Science.gov

Sample records for aircraft interior sound

  1. In-flight interior sound field mapping in propeller aircraft

    NASA Astrophysics Data System (ADS)

    van der Auweraer, H.; Gielen, L.; Otte, D.

    Interior noise in propeller aircraft is currently an important issue in the aerospace industry. Efficient noise control measures require a thorough understanding of the in-flight response of the vibro-acoustic system, formed by fuselage, trim panels and cabin cavity, to the propeller excitation. The cabin interior noise is dominated by the lower order blade pass tones of the propellers. It is therefore important to map the acoustic sound field and the trimpanel and fuselage vibration responses at these frequencies. It is further advantageous to estimate the separated contributions of the two propellers because it allows a better understanding of the coupling between the propeller sound fields, the fuselage and the cabin cavity. It also provides a convenient means to compare different flight tests, regardless of the synchrophasor setting or stability. This paper discusses the acquisition and analysis of operating data on a fully trimmed Saab 340, a twin-engine commuter aircraft. The estimation of each propeller's contribution by means of cross-spectrum and coherence analysis techniques is further explored, in relation with signal processing issues, as windowing and leakage. Some resulting in-flight cabin cavity sound field shapes and trimpanel deformations are presented and discussed.

  2. Mechanisms of transmission and control of low-frequency sound in aircraft interiors

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.

    1985-01-01

    A simplified analytical model is used to study the principal mechanisms at work in propeller noise source radiation, fuselage response, and the behavior of the coupled inner acoustic field, in order to control low frequency sound in aircraft interiors. Both active and passive methods of noise control are comparatively evaluated in light of the transmission mechanisms. Fuselage vibrational response is noted to be dominated by only a few lower order circumferential modes.

  3. Experimental and theoretical sound transmission. [reduction of interior noise in aircraft

    NASA Technical Reports Server (NTRS)

    Roskam, J.; Muirhead, V. U.; Smith, H. W.; Durenberger, D. W.

    1978-01-01

    The capabilities of the Kansas University- Flight Research Center for investigating panel sound transmission as a step toward the reduction of interior noise in general aviation aircraft were discussed. Data obtained on panels with holes, on honeycomb panels, and on various panel treatments at normal incidence were documented. The design of equipment for panel transmission loss tests at nonnormal (slanted) sound incidence was described. A comprehensive theory-based prediction method was developed and shows good agreement with experimental observations of the stiffness controlled, the region, the resonance controlled region, and the mass-law region of panel vibration.

  4. Anticipated Effectiveness of Active Noise Control in Propeller Aircraft Interiors as Determined by Sound Quality Tests

    NASA Technical Reports Server (NTRS)

    Powell, Clemans A.; Sullivan, Brenda M.

    2004-01-01

    Two experiments were conducted, using sound quality engineering practices, to determine the subjective effectiveness of hypothetical active noise control systems in a range of propeller aircraft. The two tests differed by the type of judgments made by the subjects: pair comparisons in the first test and numerical category scaling in the second. Although the results of the two tests were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference.

  5. Prediction of light aircraft interior sound pressure level using the room equation

    NASA Technical Reports Server (NTRS)

    Atwal, M.; Bernhard, R.

    1984-01-01

    The room equation is investigated for predicting interior sound level. The method makes use of an acoustic power balance, by equating net power flow into the cabin volume to power dissipated within the cabin using the room equation. The sound power level transmitted through the panels was calculated by multiplying the measured space averaged transmitted intensity for each panel by its surface area. The sound pressure level was obtained by summing the mean square sound pressures radiated from each panel. The data obtained supported the room equation model in predicting the cabin interior sound pressure level.

  6. Prediction of light aircraft interior sound pressure level from the measured sound power flowing in to the cabin

    NASA Technical Reports Server (NTRS)

    Atwal, Mahabir S.; Heitman, Karen E.; Crocker, Malcolm J.

