster over operating parameter ranges that are compatible with achievement of high efficiency, (2) to quantify the principal loss mechanisms within the thruster and (3) to obtain preliminary hydroacoustic data. The performance of the thruster was first investigated theoretically with a 3-D code to quantify the loss mechanisms and identify experimental parameter ranges of interest. The loss mechanisms of interest are ohmic losses within the channel and those resulting from electrical currents at the entrance and exit of the thruster, and enhanced frictional losses. The analysis indicated that the relative importance of the loss mechanisms was a function of the thruster design and operating parameters. The experimental investigation of the large scale propulsor is being conducted on a sea water test facility that was designed to match the capabilities of a large 6-T superconducting magnet. The facility design was such that {approximately}90{degrees} of all losses occurred within the propulsion test train (inlet nozzle, propulsor and diffuser) thus facilitating isolation of the loss mechanisms. The test thruster itself is heavily instrumented to provide local measurements of velocity, pressure, and electric fields. The predicted overall thruster performance and value of the loss mechanisms will be compared with measured values. Comparisons will also be presented of the voltage gradients between electrodes, overall thruster efficiency, axial pressure gradients across the propulsor, change in velocity profiles, axial and vertical current distributions and exit distribution of the electrolytic gases.

  11. Modeling small-scale unmanned rotorcraft for advanced flight control design

    NASA Astrophysics Data System (ADS)

    Mettler, Bernard F.

    Rotorcraft can take off and land vertically, and can perform flight ranging from hovering to airplane-like cruising with agility and maneuverability. These qualities have made them indispensable vehicles for a variety of applications. Today, there is a growing interest in using small-scale rotorcraft as platforms for unmanned aerial vehicles (UAVs). Current RUAVs, however, fail to exploit the vehicles' full potential because of deficient flight control systems. The design of high performance control systems for a vehicle with complex dynamics requires a mathematical model that accurately describes the vehicle's dynamics. Linear, low order models are preferred, setting difficult constraints on the modeling task. This thesis describes the development of a dynamic model for a small-scale Yamaha R-50 helicopter using rotorcraft system identification techniques. Based on experimental data collected from the vehicle, a parameterized model of its dynamics was identified. The parameterized model accounts for the presence of a stabilizer bar and an active yaw damping system; which are typical stability augmentation system on small-scale helicopters. Because rotorcraft dynamics change with operating conditions, both a hover and cruise flight condition were identified. The resulting models were validated against flight-test data and were shown to be highly accurate in predicting the vehicle responses, and the identified parameters were shown to be close to the theoretical values. The model helped us understand typical characteristics of small-scale rotorcraft. We used dynamic scaling rules to determine the effect of scale on the dynamic characteristics of helicopters, and at the same time, we used these rules to compare between the characteristics of the R-50 and those of a full-scale Bell UH-1H helicopter. By explicitly accounting for the stabilizer bar, we were able to use our model to determine and simulate the effect that system has on the vehicle dynamics. Finally, by using the model to analyze and optimize the RUAV's attitude control system we demonstrated that the model lends itself to advanced control design.

  12. Space station propulsion test bed

    NASA Technical Reports Server (NTRS)

    Briley, G. L.; Evans, S. A.

    1989-01-01

    A test bed was fabricated to demonstrate hydrogen/oxygen propulsion technology readiness for the intital operating configuration (IOC) space station application. The test bed propulsion module and computer control system were delivered in December 1985, but activation was delayed until mid-1986 while the propulsion system baseline for the station was reexamined. A new baseline was selected with hydrogen/oxygen thruster modules supplied with gas produced by electrolysis of waste water from the space shuttle and space station. As a result, an electrolysis module was designed, fabricated, and added to the test bed to provide an end-to-end simulation of the baseline system. Subsequent testing of the test bed propulsion and electrolysis modules provided an end-to-end demonstration of the complete space station propulsion system, including thruster hot firings using the oxygen and hydrogen generated from electrolysis of water. Complete autonomous control and operation of all test bed components by the microprocessor control system designed and delivered during the program was demonstrated. The technical readiness of the system is now firmly established.

  13. Center for Advanced Space Propulsion Second Annual Technical Symposium Proceedings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The proceedings for the Center for Advanced Space Propulsion Second Annual Technical Symposium are divided as follows: Chemical Propulsion, CFD; Space Propulsion; Electric Propulsion; Artificial Intelligence; Low-G Fluid Management; and Rocket Engine Materials.

  14. Breakthrough Propulsion Physics Research Program

    NASA Technical Reports Server (NTRS)

    Millis, Marc G.

    1996-01-01

    In 1996, a team of government, university and industry researchers proposed a program to seek the ultimate breakthroughs in space transportation: propulsion that requires no propellant mass, propulsion that can approach and, if possible, circumvent light speed, and breakthrough methods of energy production to power such devices. This Breakthrough Propulsion Physics program, managed by Lewis Research Center, is one part of a comprehensive, long range Advanced Space Transportation Plan managed by Marshall Space Flight Center. Because the breakthrough goals are beyond existing science, a main emphasis of this program is to establish metrics and ground rules to produce near-term credible progress toward these incredible possibilities. An introduction to the emerging scientific possibilities from which such solutions can be sought is also presented.

  15. Automated Rocket Propulsion Test Management

    NASA Technical Reports Server (NTRS)

    Walters, Ian; Nelson, Cheryl; Jones, Helene

    2007-01-01

    The Rocket Propulsion Test-Automated Management System provides a central location for managing activities associated with Rocket Propulsion Test Management Board, National Rocket Propulsion Test Alliance, and the Senior Steering Group business management activities. A set of authorized users, both on-site and off-site with regard to Stennis Space Center (SSC), can access the system through a Web interface. Web-based forms are used for user input with generation and electronic distribution of reports easily accessible. Major functions managed by this software include meeting agenda management, meeting minutes, action requests, action items, directives, and recommendations. Additional functions include electronic review, approval, and signatures. A repository/library of documents is available for users, and all items are tracked in the system by unique identification numbers and status (open, closed, percent complete, etc.). The system also provides queries and version control for input of all items.

  16. Propulsion on a superhydrophobic ratchet

    NASA Astrophysics Data System (ADS)

    Dupeux, Guillaume; Bourrianne, Philippe; Magdelaine, Quentin; Clanet, Christophe; Quéré, David

    2014-06-01

    Liquids in the Leidenfrost state were shown by Linke to self-propel if placed on ratchets. The vapour flow below the liquid rectified by the asymmetric teeth entrains levitating drops by viscosity. This effect is observed above the Leidenfrost temperature of the substrate, typically 200°C for water. Here we show that coating ratchets with super-hydrophobic microtextures extends quick self-propulsion down to a substrate temperature of 100°C, which exploits the persistence of Leidenfrost state with such coatings. Surprisingly, propulsion is even observed below 100°C, implying that levitation is not necessary to induce the motion. Finally, we model the drop velocity in this novel ``cold regime'' of self-propulsion.

  17. Main Propulsion Test Article (MPTA)

    NASA Technical Reports Server (NTRS)

    Snoddy, Cynthia

    2010-01-01

    Scope: The Main Propulsion Test Article integrated the main propulsion subsystem with the clustered Space Shuttle Main Engines, the External Tank and associated GSE. The test program consisted of cryogenic tanking tests and short- and long duration static firings including gimbaling and throttling. The test program was conducted on the S1-C test stand (Position B-2) at the National Space Technology Laboratories (NSTL)/Stennis Space Center. 3 tanking tests and 20 hot fire tests conducted between December 21 1 1977 and December 17, 1980 Configuration: The main propulsion test article consisted of the three space shuttle main engines, flightweight external tank, flightweight aft fuselage, interface section and a boilerplate mid/fwd fuselage truss structure.

  18. Propulsion on a superhydrophobic ratchet.

    PubMed

    Dupeux, Guillaume; Bourrianne, Philippe; Magdelaine, Quentin; Clanet, Christophe; Quéré, David

    2014-01-01

    Liquids in the Leidenfrost state were shown by Linke to self-propel if placed on ratchets. The vapour flow below the liquid rectified by the asymmetric teeth entrains levitating drops by viscosity. This effect is observed above the Leidenfrost temperature of the substrate, typically 200°C for water. Here we show that coating ratchets with super-hydrophobic microtextures extends quick self-propulsion down to a substrate temperature of 100°C, which exploits the persistence of Leidenfrost state with such coatings. Surprisingly, propulsion is even observed below 100°C, implying that levitation is not necessary to induce the motion. Finally, we model the drop velocity in this novel "cold regime" of self-propulsion. PMID:24923358

  19. Space Station Freedom propulsion activities

    NASA Technical Reports Server (NTRS)

    Spera, David A. (editor)

    1990-01-01

    The technical highlights and accomplishments made at NASA LeRC in the development of the Space Station Freedom (SSF) propulsion system are discussed. The objectives are as follows: develop and characterize resistojet-thruster components and assemblies; develop and characterize hydrogen-oxygen thruster components; and conduct system trade studies. The research projects primarily characterize propulsion performance and life. Other tests include environmental impacts, such as exhaust gas profiles and electromagnetic interference. The technical activities that are highlighted are being conducted at LeRC within the Aerospace Technology and Space Station Freedom directorates. These activities include the following: derivation of design analysis models; trade studies of design options; propulsion system impact studies; and component testing for characterization and design verification.

