... Order 12866; 2. Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034...-062-AD; Amendment 39-17251; AD 2012-22-14] RIN 2120-AA64 Airworthiness Directives; Sikorsky Aircraft... Aircraft Corporation (Sikorsky) Model S-70, S-70A, S-70C, S-70C(M), and S-70C(M1) helicopters with...
...These special conditions are issued for the Sikorsky Aircraft Corporation (Sikorsky) model S-92A helicopter. This helicopter, as modified by Sikorsky, will have novel or unusual design features associated with installing an optional SAR AFCS. The applicable airworthiness standards do not contain adequate or appropriate safety standards for this design feature. These special conditions contain......
... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-92A Helicopters AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of...: John Coffey, Aviation Safety Engineer, Boston Aircraft Certification Office, 12 New England...
... relating to the ERB on this and similar model helicopters. AD 82-17-03, issued July 30, 1982 (47 FR 35469... July 30, 1981). AD 2003-04-15, issued February 14, 2003 (68 FR 8994, February 27, 2003), requires... October 26, 2011, at 76 FR 66205, the Federal Register published our notice of proposed rulemaking...
... Corporation (Sikorsky) Model Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final... Model S-70, S-70A, and S-70C helicopters, which are restricted category helicopters derived from the military Model UH-60 helicopter. This AD would require reducing or establishing life limits for...
... Corporation (Sikorsky) Model Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... Sikorsky Model S-70, S-70A, S-70C, S-70C (M), and S-70C (M1) helicopters with General Electric (GE) T700-GE-401C or T700-GE-701C engines installed. This proposed AD is prompted by a reevaluation of the...
... April 11, 2000 (65 FR 19477-78). Regulatory Findings We have determined that this AD will not have.... Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February... Sikorsky Model S-92A helicopters. This action requires making pen and ink changes, inserting a copy of...
...'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect... Model S-76A, B, and C helicopters to require certain inspections of each spindle cuff assembly or blade fold cuff assembly for a crack. If there is a crack, this proposed AD would require replacing...
... in the Federal Register on February 11, 2009 (74 FR 6835). That action, a supplemental notice of... was published in the Federal Register on May 2, 2006 (71 FR 25783), and which proposed to require... 21, 2006 (71 FR 25783, May 2, 2006). We do not agree. Our review of the Model S-76 helicopter...
... helicopters was published in the Federal Register on May 13, 2010 (75 FR 26888). That action proposed to... FR 11034, February 26, 1979); and 3. Will not have a significant economic impact, positive or... in the tail rotor separating from the helicopter. The actions specified by this AD are intended...
Munin, Anatolii Grigor'evich
Problems related to the effect of the exterior noise produced by subsonic aircraft and helicopters on the environment and man are examined. The principal sources of noise produced by aircraft and helicopters are identified, and the physical pattern of noise generation is examined. Various method of reducing the noise of aircraft and helicopters are discussed, and methods are presented for predicting the acoustic environment at airports with allowance for the size of the aircraft park and the dynamics of flight operations.
...; 2. Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February... assemblies. This AD was prompted by four failures in the cyclic trim system on certain Enstrom model... failure of the cyclic trim system and subsequent loss of control of the helicopter. DATES: This AD...
Anderson, Joseph L.
The NASA must assess its aeronautical research program with economic as well as performance measures. It thus is interested in what price a new technology aircraft would carry to make it attractive to the buyer. But what price a given airplane or helicopter will carry is largely a reflection of the manufacturer's assessment of the competitive market into which the new aircraft will be introduced. The manufacturer must weigh any new aerodynamic or system technology innovation he would add to an aircraft by the impact of this innovation upon the aircraft's economic attractiveness and price. The intent of this paper is to give price standards against which new technologies and the NASA's research program can be assessed. Using reported prices for general aviation, helicopter, and transport aircraft, price estimating relations in terms of engine and airframe characteristics have been developed. The relations are given in terms of the aircraft type, its manufactured empty weight, engine weight, horsepower or thrust. Factors for the effects of inflation are included to aid in making predictions of future aircraft prices. There are discussions of aircraft price in terms of number of passenger seats, airplane size and research and development costs related to an aircraft model, and indirectly as to how new technologies, aircraft complexity and inflation have affected these.
Thomas, F.; Wisham, J.; Clemmer, T. P.; Orme, J. F.; Larsen, K. G.
We determined the differences in transport times and costs for patients transported by fixed-wing aircraft versus helicopter at ranges of 101 to 150 radial miles, where fixed-wing and helicopter in-hospital transports commonly overlap. Statistical analysis failed to show a significant difference between the trauma-care patients transported by helicopter (n = 109) and those transported by fixed-wing (n = 86) for age, injury severity score, hospital length of stay, hospital mortality, or discharge disability score. The times in returning patients to the receiving hospital by helicopter (n = 104) versus fixed-wing (n = 509) did not differ significantly. Helicopter transport costs per mile ($24), however, were 400% higher than those of fixed-wing aircraft with its associated ground ambulance transport costs ($6). Thus, helicopter transport is economically unjustified for interhospital transports exceeding 100 radial miles when an efficient fixed-wing service exists. PMID:2389575
Dexter, H. B.
The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified.
van Koersel, Antonius C.; Beerens, S. P.
Measurements of different types of aircraft are performed and used to obtain information on target characteristics and develop an algorithm to perform classification between jet aircraft, propeller aircraft and helicopters. To obtain a larger detection range, reduce background noise and to reduce classification errors in a multi-target environment, a real time adaptive beamformer algorithm is developed for a three microphone array. The output of the beamformer is submitted to a tracking algorithm. Acoustic signals from identified tracks are submitted to the classification algorithms. The algorithm is tested on data recorded during various field trials. The objective of the research, which is part of a research program for the Dutch Army, is to detect the passage of an aircraft with one or more mechanical wave sensors, either acoustic or seismic. After detection of a target, classification of the type of aircraft is requested (for example: helicopter-jet-propeller-rpv). If possible type identification is also requested. Earlier work showed promising results for detection and classification of helicopter targets. The projects resulted in an algorithm that can detect and classify helicopters, but it was developed to reject other targets. The chosen approach is to combine new aircraft detection and beamforming algorithms with the existing algorithms.
Anderson, Joseph L.
The NASA must assess its aeronautical research program with economic as well as performance measures. It thus is interested in what price a new technology aircraft would carry to make it attractive to the buyer. But what price a given airplane or helicopter will carry is largely a reflection of the manufacturer's assessment of the competitive market into which the new aircraft will be introduced. The manufacturer must weigh any new aerodynamic or system technology innovation he would add to an aircraft by the impact of this innovation upon the aircraft's cost to manufacture, economic attractiveness and price. The intent of this paper is to give price standards against which new technologies and the NASA's research program can be assessed. Using reported prices for sailplanes, general aviation, agriculture, helicopter, business and transport aircraft, price estimating relations in terms of engine and airframe characteristics have been developed. The relations are given in terms of the aircraft type, its manufactured empty weight, engine weight, horsepower or thrust. Factors for the effects of inflation are included to aid in making predictions of future aircraft prices. There are discussions of aircraft price in terms of number of passenger seats, airplane size and research and development costs related to an aircraft model, and indirectly how new technologies, aircraft complexity and inflation have affected these.
... Regulation; Information Collection; Corporate Aircraft Costs AGENCY: Department of Defense (DOD), General... collection requirement concerning corporate aircraft costs. Public comments are particularly invited on..., Corporate Aircraft Costs, by any of the following methods: Regulations.gov :...
Molino, J. A.
A review of 34 studies indicates that several factors or variables might be important in providing a psychoacoustic foundation for measurements of the noise from helicopters. These factors are phase relations, tail rotor noise, repetition rate, crest level, and generic differences between conventional aircraft and helicopters. Particular attention was given to the impulsive noise known as blade slap. Analysis of the evidence for and against each factor reveals that, for the present state of scientific knowledge, none of these factors should be regarded as the basis for a significant noise measurement correction due to impulsive blade slap. The current method of measuring effective perceived noise level for conventional aircraft appears to be adequate for measuring helicopter noise as well.
Beltramo, M. N.
Weight estimating relationships (WERs) and recurring production cost estimating relationships (CERs) were developed for helicopters at the system level. The WERs estimate system level weight based on performance or design characteristics which are available during concept formulation or the preliminary design phase. The CER (or CERs in some cases) for each system utilize weight (either actual or estimated using the appropriate WER) and production quantity as the key parameters.
Erickson, R. E.; Kufeld, R. M.; Cross, J. L.; Hodge, R. W.; Ericson, W. F.; Carter, R. D. G.
The flight test activities of the Rotor System Research Aircraft (RSRA), NASA 740, from June 30, 1981 to August 5, 1982 are reported. Tests were conducted in both the helicopter and compound configurations. Compound tests reconfirmed the Sikorsky flight envelope except that main rotor blade bending loads reached endurance at a speed about 10 knots lower than previously. Wing incidence changes were made from 0 to 10 deg.
Ostroff, A. J.; Wood, R. B.
A computer program was developed to integrate avionics research in navigation, guidance, controls, and displays with a realistic aircraft model. A user oriented program is described that allows a flexible combination of user supplied models to perform research in any avionics area. A preprocessor technique for selecting various models without significantly changing the memory storage is included. Also included are mathematical models for several avionics error models and for the CH-47 helicopter used in this program.
... 12866; 2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034... different life limits and the possibility that these same parts can be interchanged with civilian models with different life limits. The proposed actions are intended to establish a pro-rated in service...
... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will... fire extinguisher discharge tube (No. 1 engine tube). This proposed AD is prompted by the discovery... through 920169. This proposed AD is prompted by a recent event where an extinguishing test at a...
...: Discussion On May 14, 2012, at 77 FR 28328, the Federal Register published our notice of proposed rulemaking... NPRM (77 FR 28328, May 14, 2012). FAA's Determination We have reviewed the relevant information and... 12866; (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR...
... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation... deck tunnel assembly. This proposed AD is prompted by the discovery of cracks in T/R pylons. The.../R pylon and, if present, to repair the T/R Pylon and install a doubler on the aft shear deck...
...@faa.gov . SUPPLEMENTARY INFORMATION: Discussion On April 22, 2013, at 78 FR 23698, the Federal... opportunity to participate in developing this AD, but we received no comments on the NPRM (78 FR 23698, April... Executive Order 12866; (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44...
...'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect... references Sikorsky Maintenance Manual Temporary Revision No. 63-50, (TR 63-50), and Temporary Revision No. 5-104 (TR 5-104), both dated December 22, 2011. TR 63-50 adds the MGB inspection procedures to...
... email@example.com . SUPPLEMENTARY INFORMATION: Discussion On October 26, 2011, at 76 FR 66209, the... 12866; (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034...) manufactured with mislocated aluminum wire mesh, leaving portions of the graphite torque tube (spar)...
...: Discussion On March 29, 2012, at 77 FR 18969, the Federal Register published our notice of proposed... Safety Board, commented that they support the NPRM (77 FR 18969, March 29, 2012). FAA's Determination We... Policies and Procedures (44 FR 11034, February 26, 1979); (3) Will not affect intrastate aviation in...
... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will... the windshield that resulted in unintended movement of the engine control levers from the forward... operators may incur the following costs in order to comply with this AD. To replace the engine control...
.... Discussion On October 26, 2005, we issued AD 2005-22-01, amendment 39-14345 (70 FR 61721) for Sikorsky Model... the MRH pilot, P/N 76103-08003-101, with an MRH pilot, P/ N 76103-08003-102, would require about 0.7.... Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034,...
...-7763; email firstname.lastname@example.org . SUPPLEMENTARY INFORMATION: Discussion On June 20, 2013, at 78 FR... opportunity to participate in developing this AD, but we did not receive any comments on the NPRM (78 FR 37160... Executive Order 12866; (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44...
... of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. FOR... 10, 2009 (74 FR 65496). The NPRM proposed revising the RFM SA S92A-RFM-003, Part 1, Section 1... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3....
...: Manager, Commercial Technical Support, mailstop s581a, 6900 Main St., Stratford, CT; telephone (203) 383... Internet at http://www.regulations.gov or in person at the Docket Operations Office between 9 a.m. and 5 p... INFORMATION: Discussion On February 3, 2012, at 77 FR 5418, the Federal Register published our notice...
...'' address between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. Examining the AD Docket... Operations Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket..., mailstop s581a, 6900 Main St., Stratford, CT; telephone (203) 383-4866; email email@example.com ,...
... INFORMATION: Discussion On October 26, 2011, at 76 FR 66207, the Federal Register published our Notice of... Policies and Procedures (44 FR 11034, February 26, 1979); (3) Will not affect intrastate aviation in Alaska...-011-AD; Amendment 39-17017; AD 2012-08-01] RIN 2120-AA64 Airworthiness Directives; Sikorsky...
Reinhart, Eugene R.
Considerable attention has been focused on the life extension of ageing military and commercial aircraft by the government and major aircraft fabricators. A vital, but often neglected segment of the aircraft industry is the are of inspecting ageing fleets of corporate and privately-owned aircraft. Many of these aircraft are inspected and maintained by the various FAA-approved repair stations located around the country. Nondestructive inspection (NDI) methods, equipment, and trained inspectors are a key aspect of maintaining these aircraft; however, there are currently several issues that need to be addressed by the private sector NDI community. Personnel training and certification to an accepted standard is critically needed in this industry since experience and capability in NDI can vary considerably between FAA stations and inspectors. Also, the updating of NDI methods are standards is needed. A review of these issues and suggestions for improvement are presented.
...We propose to supersede an existing airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-64E helicopters. The existing AD requires checks of the main rotor blades for a crack. This proposed AD would retain the actions of the existing AD, would reflect that the type certificate (TC) for this model helicopter has been transferred to Erickson Air-Crane Incorporated......
Booms, T.L.; Schempf, P.F.; McCaffery, B.J.; Lindberg, M.S.; Fuller, M.R.
We conducted repeated aerial surveys for breeding cliff-nesting raptors on the Yukon Delta National Wildlife Refuge (YDNWR) in western Alaska to estimate detection probabilities of Gyrfalcons (Falco rusticolus), Golden Eagles (Aquila chrysaetos), Rough-legged Hawks (Buteo lagopus), and also Common Ravens (Corvus corax). Using the program PRESENCE, we modeled detection histories of each species based on single species occupancy modeling. We used different observers during four helicopter replicate surveys in the Kilbuck Mountains and five fixed-wing replicate surveys in the Ingakslugwat Hills near Bethel, AK. During helicopter surveys, Gyrfalcons had the highest detection probability estimate (p^;p^ 0.79; SE 0.05), followed by Golden Eagles (p^=0.68; SE 0.05), Common Ravens (p^=0.45; SE 0.17), and Rough-legged Hawks (p^=0.10; SE 0.11). Detection probabilities from fixed-wing aircraft in the Ingakslugwat Hills were similar to those from the helicopter in the Kilbuck Mountains for Gyrfalcons and Golden Eagles, but were higher for Common Ravens (p^=0.85; SE 0.06) and Rough-legged Hawks (p^=0.42; SE 0.07). Fixed-wing aircraft provided detection probability estimates and SEs in the Ingakslugwat Hills similar to or better than those from helicopter surveys in the Kilbucks and should be considered for future cliff-nesting raptor surveys where safe, low-altitude flight is possible. Overall, detection probability varied by observer experience and in some cases, by study area/aircraft type.
Folio, R Les; Harcke, H Theodore; Luzi, Scott A
Radiology-assisted autopsy traditionally has been plain film-based, but now is being augmented by computed tomography (CT). The authors present a two-fatality rotary wing crash scenario illustrating application of advanced radiographic techniques that can guide and supplement the forensic pathologist's physical autopsy. The radiographic findings also have the potential for use by the aircraft mishap investigation board. Prior to forensic autopsy, the two crash fatalities were imaged with conventional two-dimensional radiographs (digital technique) and with multidetector CT The CT data were used for multiplanar two-dimensional and three-dimensional (3D) image reconstruction. The forensic pathologist was provided with information about skeletal fractures, metal fragment location, and other pathologic findings of potential use in the physical autopsy. The radiologic autopsy served as a supplement to the physical autopsy and did not replace the traditional autopsy in these cases. Both individuals sustained severe blunt force trauma with multiple fractures of the skull, face, chest, pelvis, and extremities. Individual fractures differed; however, one individual showed hand and lower extremity injuries similar to those associated with control of the aircraft at the time of impact. The concept of "control injury" has been challenged by Campman et al., who found that control surface injuries have a low sensitivity and specificity for establishing who the pilot was in an accident. The application of new post mortem imaging techniques may help to resolve control injury questions. In addition, the combination of injuries in our cases may contribute to further understanding of control surface injury patterns in helicopter mishaps. PMID:19378913
... collection requirement concerning corporate aircraft costs. A notice was published in the Federal Register at 77 FR 20012, on April 3, 2012. One respondent submitted comments. Public comments are particularly... Regulation; Submission for OMB Review; Corporate Aircraft Costs AGENCY: Department of Defense (DOD),...
... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), (3) Will not affect intrastate aviation... Corporation (Schweizer) Model 269A, A-1, B, C, C-1, and TH-55 Series Helicopters AGENCY: Federal Aviation... reviewed Schweizer Service Bulletins No. B-295 for Model 269A, A-1, B, and C helicopters, and No....
Maxwell, R. D. J.
The methods adopted in the United Kingdom to ensure the structural integrity of military aeroplanes and helicopters from the fatigue point of view are described. The procedure adopted from the writing of the specification to the monitoring of fatigue life in service are presented along with the requirements to be met and the way in which they are satisfied. Some of the outstanding problems that remain to be solved are indicated.
... (accumulative cost 7,820. for all four spar assemblies). Authority for This Rulemaking Title 49 of the United... Executive Order 12866, (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR... aircraft, (5) Hours TIS of aircraft, (6) Description of failure if applicable, (7) Part(s) and part...
Sorensen, J. A.; Mohr, R. L.; Cline, T. B.
The extent to which instrumentation errors cause degradation in the knowledge of stability and control derivatives identified for flight tests was studied along with the resultant degradation of the flight system performance base on these derivatives. The error in measurement and data processing systems used for parameter identification, error analysis techniques, and the effects of instrumentation, errors on the accuracy of parameter estimates are discussed. The analysis programs were used to study instrumentation error effects on the accuracy of the identified stability and control derivatives of the CH-46 helicopter.
...'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Schweizer Aircraft...). SUMMARY: This document proposes to adopt a new airworthiness directive (AD) for Schweizer...
..., 1997, we issued AD 97-10-15, Amendment 39-10028 (62 FR 28321, May 23, 1997), for the Sikorsky Aircraft...'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect.... 39.13 by removing Amendment 39-10028 (62 FR 28321, May 23, 1997), and adding the following new...
Foster, C. R.
Enactment of helicopter noise certification standards for the control of noise impact contributing to community annoyance is considered in terms of the development of helicopters as an environmentally compatible air transportation mode. Increased use of helicopters for commercial applications and public awareness of aircraft noise are cited as factors making development of helicopter noise standards necessary both for the protection of the environmental interest of the community and to ensure the orderly growth of the helicopter industry itself. Noise sources, technology trends in helicopter design, and design concepts to control helicopter noise are discussed along with the regulatory background and specific helicopter regulatory concepts.
... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant... bowl assembly with a two-piece MGB filter bowl assembly and replacing the existing mounting studs. The... including those associated with a damaged MGB filter or mounting stud resulting from high...
... 27, 2010 (75 FR 4308). That action proposed to require replacing the MGB filter bowl assembly with a... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant... filter bowl assembly and replacing the existing mounting studs. The AD also requires inspecting the...
... regulations was approved previously by the Director of the Federal Register as of February 19, 2010 (75 FR..., 2009, we issued AD 2009-23- 51, Amendment 39-16190 (75 FR 5684, February 4, 2010), to require cleaning... Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78). Regulatory Findings We...
... Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78). Regulatory... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant... prevent inadvertent activation of a flotation system during installation was still installed in the...
... Register published on April 11, 2000 (65 FR 19477-78). Examining the Docket You may examine the docket that... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation... (blade) for mislocated aluminum wire mesh in the blade skin. This proposal is prompted by the...
..., Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, TX 76137; telephone (817) 222-5170; email firstname.lastname@example.org . SUPPLEMENTARY INFORMATION: Discussion On May 28, 2013, at 78 FR 31863, the Federal... Incorporated (Erickson) Model S-64E type certificate. The NPRM proposed to supersede AD 97-19- 10 (62 FR...
..., Amendment 39-10130 (62 FR 47933, September 12, 1997), to require, at 1,300 hours time-in- service (TIS), a... 39-3045 (42 FR 51565, September 29, 1977) and Amendment 39-3064 (42 FR 56600, October 27, 1977). The... Was Issued Since issuing AD 97-19-10, Amendment 39-10130 (62 FR 47933, September 12, 1997),...
... visual inspection for these two types of cracks is required in AD 2010-24-04 (75 FR 70812, November 19... Executive Order 12866, (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR... fluorescent penetrant inspection (FPI), of each main gearbox (MGB) upper housing assembly rib on the...
... Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78). Regulatory... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant... ASB specifies a fluorescent penetrant inspection (FPI) or a dye penetrant inspection (DPI). If...
... issued a notice of proposed rulemaking (NPRM) (77 FR 55166, September 7, 2012) for Sikorsky Model S-70, S... (77 FR 55166, September 7, 2012), we became aware that GE has issued T700 Turboshaft Engine Service... NPRM (77 FR 55166, September 7, 2012), but we did not receive any comments. FAA's Determination We...
... FR 19477-78). Examining the Docket You may examine the docket that contains the proposed AD, any... FR 11034, February 26, 1979); and 3. Will not have a significant economic impact, positive or... section of the Instructions ] for Continued Airworthiness (ICA) to reduce the life limit of the...
... the blades of the oil cooler impeller separating, one of which punctured the engine and transmission... protect the oil cooler from uncontained oil cooler impeller blades that could damage the oil cooler and result in loss of engine and transmission oil pressure, and subsequent loss of control of the...
... final rule is effective July 12, 2013. The effective date for AD 2012-23-13 (77 FR 71087, November 29...: Airworthiness Directive 2012-23-13, Amendment 39-17269 (77 FR 71087, November 29, 2012), currently includes the... published in the Federal Register. Comments After we published our Final rule; request for comments (77...
... April 11, 2000 (65 FR 19477-78). Examining the Docket You may examine the docket that contains the... FR 35469, August 16, 1982), requires a puck-to-disc inspection of rotor brake, part number (P/N..., 1981. AD 2003-04-15, issued February 14, 2003 (68 FR 8994, February 27, 2003), requires...
The Sikorsky S-64 Skycrane helicopter, which saw service with the U.S.Army as the CH-54 Tarhe, flew at Langley in its later version, the CH-54B. The 'Crane' was used in studies into the handling of large helicopters, and as such sported various loads attached to the airframe. The Army retired its Skycranes in the 1970s and they were completely removed from military service in the 1980s. Ex-military Skycranes entered commercial service, where they are used in various heavy-lift roles, including the lumber industry. The U.S. military preferred a heavy-lift aircraft that also had a cabin capable of carrying cargo and troops.
Linden, A. W.; Hellyar, M. W.
The Sikorsky Aircraft division of United Aircraft Corporation is constructing two uniquely designed Rotor Systems Research Aircraft (RSRA). These aircraft will be used through the 1980's to comparatively test many different types of rotors - articulated, hingeless, teetering, and gimballed, as well as advanced rotor concepts, such as reverse velocity and variable diameter rotors. The RSRA combines a new airframe with existing Sikorsky H-3 (S-61) dynamic components. A force measurement system is incorporated to permit accurate evaluation of significant rotor characteristics. Both rotor and fixed-wing control systems are provided, appropriately integrated for operation in the pure helicopter mode, compound helicopter mode, and fixed-wing mode. The RSRA is the first rotary wing aircraft designed with a crew escape system, including a pyrotechnic system to sever the main rotor blades.
Hofmann, L. G.; Hoh, R. H.; Jewell, W. F.; Teper, G. L.; Patel, P. D.
The objective of this effort is to determine IFR approach path and touchdown dispersions for manual and automatic XV-15 tilt rotor landings, and to develop missed approach criteria. Only helicopter mode XV-15 operation is considered. The analysis and design sections develop the automatic and flight director guidance equations for decelerating curved and straight-in approaches into a typical VTOL landing site equipped with an MLS navigation aid. These system designs satisfy all known pilot-centered, guidance and control requirements for this flying task. Performance data, obtained from nonstationary covariance propagation dispersion analysis for the system, are used to develop the approach monitoring criteria. The autoland and flight director guidance equations are programmed for the VSTOLAND 1819B digital computer. The system design dispersion data developed through analysis and the 1819B digital computer program are verified and refined using the fixed-base, man-in-the-loop XV-15 VSTOLAND simulation.
Mark, W. D.
Application of the transfer function approach to predict the resulting interior noise contribution requires gearbox vibration sources and paths to be characterized in the frequency domain. Tooth-face deviations from perfect involute surfaces were represented in terms of Legendre polynomials which may be directly interpreted in terms of tooth-spacing errors, mean and random deviations associated with involute slope and fullness, lead mismatch and crowning, and analogous higher-order components. The contributions of these components to the spectrum of the static transmission error is discussed and illustrated using a set of measurements made on a pair of helicopter spur gears. The general methodology presented is applicable to both spur and helical gears.
Ward, J. F.
Technology needed to provide the basis for creating a widening rotary wing market include: well defined and proven design; reductions in noise, vibration, and fuel consumption; improvement of flying and ride quality; better safety; reliability; maintainability; and productivity. Unsteady transonic flow, yawed flow, dynamic stall, and blade vortex interaction are some of the problems faced by scientists and engineers in the helicopter industry with rotorcraft technology seen as an important development for future advanced high speed vehicle configurations. Such aircraft as the Boeing Vertol medium lift Model 360 composite aircraft, the Sikorsky Advancing Blade Concept (ABC) aircraft, the Bell Textron XV-15 Tilt Rotor Aircraft, and the X-wing rotor aircraft are discussed in detail. Even though rotorcraft technology has become an integral part of the military scene, the potential market for its civil applications has not been fully developed.
Davis, S. J.; Stepniewski, W. Z.
Results are presented of a study of the relative and absolute energy consumption of helicopters, including limited comparisons with fixed-wing aircraft, and selected surface transportation vehicles. Additional comparisons were made to determine the level of reduction in energy consumption expected from the application of advanced technologies to the helicopter design and sizing process. It was found that improvements in helicopter consumption characteristics can be accomplished through the utilization of advanced technology to reduce drag, structures weight, and powerplant fuel consumption.
... prior to a change in type design, the helicopter noise levels may not, after a change in type design... helicopter prior to a change in type design, the helicopter noise levels may not, after a change in type... NOISE STANDARDS: AIRCRAFT TYPE AND AIRWORTHINESS CERTIFICATION General § 36.11 Acoustical...
... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Helicopter angle of glide: Category B. 29... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.71 Helicopter angle of glide: Category B. For each category B helicopter, except multiengine helicopters meeting...
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Helicopter angle of glide: Category B. 29... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.71 Helicopter angle of glide: Category B. For each category B helicopter, except multiengine helicopters meeting...
Langley Research Center has done extensive research into the effectiveness of tail boom strakes on conventional tail rotor helicopters. (A strake is a "spoiler" whose purpose is to alter the airflow around an aerodynamic body.) By placing strakes on a tail boom, the air loading can be changed, thrust and power requirements of the tail rotor can be reduced, and helicopter low speed flight handling qualities are improved. This research led to the incorporation of tail boom strakes on three production-type commercial helicopters manufactured by McDonnell Douglas Helicopter Company.
Kitchens, P. F.
A list of icing instrumentation requirements are presented. Because of the Army's helicopter orientation, many of the suggestions are specific to rotary wing aircraft; however, some of the instrumentation are also suitable for general aviation aircraft.
... the Federal Register on June 4, 2008 (73 FR 31780). The proposed action applied to Sikorsky Model S... Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a significant economic... Federal Regulations, which is published #0;under 50 titles pursuant to 44 U.S.C. 1510. #0; #0;The Code...
... Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78). Examining the Docket You may... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3... intervals not to exceed 500 hours TIS, remove the tail rotor servo control and pitch beam shaft, and using...
... deploy. This failure could lead to loss of access to the life raft after an emergency ditching on water... corrected, could result in failure of the life raft to deploy, which could lead to loss of access to the... are intended to prevent the handle from bending during raft deployment, which could lead to loss...
.... registry. We estimate it will take about 1 work hour to inspect the AHRS unit to determine if it is a Mod Status ``18,'' 1 work hour to fabricate and install a placard, and \\1/2\\ work hour to revise the RFM. The... complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR...
Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.
This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.
Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.
This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing's top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gasses for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well.
Lin, Z.; Zhang, W.; Chen, S.; Liu, T.; Yao, Y.
Nowadays the unmanned helicopter is widely used for its' unique strongpoint, however, the high failure rate of unmanned helicopter seriously limits its further application and development. For solving the above problems, in this paper, the reasons for the high failure rate of unmanned helicopter is analyzed and the corresponding solution schemes are proposed. The main problem of the failure cause of the unmanned helicopter is the aircraft engine fault, and the failure cause of the unmanned helicopter is analyzed particularly. In order to improving the safety performance of unmanned helicopter system, the scheme of adding the safety parachute system to the unmanned helicopter system is proposed and introduced. These schemes provide the safety redundancy of the unmanned helicopter system and lay on basis for the unmanned helicopter applying into residential areas.
Niesl, G.; Laudien, E.
Compared to fixed wing aircraft, helicopter interior noise is higher, and subjectively more annoying. This is mainly due to discrete frequencies by the main transmission system, and also from other components like main and tail rotor, engines, or cooling fans. Up to now, mainly passive measures have been used for interior noise reduction. Despite intensive experimental and theoretical investigation to improve acoustic treatment, their weight penalties remain high especially in the low frequency range. Here, active noise control offers additional capacities without excessive weight efforts. Loud-speaker based systems are sufficiently well developed for implementing a prototype system in the helicopter. Two other principles are in development: active panel control which introduces mechanical actuators to excite the cabin walls, and active control of gearbox struts with actuators in the load path between gearbox and fuselage.
Martone, Patrick; Tucker, George; Aiken, Edwin W. (Technical Monitor)
The National Aeronautics and Space Administration (NASA) Ames Research Center (ARC) is sponsoring deployment and testing of the Helicopter In-flight Tracking System (HITS) in a portion of the Gulf of Mexico offshore area. Using multilateration principles, HITS determines the location and altitude of all transponder-equipped aircraft without requiring changes to current Mode A, C or S avionics. HITS tracks both rotary and fixed-wing aircraft operating in the 8,500 sq. mi. coverage region. The minimum coverage altitude of 100 ft. is beneficial for petroleum industry, allowing helicopters to be tracked onto the pad of most derricks. In addition to multilateration, HITS provides surveillance reports for aircraft equipped for Automatic Dependent Surveillance - Broadcast (ADS-B), a new surveillance system under development by the Federal Aviation Administration (FAA). The U.S. Department of Transportation (DOT) Volpe National Transportation Systems Center (Volpe Center) is supporting NASA in managing HITS installation and operation, and in evaluating the system's effectiveness. Senses Corporation is supplying, installing and maintaining the HITS ground system. Project activities are being coordinated with the FAA and local helicopter operators. Flight-testing in the Gulf will begin in early 2002. This paper describes the HITS project - specifically, the system equipment (architecture, remote sensors, central processing system at Intracoastal City, LA, and communications) and its performance (accuracy, coverage, and reliability). The paper also presents preliminary results of flight tests.
A comprehensive presentation is made of the engineering analysis methods used in the design, development and evaluation of helicopters. After an introduction covering the fundamentals of helicopter rotors, configuration and operation, rotary wing history, and the analytical notation used in the text, the following topics are discussed: (1) vertical flight, including momentum, blade element and vortex theories, induced power, vertical drag and ground effect; (2) forward flight, including in addition to momentum and vortex theory for this mode such phenomena as rotor flapping and its higher harmonics, tip loss and root cutout, compressibility and pitch-flap coupling; (3) hover and forward flight performance assessment; (4) helicopter rotor design; (5) rotary wing aerodynamics; (6) rotary wing structural dynamics, including flutter, flap-lag dynamics ground resonance and vibration and loads; (7) helicopter aeroelasticity; (8) stability and control (flying qualities); (9) stall; and (10) noise.
... the Federal Register published on April 11, 2000 (65 FR 19477-19478), as well as at http://DocketsInfo... GIV-X Airplane; Isolation or Aircraft Electronic System Security Protection From Unauthorized Internal..., a diverse set of functions, including: 1. Flight-safety related control, communication,...
Martin, Willi; Jänker, Peter; Siemetzki, Markus; Lorkowski, Thomas; Grohmann, Boris; Maier, Rudolf; Maucher, Christoph; Klöppel, Valentin; Enenkl, Bernhard; Roth, Dieter; Hansen, Heinz
Since more than 10 years EADS Innovation Works, which is the corporate research centre of EADS (European Aeronautic Defence and Space Company), is investigating smart materials and adaptive structures for aircraft in cooperation with EADS business units. Focus of research efforts are adaptive systems for shape control, noise reduction and vibration control of both fixed and rotary wing aircraft as well as for lift optimisation of fixed wing aircraft. Two outstanding adaptive systems which have been pushed ahead in cooperation with Airbus Germany and Eurocopter Germany are adaptive servo flaps for helicopter rotor blades and innovative high lift devices for fixed wing aircraft which both were tested in flight for the first time representing world premieres. In this paper various examples of adaptive systems are presented which were developed and realized by EADS in recent years.