    1986-01-01

    The validity of the room equation of Crocker and Price (1982) for predicting the cabin interior sound pressure level was experimentally tested using a specially constructed setup for simultaneous measurements of transmitted sound intensity and interior sound pressure levels. Using measured values of the reverberation time and transmitted intensities, the equation was used to predict the space-averaged interior sound pressure level for three different fuselage conditions. The general agreement between the room equation and experimental test data is considered good enough for this equation to be used for preliminary design studies.

  7. Fourth Aircraft Interior Noise Workshop

    NASA Technical Reports Server (NTRS)

    Stephens, David G. (Compiler)

    1992-01-01

    The fourth in a series of NASA/SAE Interior Noise Workshops was held on May 19 and 20, 1992. The theme of the workshop was new technology and applications for aircraft noise with emphasis on source noise prediction; cabin noise prediction; cabin noise control, including active and passive methods; and cabin interior noise procedures. This report is a compilation of the presentations made at the meeting which addressed the above issues.

  8. Light aircraft sound transmission study

    NASA Technical Reports Server (NTRS)

    Atwal, M.; David, J.; Heitman, K.; Crocker, M. J.

    1983-01-01

    The revived interest in the design of propeller driven aircraft is based on increasing fuel prices as well as on the need for bigger short haul and commuter aircraft. A major problem encountered with propeller driven aircraft is propeller and exhaust noise that is transmitted through the fuselage sidewall structure. Part of the work which was conducted during the period April 1 to August 31, 1983, on the studies of sound transmission through light aircraft walls is presented.

  9. Propeller aircraft interior noise model

    NASA Technical Reports Server (NTRS)

    Pope, L. D.; Wilby, E. G.; Wilby, J. F.

    1984-01-01

    An analytical model was developed to predict the interior noise of propeller-driven aircraft. The fuselage model is that of a cylinder with a structurally-integral floor. The cabin sidewall is stiffened by stringers and ring frames, and the floor by longitudinal beams. The cabin interior is covered with a sidewall treatments consisting of layers of porous material and an impervious trim septum. Representation of the propeller pressure field is utilized as input data in the form of the propeller noise signature at a series of locations on a grid over the fuselage structure. Results obtained from the analytical model are compared with test data measured by NASA in a scale model cylindrical fuselage excited by a model propeller.

  10. Fireworthiness of transport aircraft interior systems

    NASA Technical Reports Server (NTRS)

    Parker, J. A.; Kourtides, D. A.

    1982-01-01

    The fire worthiness of air transport interiors was evaluated. The effect of interior systems on the survival of passengers and crew in an uncontrolled transport aircraft fire is addressed. Modification of aircraft interior subsystem components which provide improvements in aircraft fire safety are examined. Three specific subsystem components, interior panels, seats and windows, offer the most immediate and highest payoff by modifying interior materials of existing aircrafts. It is shown that the new materials modifications reduce the fire hazards because of significant reduction in their characteristic flame spread, heat release, and smoke and toxic gas emissions.

  11. Sound isolation performance of interior acoustical sash

    NASA Astrophysics Data System (ADS)

    Tocci, Gregory

    2002-05-01

    In existing, as well as new buildings, an interior light of glass mounted on the inside of a prime window is used to improve the sound transmission loss otherwise obtained by the prime window alone. Interior acoustical sash is most often 1/4 in. (6 mm) monolithic or laminated glass, and is typically spaced 3 in. to 6 in. from the glass of the prime window. This paper presents TL data measured at Riverbank Acoustical Laboratories by Solutia (formerly Monsanto) for lightweight prime windows of various types, with and without interior acoustical sash glazed with 1/4 in. laminated glass. The TL data are used to estimate the A-weighted insertion loss of interior acoustical sash when applied to prime windows glazed with lightweight glass for four transportation noise source types-highway traffic, aircraft, electric rail, and diesel rail. The analysis also has been extended to determine the insertion loss expressed as a change in OITC. The data also exhibit the reductions in insertion loss that can result from short-circuiting the interior acoustical sash with the prime window. [Work supported by Solutia, Inc.