  20. Nuclear thermal propulsion workshop overview

    NASA Technical Reports Server (NTRS)

    Clark, John S.

    1991-01-01

    NASA is planning an Exploration Technology Program as part of the Space Exploration Initiative to return U.S. astronauts to the moon, conduct intensive robotic exploration of the moon and Mars, and to conduct a piloted mission to Mars by 2019. Nuclear Propulsion is one of the key technology thrust for the human mission to Mars. The workshop addresses NTP (Nuclear Thermal Rocket) technologies with purpose to: assess the state-of-the-art of nuclear propulsion concepts; assess the potential benefits of the concepts for the mission to Mars; identify critical, enabling technologies; lay-out (first order) technology development plans including facility requirements; and estimate the cost of developing these technologies to flight-ready status. The output from the workshop will serve as a data base for nuclear propulsion project planning.

  1. Materials Advance Chemical Propulsion Technology

    NASA Technical Reports Server (NTRS)

    2012-01-01

    In the future, the Planetary Science Division of NASA's Science Mission Directorate hopes to use better-performing and lower-cost propulsion systems to send rovers, probes, and observers to places like Mars, Jupiter, and Saturn. For such purposes, a new propulsion technology called the Advanced Materials Bipropellant Rocket (AMBR) was developed under NASA's In-Space Propulsion Technology (ISPT) project, located at Glenn Research Center. As an advanced chemical propulsion system, AMBR uses nitrogen tetroxide oxidizer and hydrazine fuel to propel a spacecraft. Based on current research and development efforts, the technology shows great promise for increasing engine operation and engine lifespan, as well as lowering manufacturing costs. In developing AMBR, ISPT has several goals: to decrease the time it takes for a spacecraft to travel to its destination, reduce the cost of making the propulsion system, and lessen the weight of the propulsion system. If goals like these are met, it could result in greater capabilities for in-space science investigations. For example, if the amount (and weight) of propellant required on a spacecraft is reduced, more scientific instruments (and weight) could be added to the spacecraft. To achieve AMBR s maximum potential performance, the engine needed to be capable of operating at extremely high temperatures and pressure. To this end, ISPT required engine chambers made of iridium-coated rhenium (strong, high-temperature metallic elements) that allowed operation at temperatures close to 4,000 F. In addition, ISPT needed an advanced manufacturing technique for better coating methods to increase the strength of the engine chamber without increasing the costs of fabricating the chamber.

  2. Z-Pinch Fusion Propulsion

    NASA Technical Reports Server (NTRS)

    Miernik, Janie

    2011-01-01

    Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Shorter trips are better for humans in the harmful radiation environment of deep space. Nuclear propulsion and power plants can enable high Ispand payload mass fractions because they require less fuel mass. Fusion energy research has characterized the Z-Pinch dense plasma focus method. (1) Lightning is form of pinched plasma electrical discharge phenomena. (2) Wire array Z-Pinch experiments are commonly studied and nuclear power plant configurations have been proposed. (3) Used in the field of Nuclear Weapons Effects (NWE) testing in the defense industry, nuclear weapon x-rays are simulated through Z-Pinch phenomena.

  3. CFD Techniques for Propulsion Applications

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The symposium was composed of the following sessions: turbomachinery computations and validations; flow in ducts, intakes, and nozzles; and reacting flows. Forty papers were presented, and they covered full 3-D code validation and numerical techniques; multidimensional reacting flow; and unsteady viscous flow for the entire spectrum of propulsion system components. The capabilities of the various numerical techniques were assessed and significant new developments were identified. The technical evaluation spells out where progress has been made and concludes that the present state of the art has almost reached the level necessary to tackle the comprehensive topic of computational fluid dynamics (CFD) validation for propulsion.

  4. 46 CFR 109.555 - Propulsion boilers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Shipping 4 2011-10-01 2011-10-01 false Propulsion boilers. 109.555 Section 109.555 Shipping ...DRILLING UNITS OPERATIONS Miscellaneous § 109.555 Propulsion boilers. The master or person in charge and the...

  5. 46 CFR 109.555 - Propulsion boilers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Shipping 4 2010-10-01 2010-10-01 false Propulsion boilers. 109.555 Section 109.555 Shipping ...DRILLING UNITS OPERATIONS Miscellaneous § 109.555 Propulsion boilers. The master or person in charge and the...

  6. 46 CFR 109.555 - Propulsion boilers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Shipping 4 2013-10-01 2013-10-01 false Propulsion boilers. 109.555 Section 109.555 Shipping ...DRILLING UNITS OPERATIONS Miscellaneous § 109.555 Propulsion boilers. The master or person in charge and the...

  7. 46 CFR 109.555 - Propulsion boilers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Shipping 4 2012-10-01 2012-10-01 false Propulsion boilers. 109.555 Section 109.555 Shipping ...DRILLING UNITS OPERATIONS Miscellaneous § 109.555 Propulsion boilers. The master or person in charge and the...

  8. 46 CFR 109.555 - Propulsion boilers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Shipping 4 2014-10-01 2014-10-01 false Propulsion boilers. 109.555 Section 109.555 Shipping ...DRILLING UNITS OPERATIONS Miscellaneous § 109.555 Propulsion boilers. The master or person in charge and the...

  9. Nuclear propulsion technology advanced fuels technology

    NASA Technical Reports Server (NTRS)

    Stark, Walter A., Jr.

    1993-01-01

    Viewgraphs on advanced fuels technology are presented. Topics covered include: nuclear thermal propulsion reactor and fuel requirements; propulsion efficiency and temperature; uranium fuel compounds; melting point experiments; fabrication techniques; and sintered microspheres.

  10. Current technology in ion and electrothermal propulsion

    NASA Technical Reports Server (NTRS)

    Finke, R. C.; Murch, C. K.

    1973-01-01

    High performance propulsion devices, such as electrostatic ion engines and electrothermal thrusters, are achieving wide user acceptance. The current technology and projected development trends in the areas of ion and electrothermal propulsion systems and components are surveyed.

  11. Electrolysis Propulsion Provides High-Performance, Inexpensive, Clean Spacecraft Propulsion

    NASA Technical Reports Server (NTRS)

    deGroot, Wim A.

    1999-01-01

    An electrolysis propulsion system consumes electrical energy to decompose water into hydrogen and oxygen. These gases are stored in separate tanks and used when needed in gaseous bipropellant thrusters for spacecraft propulsion. The propellant and combustion products are clean and nontoxic. As a result, costs associated with testing, handling, and launching can be an order of magnitude lower than for conventional propulsion systems, making electrolysis a cost-effective alternative to state-of-the-art systems. The electrical conversion efficiency is high (>85 percent), and maximum thrust-to-power ratios of 0.2 newtons per kilowatt (N/kW), a 370-sec specific impulse, can be obtained. A further advantage of the water rocket is its dual-mode potential. For relatively high thrust applications, the system can be used as a bipropellant engine. For low thrust levels and/or small impulse bit requirements, cold gas oxygen can be used alone. An added innovation is that the same hardware, with modest modifications, can be converted into an energy-storage and power-generation fuel cell, reducing the spacecraft power and propulsion system weight by an order of magnitude.

  12. In-Space Propulsion Technology Program Solar Electric Propulsion Technologies

    NASA Technical Reports Server (NTRS)

    Dankanich, John W.

    2006-01-01

    NASA's In-space Propulsion (ISP) Technology Project is developing new propulsion technologies that can enable or enhance near and mid-term NASA science missions. The Solar Electric Propulsion (SEP) technology area has been investing in NASA s Evolutionary Xenon Thruster (NEXT), the High Voltage Hall Accelerator (HiVHAC), lightweight reliable feed systems, wear testing, and thruster modeling. These investments are specifically targeted to increase planetary science payload capability, expand the envelope of planetary science destinations, and significantly reduce the travel times, risk, and cost of NASA planetary science missions. Status and expected capabilities of the SEP technologies are reviewed in this presentation. The SEP technology area supports numerous mission studies and architecture analyses to determine which investments will give the greatest benefit to science missions. Both the NEXT and HiVHAC thrusters have modified their nominal throttle tables to better utilize diminished solar array power on outbound missions. A new life extension mechanism has been implemented on HiVHAC to increase the throughput capability on low-power systems to meet the needs of cost-capped missions. Lower complexity, more reliable feed system components common to all electric propulsion (EP) systems are being developed. ISP has also leveraged commercial investments to further validate new ion and hall thruster technologies and to potentially lower EP mission costs.

  13. Recent Developments in Electric Propulsion under NASA's In-Space Propulsion Technology Project

    Microsoft Academic Search

    Leonard A. Dudzinski; John W. Dankanich

    2007-01-01

    The primary source of electric propulsion development throughout NASA is managed by the In-Space Propulsion Technology Project at the NASA GRC for the Science Mission Directorate. The objective of the Electric Propulsion project area is to develop near-term electric propulsion technology to enhance or enable science mission while minimizing risk and cost to the end user. Major hardware tasks include

  14. M. Bahrami ENSC 461 (S 11) Jet Propulsion Cycle 1 Ideal JetPropulsion Cycle

    E-print Network

    Bahrami, Majid

    M. Bahrami ENSC 461 (S 11) Jet Propulsion Cycle 1 Ideal JetPropulsion Cycle Gas-turbine engines. Aircraft gas turbines operate on an open cycle called jet-propulsion cycle. Some of the major differences between the gas-turbine and jet-propulsion cycles are: gases are expanded in the turbine to a pressure

  15. Nuclear Propulsion Technical Interchange Meeting, volume 2

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The purpose of the meeting was to review the work performed in fiscal year 1992 in the areas of nuclear thermal and nuclear electric propulsion technology development. These proceedings are an accumulation of the presentations provided at the meeting along with annotations provided by authors. The proceedings cover system concepts, technology development, and system modeling for nuclear thermal propulsion (NTP) and nuclear electric propulsion (NEP). The test facilities required for the development of the nuclear propulsion systems are also discussed.