Simulators will gain an increasingly important role in training helicopter pilots only if the simulators are of sufficient fidelity to provide positive transfer of skills to the aircraft. This must be done within an economic model of return on investment. Although rotor pilot demand is still only a small percentage of overall pilot requirements, it will grow in significance. This presentation described the salient factors influencing the use of helicopter training simulators.
Howlett, J. T.; Clevenson, S. A.
The interior noise levels of existing helicopters are discussed along with an ongoing experimental program directed towards reducing these levels. Results of several noise and vibration measurements on Langley Research Center's Civil Helicopter Research Aircraft are presented, including measurements taken before and after installation of an acoustically-treated cabin. The predominant noise source in this helicopter is the first stage planetary gear-clash in the main gear box, both before and after installation of the acoustically treated cabin. Noise reductions of up to 20 db in some octave bands may be required in order to obtain interior noise levels comparable to commercial jet transports.
Cravey, Robin L.
A simple technique is presented which forms a cubic grid model of a helicopter from an Aircraft Modeling Code (AMC) input file. The AMC input file defines the helicopter fuselage as a series of polygonal cross sections. The cubic grid model is used as an input to a Finite Difference Time Domain (FDTD) code to obtain predictions of antenna performance on a generic helicopter model. The predictions compare reasonably well with measured data.
Snyder, W. J.; Schlegel, R. G.
A research aircraft for investigating the factors involved in civil helicopter operations was developed for NASA Langley Research Center. The aircraft is a reconfigured 17000 kg (36000 lb) military transport helicopter. The basic aircraft was reconfigured with advanced acoustic treatment, air-conditioning, and a 16-seat airline cabin. During the spring of 1975, the aircraft was flight tested to measure interior environment characteristics - noise and vibration - and was flown on 60 subjective flight missions with over 600 different subjects. Data flights established noise levels somewhat higher than expected, with a pure tone at 1400 Hz and vertical vibration levels between 0.07g and 0.17g. The noise and vibration levels were documented during subjective flight evaluations as being the primary source of discomfort. The aircraft will be utilized to document in detail the impact of various noise and vibration levels on passenger comfort during typical short-haul missions.
Astronaut James A. Lovell Jr., pilot of the Gemini 7 space flight, is hoisted from the water by a recovery helicopter from the Aircraft Carrier U.S.S. Wasp. Astronaut Frank Borman, command pilot, waits in the raft to be hoisted aboard the helicopter.
Cross, J. L.; Stevens, D. D.
A computerized study of operational parameters affecting helicopter fuel consumption was conducted as an integral part of the NASA Civil Helicopter Technology Program. The study utilized the Helicopter Sizing and Performance Computer Program (HESCOMP) developed by the Boeing-Vertol Company and NASA Ames Research Center. An introduction to HESCOMP is incorporated in this report. The results presented were calculated using the NASA CH-53 civil helicopter research aircraft specifications. Plots from which optimum flight conditions for minimum fuel use that can be obtained are presented for this aircraft. The results of the study are considered to be generally indicative of trends for all helicopters.
Fabunmi, James A.
The results of a feasibility study of a method for controlling the aerodynamics of helicopter rotorblades using stacks of piezoelectric ceramic plates are presented. A resonant mechanism is proposed for the amplification of the displacements produced by the stack. This motion is then converted into linear displacement for the actuation of the servoflap of the blades. A design which emulates the actuation of the servoflap on the Kaman SH-2F is used to demonstrate the fact that such a system can be designed to produce the necessary forces and velocities needed to control the aerodynamics of the rotorblades of such a helicopter. Estimates of the electrical power requirements are also presented. A Small Business Innovation Research (SBIR) Phase 2 Program is suggested, whereby a bench-top prototype of the device can be built and tested. A collaborative effort between AEDAR Corporation and Kaman Aerospace Corporation is anticipated for future effort on this project.
Exterior and interior noise problems are addressed both from the physics and engineering as well as the human factors point of view. The role of technology in closing the gap between what the customers and regulating agencies would like to have and what is available is explored. Noise regulation concepts, design, operations and testing for noise control, helicopter noise prediction, and research tools and measurements are among the topics covered.
Dajani, J. S.; Warner, D.; Epstein, D.; Obrien, J.
A general overview is presented of the role that the helicopter plays in the current aviation scene with special emphasis on its use in the airport access function. Technological problems of present-day aircraft are discussed along with some plausible solutions. The economic and regulatory aspects of commercial helicopter operations are presented. Finally six commercial operations utilizing helicopters are reviewed and conditions that enhance the success of the helicopter in the airport access function are proposed.
... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Aircraft. 327.4 Section 327.4... Aircraft. (a) This section pertains to all aircraft including, but not limited to, airplanes, seaplanes, helicopters, ultra-light aircraft, motorized hang gliders, hot air balloons, any non-powered flight devices...
... Aircraft. (a) This section pertains to all aircraft including, but not limited to, airplanes, seaplanes, helicopters, ultra-light aircraft, motorized hang gliders, hot air balloons, any non-powered flight devices or... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Aircraft. 327.4 Section...
... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Aircraft. 327.4 Section 327.4... Aircraft. (a) This section pertains to all aircraft including, but not limited to, airplanes, seaplanes, helicopters, ultra-light aircraft, motorized hang gliders, hot air balloons, any non-powered flight devices...
Chen, R.; Wen, C. Y.; Lorente, S.; Bejan, A.
Here, we show that during their half-century history, helicopters have been evolving into geometrically similar architectures with surprisingly sharp correlations between dimensions, performance, and body size. For example, proportionalities emerge between body size, engine size, and the fuel load. Furthermore, the engine efficiency increases with the engine size, and the propeller radius is roughly the same as the length scale of the whole body. These trends are in accord with the constructal law, which accounts for the engine efficiency trend and the proportionality between "motor" size and body size in animals and vehicles. These body-size effects are qualitatively the same as those uncovered earlier for the evolution of aircraft. The present study adds to this theoretical body of research the evolutionary design of all technologies [A. Bejan, The Physics of Life: The Evolution of Everything (St. Martin's Press, New York, 2016)].
Desjardins, Daniel D.; Hopper, Darrel G.
The military display market is analyzed in terms of one of its segments: helicopter displays. Parameters requiring special consideration, to include luminance ranges, contrast ratio, viewing angles, and chromaticity coordinates, are examined. Performance requirements for rotary-wing displays relative to several premier applications are summarized. Display sizes having aggregate defense applications of 5,000 units or greater and having DoD applications across 10 or more platforms, are tabulated. The issue of size commonality is addressed where distribution of active area sizes across helicopter platforms, individually, in groups of two through nine, and ten or greater, is illustrated. Rotary-wing displays are also analyzed by technology, where total quantities of such displays are broken out into CRT, LCD, AMLCD, EM, LED, Incandescent, Plasma and TFEL percentages. Custom, versus Rugged commercial, versus commercial off-the-shelf designs are contrasted. High and low information content designs are identified. Displays for several high-profile military helicopter programs are discussed, to include both technical specifications and program history. The military display market study is summarized with breakouts for the helicopter market segment. Our defense-wide study as of March 2004 has documented 1,015,494 direct view and virtual image displays distributed across 1,181 display sizes and 503 weapon systems. Helicopter displays account for 67,472 displays (just 6.6% of DoD total) and comprise 83 sizes (7.0% of total DoD) in 76 platforms (15.1% of total DoD). Some 47.6% of these rotary-wing applications involve low information content displays comprising just a few characters in one color; however, as per fixed-wing aircraft, the predominant instantiation involves higher information content units capable of showing changeable graphics, color and video.
The purpose of this research project was to trace and locate 113 P- 38 Lightning Aircraft that were constructed by Consolidated-Vultee Aviation Corporation of Nashville-Tennessee. A determination as to where they were located at the end of World War II, along with their subsequent location, was attempted. This project utilized historical research with a qualitative approach where data was accumulated, evaluated and formulated based on events that happened 70 years ago. A triangulation practice is the process of collecting data, not from just one source, but from several sources. This process helps strengthen the individual data, compensated by others to create a complete picture of the phenomenon being researched. The research does not focus on pilots that flew the P-38's. However, a few pilot names may be mentioned that were involved in an accident the aircraft may have suffered. The Army Air Force requested 2000 P-38's Model " L " built by Consolidated-Vultee for the Lockheed Aircraft Corporation in Burbank, California. The War Department did not know at the time how long the present conflict of war might last.
Meier, D R; Samper, E R
The rapid increase in the use of helicopters for hospital transport during the 1980s is the culmination of several hundred years of military medical innovation. Mass battefield casualties spurred both technologic and medical changes necessary for today's sophisticated helicopter systems in use worldwide, particularly in the United States. The Napoleonic Era and the American Civil War provided the framework for the evolution of today's state-of-the-art emergency medical techniques. The use of airplanes to evacuate the wounded eventually led to using helicopters for rescue missions in World War II. The combat experiences of the United States in Korea, the British in Malaya, and the French in Indochina proved that rotary-wing aircraft were invaluable in reducing battlefield death rates. Any skepticism about the efficacy of helicopter medical evacuation was erased during the Vietnam conflict. As an integral part of the modern battlefield, these specialized aircraft became a necessity. The observations and experience of American servicemen and medical personnel in Vietnam established the foundation for the acceptance of helicopter transport in modern hospital systems. PMID:2665130
Vonglahn, U. H.
Calculated engine core noise levels, based on NASA Lewis prediction procedures, for five representative helicopter engines are compared with measured total helicopter noise levels and ICAO helicopter noise certification requirements. Comparisons are made for level flyover and approach procedures. The measured noise levels are generally significantly greater than those predicted for the core noise levels, except for the Sikorsky S-61 and S-64 helicopters. However, the predicted engine core noise levels are generally at or within 3 dB of the ICAO noise rules. Consequently, helicopter engine core noise can be a significant contributor to the overall helicopter noise signature.
Vonglahn, U. H.
Calculated engine core noise levels, based on NASA Lewis prediction procedures, for five representative helicopter engines are compared with measured total helicopter noise levels and ICAO helicopter noise certification requirements. Comparisons are made for level flyover and approach procedures. The measured noise levels are generally significantly greater than those predicted for the core noise levels, except for the Sikorsky S-61 and S-64 helicopters. However, the predicted engine core noise levels are generally at or within 3 dB of the ICAO noise rules. Consequently, helicopter engine core noise can be a significant contributor to the overall helicopter noise signature.
... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Acoustical change: Helicopters. 36.11 Section 36.11 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT NOISE STANDARDS: AIRCRAFT TYPE AND AIRWORTHINESS CERTIFICATION General § 36.11 Acoustical...
Watts, Michael E.; Snider, Royce; Greenwood, Eric; Baden, Joel
A cooperative flight test by NASA, Bell Helicopter and the U.S. Army to characterize the steady state acoustics and measure the maneuver noise of a Bell Helicopter 430 aircraft was accomplished. The test occurred during June/July, 2011 at Eglin Air Force Base, Florida. This test gathered a total of 410 data points over 10 test days and compiled an extensive data base of dynamic maneuver measurements. Three microphone configurations with up to 31 microphones in each configuration were used to acquire acoustic data. Aircraft data included DGPS, aircraft state and rotor state information. This paper provides an overview of the test.
Menon, P. K. A.; Cheng, V. H. L.; Kim, E.
A methodology for optimal trajectory planning, useful in the nap-of-the-earth guidance of helicopters, is presented. This approach uses an adjoint-control transformation along with a one-dimensional search scheme for generating the optimal trajectories. In addition to being useful for helicopter nap-of-the-earth guidance, the trajectory planning solution is of interest in several other contexts, such as robotic vehicle guidance and terrain-following guidance for cruise missiles and aircraft. A distinguishing feature of the present research is that the terrain constraint and the threat envelopes are incorporated in the equations of motion. Second-order necessary conditions are examined.
Hirschkron, R.; Davis, R. H.; Goldstein, D. N.; Haynes, J. F.; Gauntner, J. W.
Twin helicopter engines are often sized by power requirement of safe mission completion after the failure of one of the two engines. This study was undertaken for NASA Lewis by General Electric Co. to evaluate the merits of special design features to provide a 2-1/2 minute Contingency Power rating, permitting an engine size reduction. The merits of water injection, cooling flow modulation, throttle push and an auxiliary power plant were evaluated using military life cycle cost (LCC) and commercial helicopter direct operating cost (DOC) merit factors in a rubber engine/rubber aircraft scenario.
Design of military and civil helicopters, produced by Bell Helicopter Textron, and aided by the use of COSMIC'S computer program VASP enables performance of more accurate analyses to insure product safety and improved production efficiency.
Key, D. C.; Aiken, E. W.
If the U.S. Army's desire to develop a one crew version of the Light Helicopter Family (LHX) helicopter is to be realized, both flightpath management and mission management will have to be performed by one crew. Flightpath management, the helicopter pilot, and the handling qualities of the helicopter were discussed. In addition, mission management, the helicopter pilot, and pilot control/display interface were considered. Aircrew-aircraft integration plans and programs were reviewed.
Levine, L. S.; Defelice, J. J.
A practical and well correlated procedure for predicting helicopter internal noise is presented. It accounts for the propagation of noise along multiple paths on an octave by octave basis. The method is sufficiently general to be applicable to conventional helicopters as well as other aircraft types, when the appropriate structural geometry, noise source strengths, and material acoustic properties are defined. A guide is provided for the prediction of various helicopter noise sources over a wide range of horsepower for use when measured data are not available. The method is applied to the prediction of the interior levels of the Civil Helicopter Research Aircraft (CHRA), both with and without soundproofing installed. Results include good correlation with measured levels and prediction of the speech interference level within 1.5 db at all conditions. A sample problem is also shown illustrating the use of the procedure. This example calculates the engine casing noise observed in the passenger cabin of the CHRA.
Williams, R. M.; Montana, P. S.
Current helicopters have parasite drag levels 6 to 10 times as great as fixed wing aircraft. The commensurate poor cruise efficiency results in a substantial degradation of potential mission capability. The paper traces the origins of helicopter drag and shows that the problem (primarily due to bluff body flow separation) can be solved by the adoption of a comprehensive research and development plan. This plan, known as the Fuselage Design Methodology, comprises both nonaerodynamic and aerodynamic aspects. The aerodynamics are discussed in detail and experimental and analytical programs are described which will lead to a solution of the bluff body problem. Some recent results of work conducted at the Naval Ship Research and Development Center (NSRDC) are presented to illustrate these programs. It is concluded that a 75-per cent reduction of helicopter drag is possible by the full implementation of the Fuselage Design Methodology.
Keys, C. N.; Stephniewski, W. Z. (Editor)
Application of theories, as well as, special methods of procedures applicable to performance prediction are illustrated first, on an example of the conventional helicopter and then, winged and tandem configurations. Performance prediction of conventional helicopters in hover and vertical ascent are investigated. Various approaches to performance prediction in forward translation are presented. Performance problems are discussed only this time, a wing is added to the baseline configuration, and both aircraft are compared with respect to their performance. This comparison is extended to a tandem. Appendices on methods for estimating performance guarantees and growth of aircraft concludes this volume.
Dougherty, J. J., III; Barrett, L. D.
The major reliability problems of the civil helicopter fleet as reported by helicopter operational and maintenance personnel are documented. An assessment of each problem is made to determine if the reliability can be improved by application of present technology or whether additional research and development are required. The reliability impact is measured in three ways: (1) The relative frequency of each problem in the fleet. (2) The relative on-aircraft manhours to repair, associated with each fleet problem. (3) The relative cost of repair materials or replacement parts associated with each fleet problem. The data reviewed covered the period of 1971 through 1976 and covered only turbine engine aircraft.
Helicopters are used by the military and civilian communities for a variety of tasks and must be capable of operating in poor weather conditions and at night. Accompanying extended helicopter operations is a significant increase in pilot workload and a need for better handling qualities. An overview of the status and problems in the development and specification of helicopter handling-qualities criteria is presented. Topics for future research efforts by government and industry are highlighted.
The amount of engine power required for a helicopter to hover is an important, but difficult, consideration in helicopter design. The EHPIC program model produces converged, freely distorted wake geometries that generate accurate analysis of wake-induced downwash, allowing good predictions of rotor thrust and power requirements. Continuum Dynamics, Inc., the Small Business Innovation Research (SBIR) company that developed EHPIC, also produces RotorCRAFT, a program for analysis of aerodynamic loading of helicopter blades in forward flight. Both helicopter codes have been licensed to commercial manufacturers.