  12. The effect of interior aircraft noise on pilot performance.

    PubMed

    Lindvall, Johan; Västfjall, Daniel

    2013-04-01

    This study examined the effect of the interior sounds of an aircraft cockpit on ratings of affect and expected performance decrement. While exposed to 12 interior aircraft sounds, of which half were modified to correspond to what is experienced with an active noise reduction (ANR) headset, 23 participants rated their affective reactions and how they believed their performance on various tasks would be affected. The results suggest that implementation of ANR-technique has a positive effect on ratings of expected performance. In addition, affective reactions to the noise are related to ratings of expected performance. The implications of these findings for both research and pilot performance are discussed. PMID:24032324

  13. General aviation aircraft interior noise problem: Some suggested solutions

    NASA Technical Reports Server (NTRS)

    Roskam, J.; Navaneethan, R.

    1984-01-01

    Laboratory investigation of sound transmission through panels and the use of modern data analysis techniques applied to actual aircraft is used to determine methods to reduce general aviation interior noise. The experimental noise reduction characteristics of stiffened flat and curved panels with damping treatment are discussed. The experimental results of double-wall panels used in the general aviation industry are given. The effects of skin panel material, fiberglass insulation and trim panel material on the noise reduction characteristics of double-wall panels are investigated. With few modifications, the classical sound transmission theory can be used to design the interior noise control treatment of aircraft. Acoustic intensity and analysis procedures are included.

  14. Fireworthiness of transport aircraft interior systems

    NASA Technical Reports Server (NTRS)

    Parker, J. A.; Kourtides, D. A.

    1981-01-01

    The key materials question is addressed concerning the effect of interior systems on the survival of passengers and crew in the case of an uncontrolled transport aircraft fire. Technical opportunities are examined which are available through the modification of aircraft interior subsystem components, modifications that may reasonably be expected to provide improvements in aircraft fire safety. Subsystem components discussed are interior panels, seats, and windows. By virtue of their role in real fire situations and as indicated by the results of large scale simulation tests, these components appear to offer the most immediate and highest payoff possible by modifying interior materials of existing aircraft. These modifications have the potential of reducing the rate of fire growth, with a consequent reduction of heat, toxic gas, and smoke emission throughout the habitable interior of an aircraft, whatever the initial source of the fire.

  15. Propeller aircraft interior noise model utilization study and validation

    NASA Astrophysics Data System (ADS)

    Pope, L. D.

    1984-09-01

    Utilization and validation of a computer program designed for aircraft interior noise prediction is considered. The program, entitled PAIN (an acronym for Propeller Aircraft Interior Noise), permits (in theory) predictions of sound levels inside propeller driven aircraft arising from sidewall transmission. The objective of the work reported was to determine the practicality of making predictions for various airplanes and the extent of the program's capabilities. The ultimate purpose was to discern the quality of predictions for tonal levels inside an aircraft occurring at the propeller blade passage frequency and its harmonics. The effort involved three tasks: (1) program validation through comparisons of predictions with scale-model test results; (2) development of utilization schemes for large (full scale) fuselages; and (3) validation through comparisons of predictions with measurements taken in flight tests on a turboprop aircraft. Findings should enable future users of the program to efficiently undertake and correctly interpret predictions.

  16. Propeller aircraft interior noise model utilization study and validation

    NASA Technical Reports Server (NTRS)

    Pope, L. D.

    1984-01-01

    Utilization and validation of a computer program designed for aircraft interior noise prediction is considered. The program, entitled PAIN (an acronym for Propeller Aircraft Interior Noise), permits (in theory) predictions of sound levels inside propeller driven aircraft arising from sidewall transmission. The objective of the work reported was to determine the practicality of making predictions for various airplanes and the extent of the program's capabilities. The ultimate purpose was to discern the quality of predictions for tonal levels inside an aircraft occurring at the propeller blade passage frequency and its harmonics. The effort involved three tasks: (1) program validation through comparisons of predictions with scale-model test results; (2) development of utilization schemes for large (full scale) fuselages; and (3) validation through comparisons of predictions with measurements taken in flight tests on a turboprop aircraft. Findings should enable future users of the program to efficiently undertake and correctly interpret predictions.