  16. Comparison of Mars Aircraft Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.

    2003-01-01

    The propulsion system is a critical aspect of the performance and feasibility of a Mars aircraft. Propulsion system mass and performance greatly influence the aircraft s design and mission capabilities. Various propulsion systems were analyzed to estimate the system mass necessary for producing 35N of thrust within the Mars environment. Three main categories of propulsion systems were considered: electric systems, combustion engine systems and rocket systems. Also, the system masses were compared for mission durations of 1, 2, and 4 h.

  17. Jet Propulsion Laboratory, California Institute of Technology

    E-print Network

    Waliser, Duane E.

    Jet Propulsion Laboratory, California Institute of Technology Postdoctoral Handbook Updated 9 ....................................................................................................15 Information Technology (including computer hardware and software

  18. The Future of Spacecraft Nuclear Propulsion

    NASA Astrophysics Data System (ADS)

    Jansen, F.

    2014-06-01

    This paper summarizes the advantages of space nuclear power and propulsion systems. It describes the actual status of international power level dependent spacecraft nuclear propulsion missions, especially the high power EU-Russian MEGAHIT study including the Russian Megawatt-Class Nuclear Power Propulsion System, the NASA GRC project and the low and medium power EU DiPoP study. Space nuclear propulsion based mission scenarios of these studies are sketched as well.

  19. Advanced NSTS propulsion system verification study

    NASA Technical Reports Server (NTRS)

    Wood, Charles

    1989-01-01

    The merits of propulsion system development testing are discussed. The existing data base of technical reports and specialists is utilized in this investigation. The study encompassed a review of all available test reports of propulsion system development testing for the Saturn stages, the Titan stages, and the Space Shuttle main propulsion system. The knowledge on propulsion system development and system testing available from specialists and managers was also 'tapped' for inclusion.

  20. Jet Propulsion Laboratory California Institute of Technology

    E-print Network

    Milani, Andrea

    1 Jet Propulsion Laboratory California Institute of Technology JPL Software Plan For Bepi;5 Jet Propulsion Laboratory California Institute of Technology Simulation With Asteroids · Using SSDPS #12;6 Jet Propulsion Laboratory California Institute of Technology Other Relevant Work · Ranging

  1. Advanced Chemical Propulsion for Science Missions

    Microsoft Academic Search

    Larry Liou

    2008-01-01

    The advanced chemical propulsion technology area of NASA's in-space technology project is investing in systems and components for increased performance and reduced cost of chemical propulsion technologies applicable to near-term science missions. Presently the primary investment in the advanced chemical propulsion technology area is in the AMBR high temperature storable bipropellant rocket engine. Scheduled to be available for flight development

  2. PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY

    E-print Network

    Christian, Eric

    PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL in which the solar wind is thought to originate." The mission operations team at Jet Propulsion Laboratory by NASA's Deep Space Network, which is managed by the Jet Propulsion Laboratory. ##### #1385/JPL-PIO #12;

  3. PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY

    E-print Network

    Christian, Eric

    PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL FOR IMMEDIATE RELEASE December 5, 1994 Scientists from NASA's Jet Propulsion Laboratory and the European Space, NASA project scientist at the Jet Propulsion Laboratory, who is participating in today's press

  4. PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY

    E-print Network

    Christian, Eric

    PUBLIC INFORMATION OFFICE JET PROPULSION LABORATORY CALIFORNIA INSTITUTE OF TECHNOLOGY NATIONAL manager at NASA'ís Jet Propulsion Laboratory. Distance from Earth at perihelion, or closest approach above the Sun's poles. The Jet Propulsion Laboratory manages the U.S. portion of the mission for NASA

  5. Characterization of advanced electric propulsion systems

    NASA Technical Reports Server (NTRS)

    Ray, P. K.

    1982-01-01

    Characteristic parameters of several advanced electric propulsion systems are evaluated and compared. The propulsion systems studied are mass driver, rail gun, argon MPD thruster, hydrogen free radical thruster and mercury electron bombardment ion engine. Overall, ion engines have somewhat better characteristics as compared to the other electric propulsion systems.

  6. In Silico Reconstitution of Listeria Propulsion

    E-print Network

    Munro, Ed

    In Silico Reconstitution of Listeria Propulsion Exhibits Nano-Saltation Jonathan B. Alberts monocytogenes propulsion that explicitly simulates a large number of monomer-scale biochemical and mechanical reconstitution of Listeria propulsion exhibits nano-saltation. PLoS Biol 2(12): e412. Introduction Cellular

  7. Flow Analysis of Solar Thermal Propulsion System

    Microsoft Academic Search

    Dai Jian-feng; Li Xing; Zhao Pei; Sun Yi-bin; Mu Xiao-wen; Wang Jun-hong

    2010-01-01

    A commercial CFD scheme FLUENT was used to simulate the working fluid (H2) flow process in solar thermal propulsion system. According to the ground test operating conditions and parameters of the solar thermal propulsion system, the system properties such as hydrogen flow, heat transfer in the solar thermal propulsion system were studied. The flow field structure of the system and

  8. Apollo Lunar Module Propulsion Systems Overview

    NASA Technical Reports Server (NTRS)

    Interbartolo, Michael

    2009-01-01

    This slide presentation describes the propulsion system for the Apollo Lunar Module (LM). It defines they systems for the LM propulsion and the control system. It lists the times during the mission at which each system was used. It describes the basic components and the operation of the Descent and Ascent Propulsion systems. It also describes LM reaction control system.

  9. ADVANCED PROPULSION FOR THE XXI ” CENTURY

    E-print Network

    unknown authors

    This paper presents an overview of advanced space propulsion concepts and their research activities at the beginning of the 2lSt Century. If successfully developed, these concepts will enable in the coming decades the implementation of propulsion technologies that will reduce the cost of access to space and/or enable aggressive exploration, and ultimately exploitation of the Solar System and beyond. This paper focuses primarily on mid- to far-term in-space propulsion applications, although advanced launch concepts (e.g., launch assist catapults) are also discussed briefly. Examples of advanced propulsion concepts to be discussed include advanced chemical propulsion (high-energy density materials, gelled propellants, etc.), nuclear propulsion (fission, fusion, and antimatter annihilation), electric propulsion (solar- and nuclear-electric propulsion power systems and electric propulsion thrusters), micropropulsion, beamed-energy propulsion (e.g., solar/laser/microwave thermaYelectric combinations), beamed-momentum propulsion (e.g., solar/laser/microwave sails, electromagnetic/plasma sails), aero/gravity assist, launch assist catapults, tethers (momentum exchange and electrodynamic), extra-terrestrial resource utilization, and breakthrough physics propulsion.

  10. NASA Propulsion Engineering Research Center, Volume 2

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This is the second volume in the 1994 annual report for the NASA Propulsion Engineering Research Center's Sixth Annual Symposium. This conference covered: (1) Combustors and Nozzles; (2) Turbomachinery Aero- and Hydro-dynamics; (3) On-board Propulsion systems; (4) Advanced Propulsion Applications; (5) Vaporization and Combustion; (6) Heat Transfer and Fluid Mechanics; and (7) Atomization and Sprays.

  11. DEVELOPING ELECTRIC-PROPULSION POWERPLANTS

    Microsoft Academic Search

    1963-01-01

    Auxiliary power supplies available now or in the future are discussed, ; and considerations involved in designing propulsion systems are examined. Basic ; problems in powerplant design are pointed out; and design and development of ; turboelectric, thermionic, and magnetohydrodynamic systems for converting heat to ; electrical energy are reviewed. (D.C.W.);

  12. In-space nuclear propulsion

    NASA Astrophysics Data System (ADS)

    Bruno, C.; Dujarric, C.

    2013-02-01

    The past and the recent status of nuclear propulsion (NP) for application to space mission is presented. The case for using NP in manned space missions is made based on fundamental physics and on the necessity to ensure safe radiation doses to future astronauts. In fact, the presence of solar and galactic-cosmic radiation poses substantial risks to crews traveling for months in a row to destinations such as asteroids and Mars. Since passive or active shields would be massive to protect against the more energetic part of the radiation energy spectrum, the only alternative is to reduce dose by traveling faster. Hence the importance of propulsion systems with much higher specific impulse than that of current chemical systems, and thus the use of nuclear propulsion. Nuclear-thermal and nuclear-electric propulsions are then discussed in view of their potential application to missions now in the preliminary planning stage by space agencies and industries and being considered by the ISECG international panel. In this context, recent ideas for future use of the ISS that may require NP are also presented.