Rogers, Sarah Alicia
Selecting the optimal location for a new antenna on an aircraft is a difficult task. Given the limited space that is available on the fuselage, there maybe only a few available locations from which to choose. The performance of a new antenna is often hindered by nearby structures on the aircraft, which may block or diffract the antenna's desired radiation. In addition, given that there are many other antennas and electronic systems onboard aircraft, potential interference produced by the new antenna must also be considered. The choice of the best antenna location must therefore be based on the careful study of the electromagnetic performance of the antenna at each location. Given that it is unlikely that a new antenna can be physically tested in various locations on an operational aircraft, recourse must be made to computer simulation. In this work, the selection of an appropriate location for a new satellite communication antenna is considered for the CH-146 Griffon helicopter. To this end, a new computer electromagnetic model of the CH-146 Griffon helicopter was created, validated, and used to characterize the helicopter's electromagnetic environment. A commercial computational software called FEKO was subsequently used to calculate the radiation patterns, near-fields, and surface current distribution generated on the helicopter model by a broad-patterned antenna installed at three different locations on the aircraft. A subsequent analysis of the calculated results was then used to determine the best of the three possible placements of the proposed satellite communications antenna.
... January 23, 2012 (77 FR 729, January 6, 2012). We must receive comments on this AD by August 17, 2012... issued AD 2011-26-10, amendment 39-16900 (77 FR 729, January 6, 2012) for Enstrom Model F-28C, F-28C-2, F...; 2. Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034,...
Hart, Sandra G.
The state-of-the-art helicopter and its pilot are examined using the tools of human-factors analysis. The significant role of human error in helicopter accidents is discussed; the history of human-factors research on helicopters is briefly traced; the typical flight tasks are described; and the noise, vibration, and temperature conditions typical of modern military helicopters are characterized. Also considered are helicopter controls, cockpit instruments and displays, and the impact of cockpit design on pilot workload. Particular attention is given to possible advanced-technology improvements, such as control stabilization and augmentation, FBW and fly-by-light systems, multifunction displays, night-vision goggles, pilot night-vision systems, night-vision displays with superimposed symbols, target acquisition and designation systems, and aural displays. Diagrams, drawings, and photographs are provided.
...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Cranes, Derricks, Hoists, Elevators, and Conveyors § 1926.551 Helicopters. (a) Helicopter regulations. Helicopter cranes shall be expected to comply with...
Bailey, J. Earl
Aircraft and helicopter accidents due to severe dynamic wind and turbulence continue to present challenging design problems. The development of the current set of design analysis tools for a aircraft wind and turbulence design began in the 1940's and 1950's. The areas of helicopter dynamic wind and turbulence modeling and vehicle response to severe dynamic wind inputs (microburst type phenomena) during takeoff and landing remain as major unsolved design problems from a lack of both environmental data and computational methodology. The development of helicopter and V/STOL dynamic wind and turbulence response computation methology is reviewed, the current state of the design art in industry is outlined, and comments on design methodology are made which may serve to improve future flight vehicle design.
Sherman, Porter D.; Warburton, Frank W.
The application of fuzzy logic to a wide range of control problems has been gaining momentum internationally, fueled by a concentrated Japanese effort. Advanced Research & Development within the Engineering Department at Sikorsky Aircraft undertook a fuzzy logic research effort designed to evaluate how effective fuzzy logic control might be in relation to helicopter operations. The mode switching module in the advanced flight control portion of Sikorsky's motion based simulator was identified as a good candidate problem because it was simple to understand and contained imprecise (fuzzy) decision criteria. The purpose of the switching module is to aid a helicopter pilot in entering and leaving coordinated turns while in flight. The criteria that determine the transitions between modes are imprecise and depend on the varied ranges of three flight conditions (i.e., simulated parameters): Commanded Rate, Duration, and Roll Attitude. The parameters were given fuzzy ranges and used as input variables to a fuzzy rulebase containing the knowledge of mode switching. The fuzzy control program was integrated into a real time interactive helicopter simulation tool. Optimization of the heading hold and turn coordination was accomplished by interactive pilot simulation testing of the handling quality performance of the helicopter dynamic model. The fuzzy logic code satisfied all the requirements of this candidate control problem.
Dedrick, D K; Darga, A; Landis, D; Burney, R E
Rotary aircraft play a growing role in the transport of critically ill patients who may require emergency treatment, including defibrillation, during transport. The close quarters and proximity of vital electronic equipment have generated concern among personnel carrying out defibrillation in the air. We address the chief safety issues in helicopter defibrillation by providing measurements of the transient leakage current resulting from contact with a paddle and tested in-flight electronic interference and survey the defibrillation experience of helicopter programs. Our data show that airborne defibrillation is safe. A maximum of 1.5 mA of transient leakage current was measured from a standard battery-powered defibrillator, well within the accepted safety standard of 50 mA. In flight, there was no interference with the avionics or medical equipment, and adequate clearance was available for personnel. Of the helicopter programs surveyed, 69 (87%) had defibrillated in flight without incident. We conclude that defibrillation can be performed in the helicopter without hesitation whether on the ground or in the air, provided standard defibrillation precautions are observed. PMID:2910165
Astronaut Frank Borman, command pilot of the Gemini 7 space flight, is hoisted from the water by a recovery helicopter from the Aircraft Carrier U.S.S. Wasp. Below him, Navy divers sit in the life raft next to the Gemini spacecraft.
Yeo, Hyeonsoo; Johnson, Wayne
A design and aeromechanics investigation was conducted for a 100,000-lb compound helicopter with a single main rotor, which is to cruise at 250 knots at 4000 ft/95 deg F condition. Performance, stability, and control analyses were conducted with the comprehensive rotorcraft analysis CAMRAD II. Wind tunnel test measurements of the performance of the H-34 and UH-1D rotors at high advance ratio were compared with calculations to assess the accuracy of the analysis for the design of a high speed helicopter. In general, good correlation was obtained when an increase of drag coefficients in the reverse flow region was implemented. An assessment of various design parameters (disk loading, blade loading, wing loading) on the performance of the compound helicopter was conducted. Lower wing loading (larger wing area) and higher blade loading (smaller blade chord) increased aircraft lift-to-drag ratio. However, disk loading has a small influence on aircraft lift-to-drag ratio. A rotor parametric study showed that most of the benefit of slowing the rotor occurred at the initial 20 to 30% reduction of the advancing blade tip Mach number. No stability issues were observed with the current design. Control derivatives did not change significantly with speed, but the did exhibit significant coupling.
Dexter, H. B.
Flight experience gained with numerous composite aircraft structures is discussed. Both commercial transports and helicopters are included. Design concepts with significant mass savings and appropriate inspection and maintenance procedures are among the factors considered. Also, a major NASA/U.S. industry technology program to reduce fuel consumption of commercial transport aircraft through the use of advanced composites is described, including preliminary results. Ground and flight environmental effects on the composite materials used in the flight service programs are also discussed.
Clevenson, S. A.; Leatherwood, J. D.
The effects of helicopter interior noise on passenger annoyance for both reverie and listening situations was investigated. The relative effectiveness of several metrics for quantifying annoyance response for these situations was also studied. The noise stimuli were based upon recordings of the interior noise of civil helicopter research aircraft. These noises were presented at levels ranging from approximately 70 to 86 d with various tonal components selectively attenuated to give a range of spectra. The listening task required the subjects to listen to and record phonetically-balanced words presented within the various noise environments. Results indicate that annoyance during a listening condition is generally higher than annoyance under a reverie condition for corresponding interior noise environments. Attenuation of the tonal components results in increases in listening performance but has only a small effect upon annoyance for a given noise level.
McBratney, Colleen M; Rush, Stephen; Kharod, Chetan U
USAF Pararescuemen (PJs) respond to downed aircrew as a fundamental mission for personnel recovery (PR), one of the Air Force's core functions. In addition to responding to these in Military settings, the PJs from the 212 Rescue Squadron routinely respond to small plane crashes in remote regions of Alaska. While there is a paucity of information on the latter, there have been articles detailing injuries sustained from helicopter crashes and while ejecting or parachuting from fixed wing aircraft. The following represents a new chapter added to the Pararescue Medical Operations Handbook, Sixth Edition (2014, editors Matt Wolf, MD, and Stephen Rush, MD, in press). It was designed to be a quick reference for PJs and their Special Operations flight surgeons to help with understanding of mechanism of injury with regard to pilot ejection, parachute, and helicopter accident injuries. It outlines the nature of the injuries sustained in such mishaps and provides an epidemiologic framework from which to approach the problem. PMID:25399374
The bibliography contains citations concerning design, manufacture, and history of aircraft incorporating stealth technology. Citations focus on construction materials, testing, aircraft performance, and technology assessment. Fighter aircraft, bombers, missiles, and helicopters represent coverage. (Contains 50-250 citations and includes a subject term index and title list.)
NASA Langley Research Centers (LaRC) Electromagnetics Research Branch (ERB) performs antenna radiation pattern measurements on a communications antenna mounted on a 1/7th scale model of a US ARMY Apache Helicopter. The NASA LaRC ERB participates in a government industry, and university sponsored helicopter consortium to advance computational electromagnetics (CEM) code development for antenna radiation pattern predictions. Scale model antenna measurements serve as verification tools and are an integral part of the CEM code development process.
Friedman, R; Leicht, M J; Brotman, S
An analysis of the first seven years of performance of our hospital-based emergency medical services (EMS) helicopter was conducted to evaluate the possible need for a second aircraft. A survey of seven hospitals currently operating two or more helicopters resulted in a consensus that one helicopter can effectively perform only 70 to 90 flights per month. The number of requests for our helicopter service has increased 148% from 610 to 1,512 in seven years while the number of completed missions has increased only 92% from 486 (40.5/month) to 935 (78/month). Requests denied due to inclement weather (265 in 1988) cannot be captured with a second visual-flight-rated (VFR) EMS helicopter; however, those missed due to maintenance requirements of the helicopter and overlapping requests (232 in 1988) can be captured. The need for a second aircraft exists when the number of requests for the service grows while the number of captured flights plateaus. Our data and industry survey suggests this will occur at 75 captured flights per month. Affordability and continued overall growth of trauma and other critical care referrals to the base hospital(s) is mandatory. This study provides a model for hospital-based EMS helicopter operators to apply to the decision whether to add a second aircraft. PMID:10296622
Watts, Michael E.; Greenwood, Eric; Smith, Charles D.; Snider, Royce; Conner, David A.
A cooperative ight test by NASA, Bell Helicopter and the U.S. Army to characterize the steady state acoustics and measure the maneuver noise of a Bell Helicopter 430 aircraft was accomplished. The test occurred during June/July 2011 at Eglin Air Force Base, Florida. This test gathered a total of 410 test points over 10 test days and compiled an extensive database of dynamic maneuver measurements. Three microphone arrays with up to 31 microphon. es in each were used to acquire acoustic data. Aircraft data included Differential Global Positioning System, aircraft state and rotor state information. This paper provides an overview of the test and documents the data acquired.
Doehler, H.-U.; Schmerwitz, Sven; Lueken, Thomas
Helicopter guidance in situations where natural vision is reduced is still a challenging task. Beside new available sensors, which are able to "see" through darkness, fog and dust, display technology remains one of the key issues of pilot assistance systems. As long as we have pilots within aircraft cockpits, we have to keep them informed about the outside situation. "Situational awareness" of humans is mainly powered by their visual channel. Therefore, display systems which are able to cross-fade seamless from natural vision to artificial computer vision and vice versa, are of greatest interest within this context. Helmet-mounted displays (HMD) have this property when they apply a head-tracker for measuring the pilot's head orientation relative to the aircraft reference frame. Together with the aircraft's position and orientation relative to the world's reference frame, the on-board graphics computer can generate images which are perfectly aligned with the outside world. We call image elements which match the outside world, "visual-conformal". Published display formats for helicopter guidance in degraded visual environment apply mostly 2D-symbologies which stay far behind from what is possible. We propose a perspective 3D-symbology for a head-tracked HMD which shows as much as possible visual-conformal elements. We implemented and tested our proposal within our fixed based cockpit simulator as well as in our flying helicopter simulator (FHS). Recently conducted simulation trials with experienced helicopter pilots give some first evaluation results of our proposal.
Brodin, Gary; Cooper, John; Walsh, David; Stevens, Jeff
This paper presents the results of an experiment to investigate the impact of helicopter rotor blades on GPS signal reception. An offshore transport helicopter was equipped with a measurement system including a TSO-C129 compliant receiver and a custom research receiver. GPS signals passing through rotor discs of this aircraft were found to suffer a reduction in received signal strength, leading to potential navigation and RAIM availability concerns. The phenomenon will vary between installations and receiver types. Test procedures to identify the occurrence of the phenomenon in operational GPS installations are presented, together with possible in-service monitoring programs to assess the impact on the navigation function.
Bushko, Dariusz A.; Fenn, Ralph C.; Gerver, Michael J.; Berry, John R.; Phillips, Frank; Merkley, Donald J.
The unique configuration of the rotorcraft generates problems unknown to fixed wing aircraft. These problems include high vibration and noise levels. This paper presents the development and test results of a Terfenol-D based actuator designed to operate in an individual blade control system in order to reduce vibration and noise and increase performance on Army UH- 60A helicopter. The full-scale, magnetostrictive, Terfenol-D based actuator was tested on a specially designed testbed that simulated operational conditions of a helicopter blade in the laboratory. Tests of actuator performance (strike, force moment, bandwidth, fatigue life under operational loading) were performed.
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Top view from gantry, showing helicopter in final position after sliding 23 feet from initial impact. Photographed at the Impact Dynamics Research Facility, building 1297.
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Overall view of the nose landing gear (originally from Sikorsky S-76 helicopter). Photographed at the Impact Dynamics Research Facility, building 1297.
Becelli, Roberto; Morello, Roberto; Renzi, Giancarlo; Matarazzo, Giorgio; Dominici, Chiara
Injuries in civil aviation can occur as a consequence of work-related accidents happening in airport. The ground crew can sustain slips, trips, falls, and machinery accidents. Most such accidents are observed when aircraft is departing. This clinical report describes a case of an airport ground assistant severely injured by a helicopter after the strike with a main rotor blade that was slowing after that the craft was landed and the engine was stopped, and reports surgical emergency treatment of life-threatening facial lesions. PMID:21778853
Dextern, H. B.
Confidence in the long term durability of advanced composites is developed through a series of flight service programs. Service experience is obtained by installing secondary and primary composite components on commercial and military transport aircraft and helicopters. Included are spoilers, rudders, elevators, ailerons, fairings and wing boxes on transport aircraft and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on helicopters. Materials included in the evaluation are boron/epoxy, Kevlar/epoxy, graphite/epoxy and boron/aluminum. Inspection, maintenance, and repair results for the components in service are reported. The effects of long term exposure to laboratory, flight, and outdoor environmental conditions are reported for various composite materials. Included are effects of moisture absorption, ultraviolet radiation, and aircraft fuels and fluids.
Simon, Donald L.; Litt, Jonathan S.
An accurate indication of available power is required for helicopter mission planning purposes. Available power is currently estimated on U.S. Army Blackhawk helicopters by performing a Maximum Power Check (MPC), a manual procedure performed by maintenance pilots on a periodic basis. The MPC establishes Engine Torque Factor (ETF), an indication of available power. It is desirable to replace the current manual MPC procedure with an automated approach that will enable continuous real-time assessment of available power utilizing normal mission data. This report presents an automated power assessment approach which processes data currently collected within helicopter Health and Usage Monitoring System (HUMS) units. The overall approach consists of: 1) a steady-state data filter which identifies and extracts steady-state operating points within HUMS data sets; 2) engine performance curve trend monitoring and updating; and 3) automated ETF calculation. The algorithm is coded in MATLAB (The MathWorks, Inc.) and currently runs on a PC. Results from the application of this technique to HUMS mission data collected from UH-60L aircraft equipped with T700-GE-701C engines are presented and compared to manually calculated ETF values. Potential future enhancements are discussed.
Hilton, D. A.; Henderson, H. R.; Maglieri, D. J.; Bigler, W. B., II
In order to expand the data base of helicopter external noise characteristics, a flyover noise measurement program was conducted utilizing the NASA Civil Helicopter Research Aircraft. The remotely operated multiple array acoustics range (ROMAAR) and a 2560-m linear microphone array were utilized for the purpose of documenting the noise characteristics of the test helicopter during flyby and landing operations. By utilizing both ROMAAR concept and the linear array, the data necessary to plot the ground noise footprints and noise radiation patterns were obtained. Examples of the measured noise signature of the test helicopter, the ground noise footprint or contours, and the directivity patterns measured during level flyby and landing operations of a large, multibladed, nonbanging helicopter, the CH-53, are presented.