  17. Fireworthiness of transport aircraft interior systems

    NASA Technical Reports Server (NTRS)

    Parker, J. A.; Kourtides, D. A.

    1981-01-01

    This paper presents an overview of certain aspects of the evaluation of the fireworthiness of transport aircraft interiors. First, it addresses the key materials question concerning the effect of interior systems on the survival of passengers and crew in the case of an uncontrolled fire. Second, it examines some technical opportunities that are available today through the modification of aircraft interior subsystem components, modifications that may reasonably by expected to provide improvements in aircraft fire safety. Cost and risk benefits still remain to be determined.

  18. Ignition characteristics of some aircraft interior fabrics

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Brandt, D. L.

    1978-01-01

    Six samples of aircraft interior fabrics were evaluated with regard to resistance to ignition by radiant heat. Five samples were aircraft seat upholstery fabrics and one sample was an aircraft curtain fabric. The aircraft seat fabrics were 100% wool (2 samples), 83% wool/17% nylon, 49% wool/51% polyvinyl chloride, and 100% rayon. The aircraft curtain fabric was 92% modacrylic/8% polyester. The five samples of aircraft seat upholstery fabrics were also evaluated with regard to resistance to ignition by a smoldering cigarette. The four samples of wool-containing aircraft seat fabrics appeared to be superior to the sample of rayon seat fabric in resistance to ignition, both by radiant heat and by a smoldering cigarette.

  19. Prediction of light aircraft interior noise

    NASA Technical Reports Server (NTRS)

    Howlett, J. T.; Morales, D. A.

    1976-01-01

    At the present time, predictions of aircraft interior noise depend heavily on empirical correction factors derived from previous flight measurements. However, to design for acceptable interior noise levels and to optimize acoustic treatments, analytical techniques which do not depend on empirical data are needed. This paper describes a computerized interior noise prediction method for light aircraft. An existing analytical program (developed for commercial jets by Cockburn and Jolly in 1968) forms the basis of some modal analysis work which is described. The accuracy of this modal analysis technique for predicting low-frequency coupled acoustic-structural natural frequencies is discussed along with trends indicating the effects of varying parameters such as fuselage length and diameter, structural stiffness, and interior acoustic absorption.

  20. Prediction of light aircraft interior noise

    NASA Technical Reports Server (NTRS)

    Howlett, J. T.; Morales, D. A.

    1976-01-01

    A computerized interior noise prediction method for light aircraft is described. An existing analytical program, development for commercial jets, forms the basis of some modal analysis work which is described. The accuracy of this modal analysis technique for predicting low-frequency coupled acoustic-structural natural frequencies is discussed along with trends indicating the effects of varying parameters such as fuselage length and diameter, structural stiffness, and interior acoustic absorption.

  1. VIEW OF SOUTHEASTERN INTERIOR SPACE, FACING NORTHWEST. Douglas Aircraft ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF SOUTHEASTERN INTERIOR SPACE, FACING NORTHWEST. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  2. VIEW OF CENTRAL INTERIOR SPACE, FACING NORTHEAST. Douglas Aircraft ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF CENTRAL INTERIOR SPACE, FACING NORTHEAST. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  3. Damped Windows for Aircraft Interior Noise Control

    NASA Technical Reports Server (NTRS)

    Buehrle, Ralph D.; Klos, Jacob; Gibbs, Gary P.