  13. Ren Fradet Jet Propulsion Laboratory,

    E-print Network

    Sekercioglu, Y. Ahmet

    to -87 degrees C, and rarely get above 0 degrees C at Curiosity's latitude · A day on Mars lasts 1Curiosity Her Successes and Challenges René Fradet Jet Propulsion Laboratory, California Institute of Technology Copyright 2013 California Institute of Technology. Government sponsorship acknowledged #12;Mars

  14. Antiproton Driven Fusion Propulsion System

    Microsoft Academic Search

    Ricky Tang; Terry Kammash; Alec Gallimore

    2008-01-01

    A fusion propulsion system in which the plasma is heated to thermonuclear temperature by antiproton annihilation reactions is proposed. It makes use of an open-ended magnetic confinement device known as the gasdynamic mirror (GDM) in which the plasma - such as deuteriumtritium (DT) - is confined long enough to be heated before being ejected through one mirror (serving as a

  15. Vehicular propulsion gas turbine motor

    Microsoft Academic Search

    S. Forster; G. Hewing; M. Kleemann

    1980-01-01

    A description is given of a vehicular propulsion gas turbine motor comprising, in addition to the gas turbine and its upstream combustion chamber with its fuel and air supply ducts, an air input compressor driven by said gas turbine and a counter-current recuperative heat exchanger for heating the air input supplied by said compressor with heat supplied by combustion product

  16. MAP Propulsion System Thermal Design

    NASA Astrophysics Data System (ADS)

    Mosier, Carol L.

    2003-01-01

    The propulsion system of the Microwave Anisotropy Probe (MAP) had stringent requirements that made the thermal design unique. To meet instrument stability requirements the system had to be designed to keep temperatures of all components within acceptable limits without heater cycling. Although the spacecraft remains at a fixed 22° sun angle at L2, the variations in solar constant, property degradation, and bus voltage range all significantly affect the temperature. Large portions of the fuel lines are external to the structure and all components are mounted to non-conductive composite structure. These two facts made the sensitivity to the MLI effective emissivity and bus temperature very high. Approximately two years prior to launch the propulsion system was redesigned to meet MAP requirements. The new design utilized hardware that was already installed in order to meet schedule constraints. The spacecraft design and the thermal requirements were changed to compensate for inadequacies of the existing hardware. The propulsion system consists of fuel lines, fill and drain lines/valve, eight thrusters, a HXCM, and a propulsion tank. A voltage regulator was added to keep critical components within limits. Software was developed to control the operational heaters. Trim resistors were put in series with each operational heater circuits and the tank survival heater. A highly sophisticated test program, which included ``real time'' model correlation, was developed to determine trim resistors sizes. These trim resistors were installed during a chamber break and verified during thermal balance testing.

  17. MAP Propulsion System Thermal Design

    NASA Technical Reports Server (NTRS)

    Mosier, Carol L.

    2003-01-01

    The propulsion system of the Microwave Anisotropy Probe (MAP) had stringent requirements that made the thermal design unique. To meet instrument stability requirements the system had to be designed to keep temperatures of all components within acceptable limits without heater cycling. Although the spacecraft remains at a fixed 22 sun angle at L2, the variations in solar constant, property degradation, and bus voltage range all significantly affect the temperature. Large portions of the fuel lines are external to the structure and all components are mounted to non-conductive composite structure. These two facts made the sensitivity to the MLI effective emissivity and bus temperature very high. Approximately two years prior to launch the propulsion system was redesigned to meet MAP requirements. The new design utilized hardware that was already installed in order to meet schedule constraints. The spacecraft design and the thermal requirements were changed to compensate for inadequacies of the existing hardware. The propulsion system consists of fuel lines, fill and drain lines/valve, eight thrusters, a HXCM, and a propulsion tank. A voltage regulator was added to keep critical components within limits. Software was developed to control the operational heaters. Trim resistors were put in series with each operational heater circuits and the tank survival heater. A highly sophisticated test program, which included real time model correlation, was developed to determine trim resistors sizes. These trim resistors were installed during a chamber break and verified during thermal balance testing.

  18. Space nuclear thermal propulsion program

    Microsoft Academic Search

    Haslett

    1994-01-01

    This report describes te development and funding problems of the space nuclear thermal propulsion program (SNTP). The SNTP program was transferred to the air force, and almost immediately , they indicated that they would have to terminate the program because of a decreasing defense budget and other air force priorities. Congress continued to strongly support the program and $55 million

  19. NUCLEAR PROPULSION FOR MERCHANT SHIPS

    Microsoft Academic Search

    S. L. Smith; J. E. Richards

    1959-01-01

    Views arising from the British Shipbuilding Research Association studies ; on the possible application of nuclear propulsion to merchant ships are presented. ; The capital cost of nuclear reactors is much higher than that of oil-fired ; boilers and for this and other reasons the first commercial application of ; nuclear power will possibly be to a large oil tanker.

  20. Using tightly-coupled CFD/CSD simulation for rotorcraft stability analysis

    NASA Astrophysics Data System (ADS)

    Zaki, Afifa Adel

    Dynamic stall deeply affects the response of helicopter rotor blades, making its modeling accuracy very important. Two commonly used dynamic stall models were implemented in a comprehensive code, validated, and contrasted to provide improved analysis accuracy and versatility. Next, computational fluid dynamics and computational structural dynamics loose coupling methodologies are reviewed, and a general tight coupling approach was implemented and tested. The tightly coupled computational fluid dynamics and computational structural dynamics methodology is then used to assess the stability characteristics of complex rotorcraft problems. An aeroelastic analysis of rotors must include an assessment of potential instabilities and the determination of damping ratios for all modes of interest. If the governing equations of motion of a system can be formulated as linear, ordinary differential equations with constant coefficients, classical stability evaluation methodologies based on the characteristic exponents of the system can rapidly and accurately provide the system's stability characteristics. For systems described by linear, ordinary differential equations with periodic coefficients, Floquet's theory is the preferred approach. While these methods provide excellent results for simplified linear models with a moderate number of degrees of freedom, they become quickly unwieldy as the number of degrees of freedom increases. Therefore, to accurately analyze rotorcraft aeroelastic periodic systems, a fully nonlinear, coupled simulation tool is used to determine the response of the system to perturbations about an equilibrium configuration and determine the presence of instabilities and damping ratios. The stability analysis is undertaken using an algorithm based on a Partial Floquet approach that has been successfully applied with computational structural dynamics tools on rotors and wind turbines. The stability analysis approach is computationally inexpensive and consists of post processing aeroelastic data, which can be used with any aeroelastic rotorcraft code or with experimental data.

  1. One Engine Inoperative (OEI) and Autorotation For Heavy Lift Rotorcraft Systems

    NASA Technical Reports Server (NTRS)

    Wood, Tom

    2012-01-01

    Federal Aviation Administration will certainly require the Heavy Lift Rotorcraft to be operated under Category A performance and operations requirements. Because of the weight, no operation will be allowed except Category A according to FAA Part 29.1(c). This means that any where along the flight path, the aircraft must be able to land safely following an engine failure or continue flight. A repeatable flight profile must be developed and executed to ensure that the aircraft can be safely landed or flown away depending on its location on the flight profile. This means that there will be no Height-Velocity testing required as is currently required for Part 29 Category B. Since all the configurations shown to date are different than existing rotorcraft, each type would have to develop their individual requirements under existing special conditions FAA Part 21.17(b). This means the FAA will take the opportunity to negotiate additional requirements or change requirements to ensure safety. For example, since the tiltrotor did not fit normal rotorcraft category, new rules were negotiated between the applicant and the FAA. As a result of this negotiation, performance requirements for Category A were increased. The rules were written in terms of guaranteed performance instead of Category A requirements. Detailed discussion will follow later. The proposed tiltrotor would likely follow along with the current tiltrotor rules with the possibility of increase Category A performance requirements. Compounding with addition of wing and auxiliary thrust to both the tandem and coaxial rotor would result in new special condition aircraft. To my knowledge, no compound tandem or compound coaxial rotor has ever been certified by FAA.

  2. Flight Acoustic Testing and For the Rotorcraft Noise Data Acquisition Model (RNM)

    NASA Technical Reports Server (NTRS)

    Burley, Casey L.; Smith, Charles D.; Conner, David A.

    2006-01-01

    Two acoustic flight tests have been conducted on a remote test range at Eglin Air Force Base in the panhandle of Florida. The first was the "Acoustics Week" flight test conducted in September 2003. The second was the NASA Heavy Lift Rotorcraft Acoustics Flight Test conducted in October-November 2005. Benchmark acoustic databases were obtained for a number of rotorcraft and limited fixed wing vehicles for a variety of flight conditions. The databases are important for validation of acoustic prediction programs such as the Rotorcraft Noise Model (RNM), as well as for the development of low noise flight procedures and for environmental impact assessments. An overview of RNM capabilities and a detailed description of the RNM/ART (Acoustic Repropagation Technique) process are presented. The RNM/ART process is demonstrated using measured acoustic data for the MD600N. The RNM predictions for a level flyover speed sweep show the highest SEL noise levels on the flight track centerline occurred at the slowest vehicle speeds. At these slower speeds, broadband noise content is elevated compared to noise levels obtained at the higher speeds. A descent angle sweep shows that, in general, ground noise levels increased with increasing descent rates. Vehicle orientation in addition to vehicle position was found to significantly affect the RNM/ART creation of source noise semi-spheres for vehicles with highly directional noise characteristics and only mildly affect those with weak acoustic directionality. Based on these findings, modifications are proposed for RNM/ART to more accurately define vehicle and rotor orientation.