Logan, A. H.; Banerjee, D.
In optimizing a helicopter configuration, Hughes Helicopters uses a program called Computer Aided Sizing of Helicopters (CASH), written and updated over the past ten years, and used as an important part of the preliminary design process of the AH-64. First, measures of effectiveness must be supplied to define the mission characteristics of the helicopter to be designed. Then CASH allows the designer to rapidly and automatically develop the basic size of the helicopter (or other rotorcraft) for the given mission. This enables the designer and management to assess the various tradeoffs and to quickly determine the optimum configuration.
Boothe, Edward M.
The initial advisory circular was produced in 1984 (AC 120-XX). It was not finalized, however, because the FAR's for pilot certification did not recognize helicopter simulators and, therefore, permitted no credit for their use. That is being rectified, and, when the new rules are published, standards must be available for qualifying simulators. Because of the lack of a data base to support specification of these standards, the FAA must rely on the knowledge of experts in the simulator/training industry. A major aim of this workshop is to form a working group of these experts to produce a set of standards for helicopter training simulators.
Hart, Sandra G.; Rutkowski, Michael
In response to the President's challenge to reduce civil aviation accidents by a factor of 10 by the year 2022, NASA has embarked on an ambitious safety program in partnership with other government agencies and industry. The helicopter element of the NASA initiative has been guided by a series of accident analyses aimed at identifying the most frequent causes and consequences and initiating research to prevent or mitigate these factors. This talk will summarize the key findings of three of the accident analyses, the major elements of the safety program, and how helicopter safety research relates to the safety program.
Small Unmanned Aircraft Systems (UAS) are considered the stepping stone for the integration of civil unmanned vehicles in the National Airspace System (NAS) because of their low cost and risk. Such systems are aimed at a variety of applications including search and rescue, surveillance, communications, traffic monitoring and inspection of buildings, power lines and bridges. Amidst these systems, small helicopters play an important role because of their capability to hold a position, to maneuver in tight spaces and to take off and land from virtually anywhere. Nevertheless civil adoption of such systems is minimal, mostly because of regulatory problems that in turn are due to safety concerns. This dissertation examines the risk to safety imposed by UAS in general and small helicopters in particular, focusing on accidents resulting in a ground impact. To improve the performance of small helicopters in this area, the use of autonomous autorotation is proposed. This research goes beyond previous work in the area of autonomous autorotation by developing an on-line, model-based, real-time controller that is capable of handling constraints and different cost functions. The approach selected is based on a non-linear model-predictive controller, that is augmented by a neural network to improve the speed of the non-linear optimization. The immediate benefit of this controller is that a class of failures that would otherwise result in an uncontrolled crash and possible injuries or fatalities can now be accommodated. Furthermore besides simply landing the helicopter, the controller is also capable of minimizing the risk of serious injury to people in the area. This is accomplished by minimizing the kinetic energy during the last phase of the descent. The presented research is designed to benefit the entire UAS community as well as the public, by allowing for safer UAS operations, which in turn also allow faster and less expensive integration of UAS in the NAS.
Adams, Richard J.
Helicopter simulators have been approved by means of special exemption; there are no FAA standards for simulators used in training or airmen Certification checking. The fixed-wing industry provides a precedent which can be used for expediting implementation of helicopter simulators. The analysis in this paper is founded on the experience with that precedent and is driven by a clear definition of helicopter user needs for (1) improved training at lower cost, (2) more comprehensive emergency training at lower risk, (3) increased fidelity of transition and instrument training compared with low-cost aircraft alternatives, and (4) certification credit for improved simulator training.
Ollerhead, J. B.
Following a brief review of the background to the study, an extensive experiment is described which was undertaken to assess the practical differences between numerous alternative methods for calculating the perceived levels of individual aircraft flyover wounds. One hundred and twenty recorded sounds, including jets, turboprops, piston aircraft and helicopters were rated by a panel of subjects in a pair comparison test. The results were analyzed to evaluate a number of noise rating procedures, in terms of their ability to accurately estimate both relative and absolute perceived noise levels over a wider dynamic range (84-115 dB SPL) than had generally been used in previous experiments. Performances of the different scales were examined in detail for different aircraft categories, and the merits of different band level summation procedures, frequency weighting functions, duration and tone corrections were investigated.
Focke, H; Kruger, K B
This report presents some of the problems concerning tests of helicopters, such as forced landings, controllability and stability, general safety, piloting maneuvers, performance, servicing, and the production of lift of a propeller. Test flights are described including a 67.67 mph flight by Hanna Reitsch.
Crocco, G Arturo
The equilibrium, in still air, of a "stationary" helicopter (i.e., of one having neither vertical nor translational velocity, but a tendency to remain practically motionless within restricted limits of space) presents some difficulty in practice and justifies a theoretical investigation of its "inherent stability," i.e., independent of the pilot.
Yu, Yung H.; Schmitz, Frederic H.; Morse, Andrew H.
Progress in aeroacoustical theory and experiments reviewed. Report summarizes continuing U.S. Army programs of research into causes of noise generated by helicopters. Topics of study include high-speed impulsive noise, blade/vortex-interaction noise, and low-frequency harmonic noise.
Ollerhead, J. B.
The adequacy of the effective perceived noise level (EPNL) procedure for rating helicopter noise annoyance was investigated. Recordings of 89 helicopters and 30 fixed wing aircraft (CTOL) flyover sounds were rated with respect to annoyance by groups of approximately 40 subjects. The average annoyance scores were transformed to annoyance levels defined as the equally annoying sound levels of a fixed reference sound. The sound levels of the test sounds were measured on various scales, with and without corrections for duration, tones, and impulsiveness. On average, the helicopter sounds were judged equally annoying to CTOL sounds when their duration corrected levels are approximately 2 dB higher. Multiple regression analysis indicated that, provided the helicopter/CTOL difference of about 2 dB is taken into account, the particular linear combination of level, duration, and tone corrections inherent in EPNL is close to optimum. The results reveal no general requirement for special EPNL correction terms to penalize helicopter sounds which are particularly impulsive; impulsiveness causes spectral and temporal changes which themselves adequately amplify conventionally measured sound levels.
Simons, C. A. B. A. E.; Sanabria-Walter, C.; Polinder, H.
During the past decades, superconducting electrical machines have become more suitable to replace conventional iron based designs, because of their lower weight and higher torque density. These properties make them good candidates for use in More Electric Aircraft (MEA). Especially helicopter propulsion systems could benefit from the increased performance. This paper describes the feasibility study of a superconducting motor to be used for helicopter propulsion as part of a More Electric Aircraft (MEA). For this, the armature, field windings and cryostat are designed, aiming at meeting the difficult specifications. Since superconductors have virtually no electrical resistance when cooled down below a certain critical temperature, they can be used to build high field and low weight coils for electrical machines. Especially the possibility to not use iron can make the superconducting motor lighter with a higher power density compared with conventional Permanent Magnet (PM) motors.
Kaufmann, David N.
The period between 1 July and 31 December, 1992, was spent developing a research plan as well as a navigation system document and flight test plan to investigate helicopter precision approach capability using the Global Positioning System (GPS). In addition, all hardware and software required for the research was acquired, developed, installed, and verified on both the test aircraft and the ground-based reference station.
Sturgeon, W. R.; Phillips, J. D.
A mathematical model suitable for real time simulation of the CH-53 helicopter is presented. This model, which is based on modified nonlinear classical rotor theory and nonlinear fuselage aerodynamics, will be used to support terminal-area guidance and navigation studies on a fixed-base simulator. Validation is achieved by comparing the model response with that of a similar aircraft and by a qualitative comparison of the handling characteristics made by experienced pilots.
Carson Helicopters Inc. licensed the Langley RC4 series of airfoils in 1993 to develop a replacement main rotor blade for their Sikorsky S-61 helicopters. The company's fleet of S-61 helicopters has been rebuilt to include Langley's patented airfoil design, and the helicopters are now able to carry heavier loads and fly faster and farther, and the main rotor blades have twice the previous service life. In aerial firefighting, the performance-boosting airfoils have helped the U.S. Department of Agriculture's Forest Service control the spread of wildfires. In 2003, Carson Helicopters signed a contract with Ducommun AeroStructures Inc., to manufacture the composite blades for Carson Helicopters to sell
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Roof instrument panel between pilot stations - left view. Photographed at the Impact Dynamics Research Facility, building 1297.
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Roof instrument panel between pilot stations, right view. Photographed at the Impact Dynamics Research Facility, building 1297.
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Left view of cockpit showing manikin head against panel. Photographed at the Impact Dynamics Research Facility, building 1297.
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Right view of cabin showing troop seat fabric failure. Photographed at the Impact Dynamics Research Facility, building 1297.
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Sub-floor, inside view showing details of limited crushing. Photographed at the Impact Dynamics Research Facility, building 1297.
Morgan, Homer G.; Pao, S. P.; Powell, C. A.
The helicopter acoustics program at NASA Langley has included technology for elements of noise control ranging from sources of noise to receivers of noise. The scope of Langley contributions for about the last decade is discussed. Specifically, the resolution of two certification noise quantification issues by subjective acoustics research, the development status of the helicopter system noise prediction program ROTONET are reviewed and the highlights from research on blade rotational, broadband, and blade vortex interaction noise sources are presented. Finally, research contributions on helicopter cabin (or interior) noise control are presented. A bibliography of publications from the Langley helicopter acoustics program for the past 10 years is included.
... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Aircraft and air delivery. 1002.17 Section 1002.17 Parks, Forests, and Public Property PRESIDIO TRUST RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 1002.17 Aircraft and air delivery. (a) Delivering or retrieving a person or object by parachute, helicopter, or other...
Crowley, K. C.; Jaeger, M. A.; Meldrum, D. F.
The application of computer programs for predicting the noise-time histories and noise contours for five types of aircraft is reported. The aircraft considered are: (1) turbojet, (2) turbofan, (3) turboprop, (4) V/STOL, and (5) helicopter. Three principle considerations incorporated in the design of the noise prediction program are core effectiveness, limited input, and variable output reporting.
Gustafson, F B; Myers, G C , Jr
Theoretical studies have predicted that operation of helicopter rotor beyond certain combinations of thrust, forward speed, and rotational speed might be prevented by rapidly increasing stalling of the retreating blade. The same studies also indicate that the efficiency of the rotor will increase until these limits are reached or closely approached, so that it is desirable to design helicopter rotors for operation close to the limits imposed by blade stalling. Inasmuch as the theoretical predictions of blade stalling involve numerous approximations and assumptions, an experimental investigation was needed to determine whether, in actual practice, the stall did occur and spread as predicted and to establish the amount of stalling that could be present without severe vibration or control difficulties being introduced. This report presents the results of such an investigation.
Baisley, R. L.
The results of an evaluation of police helicopter effectiveness revealed a need for improved visual capability. A JPL program developed a method that would enhance visual observation capability for both day and night usage and demonstrated the feasibility of the adopted approach. This approach made use of remote pointable optics, a display screen, a slaved covert searchlight, and a coupled camera. The approach was proved feasible through field testing and by judgement against evaluation criteria.
... (expiration date). For the MDHI Model MD900 helicopters, AD 2006-18-01 (71 FR 51095, August 29, 2006) already... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska... the MDHI Model MD900 helicopters, AD 2006-18-01 (71 FR 51095, August 29, 2006) contains additional...
...We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron, Inc. (Bell), Model 412 and 412EP helicopters. This AD requires creating a component history card or equivalent record and begin counting and recording the number of accumulated landings for each high aft crosstube assembly (crosstube). Also, this AD requires installing ``caution'' decals regarding towing of a......
... the MDHI Model MD900 helicopters with certain main rotor blade (MRB) retention bolts (bolts) installed...'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect... MD 900 helicopters with a main rotor blade retention bolt (bolt), part number (P/N)...
... (76 FR 66609, October 27, 2011) for Bell Model 407 helicopters with a servo, part number (P/N) 206-076... issued AD 2011-15-51 (76 FR 66609, October 27, 2011), Transport Canada issued AD No. CF-2011-17R1, dated... helicopters. AD Requirements This AD retains the inspection requirements of AD 2011-15-51 (76 FR...
Dinyovszky, P.; Twomey, W. J.
Under a rotorcraft structural dynamics program sponsored by the NASA Langley Research Center, Sikorsky Aircraft, together with the other major helicopter airframe manufacturers, is engaged in a study to improve the use of finite element analysis to predict the dynamic behavior of helicopter airframes. This program, which was designated DAMVIBS (Design Analysis Methods for VIBrationS), includes activities in the areas of: planning, creating, and documenting finite element models of helicopter airframes; the performance of ground vibration tests; and the correlation of test and analysis. The work performed at Sikorsky Aircraft for planning, creating, and documenting a finite element model of the UH-60A BLACK HAWK helicopter airframe is summarized. A complete description of the components of the helicopter which are to be represented in the model is presented and includes: the structural arrangement, the identification of primary and secondary structure, the components of the drive and power trains, and the attachment of large weight items to the structure. Also presented are the techniques which were used to formulate the structural finite element model for static analysis, for forming the mass and vibration models for dynamic analysis, and the procedures which were used to check out and verify the integrity of the model. Initial predictions for the vibration modes for the helicopter are included.
Henderson, H. R.; Peegg, R. J.; Hilton, D. A.
A field noise measurement program has been conducted on a standard OH-6A helicopter and one that had been modified by reducing the rotor speed, altering rotor tip shape, and treating the engine exhaust and inlet to reduce the external noise levels. The modifications consisted of extensive aircraft design changes resulting in substantial noise reductions following state-of-art noise reduction techniques. The purpose of this study was to document the ground noise characteristics of each helicopter during flyover, hover, landing, and take-off operations. Based on an analysis of the measured results, the average of the overall on-track noise levels of the final modified helicopter was approximately 14 db lower than that for the standard helicopter. Narrow-band-spectra data of the hovering helicopter show a reduction in the overall noise due to the reductions achieved for the lifting main and antitorque tail rotor, engine exhaust, and gear box noise for the modified helicopter. The noise results of the test program are found to correlate generally with noise measurements made previously on this type of aircraft.
The linear performance definition curves for the lift fan aircraft, tilt rotor aircraft, and advanced helicopter are given. The computer program written to perform the mission analysis for this study is also documented, and examples of its use are shown. Methods used to derive the performance coefficients for use in the mission analysis of the lift fan aircraft are described.
Dunn, D. G.; Peart, N. A.
Calculation procedures are presented for predicting the noise-time histories and noise contours (footprints) of five basic types of aircraft; turbojet, turofan, turboprop, V/STOL, and helicopter. The procedures have been computerized to facilitate prediction of the noise characteristics during takeoffs, flyovers, and/or landing operations.
Dexter, H. B.
The paper considers the use of composite components in commercial aircraft. NASA has been active in sponsoring flight service programs with advanced composites for the last 10 years, with 2.5 million total composite component hours accumulated since 1970 on commercial transports and helicopters with no significant degradation in residual strength of composite components. Design, inspection, and maintenance procedures have been developed; a major NASA/US industry technology program has been developed to reduce fuel consumption of commercial transport aircraft through the use of advanced composites.
Harlow, Charles; Zhu, Weihong
Accurate data is important in the aviation planning process. In this project we consider systems for measuring aircraft activity at airports. This would include determining the type of aircraft such as jet, helicopter, single engine, and multiengine propeller. Some of the issues involved in deploying technologies for monitoring aircraft operations are cost, reliability, and accuracy. In addition, the system must be field portable and acceptable at airports. A comparison of technologies was conducted and it was decided that an aircraft monitoring system should be based upon acoustic technology. A multimedia relational database was established for the study. The information contained in the database consists of airport information, runway information, acoustic records, photographic records, a description of the event (takeoff, landing), aircraft type, and environmental information. We extracted features from the time signal and the frequency content of the signal. A multi-layer feed-forward neural network was chosen as the classifier. Training and testing results were obtained. We were able to obtain classification results of over 90 percent for training and testing for takeoff events.
The opportunities for improved training and checking by using helicopter simulators are greater than they are for airplane pilot training. Simulators permit the safe creation of training environments that are conducive to the development of pilot decision-making, situational awareness, and cockpit management. This paper defines specific attributes required in a simulator to meet a typical helicopter operator's training and checking objectives.
Exterior and interior helicopter noise problems are addressed from the physics and engineering as well as the human factors point of view. Noise regulation concepts, human factors and criteria, rotor noise generation and control, design, operations and testing for noise control, helicopter noise prediction, and research tools and measurements are covered.
van Koersel, Antonius C.