    2004-01-01

    Windows are a significant path for structure-borne and air-borne noise transmission into aircraft. To improve the acoustical performance, damped windows were fabricated using two or three layers of plexiglas with transparent viscoelastic damping material sandwiched between the layers. In this paper, numerical and experimental results are used to evaluate the acoustic benefits of damped windows. Tests were performed in the Structural Acoustic Loads and Transmission Facility at NASA Langley Research Center to measure the transmission loss for diffuse acoustic excitation and radiated sound power for point force excitation. Comparisons between uniform and damped plexiglas windows showed increased transmission loss of 6 dB at the first natural frequency, 6 dB at coincidence, and 4.5 dB over a 50 to 4k Hz range. Radiated sound power was reduced up to 7 dB at the lower natural frequencies and 3.7 dB over a 1000 Hz bandwidth. Numerical models are presented for the prediction of radiated sound power for point force excitation and transmission loss for diffuse acoustic excitation. Radiated sound power and transmission loss predictions are in good agreement with experimental data. A parametric study is presented that evaluates the optimum configuration of the damped plexiglas windows for reducing the radiated sound power.

  4. Lightweight sidewalls for aircraft interior noise control

    NASA Technical Reports Server (NTRS)

    May, D. N.; Plotkin, K. J.; Selden, R. G.; Sharp, B. H.

    1985-01-01

    A theoretical and experimental study was performed to devise lightweight sidewalls for turboprop aircraft. Seven concepts for new sidewalls were analyzed and tested for noise reduction using flat panels of 1.2 m x 1.8 m (4 ft x 6 ft), some of which were aircraft-type constructions and some of which were simpler, easier-to-construct panels to test the functioning of an acoustic principle. Aircraft-application sidewalls were then conceived for each of the seven concepts, and were subjectively evaluated for their ability to meet aircraft nonacoustic design requirements. As a result of the above, the following sidewall concepts were recommended for further investigation: a sidewall in which the interior cavity is vented to ceiling and underfloor areas; sidewalls with wall-mounted resonators, one having a conventional trim panel and one a limp one; and a sidewall with a stiff outer wall and a limp trim panel. These sidewalls appear to promise lower weights than conventional sidewalls adjusted to meet similar acoustic requirements, and further development may prove them to be practical.

  5. Analytical Studies of Boundary Layer Generated Aircraft Interior Noise

    NASA Technical Reports Server (NTRS)

    Howe, M. S.; Shah, P. L.

    1997-01-01

    An analysis is made of the "interior noise" produced by high, subsonic turbulent flow over a thin elastic plate partitioned into "panels" by straight edges transverse to the mean flow direction. This configuration models a section of an aircraft fuselage that may be regarded as locally flat. The analytical problem can be solved in closed form to represent the acoustic radiation in terms of prescribed turbulent boundary layer pressure fluctuations. Two cases are considered: (i) the production of sound at an isolated panel edge (i.e., in the approximation in which the correlation between sound and vibrations generated at neighboring edges is neglected), and (ii) the sound generated by a periodic arrangement of identical panels. The latter problem is amenable to exact analytical treatment provided the panel edge conditions are the same for all panels. Detailed predictions of the interior noise depend on a knowledge of the turbulent boundary layer wall pressure spectrum, and are given here in terms of an empirical spectrum proposed by Laganelli and Wolfe. It is expected that these analytical representations of the sound generated by simplified models of fluid-structure interactions can used to validate more general numerical schemes.

  6. Propeller aircraft interior noise model: User's manual for computer program

    NASA Technical Reports Server (NTRS)

    Wilby, E. G.; Pope, L. D.

    1985-01-01

    A computer program entitled PAIN (Propeller Aircraft Interior Noise) has been developed to permit calculation of the sound levels in the cabin of a propeller-driven airplane. The fuselage is modeled as a cylinder with a structurally integral floor, the cabin sidewall and floor being stiffened by ring frames, stringers and floor beams of arbitrary configurations. The cabin interior is covered with acoustic treatment and trim. The propeller noise consists of a series of tones at harmonics of the blade passage frequency. Input data required by the program include the mechanical and acoustical properties of the fuselage structure and sidewall trim. Also, the precise propeller noise signature must be defined on a grid that lies in the fuselage skin. The propeller data are generated with a propeller noise prediction program such as the NASA Langley ANOPP program. The program PAIN permits the calculation of the space-average interior sound levels for the first ten harmonics of a propeller rotating alongside the fuselage. User instructions for PAIN are given in the report. Development of the analytical model is presented in NASA CR 3813.