  3. Mission-oriented requirements for updating MIL-H-8501. Volume 1: STI proposed structure. [military rotorcraft

    NASA Technical Reports Server (NTRS)

    Clement, W. F.; Hoh, R. H.; Ferguson, S. W., III; Mitchell, D. G.; Ashkenas, I. L.; Mcruer, D. T.

    1985-01-01

    The structure of a new flying and ground handling qualities specification for military rotorcraft is presented. This preliminary specification structure is intended to evolve into a replacement for specification MIL-H-8501A. The new structure is designed to accommodate a variety of rotorcraft types, mission flight phases, flight envelopes, and flight environmental characteristics and to provide criteria for three levels of flying qualities, a systematic treatment of failures and reliability, both conventional and multiaxis controllers, and external vision aids which may also incorporate synthetic display content. Existing and new criteria were incorporated into the new structure wherever they could be substantiated.

  4. A rotorcraft flight database for validation of vision-based ranging algorithms

    NASA Technical Reports Server (NTRS)

    Smith, Phillip N.

    1992-01-01

    A helicopter flight test experiment was conducted at the NASA Ames Research Center to obtain a database consisting of video imagery and accurate measurements of camera motion, camera calibration parameters, and true range information. The database was developed to allow verification of monocular passive range estimation algorithms for use in the autonomous navigation of rotorcraft during low altitude flight. The helicopter flight experiment is briefly described. Four data sets representative of the different helicopter maneuvers and the visual scenery encountered during the flight test are presented. These data sets will be made available to researchers in the computer vision community.

  5. Automatic Tip Vortex Core Profiling for Numerical Flow Simulations of Rotorcraft in Hover

    NASA Technical Reports Server (NTRS)

    Kao, David L.; Chaderjian, Neal M.

    2010-01-01

    An automated approach is presented that extracts visual and quantitative data from vortex cores produced by Navier-Stokes simulations of rotorcraft in hover mode. This approach extracts contiguous rotor tip vortex-core trajectories, cross-flow velocity profiles, and vortex-core diameter variation with wake age (azimuth angle). This automated approach is faster and more accurate than a conventional manual approach. Moreover, this new approach allows for an efficient way to quantitatively compare vortex-core profiles from different flow simulations, e.g., grid resolution studies, and validate computed results with experimental data

  6. Aircraft noise prediction program theoretical manual: Rotorcraft System Noise Prediction System (ROTONET), part 4

    NASA Technical Reports Server (NTRS)

    Weir, Donald S.; Jumper, Stephen J.; Burley, Casey L.; Golub, Robert A.

    1995-01-01

    This document describes the theoretical methods used in the rotorcraft noise prediction system (ROTONET), which is a part of the NASA Aircraft Noise Prediction Program (ANOPP). The ANOPP code consists of an executive, database manager, and prediction modules for jet engine, propeller, and rotor noise. The ROTONET subsystem contains modules for the prediction of rotor airloads and performance with momentum theory and prescribed wake aerodynamics, rotor tone noise with compact chordwise and full-surface solutions to the Ffowcs-Williams-Hawkings equations, semiempirical airfoil broadband noise, and turbulence ingestion broadband noise. Flight dynamics, atmosphere propagation, and noise metric calculations are covered in NASA TM-83199, Parts 1, 2, and 3.

  7. Civil applications of high-speed rotorcraft and powered-lift aircraft configurations

    NASA Technical Reports Server (NTRS)

    Albers, James A.; Zuk, John

    1987-01-01

    Advanced subsonic vertical and short takeoff and landing (V/STOL) aircraft configurations offer new transportation options for civil applications. Described is a range of vehicles from low-disk to high-disk loading aircraft, including high-speed rotorcraft, V/STOL aircraft, and short takeoff and landing (STOL) aircraft. The status and advantages of the various configurations are described. Some of these show promise for relieving congestion in high population-density regions and providing transportation opportunities for low population-density regions.

  8. A comprehensive analytical model of rotorcraft aerodynamics and dynamics. Part 1: Analysis development

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1980-01-01

    Structural, inertia, and aerodynamic models were combined to form a comprehensive model of rotor aerodynamics and dynamics that is applicable to a wide range of problems and a wide class of vehicles. A digital computer program is used to calculate rotor performance, loads, and noise; helicopter vibration and gust response; flight dynamics and handling qualities; and system aeroelastic stability. The analysis is intended for use in the design, testing, and evaluation of rotors and rotorcraft, and to be a basis for further development of rotary wing theories.

  9. Integration of Environment Sensing and Control Functions for Robust Rotorcraft UAV (RUAV) Guidance

    NASA Astrophysics Data System (ADS)

    Dadkhah Tehrani, Navid

    Unmanned Air Vehicles (UAVs) have started supplanting manned aircraft in a broad range of tasks. Vehicles such as miniature rotorcrafts with broad maneuvering range and small size can enter remote locations that are hard to reach using other air and ground vehicles. Developing a guidance system which enables a Rotorcraft UAV (RUAV) to perform such tasks involves combing key elements from robotics motion planning, control system design, trajectory optimization as well as dynamics modeling. The focus of this thesis is to integrate a guidance system for a small-scale rotorcraft to enable a high level of performance and situational awareness. We cover large aspects of the system integration including modeling, control system design, environment sensing as well as motion planning in the presence of uncertainty. The system integration in this thesis is performed around a Blade-CX2 miniature coaxial helicopter. The first part of the thesis focuses on the development of the parameterized model for the Blade-CX2 helicopter with an emphasis on the coaxial rotor configuration. The model explicitly accounts for the dynamics of lower rotor and uses an implicit lumped parameter model for the upper rotor and stabilizer-bar. The parameterized model was identified using frequency domain system identification. In the second part of the thesis, we use the identified model to design a control law for the Blade-CX2 helicopter. The control augmentation for the Blade-CX2 helicopter was based on a nested attitude-velocity loop control architecture and was designed following classical loop-shaping and dynamic inversion techniques. A path following layer wrapped around the velocity control system enables the rotorcraft to follow reference trajectories specified by a sequence of waypoints and velocity vectors. Such reference paths are common in autonomous guidance systems. Finally, the third part of the thesis addresses the problem of autonomous navigation through a partially known or unknown 3D cluttered environment. The proposed multi-layer hierarchical guidance framework is based on optimal control principles and relies on the interaction of several subsystems such as environment sensing and mapping, Cost-to-Go (CTG) function update, reactive planning and Receding Horizon (RH) optimization. It is also tightly integrated with the path following controller.

  10. Simulation and analysis of image-based navigation system for rotorcraft low-altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Phatak, Anil V.

    1988-01-01

    The automation of helicopter NOE flight entails the modification of nominal trajectories on the basis of the detection and location of obstacles by means of onboard sensors. This process is presently studied using a sequence of images from a passive sensor mounted at the helicopter's center of gravity and oriented with the viewing axis along the rotorcraft's longitudinal body-axis. Three different Kalman filters are used to estimate the location of an object on the ground during the course of various simulated helicopter maneuvers; two of the three filters are found to yield good object location estimates.

  11. Engineering science research issues in high power density transmission dynamics for aerospace applications. [rotorcraft geared rotors

    NASA Technical Reports Server (NTRS)

    Singh, Rajendra; Houser, Donald R.

    1993-01-01

    This paper discusses analytical and experimental approaches that will be needed to understand dynamic, vibro-acoustic and design characteristics of high power density rotorcraft transmissions. Complexities associated with mathematical modeling of such systems will be discussed. An overview of research work planned during the next several years will be presented, with emphasis on engineering science issues such as gear contact mechanics, multi-mesh drive dynamics, parameter uncertainties, vibration transmission through bearings, and vibro-acoustic characteristics of geared rotor systems and housing-mount structures. A few examples of work in progress are cited.

  12. Rotorcraft pursuit-evasion in nap-of-the-earth flight

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Cheng, V. H. L.; Kim, E.

    1990-01-01

    Two approaches for studying the pursuit-evasion problem between rotorcraft executing nap-of-the-earth flight are presented. The first of these employs a constant speed kinematic helicopter model, while the second approach uses a three degree of freedom point-mass model. The candidate solutions to the first differential game are generated by integrating the state-costate equations backward in time. The second problem employs feedback linearization to obtain guidance laws in nonlinear feedback form. Both approaches explicitly use the terrain profile data. Sample extremals are presented.

  13. Semi-active magnetorheological seat suspensions for enhanced crashworthiness and vibration isolation of rotorcraft seats

    NASA Astrophysics Data System (ADS)

    Hiemenz, Gregory J.