A technology demonstrator that detects and classifies different helicopter types automatically, was developed at TNO-FEL. The demonstrator is based on a PC, which receives its acoustic input from an all-weather microphone. The demonstrator uses commercial off-the-shelf hardware to digitize the acoustic signal. The user-interface and the signal processing software are written in MatLabTM. The demonstrator detects the noise from helicopters; the classification is performed using a database with helicopter-specific features. The demonstrator currently contains information of 11 different helicopter types, but can easily be expanded to include additional types of helicopters. The input signal is analyzed in real time, the result is a classification ranging from `no target' to `helicopter type x', e.g. Lynx Mk2. If the helicopter is classified, its relative speed is estimated as well. The algorithm was developed and tested using a database of different helicopters (hovering and moving) recorded at distances ranging from 90 meter up to 8 kilometer. The sensitivity to noise was investigated using jet, tank, artillery and environmental (wind and turbulence) noise as input.
Shepherd, K. P.
The test stimuli recorded during a recent field study consisted of 16 sounds, each presented at 4 peak noise levels. Two helicopters and a fixed-wing aircraft were used. The impulsive characteristics of one helicopter were varied by operating at different rotor speeds, whereas the other helicopter, the noise of which was dominated by the tail rotor, displayed little variation in blade-slap noise. Thirty-two subjects made noisiness judgments on a continuous, 11 point, numerical scale. Preliminary results indicate that proposed impulsiveness corrections provide no significant improvement in the noisiness predictive ability of Effective Perceived Noise Levels (EPNL). For equal EPNL, the two categories of helicopter stimuli, one of which was far more impulsive than the other, showed no difference in judged noisiness. Examination of the physical characteristics of the sounds presented in the laboratory highlighted the difficulty of reproducing acoustical signals with high-crest factors.
Reinmann, J. J.; Shaw, R. J.; Olsen, W. A., Jr.
Research activity is described for: ice protection systems, icing instrumentation, experimental methods, analytical modeling for the above, and in flight research. The renewed interest in aircraft icing has come about because of the new need for All-Weather Helicopters and General Aviation aircraft. Because of increased fuel costs, tomorrow's Commercial Transport aircraft will also require new types of ice protection systems and better estimates of the aeropenalties caused by ice on unprotected surfaces. The physics of aircraft icing is very similar to the icing that occurs on ground structures and structures at sea; all involve droplets that freeze on the surfaces because of the cold air. Therefore all icing research groups will benefit greatly by sharing their research information.
Albers, J.; Zuk, J.
New aircraft technologies are presented that have the potential to expand the air transportation system and reduce congestion through new operating capabilities while also providing greater levels of safety and environmental compatibility. These new capabilities will result from current and planned civil aeronautics technology at the NASA Ames, Lewis, and Langley Research Centers and will cover the complete spectrum of current aircraft and new vehicle concepts including rotorcraft (helicopters and tilt rotors), vertical and short takeoff and landing (V/STOL), and short takeoff and landing (STOL) aircraft, subsonic transports, high-speed transports, and hypersonic/transatmospheric vehicles. New technologies will improve efficiency, affordability, safety, and environmental compatibility of current aircraft and will enable the development of new transportation system. The new capabilities of vehicles could lead to substantial market opportunities and economic growth and could improve the competitive position of the U.S. aerospace industry.
Dexter, H. B.
Commercial aircraft manufacturers are making production commitments to composite structure for future aircraft and modifications to current production aircraft. Flight service programs with advanced composites sponsored by NASA during the past 10 years are described. Approximately 2.5 million total composite component flight hours have been accumulated since 1970 on both commercial transports and helicopters. Design concepts with significant mass savings were developed, appropriate inspection and maintenance procedures were established, and satisfactory service was achieved for the various composite components. A major NASA/U.S. industry technology program to reduce fuel consumption of commercial transport aircraft through the use of advanced composites was undertaken. Ground and flight environmental effects on the composite materials used in the flight service programs supplement the flight service evaluation.
...”. (c) Each access to a helicopter landing area must be marked: “BEWARE OF TAIL ROTOR”. (d) Each marking... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter facilities. 108.653 Section 108.653 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.653 Helicopter facilities. (a) Each helicopter...
Hubbard, H. H.; Maglieri, D. J.; Stephens, D. G.
A broad perspective of needs in helicopter exterior and interior control is presented. Emphasis is given to those items which support noise certification of civil helicopters and which result in reduced environmental noise impact to community residents as well as to helicopter passengers. The activities described are related to the Langley responsibilities for helicopter acoustics as defined by NASA roles and missions.
Webb, Jr., John G.; Gray, Roger M.
A helicopter discrimination apparatus for a radar utilizing doppler filtering to discriminate between a missile and ground clutter. The short duration of the doppler filter pulses which are emitted by helicopter rotor blades are processed to prevent false alarms, thus allowing the radar-protected helicopter to operate in formation with other helicopters while maintaining protection against infra-red-seeking missiles.
Two different approaches based on sequential experimental design concepts have been studied for helicopter rotor tuning, which is the process of adjusting the rotor blades so as to reduce the aircraft vibration and the spread of rotors. One uses an interval model adapted sequentially to improve the search for the blade adjustments. The other uses a probability model to search for the blade adjustments with the maximal probability of success. In the first approach, an interval model is used to represent the range of effect of blade adjustments on helicopter vibration, so as to cope with the nonlinear and stochastic nature of aircraft vibration. The coefficients of the model are initially defined according to sensitivity coefficients between the blade adjustments and helicopter vibration, to include the expert knowledge of the process. The model coefficients are subsequently transformed into intervals and updated after each tuning iteration to improve the model's estimation accuracy. The search for the blade adjustments is performed according to this model by considering the vibration estimates of all of the flight regimes so as to provide a comprehensive solution for rotor tuning. The second approach studied uses a probability model to maximize the likelihood of success of the selected blade adjustments. The underlying model in this approach consists of two segments: a deterministic segment to include a linear regression model representing the relationships between the blade adjustments and helicopter vibration, and a stochastic segment to comprise probability densities of the vibration components. The blade adjustments with the maximal probability of generating acceptable vibration are selected as recommended adjustments. The effectiveness of the proposed approaches is evaluated in simulation based on a series of neural networks trained with actual vibration data. To incorporate the stochastic behavior of the helicopter vibration and better simulate the tuning
Stephens, D. G.; Leatherwood, J. D.
Ride quality criteria for noise, vibration, and their combination in the helicopter cabin environment are discussed. Results are presented of laboratory and field studies of passenger responses to interior noise and vibration during the performance of a listening task and during reverie, as well as to the interaction of noise with multi-frequency and multi-axis vibration. A study of means for reducing helicopter interior noise based on analytical, experimental and flight studies of the near-field noise source characteristics of the aircraft, the transmission of noise through aircraft structures and the attenuation of noise by various noise control treatments is then presented which has resulted in a reduction of 3 dB in helicopter cabin noise. Finally, a model under development to evaluate passenger acceptance of a helicopter noise and vibration environment is indicated which incorporates the observed noise and vibration effects on comfort and is expected to provide insights for more effective noise and vibration control.
Farazian, K.; Abbe, B.; Divsalar, D.; Raphaeli, D.; Tulintseff, A.; Wu, T.; Hinedi, S.
In this paper, the development of low-cost satellite communications (SATCOM) system for helicopters and General Aviation (GA) aircrafts is described. System design and standards analysis have been conducted to meet the low-cost, light-weight, small-size and low-power system requirements for helicopters and GA aircraft environments. Other specific issues investigated include coding schemes, spatial diversity, and antenna arraying techniques. Coding schemes employing Channel State Information (CSI) and inverleaving have been studied in order to mitigate severe banking angle fading and the periodic RF signal blockage due to the helicopter rotor blades. In addition, space diversity and antenna arraying techniques have been investigated to further reduce the fading effects and increase the link margin.
Sternfeld, H., Jr.; Wiedersum, C. W.
A means of estimating the noise generated by a helicopter main rotor using information which is generally available during the preliminary design phase of aircraft development is presented. The method utilizes design charts and tables which do not require an understanding of acoustical theory or computational procedures in order to predict the perceived noise level, a weighted sound pressure level, or C weighted sound pressure level of a single hovering rotor. A method for estimating the effective perceived noise level in forward flight is also included. In order to give the designer an assessment of the relative rotor performance, which may be traded off against noise, an additional chart for estimating the percent of available rotor thrust which must be expended in lifting the rotor and drive system, is included as well as approach for comparing the subjective acceptability of various rotors once the absolute sound pressure levels are predicted.
Sindlinger, A.; Meuter, M.; Barraci, N.; Güttler, M.; Klingauf, U.; Schiefele, J.; Howland, D.
Helicopters are widely used for operations close to terrain such as rescue missions; therefore all-weather capabilities are highly desired. To minimize or even avoid the risk of collision with terrain and obstacles, Synthetic Vision Systems (SVS) could be used to increase situational awareness. In order to demonstrate this, helicopter flights have been performed in the area of Zurich, Switzerland A major component of an SVS is the three-dimensional (3D) depiction of terrain data, usually presented on the primary flight display (PFD). The degree of usability in low level flight applications is a function of the terrain data quality. Today's most precise, large scale terrain data are derived from airborne laser scanning technologies such as LIDAR (light detection and ranging). A LIDAR dataset provided by Swissphoto AG, Zurich with a resolution of 1m was used. The depiction of high resolution terrain data consisting of 1 million elevation posts per square kilometer on a laptop in an appropriate area around the helicopter is challenging. To facilitate the depiction of the high resolution terrain data, it was triangulated applying a 1.5m error margin making it possible to depict an area of 5x5 square kilometer around the helicopter. To position the camera correctly in the virtual scene the SVS had to be supplied with accurate navigation data. Highly flexible and portable measurement equipment which easily could be used in most aircrafts was designed. Demonstration flights were successfully executed in September, October 2005 in the Swiss Alps departing from Zurich.
Damarla, T. Raju; Ufford, David
Unattended ground sensors (UGS) are routinely used to collect intelligence, surveillance, and reconnaissance (ISR) information. Unattended ground sensors consisting of microphone array and geophone are employed to detect rotary wing aircraft. This paper presents an algorithm for the detection of helicopters based on a fusion of rotor harmonics and acoustic-seismic coupling. The main rotor blades of helicopters operate at a fixed RPM to prevent stalling or mechanical damage. In addition, the seismic spectrum is dominated by the acoustic-seismic coupling generated by these rotors; much more so than ground vehicles and other targets where mechanical coupling and a more broadband acoustic source are strong factors. First, an autocorrelation detection method identifies the constant fundamental generated by the helicopter main rotor. Second, key matching frequencies between the acoustic and seismic spectrum are used to locate possible coupled components. Detection can then be based on the ratio of the coupled seismic energy to total seismic energy. The results of the two methods are fused over a few seconds time to provide an initial and continued detection of a helicopter within the sensor range. Performance is measured on data as a function of range and sound pressure level (SPL).
Santa Maria, Odilyn L.
A method to separate main rotor and tail rotor noise from a helicopter in flight is explored. Being the sum of two periodic signals of disproportionate, or incommensurate frequencies, helicopter noise is neither periodic nor stationary, but possibly harmonizable. The single Fourier transform divides signal energy into frequency bins of equal size. Incommensurate frequencies are therefore not adequately represented by any one chosen data block size. A two-dimensional Fourier analysis method is used to show helicopter noise as harmonizable. The two-dimensional spectral analysis method is first applied to simulated signals. This initial analysis gives an idea of the characteristics of the two-dimensional autocorrelations and spectra. Data from a helicopter flight test is analyzed in two dimensions. The test aircraft are a Boeing MD902 Explorer (no tail rotor) and a Sikorsky S-76 (4-bladed tail rotor). The results show that the main rotor and tail rotor signals can indeed be separated in the two-dimensional Fourier transform spectrum. The separation occurs along the diagonals associated with the frequencies of interest. These diagonals are individual spectra containing only information related to one particular frequency.
Kaufmann, David N.
The results of flight tests to determine the feasibility of using the Global Positioning System (GPS) in the Differential mode (DGPS) to provide high accuracy, precision navigation and guidance for helicopter approaches to landing are presented. The airborne DGPS receiver and associated equipment is installed in a NASA UH-60 Black Hawk helicopter. The ground-based DGPS reference receiver is located at a surveyed test site and is equipped with a real-time VHF data link to transmit correction information to the airborne DGPS receiver. The corrected airborne DGPS information, together with the preset approach geometry, is used to calculate guidance commands which are sent to the aircraft's approach guidance instruments. The use of DGPS derived guidance for helicopter approaches to landing is evaluated by comparing the DGPS data with the laser tracker truth data. The errors indicate that the helicopter position based on DGPS guidance satisfies the International Civil Aviation Organization (ICAO) Category 1 (CAT 1) lateral and vertical navigational accuracy requirements.
Hart, Sandra G.; Sridhar, Banavar (Technical Monitor)
Even under optimal conditions, helicopter flight is a most demanding form of human-machine interaction, imposing continuous manual, visual, communications, and mental demands on pilots. It is made even more challenging by small margins for error created by the close proximity of terrain in NOE flight and missions flown at night and in low visibility. Although technology advances have satisfied some current and proposed requirements, hardware solutions alone are not sufficient to ensure acceptable system performance and pilot workload. However, human factors data needed to improve the design and use of helicopters lag behind advances in sensor, display, and control technology. Thus, it is difficult for designers to consider human capabilities and limitations when making design decisions. This results in costly accidents, design mistakes, unrealistic mission requirements, excessive training costs, and challenge human adaptability. NASA, in collaboration with DOD, industry, and academia, has initiated a program of research to develop scientific data bases and design principles to improve the pilot/vehicle interface, optimize training time and cost, and maintain pilot workload and system performance at an acceptable level. Work performed at Ames, and by other research laboratories, will be reviewed to summarize the most critical helicopter human factors problems and the results of research that has been performed to: (1) Quantify/model pilots use of visual cues for vehicle control; (2) Improve pilots' performance with helmet displays of thermal imagery and night vision goggles for situation awareness and vehicle control; (3) Model the processes by which pilots encode maps and compare them to the visual scene to develop perceptually and cognitively compatible electronic map formats; (4) Evaluate the use of spatially localized auditory displays for geographical orientation, target localization, radio frequency separation; (5) Develop and flight test control
Bruckart, J E
Aircraft systems and medical devices generate electromagnetic fields. Electromagnetic interference (EMI) can cause faulty operation of aircraft systems or medical devices and endanger patients or aircraft crewmembers. A ground and inflight study was conducted to describe the electromagnetic fields in typical operations. Broadband isotropic field sensors measured electric fields from 5 kHz to 3 MHz, 3 to 500 MHz, and 0.5 MHz to 6 GHz. Fields were measured at 0.5 m space intervals in JOH-58A, JUH-1H, and JUH-60A helicopters with systems off, operating RPM, 5-ft hover, 50-ft hover, and cruise. Electric fields in the environment were homogeneous and less than 0.1 V/m. Fields in the helicopters increased during ascent, but remained less than 2 V/m except during radio transmissions. EMI effect of the Physio Control Lifepack 8 was demonstrated during FM radio transmission. The results are useful in evaluating electromagnetic emissions and predicting operations that may result in an inflight malfunction of a medical device or aircraft system. PMID:1445153
Bruckart, James E.
Aircraft systems and medical devices generate electromagnetic fields. EMI can cause faulty operation of aircraft systems or medical devices and endanger patients or aircraft crewmembers. A ground and inflight study was conducted to describe the electromagnetic fields in typical operations. Broadband isotropic field sensors measured electric fields from 5 kHz to 3 MHz, 3 to 500 MHz, and 0.5 MHz to 6 GHz. Fields were measured at 0.5 m space intervals in JOH-58A, JUH-1H, and JUH-60A helicopters with systems off, operating RPM, 5-ft hover, 50-ft hover, and cruise. Electric fields in the environment were homogeneous and less than 0.1 V/m. Fields in the helicopters increased during ascent, but remained less than 2 V/m except during radio transmissions. EMI effect of the Physio Control Lifepack 8 was demonstrated during FM radio transmission. The results are useful in evaluating electromagnetic emissions and predicting operations that may result in an inflight malfunction of a medical device or aircraft system.
Farley, Gary L.; Boitnott, Richard L.; Carden, Huey D.
Results are presented from the U.S. Army-Aerostructures Directorate/NASA-Langley Research Center joint research program on helicopter crashworthiness. Through the on-going research program an in-depth understanding was developed on the cause/effect relationships between material and architectural variables and the energy-absorption capability of composite material and structure. Composite materials were found to be efficient energy absorbers. Graphite/epoxy subfloor structures were more efficient energy absorbers than comparable structures fabricated from Kevlar or aluminum. An accurate method predicting the energy-absorption capability of beams was developed.
Cleary, B.; Pearson, R. W.; Greenwood, S. W.; Kaplan, L.