  7. Fire containment tests of aircraft interior panels

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.; Leon, H. A.; Williamson, R. B.; Hasegawa, H.; Fisher, F.; Draemel, R.; Marcussen, W. H.; Hilado, C. J.

    1976-01-01

    The paper describes an experimental program carried out to evaluate a possible method for testing the fire-containment qualities of aircraft interior panels. The experimental apparatus consisted of a burner that simulates various fire loads under different ventilation conditions in an enclosure of approximately the same size as an aircraft lavatory module. Two fire-containment tests are discussed in which two adjoining walls of the enclosure were made from state-of-the-art composite panels; rats were exposed to the combustion products in order to evaluate the toxic threat posed by those products. The results show that the burner can be employed to represent various fire-load conditions and that the methodology developed for fire containment can be useful in evaluating the fire resistance of composite panels before conducting large-scale tests. It is concluded that elements of the fire-containment criteria include the temperature rise on the backface of the panels as a function of time, the flame burn-through by either decomposition or severe distortion of the material, and the toxicity of the combustion gases evolved.

  8. Aircraft noise propagation. [sound diffraction by wings

    NASA Technical Reports Server (NTRS)

    Hadden, W. J.; Pierce, A. D.

    1978-01-01

    Sound diffraction experiments conducted at NASA Langley Research Center to study the acoustical implications of the engine over wing configuration (noise-shielding by wing) and to provide a data base for assessing various theoretical approaches to the problem of aircraft noise reduction are described. Topics explored include the theory of sound diffraction around screens and wedges; the scattering of spherical waves by rectangular patches; plane wave diffraction by a wedge with finite impedence; and the effects of ambient flow and distribution sources.

  9. Sound Generation by Aircraft Wake Vortices

    NASA Technical Reports Server (NTRS)

    Hardin, Jay C.; Wang, Frank Y.

    2003-01-01

    This report provides an extensive analysis of potential wake vortex noise sources that might be utilized to aid in their tracking. Several possible mechanisms of aircraft vortex sound generation are examined on the basis of discrete vortex dynamic models and characteristic acoustic signatures calculated by application of vortex sound theory. It is shown that the most robust mechanisms result in very low frequency infrasound. An instability of the vortex core structure is discussed and shown to be a possible mechanism for generating higher frequency sound bordering the audible frequency range. However, the frequencies produced are still low and cannot explain the reasonably high-pitched sound that has occasionally been observed experimentally. Since the robust mechanisms appear to generate only very low frequency sound, infrasonic tracking of the vortices may be warranted.

  10. Visualizing interior and exterior jet aircraft noise

    NASA Astrophysics Data System (ADS)

    Moondra, Manmohan S.

    In today's competitive aerospace industry, the quest for quiet has drawn significant attention to both the interior and exterior design of an airplane. Understanding the noise generation mechanisms of a jet aircraft is a crucial first step toward developing the most cost-effective noise and vibrations abatement methods. In this investigation, the Helmholtz Equation Least Squares (HELS) based nearfield acoustic holography will be used to understand noise transmission caused by jet engine and turbulence into the fuselage of a jet aircraft cruising at 30,000 ft. Modern propulsive jet engines produce exterior noise sources with a high amplitude noise field and complicated characteristics, which makes them very difficult to characterize. In particular, there are turbulent eddies that are moving through the jet at high speeds along the jet boundary. These turbulent eddies in the shear layer produce a directional and frequency dependent noise. The original HELS approach assumes a spherical source at the origin and computes the acoustic field based on spherical emission from this source. This assumption of one source at the origin is not sufficient to characterize a complex source like a jet. As such, a modified HELS approach is introduced that will help improve the source characterization as it is not dependent on a single source at the origin but a number of virtual sources throughout the space. Custom microphones are created to take acoustic pressure measurements around the jet engine. These measured acoustic pressures are then taken as input to the modified HELS algorithm to visualize the noise pattern of a subsonic jet engine.