    This research focuses on the use of magnetorheological (MR) dampers for enhanced occupant protection during harsh vertical landings as well as isolation of the occupant from cockpit vibrations. The capabilities of the current state-of-the-art in helicopter crew seat energy absorption systems are highly limited because they cannot be optimally adapted to each individual crash scenario (i.e. variations in both occupant weight and crash load level). They also present an unnecessarily high risk of injury by not minimizing the load transmitted to the occupant during a crash. Additionally, current rotorcraft seats provide no means of isolating the occupant from harmful cockpit vibrations. The objective of this research was to investigate and demonstrate the feasibility and benefits of an MR-based suspension for rotorcraft seats. As such, this research began with an in-depth investigation into design feasibility. Three MR seat suspension design cases are investigated: (1) for only vibration isolation, (2) for adaptive occupant protection, and (3) for combined adaptive occupant protection and vibration isolation. It is shown that MR-based suspensions are feasible for each of these cases and the performance benefits and tradeoffs are discussed for each case. Next, to further illustrate the occupant protection benefits gained with an MR-based suspension, three control strategies were developed and performance metrics were compared. It was shown that MR dampers can be controlled such that they will automatically adapt to the crash load level as well as occupant weight. By using feedback of sensor signals, MR dampers were adjusted to utilize the full stroke capability of the seat suspension regardless crash level and occupant weight. The peak load transmitted to the occupant and the risk of spinal injury, therefore, was always minimized. Because this control significantly reduced or eliminated injury risk during less severe landings, it is a significant advance over the current state-of-the-art rotorcraft seat suspensions which can provide no better than 20% risk of occupant injury. Finally, an MR-based seat suspension designed solely for the purposes of vibration isolation was designed, analyzed, and experimentally demonstrated. MR dampers were integrated into the current crashworthy SH-60 crew seat with minimal weight impact such that the original crashworthy capabilities were maintained. Then, utilizing semi-active control, experimental vibration testing demonstrated that the system reduced vertical cockpit vibrations transmitted to the occupant by 76%. This is a significant advance over current state-of-the-art rotorcraft seats which provide no attenuation of cockpit vibrations.

  14. Exotic propulsion systems - A space exploration imperative

    NASA Astrophysics Data System (ADS)

    Haloulakos, V. E.

    1992-07-01

    Treatment is given to the need for and use of unusual propulsion systems in the forthcoming development of space vehicles. The requirements of lunar and Martian outposts are set forth, and the expected delta velocities, vehicle masses, and specific energy levels are listed. Exotic propulsion systems are considered that can provide the specific impulse levels needed for the scenarios discussed. Discussed are antimatter propulsion, teleportation, and antigravity machines, and the theoretical and practical implications of their development and use are mentioned. The use of antiprotons in medical treatment and materials processing is explained and extended to the propulsion application. The paper demonstrates the potential of exotic propulsion systems to contribute to space exploration.

  15. Software To Secure Distributed Propulsion Simulations

    NASA Technical Reports Server (NTRS)

    Blaser, Tammy M.

    2003-01-01

    Distributed-object computing systems are presented with many security threats, including network eavesdropping, message tampering, and communications middleware masquerading. NASA Glenn Research Center, and its industry partners, has taken an active role in mitigating the security threats associated with developing and operating their proprietary aerospace propulsion simulations. In particular, they are developing a collaborative Common Object Request Broker Architecture (CORBA) Security (CORBASec) test bed to secure their distributed aerospace propulsion simulations. Glenn has been working with its aerospace propulsion industry partners to deploy the Numerical Propulsion System Simulation (NPSS) object-based technology. NPSS is a program focused on reducing the cost and time in developing aerospace propulsion engines

  16. Magnetic levitation and MHD propulsion

    NASA Astrophysics Data System (ADS)

    Tixador, P.

    1994-04-01

    Magnetic levitation and MHD propulsion are now attracting attention in several countries. Different superconducting MagLev and MHD systems will be described concentrating on, above all, the electromagnetic aspect. Some programmes occurring throughout the world will be described. Magnetic levitated trains could be the new high speed transportation system for the 21st century. Intensive studies involving MagLev trains using superconductivity have been carried out in Japan since 1970. The construction of a 43 km long track is to be the next step. In 1991 a six year programme was launched in the United States to evaluate the performances of MagLev systems for transportation. The MHD (MagnetoHydroDynamic) offers some interesting advantages (efficiency, stealth characteristics, ...) for naval propulsion and increasing attention is being paid towards it nowadays. Japan is also up at the top with the tests of Yamato I, a 260 ton MHD propulsed ship. Depuis quelques années nous assistons à un redémarrage de programmes concernant la lévitation et la propulsion supraconductrices. Différents systèmes supraconducteurs de lévitation et de propulsion seront décrits en examinant plus particulièrement l'aspect électromagnétique. Quelques programmes à travers le monde seront abordés. Les trains à sustentation magnétique pourraient constituer un nouveau mode de transport terrestre à vitesse élevée (500 km/h) pour le 21^e siècle. Les japonais n'ont cessé de s'intéresser à ce système avec bobine supraconductrice. Ils envisagent un stade préindustriel avec la construction d'une ligne de 43 km. En 1991 un programme américain pour une durée de six ans a été lancé pour évaluer les performances des systèmes à lévitation pour le transport aux Etats Unis. La MHD (Magnéto- Hydro-Dynamique) présente des avantages intéressants pour la propulsion navale et un regain d'intérêt apparaît à l'heure actuelle. Le japon se situe là encore à la pointe des développements actuels avec en particulier les premiers essais en rade de Kobe de Yamato I, navire de 260 tonnes, entraîné par MHD.

  17. Status of automatic guidance systems for rotorcraft in low altitude flight

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Cheng, Victor H. L.; Swenson, Harry N.

    1992-01-01

    Rotorcraft operating in high-threat environments fly close to the earth's surface to utilize surrounding terrain, vegetation, or man-made objects to minimize the risk of being detected by an enemy. The piloting of the rotorcraft is at best a very demanding task and the pilots need help from on-board automation tools in order to devote more time to mission-related activities. The Automated Nap-of-the-Earth (NOE) Flight Program is a cooperative NASA/Army program aimed at the development of technologies for enhancing piloted low-altitude/NOE flight path management and control through computer and sensor aiding. The long-term objective is to work towards achieving automation for aiding the pilot in NOE flight with a flight demonstration of resulting computer/sensor aiding concepts at an established course. The technology for pilot-centered NOE automation is not currently available. Success in automating NOE functions will depend on major breakthroughs in real-time flight path planning algorithms, effective methods for the pilot to interface to the automatic modes, understanding of visual images, sensor data processing/fusion, and sensor development. Our approach to developing the technologies required to solve this problem consist of the following phases: (1) algorithm development, (2) laboratory evaluation, (3) piloted ground simulation, and (4) evaluation in flight. An overview of the research in this area at NASA Ames Research Center is given.

  18. Preliminary design features of the RASCAL: A NASA /Army rotorcraft in-flight simulator

    NASA Technical Reports Server (NTRS)

    Aiken, Edwin W.; Jacobsen, Robert A.; Eshow, Michelle M.; Hindson, William S.; Doane, Douglas H.

    1993-01-01

    Salient design features of a new NASA/Army research rotorcraft - the Rotorcraft-Aircrew Systems Concepts Airborne Laboratory (RASCAL) - are described. Using a UH-60A Black Hawk helicopter as a baseline vehicle, the RASCAL will be a flying laboratory capable of supporting the research requirements of major NASA and Army guidance, control, and display research programs. The paper describes the research facility requirements of these programs together with other critical constraints on the design of the research system, including safety-of-flight. Research program schedules demand a phased development approach, wherein specific research capability milestones are met and flight research projects are flown throughout the complete development cycle of the RASCAL. This development approach is summarized, and selected features of the research system are described. The research system includes a full-authority, programmable, fault-tolerant/fail-safe, fly-by-wire flight control system and a real-time obstacle detection and avoidance system which will generate low-altitude guidance commands to the pilot on a wide field-of-view, color helmet-mounted display.

  19. Preliminary design features of the RASCAL - A NASA/Army rotorcraft in-flight simulator

    NASA Technical Reports Server (NTRS)

    Aiken, Edwin W.; Jacobsen, Robert A.; Eshow, Michelle M.; Hindson, William S.; Doane, Douglas H.

    1992-01-01

    Salient design features of a new NASA/Army research rotorcraft - the Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL) - are described. Using a UH-60A Black Hawk helicopter as a baseline vehicle, the RASCAL will be a flying laboratory capable of supporting the research requirements of major NASA and Army guidance, control, and display research programs. The paper describes the research facility requirements of these programs together with other critical constraints on the design of the research system, including safety-of-flight. Research program schedules demand a phased development approach, wherein specific research capability milestones are met and flight research projects are flown throughout the complete development cycle of the RASCAL. This development approach is summarized, and selected features of the research system are described. The research system includes a full-authority, programmable, fault-tolerant/fail-safe, fly-by-wire flight control system and a real-time obstacle detection and avoidance system which will generate low-latitude guidance commands to the pilot on a wide field-of-view, color helmet-mounted display.

  20. Flight-Test Validation and Flying Qualities Evaluation of a Rotorcraft UAV Flight Control System

    NASA Technical Reports Server (NTRS)

    Mettler, Bernard; Tuschler, Mark B.; Kanade, Takeo

    2000-01-01

    This paper presents a process of design and flight-test validation and flying qualities evaluation of a flight control system for a rotorcraft-based unmanned aerial vehicle (RUAV). The keystone of this process is an accurate flight-dynamic model of the aircraft, derived by using system identification modeling. The model captures the most relevant dynamic features of our unmanned rotorcraft, and explicitly accounts for the presence of a stabilizer bar. Using the identified model we were able to determine the performance margins of our original control system and identify limiting factors. The performance limitations were addressed and the attitude control system was 0ptimize.d for different three performance levels: slow, medium, fast. The optimized control laws will be implemented in our RUAV. We will first determine the validity of our control design approach by flight test validating our optimized controllers. Subsequently, we will fly a series of maneuvers with the three optimized controllers to determine the level of flying qualities that can be attained. The outcome enable us to draw important conclusions on the flying qualities requirements for small-scale RUAVs.