The extent of the threat to the US helicopter industry posed by a determined effort by foreign manufacturers, European companies in particular, to supply their own domestic markets and also to penetrate export markets, including the USA is assessed. Available data on US and world markets for civil and military uses are collated and presented in both graphic and tabular form showing the past history of production and markets and, where forecasts are available, anticipated future trends. The data are discussed on an item-by-item basis and inferences are drawn in as much depth as appears justified.
Gilmore, John F.
This paper describes an autonomous airborne vehicle being developed at the Georgia Tech Engineering Experiment Station. The Autonomous Helicopter System (AHS) is a multi-mission system consisting of three distinct sections: vision, planning and control. Vision provides the local and global scene analysis which is symbolically represented and passed to planning as the initial route planning constraints. Planning generates a task dependent path for the vehicle to traverse which assures maximum mission system success as well as safety. Control validates the path and either executes the given route or feeds back to previous sections in order to resolve conflicts.
Some of the power train transmission gears in helicopter drive systems can become critical components as performance requirements are increased; accordingly, increasing attention must be paid to new alloys in order to obtain required performance reliability and survivability. Candidate advanced alloys, with improved high temperature properties, while increasing the resistance to scoring and scuffing, tend to have lower ductility and fracture toughness. An attempt is made to identify design materials, and process problems and requirements. In addition, it is recommended that the characterization of candidate steels be accelerated; preliminary investigation indicates that new alloys may provide improved capability against surface distress.
Cunningham, T. B.; Nunn, E. C.
High gain control is explored through a design study of the CH-47B helicopter. The plans are designed to obtain the maximum bandwidth possible given the hardware constraints. Controls are designed with modal control theory to specific bandwidths and closed loop mode shapes. Comparisons are made to an earlier complementary filter approach. Bandwidth improvement by removal of limitations is explored in order to establish hardware and mechanization options. Improvements in the pitch axis control system and in the rate gyro sensor noise characteristics in all axes are discussed. The use of rotor state feedback is assessed.
Howland, G. R.; Durno, J. A.; Twomey, W. J.
Sikorsky Aircraft, together with the other major helicopter airframe manufacturers, is engaged in a study to improve the use of finite element analysis to predict the dynamic behavior of helicopter airframes, under a rotorcraft structural dynamics program called DAMVIBS (Design Analysis Methods for VIBrationS), sponsored by the NASA-Langley. The test plan and test results are presented for a shake test of the UH-60A BLACK HAWK helicopter. A comparison is also presented of test results with results obtained from analysis using a NASTRAN finite element model.
Moore, C. B.; Jones, J. J.; Hunyady, S. J.
Charge control tests were carried out on a ground based, Marine Corps helicopter to determine if control of the electric fields acting on the engine exhaust gases could be used to reduce the electrification of the helicopter when it operated in a dusty atmosphere. The test aircraft was flown to a dusty, unpaved area and was then isolated electrically from the earth. When the helicopter engines were operated at ground idle with the rotor locked, the isolated aircraft charged positively, as had been observed previously. However, when the rotor brake was released and the turning rotor created a downdraft that raised dust clouds, the aircraft always became charged more positively, to potentials ranging form +30 to +45 kV. The dust clouds raised by the rotor downwash invariably carried negative space charges with concentrations of up to -100 nC/cu m and caused surface electric fields with strengths of up to 10 kV/m immediately down wind of the aircraft. The natural charging of the helicopter operating in these dust clouds was successfully opposed by control of the electric fields acting on the hot, electrically conductive exhaust gases. The control was achieved by placing electrostatic shield around the exhausts.
Lee, J. D.; Harding, R.; Palko, R. L.
A helicopter icing flight test program in the hover mode was conducted with a UH-1H aircraft. The ice formations were documented after landing by means of silicone rubber molds, stereo photography and outline tracings for later use in aerodynamic analyses. The documentation techniques are described and the results presented for a typical flight.
Savage, James; Harrington, Walter; McKinley, R. Andrew; Burns, H. N.; Braddom, Steven; Szoboszlay, Zoltan
A joint-service team led by the Air Force Research Laboratory's Munitions and Sensors Directorates completed a successful flight test demonstration of the 3D-LZ Helicopter LADAR Imaging System. This was a milestone demonstration in the development of technology solutions for a problem known as "helicopter brownout", the loss of situational awareness caused by swirling sand during approach and landing. The 3D-LZ LADAR was developed by H.N. Burns Engineering and integrated with the US Army Aeroflightdynamics Directorate's Brown-Out Symbology System aircraft state symbology aboard a US Army EH-60 Black Hawk helicopter. The combination of these systems provided an integrated degraded visual environment landing solution with landing zone situational awareness as well as aircraft guidance and obstacle avoidance information. Pilots from the U.S. Army, Air Force, Navy, and Marine Corps achieved a 77% landing rate in full brownout conditions at a test range at Yuma Proving Ground, Arizona. This paper will focus on the LADAR technology used in 3D-LZ and the results of this milestone demonstration.
A conceptual predesign of a compound helicopter for conducting rotor research is presented. The aircraft was selected by the Government as the better of two concepts submitted. The helicopter is a three place vehicle in the 24,000 pound gross weight class. It has been determined that the helicopter satisfies the requirements for the rotor research mission. The model has been predesigned sufficiently to allow an assessment of its performance and stability and control characteristics. A brief treatment of these subjects is included.
Nagel, David C.; Hart, Sandra G.
Helicopter flight is among the most demanding of all human-machine integrations. The inherent manual control complexities of rotorcraft are made even more challenging by the small margin for error created in certain operations, such as nap-of-the-Earth (NOE) flight, by the proximity of the terrain. Accident data recount numerous examples of unintended conflict between helicopters and terrain and attest to the perceptual and control difficulties associated with low altitude flight tasks. Ames Research Center, in cooperation with the U.S. Army Aeroflightdynamics Directorate, has initiated an ambitious research program aimed at increasing safety margins for both civilian and military rotorcraft operations. The program is broad, fundamental, and focused on the development of scientific understandings and technological countermeasures. Research being conducted in several areas is reviewed: workload assessment, prediction, and measure validation; development of advanced displays and effective pilot/automation interfaces; identification of visual cues necessary for low-level, low-visibility flight and modeling of visual flight-path control; and pilot training.
Pogorzelski, Ronald J.; Cable, Vaughn P.
This effort was directed toward demonstration of the efficacy of a concept for mitigation of the rotor blade modulation problem in helicopter communications. An antenna is envisioned with radiating elements mounted on the rotor and rotating with it. The rf signals are coupled to the radio stationary with respect to the airframe via a coupler of unique design. The coupler has an rf cavity within which a mode is established and the field distribution of this mode is sampled by probes rotating with the radiating elements. In this manner the radiated pattern is "despun" with respect to the rotor. Theoretical analysis has indicated that this arrangement will be less susceptible to rotor blade modulation that would be a conventional fixed mounted antenna. A small coupler operating at S-band was designed, fabricated, and mounted on a mockup representative of a helicopter body. A small electric motor was installed to rotate the rotor portion of the coupler along with a set of radiating elements during testing. This test article was be evaluated using the JPL Mesa Antenna Measurement Facility to establish its ability to mitigate rotor blade modulation. It was found that indeed such a coupler will result in a despun pattern and that such a pattern can be effective in mitigation of rotor blade modulation.
...). SUPPLEMENTARY INFORMATION: Airworthiness Directive 2011-12-10, Amendment 39-16717 (76 FR 35330, June 17, 2011.... That AD applies to Robinson Helicopter Company (Robinson) Model R22, R22 Alpha, R22 Beta, R22...
Bauchspies, J. S.; Bryant, W. R., Jr.; Simpson, W. E.
The design requirements for a family or type of Public Service Helicopter (PSH) is examined which will satisfy the needs of municipal and state governments in the following mission areas: Emergency Medical Service--Airborne Rescue Squad; Law Enforcement; Search and Rescue; and Environmental Control (Fire Fighting, Pollution, Resource Management). The report compares both design and performance requirements as specified by the PSH user's group against current technological capabilities, RTOPS and US Army LHX design requirements. The study explores various design trade-offs and options available to the aircraft designer/manufacturer in order to meet the several criteria specified by the PSH user's group. In addition, the report includes a brief assessment of the feasibility of employing certain advanced rotorcraft designs to meet the stringent combination of operational capabilities desired by the Public Service Helicopter Users.
Almsted, Larry D.; Becker, Robert C.; Zelenka, Richard E.
Collision avoidance is of concern to all aircraft, requiring the detection and identification of hazardous terrain or obstacles in sufficient time for clearance maneuvers. The collision avoidance requirement is even more demanding for helicopters, as their unique capabilities result in extensive operations at low-altitude, near to terrain and other hazardous obstacles. TO augment the pilot's visual collision avoidance abilities, some aircraft are equipped with 'enhanced-vision' systems or terrain collision warning systems. Enhanced-vision systems are typically very large and costly systems that are not very covert and are also difficult to install in a helicopter. The display is typically raw images from infrared or radar sensors, and can require a high degree of pilot interpretation and attention. Terrain collision warning system that rely on stored terrain maps are often of low resolution and accuracy and do not represent hazards to the aircraft placed after map sampling. Such hazards could include aircraft parked on runway, man- made towers or buildings and hills. In this paper, a low cost dual-function scanning pencil-beam, millimeter-wave radar forward sensor is used to determine whether an aircraft's flight path is clear of obstructions. Due to the limited space and weight budget in helicopters, the system is a dual function system that is substituted in place of the existing radar altimeter. The system combines a 35 GHz forward looking obstacle avoidance radar and a 4.3 GHz radar altimeter. The forward looking 35 GHz 3D radar's returns are used to construct a terrain and obstruction database surrounding an aircraft, which is presented to the pilot as a synthetic perspective display. The 35 GHz forward looking radar and the associated display was evaluated in a joint NASA Honeywell flight test program in 1996. The tests were conducted on a NASA/Army test helicopter. The test program clearly demonstrated the systems potential usefulness for collision avoidance.
Wagner, R. A.
A review of helicopter noise measurement programs and noise reduction/economic studies of FAA is given along with a critique of a study which addresses the economic impact of noise reduction on helicopter noise. Modification of several helicopters to reduce noise and demonstrate the economic impact of the application of the current state-of-the-art technology is discussed. Specific helicopters described include Boeing Vertol 347 Helicopter, Hughes OH-6 Helicopter, and Hughes 269C Helicopter. Other topics covered include: (1) noise trends and possible noise limits; (2) accuracy of helicopter noise prediction techniques; (3) limited change possibilities of derivatives; and (4) rotor impulsive noise. The unique operational capabilities of helicopters and the implications relative to noise regulations and certification are discussed.
Helicopters have been proven to be economical and convenient vehicles with their ability to land, take -off and maneuver in areas inaccessible to fixed-wing aircraft. However, the noise they generate can severely restrict their usage in both civilian and military operations. When it occurs, helicopter impulsive noise is the loudest and the most annoying. The noise usually can be broken down to high -speed impulsive noise and blade-vortex interaction noise. The physical phenomena of helicopter blade-vortex interaction are especially complicated and include three-dimensional unsteady transonic flow and regions of vorticity. A computational and analytical study of the helicopter impulsive noise has been conducted herein, particularly of the blade-vortex interaction noise. The fundamental theory and noise mechanisms are introduced and discussed. The computational study includes two-dimensional and three -dimensional approaches. The two-dimensional unsteady transonic small disturbance model was extended to include viscous effects and monotone switches. The noise generation mechanisms due to the blade-vortex interaction are discussed. A rotating Kirchhoff method is developed to predict high-speed impulsive noise and blade-vortex interaction noise. A three-dimensional full potential CFD code was used for calculation of the nonlinear aerodynamic near-field, then a couple of extended Kirchhoff formulations with a rotational control surface are used to compute the far-field acoustic signals. The computed numerical results showed a good agreement with experimental results. The results also identify the important parameters for the impulsive noise control. This new rotating Kirchhoff method can be used to predict the helicopter impulsive noise accurately and is believed to be better in many ways than other existing methods.
Arlowe, H. D.
The Sandia Helicopter Acoustic Detector was developed to provide a low cost alternative to radar for countering the helicopter threat at new DOE facilities. The main buildings of these new designs are generally hardened to provide significant delay to a helicopter borne adversary team. Under these circumstances the sensor is only required to detect helicopters that are in their final landing phase and at close range (less than 75 m). This short detection range allows the use of a fairly simple acoustic detection algorithm without making the system overly sensitive to wind noise, motor vehicles, and ventilation/heat exchange blowers. This work was sponsored by the Department of Energy/Office of Safeguards and Security as part of the overall Sandia Fixed Facility Physical Protection Program.
Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Sub-floor, inside view between station 175 and 143, showing limited crushing. Photographed at the Impact Dynamics Research Facility, building 1297.
Auffret, R.; Delahaye, R. P.; Metges, P. J.; VICENS
Pathological forms of spinal pain engendered by piloting helicopters were clinically studied. Lumbalgia and pathology of the dorsal and cervical spine are discussed along with their clinical and radiological signs and origins.
Swenson, Harry N.; Paulk, Clyde H., Jr.; Kilmer, Robert L.; Kilmer, Frank J.
Report evaluates three similar video displays for guidance of helicopter pilots in low-level flight at night in adverse weather. Computer produces guidance information for pilot by integrating data from terrain-following radar, forward-looking infrared (FLIR) imagery, and data from such autonomous navigation instruments as inertial navigation systems and Doppler radar. FLIR imagery, information on status of helicopter, and command symbols incorporated in one head-down display.
Most helicopters now in service have a transmission with a planetary design. Studies have shown that some helicopters would be lighter and more reliable if they had a transmission with a split-torque design instead. However, a split-torque design has never been used by a U.S. helicopter manufacturer because there has been no proven method to ensure equal sharing of the load among the multiple load paths. The Sikorsky/Boeing team has chosen to use a split-torque transmission for the U.S. Army's Comanche helicopter, and Sikorsky Aircraft is designing and manufacturing the transmission. To help reduce the technical risk of fielding this helicopter, NASA and the Army have done the research jointly in cooperation with Sikorsky Aircraft. A theory was developed that equal load sharing could be achieved by proper configuration of the geartrain, and a computer code was completed in-house at the NASA Lewis Research Center to calculate this optimal configuration.
Acree, C. W., Jr.
The helicopter version of the Rotor Systems Research Aircraft (RSRA) is designed to make simultaneous measurements of all rotor forces and moments in flight analogous to a wind tunnel balance. Loads are measured by a combination of load cells, strain gages, and hydropneumatic active isolators which use pressure gages to measure loads. Complete evaluation of system performance required calibration of the rotor force and moment measuring system when installed in the aircraft. Measurement system responses to rotor loads obtained during the first static calibration of the RSRA helicopter are plotted and discussed. Plots of the raw transducer data are included.
Burks, John S.
Performance projections into the next half-century of VTOL aircraft design are presently made on the basis of recent design trends. Attention is given to the technology-development and commercial prospects for tilt-rotor, thrust-vectoring hover, lighter-than-air, and speculative electromagnetic-propulsion, remotely-beamed power systems. Highly automated air traffic control systems are envisioned which will incorporate AI, satellite positioning, synthetic vision, obstacle detection/avoidance and fiber-optic transmission to safely manage giant airborne mass-transit commuter systems. It is expected that tilt-rotor aircraft will become the dominant VTOL configuration as time passes.
Greene, Randall; Seebass, Richard
This talk address the market and technology for a corporate supersonic transport. It describes a candidate configuration. There seems to be a sufficient market for such an aircraft, even if restricted to supersonic operation over water. The candidate configuration's sonic boom overpressure may be small enough to allow overland operation as well.
... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Naval Helicopter Association Reunion... Norfolk, VA to support the Naval Helicopter Association Reunion Helicopter Demonstration. This action is necessary to provide for the safety of life on navigable waters during the Naval Helicopter...
Hoffstedt, D. J.
Utilization of the new, lightweight, high-strength, aerospace structural-composite (filament/matrix) materials, when specifically designed into a new aircraft, promises reductions in structural empty weight of 12 percent at recurring costs competive with metals. A program of basic and applied research and demonstration is identified with the objective of advancing the state of the art to the point where civil helicopters are confidently designed, produced, certified, and marketed by 1985. A structural empty-weight reduction of 12 percent was shown to significantly reduce energy consumption in modern high-performance helicopters.
Lewis, Michael S.; Mansur, M. Hossein; Chen, Robert T. N.
The Helicopter Air Combat system was used to conduct a pilot simulation study investigating the handling qualities and flight characteristics required for helicopter air-to-air combat. Results indicate that a well-damped directional response, low sideforce caused by sideslip, and some effective dihedral are all desirable for weapon system performance, good handling qualities, and low pilot workload. An angular rate command system was favored over the attitude-type pitch and roll response for most applications, and an enhanced maneuver envelope size over that of current generation aircraft was found to be of advantage.