  1. Projection Moire Interferometry for Rotorcraft Applications: Deformation Measurements of Active Twist Rotor Blades

    NASA Technical Reports Server (NTRS)

    Fleming, Gary A.; Soto, Hector L.; South, Bruce W.

    2002-01-01

    Projection Moire Interferometry (PMI) has been used during wind tunnel tests to obtain azimuthally dependent blade bending and twist measurements for a 4-bladed Active Twist Rotor (ATR) system in simulated forward flight. The ATR concept offers a means to reduce rotor vibratory loads and noise by using piezoelectric active fiber composite actuators embedded in the blade structure to twist each blade as they rotate throughout the rotor azimuth. The twist imparted on the blades for blade control causes significant changes in blade loading, resulting in complex blade deformation consisting of coupled bending and twist. Measurement of this blade deformation is critical in understanding the overall behavior of the ATR system and the physical mechanisms causing the reduction in rotor loads and noise. PMI is a non-contacting, video-based optical measurement technique capable of obtaining spatially continuous structural deformation measurements over the entire object surface within the PMI system field-of-view. When applied to rotorcraft testing, PMI can be used to measure the azimuth-dependent blade bending and twist along the full span of the rotor blade. This paper presents the PMI technique as applied to rotorcraft testing, and provides results obtained during the ATR tests demonstrating the PMI system performance. PMI measurements acquired at select blade actuation conditions generating minimum and maximum rotor loads are provided to explore the interrelationship between rotor loads, blade bending, and twist.

  2. Deriving Function-failure Similarity Information for Failure-free Rotorcraft Component Design

    NASA Technical Reports Server (NTRS)

    Roberts, Rory A.; Stone, Robert B.; Tumer, Irem Y.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Performance and safety are the top concerns of high-risk aerospace applications at NASA. Eliminating or reducing performance and safety problems can be achieved with a thorough understanding of potential failure modes in the design that lead to these problems. The majority of techniques use prior knowledge and experience as well as Failure Modes and Effects as methods to determine potential failure modes of aircraft. The aircraft design needs to be passed through a general technique to ensure that every potential failure mode is considered, while avoiding spending time on improbable failure modes. In this work, this is accomplished by mapping failure modes to certain components, which are described by their functionality. In turn, the failure modes are then linked to the basic functions that are carried within the components of the aircraft. Using the technique proposed in this paper, designers can examine the basic functions, and select appropriate analyses to eliminate or design out the potential failure modes. This method was previously applied to a simple rotating machine test rig with basic functions that are common to a rotorcraft. In this paper, this technique is applied to the engine and power train of a rotorcraft, using failures and functions obtained from accident reports and engineering drawings.

  3. Application of Function-Failure Similarity Method to Rotorcraft Component Design

    NASA Technical Reports Server (NTRS)

    Roberts, Rory A.; Stone, Robert E.; Tumer, Irem Y.; Clancy, Daniel (Technical Monitor)

    2002-01-01

    Performance and safety are the top concerns of high-risk aerospace applications at NASA. Eliminating or reducing performance and safety problems can be achieved with a thorough understanding of potential failure modes in the designs that lead to these problems. The majority of techniques use prior knowledge and experience as well as Failure Modes and Effects as methods to determine potential failure modes of aircraft. During the design of aircraft, a general technique is needed to ensure that every potential failure mode is considered, while avoiding spending time on improbable failure modes. In this work, this is accomplished by mapping failure modes to specific components, which are described by their functionality. The failure modes are then linked to the basic functions that are carried within the components of the aircraft. Using this technique, designers can examine the basic functions, and select appropriate analyses to eliminate or design out the potential failure modes. The fundamentals of this method were previously introduced for a simple rotating machine test rig with basic functions that are common to a rotorcraft. In this paper, this technique is applied to the engine and power train of a rotorcraft, using failures and functions obtained from accident reports and engineering drawings.

  4. Laser Ablation Propulsion A Study

    NASA Astrophysics Data System (ADS)

    Irfan, Sayed A.; Ugalatad, Akshata C.

    Laser Ablation Propulsion (LAP) will serve as an alternative propulsion system for development of microthrusters. The principle of LAP is that when a laser (pulsed or continuous wave) with sufficient energy (more than the vaporization threshold energy of material) is incident on material, ablation or vaporization takes place which leads to the generation of plasma. The generated plasma has the property to move away from the material hence pressure is generated which leads to the generation of thrust. Nowadays nano satellites are very common in different space and defence applications. It is important to build micro thruster which are useful for orienting and re-positioning small aircraft (like nano satellites) above the atmosphere. modelling of LAP using MATLAB and Mathematica. Schematic is made for the suitable optical configuration of LAP. Practical experiments with shadowgraphy and self emission techniques and the results obtained are analysed taking poly (vinyl-chloride) (PVC) as propellant to study the

  5. Progress in revolutionary propulsion physics

    E-print Network

    Marc G. Millis

    2011-01-05

    Prior to 1988, traversable wormholes were just science fiction. Prior to 1994, warp drives were just fiction. Since then, these notions matured into published scientific discourse, where key issues and unknowns continue to be raised and investigated. In 2009, the American Institute of Aeronautics and Astronautics published a peer-reviewed, expansive technical volume on these and other investigations toward breakthrough propulsion. This paper summarizes the key assertions from that 739-page volume, describing the collective state-of-the-art and candidate research steps that will lead to discovering if, or how, such breakthroughs might finally be achieved. Coverage includes: prerequisites for space drive physics, manipulating gravity or inertia for propulsion, lessons from superconductor experiments, null results with "lifters", implications of photon momentum in media, quantum vacuum physics, and the faster-than-light implications of general relativity and quantum non-locality.

  6. Planetary explorer liquid propulsion study

    NASA Technical Reports Server (NTRS)

    Mckevitt, F. X.; Eggers, R. F.; Bolz, C. W.

    1971-01-01

    An analytical evaluation of several candidate monopropellant hydrazine propulsion system approaches is conducted in order to define the most suitable configuration for the combined velocity and attitude control system for the Planetary Explorer spacecraft. Both orbiter and probe-type missions to the planet Venus are considered. The spacecraft concept is that of a Delta launched spin-stabilized vehicle. Velocity control is obtained through preprogrammed pulse-mode firing of the thrusters in synchronism with the spacecraft spin rate. Configuration selection is found to be strongly influenced by the possible error torques induced by uncertainties in thruster operation and installation. The propulsion systems defined are based on maximum use of existing, qualified components. Ground support equipment requirements are defined and system development testing outlined.

  7. Attitude propulsion technology for TOPS

    NASA Technical Reports Server (NTRS)

    Moynihan, P. I.

    1972-01-01

    The thermoelectric outer planet spacecraft (TOPS) attitude propulsion subsystem (APS) effort is discussed. It includes the tradeoff rationale that went into the selection of an anhydrous hydrazine baseline system, followed by a discussion of the 0.22 N thruster and its integration into a portable, self-contained propulsion module that was designed, developed, and man rated to support the TOPS single-axis attitude control tests. The results of a cold-start feasibility demonstration with a modified thruster are presented. A description of three types of 0.44 thrusters that were procured for in-house evaluation is included along with the results of the test program. This is followed by a description of the APS feed system components, their evaluations, and a discussion of an evaluation of elastomeric material for valve seat seals. A list of new technology items which will be of value for application to future systems of this type is included.

  8. Heavy Vehicle Propulsion Materials Program

    SciTech Connect

    Diamond, S.; Johnson, D.R.

    1999-04-26

    The objective of the Heavy Vehicle Propulsion Materials Program is to develop the enabling materials technology for the clean, high-efficiency diesel truck engines of the future. The development of cleaner, higher-efficiency diesel engines imposes greater mechanical, thermal, and tribological demands on materials of construction. Often the enabling technology for a new engine component is the material from which the part can be made. The Heavy Vehicle Propulsion Materials Program is a partnership between the Department of Energy (DOE), and the diesel engine companies in the United States, materials suppliers, national laboratories, and universities. A comprehensive research and development program has been developed to meet the enabling materials requirements for the diesel engines of the future. Advanced materials, including high-temperature metal alloys, intermetallics, cermets, ceramics, amorphous materials, metal- and ceramic-matrix composites, and coatings, are investigated for critical engine applications.

  9. The 21st century propulsion

    NASA Technical Reports Server (NTRS)

    Haloulakos, V. E.; Boehmer, C.

    1990-01-01

    The prediction of future space travel in the next millennium starts by examining the past and extrapolating into the far future. Goals for the 21st century include expanded space travel and establishment of permanent manned outposts, and representation of Lunar and Mars outposts as the most immediate future in space. Nuclear stage design/program considerations; launch considerations for manned Mars missions; and far future propulsion schemes are outlined.

  10. Quiet powered-lift propulsion

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Latest results of programs exploring new propulsion technology for powered-lift aircraft systems are presented. Topics discussed include results from the 'quiet clean short-haul experimental engine' program and progress reports on the 'quiet short-haul research aircraft' and 'tilt-rotor research aircraft' programs. In addition to these NASA programs, the Air Force AMST YC 14 and YC 15 programs were reviewed.