Aragon, Cecilia R.
Many aircraft accidents each year are caused by encounters with unseen airflow hazards near the ground such as vortices, downdrafts, wind shear, microbursts, or other turbulence. While such hazards frequently pose problems to fixed-wing airplanes, they are especially dangerous to helicopters, which often have to operate in confined spaces and under operationally stressful conditions. We are developing flight-deck visualizations of airflow hazards during helicopter takeoff and landing operations, and are evaluating their effectiveness with usability studies. Our hope is.that this work will lead to the production of an airflow hazard detection system for pilots that will save lives.
Gemini 4 astronauts, James A. McDivitt (right), command pilot, and Edward H. White II, (left), pilot, relax aboard a U.S. Navy helicopter on their way to the aircraft carrier U.S.S. Wasp after recovery from the Gemini 4 spacecraft. They had been picked up out of the Atlantic Ocean following a successful splashdown (33532); White (left) and McDivitt listen to the voice of President Lyndon B. Johnson as he congratulated them by telephone on the successful mission. They are shown aboard the carrier U.S.S. Wasp just after their recovery (33533).
Kelley, Henry L.
Variable-tilt helicopter rotor mast proposed to improve helicopter performance and reduce vibration, especially at upper end of forward-speed range of helicopters. Achieved by use of universal coupling in main rotor mast or by tilting entire engine-and-transmission platform. Performance, energy efficiency, and safety enhanced.
... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter decks. 108.486 Section 108.486 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.486 Helicopter decks....
... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter facilities. 108.653 Section 108.653 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS DESIGN AND EQUIPMENT Equipment Markings and Instructions § 108.653 Helicopter facilities. (a) Each helicopter...
Amer, Kenneth B
A theoretical analysis of helicopter maneuver stability is made and the results are compared with experimental results for both a single and a tandem rotor helicopter. Techniques are described for measuring in flight the significant stability derivatives for use with the theory to aid in design studies of means for achieving marginal maneuver stability for a prototype helicopter.
... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter fueling. 109.577 Section 109.577 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS Miscellaneous § 109.577 Helicopter fueling. (a) The master or person in charge shall designate persons to conduct helicopter fueling operations....
Flight fascinates people of all ages. Recent advances in battery technology have extended the capabilities of model airplanes and toy helicopters. For those who have never outgrown a childhood enthusiasm for the wonders of flight, it is possible to buy inexpensive, remotely controlled planes and helicopters. A toy helicopter offers an opportunity…
Hofer, G; Voelckel, W G
Helicopter emergency medical service (HEMS) have become a main part of prehospital emergency medical services over the last 40 years. Recently, an ongoing discussion about financial shortage and personal shortcomings question the role of cost-intensive air rescue. Thus, the value of HEMS must be examined and discussed appropriately. Since the number of physician-staffed ground ambulances may decrease due to the limited availability of qualified physicians, HEMS may fill the gap. In addition patient transfer to specialized hospitals will require an increasing number of air transports in order to minimize prehospital time. The higher risk ratio for HEMS missions when compared with ground rescue requires a rigorous quality management system. When it comes to missions in remote and exposed areas, the scope of medical treatment must be adjusted to the individual situation. Medical competence is key in order to balance guideline compliant or maximal care versus optimal care characterized as a mission-specific, individualized emergency care concept. Although, medical decision making and treatment is typically based on the best scientific evidence, personal skills, competence, and the mission scenario will determine the scope of interventions suitable to improve outcome. Thus, the profile of requirements for the HEMS medical crew is high. PMID:24618925
Linden, A. W.
Handling qualities of the RSRA (rotor systems research aircraft), a special test vehicle with optional configurations (forewings, removable horizontal tailplanes, main rotor, tail rotor, and twin engines for forward flight all removable), are described. The aircraft can be fitted to fly as a conventional rotary-wing aircraft, fixed-wing aircraft, or compound helicopter, and is designed for testing existing and future rotor systems in flight. Controls include full-authority fly-by-wire controls and mechanical controls for rotary wing and for fixed wing. Stability augmentation, rotor test measurement systems, variable center of gravity capability, and rotor loading potential of the RSRA are also described.
Warmbrodt, W.; Hull, R.
A time-domain analysis of coupled engine/drive train/rotor dynamics of a twin-engine, single main rotor helicopter model has been performed. The analysis incorporates an existing helicopter model with nonlinear simulations of a helicopter turboshaft engine and its fuel controller. System dynamic behavior is studied using the resulting simulation which included representations for the two engines and their fuel controllers, drive system, main rotor, tail rotor, and aircraft rigid body motions. Time histories of engine and rotor RPM response to pilot control inputs are studied for a baseline rotor and propulsion system model. Sensitivity of rotor RPM droop to fuel controller gain changes and collective input feed-forward gain changes are studied. Torque-load-sharing between the two engines is investigated by making changes in the fuel controller feedback paths. A linear engine model is derived from the nonlinear engine simulation and used in the coupled system analysis. This four-state linear engine model is then reduced to a three-state model. The effect of this simplification on coupled system behavior is shown.
Tumer, Irem Y.; Huff, Edward M.
Research on the nature of the vibration data collected from helicopter transmissions during flight experiments has led to several crucial observations believed to be responsible for the high rates of false alarms and missed detections in aircraft vibration monitoring systems. This work focuses on one such finding, namely, the need to consider additional sources of information about system vibrations. In this light, helicopter transmission vibration data, collected using triaxial accelerometers, were explored in three different directions, analyzed for content, and then combined using Principal Components Analysis (PCA) to analyze changes in directionality. In this paper, the PCA transformation is applied to 176 test conditions/data sets collected from an OH58C helicopter to derive the overall experiment-wide covariance matrix and its principal eigenvectors. The experiment-wide eigenvectors. are then projected onto the individual test conditions to evaluate changes and similarities in their directionality based on the various experimental factors. The paper will present the foundations of the proposed approach, addressing the question of whether experiment-wide eigenvectors accurately model the vibration modes in individual test conditions. The results will further determine the value of using directionality and triaxial accelerometers for vibration monitoring and anomaly detection.
Watts, Michael E.; Greenwood, Eric; Stephenson, James
This paper presents an overview of a flight test campaign performed at different test sites whose altitudes ranged from 0 to 7000 feet above mean sea level (AMSL) between September 2014 and February 2015. The purposes of this campaign were to: investigate the effects of altitude variation on noise generation, investigate the effects of gross weight variation on noise generation, establish the statistical variability in acoustic flight testing of helicopters, and characterize the effects of transient maneuvers on radiated noise for a medium-lift utility helicopter. In addition to describing the test campaign, results of the acoustic effects of altitude variation for the AS350 SD1 and EH-60L aircraft are presented. Large changes in acoustic amplitudes were observed in response to changes in ambient conditions when the helicopter was flown at constant indicated airspeed and gross weight at the three test sites. However, acoustic amplitudes were found to scale with ambient pressure when flight conditions were defined in terms of the non-dimensional parameters, such as the weight coefficient and effective hover tip Mach number.
Stahl, Christoph; Schoppmann, Paul
The results of a case study about the application of an advanced method for automatic target recognition to infrared imagery taken from police helicopter missions are presented. The method consists of the following steps: preprocessing, classification, fusion, postprocessing and tracking, and combines the three paradigms image pyramids, neural networks and bayesian nets. The technology has been developed using a variety of different scenes typical for military aircraft missions. Infrared cameras have been in use for several years at the Bavarian police helicopter forces and are highly valuable for night missions. Several object classes like 'persons' or 'vehicles' are tested and the possible discrimination between persons and animals is shown. The analysis of complex scenes with hidden objects and clutter shows the potentials and limitations of automatic target recognition for real-world tasks. Several display concepts illustrate the achievable improvement of the situation awareness. The similarities and differences between various mission types concerning object variability, time constraints, consequences of false alarms, etc. are discussed. Typical police actions like searching for missing persons or runaway criminals illustrate the advantages of automatic target recognition. The results demonstrate the possible operational benefits for the helicopter crew. Future work will include performance evaluation issues and a system integration concept for the target platform.
SantaMaria, Odilyn L.; Farassat, F.; Morris, Philip J.
A method to separate main rotor and tail rotor noise from a helicopter in flight is explored. Being the sum of two periodic signals of disproportionate, or incommensurate frequencies, helicopter noise is neither periodic nor stationary. The single Fourier transform divides signal energy into frequency bins of equal size. Incommensurate frequencies are therefore not adequately represented by any one chosen data block size. A two-dimensional Fourier analysis method is used to separate main rotor and tail rotor noise. The two-dimensional spectral analysis method is first applied to simulated signals. This initial analysis gives an idea of the characteristics of the two-dimensional autocorrelations and spectra. Data from a helicopter flight test is analyzed in two dimensions. The test aircraft are a Boeing MD902 Explorer (no tail rotor) and a Sikorsky S-76 (4-bladed tail rotor). The results show that the main rotor and tail rotor signals can indeed be separated in the two-dimensional Fourier transform spectrum. The separation occurs along the diagonals associated with the frequencies of interest. These diagonals are individual spectra containing only information related to one particular frequency.
Lowson, M. V.
Results are reported from an exact analytic model for the kinematics of noise radiation due to blade-vortex interaction which gives new predictions of the directionality of BVI noise from helicopters. It is shown that the blade-vortex interaction process will give rise to focused regions of intense noise which can decay locally at a rate less than inverse square law. This finding has obvious consequences for helicopter detection and community annoyance. However, the model also gives explicit prediction of the location of the regions of intense noise, and of the location in the disc of the interaction source responsible. Thus the model can also be used to suggest methods for exploiting directionality effects to reduce noise from helicopter operations.
Weiberg, J. A.; Maisel, M. D.
The XV-15 aircraft was tested in the Ames 40 by 80 Foot Wind Tunnel for preliminary evaluation of aerodynamic and aeroelastic characteristics prior to flight. The tests were undertaken to investigate the aircraft performance, stability, control and structural loads for flight modes from helicopter through transition and airplane mode up to the tunnel capability of 170 knots. Results from these tests are presented.
Wu, Te-Kao; Farazian, K.; Golshan, N.; Divsalar, D.; Hinedi, S.; Woo, K.
In this paper, the feasibility of using an L-band low gain antenna (LGA) as a mobile terminal antenna for helicopters is described. The objective is to select the lowest cost antenna system which can be easily mounted on a helicopter and capable of communicating with a geosynchronous satellite. To ensure that all the antenna options are being considered, the steerable high gain reflector and medium gain array antennas as well as LGA are studied and compared in an exhaustive survey. The high gain reflector antenna in L-band is usually very large in size and heavy in weight. In addition, a bulky and expensive tracking system is needed to steer the antenna beam to the satellite direction. The medium gain antennas (including mechanically and electronically steered arrays) are also more expensive and less reliable than an LGA due to the addition of a beam steering system to track the satellite. The omni-directional LGA is simple, reliable, and inexpensive. It is typically ten times smaller than the medium gain antenna. This makes the position, selection, and mounting on the helicopter relatively easier. Therefore, the LGA is selected as a mobile terminal antenna for helicopters. Among the many LGA's (cross-dipole, helix, spiral, and slot antennas), the helix antenna is the most inexpensive. One can also change the size, shape, or pitch angle of the helix to optimize the gain in the desired direction. Therefore, the helix antenna is selected for further study. Both 2-arm and 4-arm helices are studied theoretically and experimentally to determine the antenna's performance and the scattering effects from the helicopter body and the blades. The multipath, Doppler, and Doppler rate issues as well as the periodic fading effects caused by the helicopter rotor blades will be briefly discussed in the paper.
Davis, S. J.; Rosenstein, H. J.
The results are presented of a study to identify those helicopter technology areas which would result in the largest energy (or fuel) savings when applied to large tandem (100 passenger) civil helicopters in the 1985 time frame. Baseline aircraft using 1975 technology in the areas of powerplant, rotor efficiency, parasite drag and structure were sized to a very short haul mission of 100 N.M. and a short haul mission of 200 N.M. A systematic parametric analysis was then conducted to assess the impact of technology improvements. Projections of the technology levels that could be obtained in the 1985 time frame were made and the resources estimated to achieve them. Based on these data, the highest payoff (lowest energy) helicopter technologies are identified.
Clevenson, S. A.; Leatherwood, J. D.; Hollenbaugh, D. D.
Balka (1981) has identified the attainment of a 'jet-smooth' ride as a primary goal of the helicopter industry for commercial and certain military helicopters. It was noted that criteria accounting for both multiple axis vibration and interior noise are needed. The present investigation has the objective to present a vibration and interior noise data base in a format suitable for direct evaluation of aircraft ride quality. The investigation is also concerned with an assessment of the measured environment against available criteria as an indication of the state-of-the-art for current machines. Interior noise and vibration measurements were obtained on eight military helicopters during routine operational flights. The data are presented in the form of a number of parameters.
Drennen, T.; Bowen, B.
The main Army Helicopter Improvement Program (AHIP) mission is to navigate precisely, locate targets accurately, communicate their position to other battlefield elements, and to designate them for laser guided weapons. The onboard navigation and mast-mounted sight (MMS) avionics enable accurate tracking of current aircraft position and subsequent target location. The AHIP crewstation development was based on extensive mission/task analysis, function allocation, total system design, and test and verification. The avionics requirements to meet the mission was limited by the existing aircraft structural and performance characteristics and resultant space, weight, and power restrictions. These limitations and night operations requirement led to the use of night vision goggles. The combination of these requirements and limitations dictated an integrated control/display approach using multifunction displays and controls.
Haslim, Leonard A.
Telescoping boom and associated mechanisms attached to helicopter aid rescue operations by extending lifeline beyond sweep of main rotor. Pilot observes rescuee and control position of helicopter more effectively than if rescuee directly below and hidden from pilot's view. Rescuee outside downdraft of rotor, which is often powerful enough to blow away or submerge someone in water. Used for marine or land operations. Boom thin and lightweight because it need not support weight of rescuee. Lifeline pulls away from boom after secured around rescuee, who is lifted directly into cabin by winch. Potential application for in situ erection of telescopic space structures.
Dambra, F.; Damongeot, A.
Psychoacoustic studies of helicopter impulsive noise were conducted in order to qualify additional annoyance due to this feature and to develop physical impulsiveness descriptors to develop impulsivity correction methods. The currently proposed descriptors and methods of impulsiveness correction are compared using a multilinear regression analysis technique. It is shown that the presently recommended descriptor and correction method provides the best correlation with the subjective evaluations of real helicopter impulsive noises. The equipment necessary for data processing in order to apply the correction method is discussed.
Schlinker, R. H.; Amiet, R. K.
An experimental and theoretical study was conducted to assess the importance of trailing edge noise as a helicopter main rotor broadband noise source. The noise mechanism was isolated by testing a rotor blade segment in an open jet acoustic wind tunnel at close to full scale Reynolds numbers. Boundary layer data and acoustic data were used to develop scaling laws and assess a first principles trailing edge noise theory. Conclusions from the isolated blade study were analytically transformed to the rotating frame coordinate system to develop a generalized rotor noise prediction. Trailing edge noise was found to contribute significantly to the total helicopter noise spectrum at high frequencies.
Schlinker, R. H.; Amiet, R. K.
An experimental and theoretical study was conducted to assess the importance of trailing edge noise as a helicopter main rotor broadband noise source. The noise mechanism was isolated by testing a rotor blade segment in an open jet acoustic wind tunnel at close to full scale Reynolds numbers. Boundary layer data and acoustic data were used to develop scaling laws and assess a first principles trailing edge noise theory. Conclusions from the isolated blade study were analytically transformed to the rotating frame coordinate system to develop a generalized rotor noise prediction. Trailing edge noise was found to contribute significantly to the total helicopter noise spectrum at high frequencies.
Heredia, Guillermo; Ollero, Aníbal
The Helicopter Adaptive Aircraft (HADA) is a morphing aircraft which is able to take-off as a helicopter and, when in forward flight, unfold the wings that are hidden under the fuselage, and transfer the power from the main rotor to a propeller, thus morphing from a helicopter to an airplane. In this process, the reliable folding and unfolding of the wings is critical, since a failure may determine the ability to perform a mission, and may even be catastrophic. This paper proposes a virtual sensor based Fault Detection, Identification and Recovery (FDIR) system to increase the reliability of the HADA aircraft. The virtual sensor is able to capture the nonlinear interaction between the folding/unfolding wings aerodynamics and the HADA airframe using the navigation sensor measurements. The proposed FDIR system has been validated using a simulation model of the HADA aircraft, which includes real phenomena as sensor noise and sampling characteristics and turbulence and wind perturbations. PMID:22294922