  11. Impeller for Water Jet Propulsion

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Marshall Space Flight Center engineers helped North American Marine Jet (NAMJ), Inc. improve the proposed design of a new impeller for jet propulsion system. With a three-dimensional computer model of the new marine jet engine blades, engineers were able to quickly create a solid ploycarbonate model of it. The rapid prototyping allowed the company to avoid many time-consuming and costly steps in creating the impeller.

  12. Magnetic levitation and MHD propulsion

    Microsoft Academic Search

    P. Tixador

    1994-01-01

    Magnetic levitation and MHD propulsion are now attracting attention in several countries. Different superconducting MagLev and MHD systems will be described concentrating on, above all, the electromagnetic aspect. Some programmes occurring throughout the world will be described. Magnetic levitated trains could be the new high speed transportation system for the 21st century. Intensive studies involving MagLev trains using superconductivity have

  13. Electrodynamic Tethers for Spacecraft Propulsion

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Estes, Robert D.; Lorenzini, Enrico; Martinez-Sanchez, Manuel; Sanmartin, Juan; Vas, Irwin

    1998-01-01

    Relatively short electrodynamic tethers can use solar power to 'push' against a planetary magnetic field to achieve propulsion without the expenditure of propellant. The groundwork has been laid for this type of propulsion. NASA began developing tether technology for space applications in the 1960's. Important recent milestones include retrieval of a tether in space (TSS-1, 1992), successful deployment of a 20-km-long tether in space (SEDS-1, 1993), and operation of an electrodynamic tether with tether current driven in both directions-power and thrust modes (PMG, 1993). The planned Propulsive Small Expendable Deployer System (ProSEDS) experiment will demonstrate electrodynamic tether thrust during its flight in early 2000. ProSEDS will use the flight-proven Small Expendable Deployer System (SEDS) to deploy a 5 km bare copper tether from a Delta II upper stage to achieve approximately 0.4 N drag thrust, thus deorbiting the stage. The experiment will use a predominantly 'bare' tether for current collection in lieu of the endmass collector and insulated tether approach used on previous missions. Theory and ground-based plasma chamber testing indicate that the bare tether is a highly-efficient current collector. The flight experiment is a precursor to utilization of the technology on the International Space Station for reboost application and the more ambitious electrodynamic tether upper stage demonstration mission which will be capable of orbit raising, lowering and inclination changes - all using electrodynamic thrust. In addition, the use of this type of propulsion may be attractive for future missions at Jupiter and any other planetary body with a magnetosphere.

  14. Interstellar Propulsion Research Within NASA

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Cook, Stephen (Technical Monitor)

    2001-01-01

    NASA is actively conducting advanced propulsion research and technology development in various in-space transportation technologies with potential application to interstellar missions and precursors. Within the last few years, interest in the scientific community in interstellar missions as well as outer heliospheric missions, which could function as interstellar precursor missions, has increased. A mission definition team was charted by NASA to define such a precursor, The Interstellar Probe, which resulted in a prioritization of relatively near-term transportation technologies to support its potential implementation. In addition, the goal of finding and ultimately imaging extra solar planets has raised the issue of our complete inability to mount an expedition to such as planet, should one be found. Even contemplating such a mission with today's technology is a stretch of the imagination. However, there are several propulsion concepts, based on known physics, that have promise to enable interstellar exploration in the future. NASA is making small, incremental investments in some key advanced propulsion technologies in an effort to advance their state-of-the-art in support potential future mission needs. These technologies, and their relative maturity, are described.

  15. HSCT integrated propulsion control issues

    NASA Technical Reports Server (NTRS)

    Carlin, Christopher M.

    1992-01-01

    The propulsion control system affects the economics of the HSCT through the mechanisms indicated. Weight reduction is paramount in an aircraft of this type. Significant reductions are possible relative to the SST or even current technology if improvements are made in areas such as high temperature electronics. Dependability is an increasingly important parameter in all aircraft, but the higher capital cost of the HSCT makes it doubly important. Conversely the more difficult HSCT design problem makes it more difficult to achieve. Integration of propulsion controls will make it possible to improve both the static and dynamic performance of the HSCT propulsion system. Noise and emissions requirements may introduce novel control system requirements such as automatically programmed takeoff thrust for noise abatement. Control system development technology is evolving. For HSCT, highly automated and thoroughly validated tools will be required to reliably achieve desired system performance at introduction, and to reduce development costs. A technology plan was developed to prepare for HSCT development. This presentation addresses the portion of the plan required to demonstrate technology readiness for the HSCT in the late 1990's rather than the technology development currently in progress.

  16. Space station propulsion requirements study

    NASA Technical Reports Server (NTRS)

    Wilkinson, C. L.; Brennan, S. M.

    1985-01-01

    Propulsion system requirements to support Low Earth Orbit (LEO) manned space station development and evolution over a wide range of potential capabilities and for a variety of STS servicing and space station operating strategies are described. The term space station and the overall space station configuration refers, for the purpose of this report, to a group of potential LEO spacecraft that support the overall space station mission. The group consisted of the central space station at 28.5 deg or 90 deg inclinations, unmanned free-flying spacecraft that are both tethered and untethered, a short-range servicing vehicle, and a longer range servicing vehicle capable of GEO payload transfer. The time phasing for preferred propulsion technology approaches is also investigated, as well as the high-leverage, state-of-the-art advancements needed, and the qualitative and quantitative benefits of these advancements on STS/space station operations. The time frame of propulsion technologies applicable to this study is the early 1990's to approximately the year 2000.

  17. Space station propulsion analysis study

    NASA Technical Reports Server (NTRS)

    Donovan, R. M.; Sovey, J. S.; Hannum, N. B.

    1984-01-01

    This paper summarizes the impacts on the weight, volume and power usage of a manned space station and its 90-day resupply for three integrated, auxiliary propulsion subsystems. The study was performed in coordination with activities of the Space Staton Concept Development Group (CDG). The study focused on three space station propulsion high-low thrust options that make use of fluids that will be available on the manned space station. Specific uses of carbon dioxide, water and cryogen boiloff were considered. For each of the options the increase in station hardware mass and volume to accommodate the dual thrust option is offset by the resupply savings, relative to the reference hydrazine system, after one to several resupplies. Over the life of the station the savings in cost of logistics could be substantial. The three options are examples of alternative technology paths that, because of the opportunity they provide for integration with the environmental control life support system (ECLSS) and OTV propellant storage systems, may reduce the scarring which is required on the early station to meet the increasing propulsion requirements of the growth station.

  18. A Closed-Loop Optimal Neural-Network Controller to Optimize Rotorcraft Aeromechanical Behaviour. Volume 1; Theory and Methodology

    NASA Technical Reports Server (NTRS)

    Leyland, Jane Anne

    2001-01-01

    Given the predicted growth in air transportation, the potential exists for significant market niches for rotary wing subsonic vehicles. Technological advances which optimise rotorcraft aeromechanical behaviour can contribute significantly to both their commercial and military development, acceptance, and sales. Examples of the optimisation of rotorcraft aeromechanical behaviour which are of interest include the minimisation of vibration and/or loads. The reduction of rotorcraft vibration and loads is an important means to extend the useful life of the vehicle and to improve its ride quality. Although vibration reduction can be accomplished by using passive dampers and/or tuned masses, active closed-loop control has the potential to reduce vibration and loads throughout a.wider flight regime whilst requiring less additional weight to the aircraft man that obtained by using passive methads. It is ernphasised that the analysis described herein is applicable to all those rotorcraft aeromechanical behaviour optimisation problems for which the relationship between the harmonic control vector and the measurement vector can be adequately described by a neural-network model.

  19. Components of the Solar Thermal Propulsion Engine

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Researchers at the Marshall Space Flight Center (MSFC) have designed, fabricated, and tested the first solar thermal engine, a non-chemical rocket engine that produces lower thrust but has better thrust efficiency than a chemical combustion engine. This photograph shows components for the thermal propulsion engine being laid out prior to assembly. MSFC turned to solar thermal propulsion in the early 1990s due to its simplicity, safety, low cost, and commonality with other propulsion systems. As part of MSFC's Space Transportation Directorate, the Propulsion Research Center serves as a national resource for research of advanced, revolutionary propulsion technologies. The mission is to move the Nation's capabilities beyond the confines of conventional chemical propulsion into an era of aircraft-like access to Earth-orbit, rapid travel throughout the solar system, and exploration of interstellar space.

  20. The NASA low thrust propulsion program

    NASA Technical Reports Server (NTRS)

    Stone, James R.; Bennett, Gary L.

    1989-01-01

    The NASA OAST Propulsion, Power, and Energy Division supports a low thrust propulsion program aimed at providing high performance options for a broad range of near-term and far-term mission and vehicles. Low thrust propulsion has a major impact on the mission performance of essentially all spacecraft and vehicles. On-orbit lifetimes, payloads, and trip times are significantly impacted by low thrust propulsion performance and integration features for Earth-to-orbit (ETO) vehicles, Earth-orbit and planetary spacecraft, and large platforms in Earth orbit. Major emphases are on low thrust chemical propulsion, both storables and hydrogen/oxygen; low-power (auxiliary) electric arcjects and resistojets; and high-power (primary) electric propulsion, including ion, magnetoplasmadynamic (MPD), and electrodeless concepts. The major recent accomplishments of the program are presented and their impacts discussed.