  11. Interior noise considerations for powered-lift STOL aircraft

    NASA Technical Reports Server (NTRS)

    Barton, C. K.

    1975-01-01

    Powered-lift configurations which are currently under development for future use on STOL aircraft involve impingement of the jet engine exhaust onto wing and flap surfaces. Previous studies have suggested that the impinging jet produces higher noise levels at lower frequencies than does the jet alone. These higher levels, together with the close proximity of the engine and flap noise sources to the fuselage sidewall, suggest that the noise levels in these aircraft may be high enough to interfere with passenger comfort. To investigate this possibility, interior noise levels were estimated for both an upper surface blown (USB) and an externally blown flap (EBF) configuration. This paper describes the procedure used to estimate the interior noise levels and compares these levels with levels on existing jet aircraft and on ground transportation vehicles. These estimates indicate high levels in the STOL aircraft; therefore, areas of possible improvements in technology for control of STOL interior noise are also discussed.

  12. Measurement, analysis, and prediction of aircraft interior noise

    NASA Technical Reports Server (NTRS)

    Howlett, J. T.; Williams, L. H.; Catherines, J. J.; Jha, S. K.

    1976-01-01

    Considerations of comfort of passengers and crew in light aircraft and helicopters indicate substantial benefits may be obtained by the reduction of interior noise levels. This paper discusses an ongoing research effort to reduce interior noise in such vehicles. Data from both field and laboratory studies for a light aircraft are presented. The laboratory data indicate that structural vibration is an efficient source of interior noise and should be considered in the reduction of interior noise. Flight data taken on a helicopter before and after installation of acoustic treatment demonstrate that over 30 dB of noise reduction can be obtained in certain portions of the spectra. However, subjective evaluations of the treated vehicle indicate that further reductions in interior noise are desirable. An existing interior noise prediction method which was developed for large jet transports was applied to study low-frequency noise in a light aircraft fuselage. The results indicate that improvements in the analytical model may be necessary for the prediction of interior noise of light aircraft.

  13. Study of materials performance model for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Leary, K.; Skratt, J.

    1980-01-01

    A demonstration version of an aircraft interior materials computer data library was developed and contains information on selected materials applicable to aircraft seats and wall panels, including materials for the following: panel face sheets, bond plies, honeycomb, foam, decorative film systems, seat cushions, adhesives, cushion reinforcements, fire blocking layers, slipcovers, decorative fabrics and thermoplastic parts. The information obtained for each material pertains to the material's performance in a fire scenario, selected material properties and several measures of processability.

  14. Effects of interior aircraft noise on speech intelligibility and annoyance

    NASA Technical Reports Server (NTRS)

    Pearsons, K. S.; Bennett, R. L.

    1977-01-01

    Recordings of the aircraft ambiance from ten different types of aircraft were used in conjunction with four distinct speech interference tests as stimuli to determine the effects of interior aircraft background levels and speech intelligibility on perceived annoyance in 36 subjects. Both speech intelligibility and background level significantly affected judged annoyance. However, the interaction between the two variables showed that above an 85 db background level the speech intelligibility results had a minimal effect on annoyance ratings. Below this level, people rated the background as less annoying if there was adequate speech intelligibility.

  15. NASTRAN application for the prediction of aircraft interior noise

    NASA Astrophysics Data System (ADS)

    Marulo, Francesco; Beyer, Todd B.

    1987-08-01

    The application of a structural-acoustic analogy within the NASTRAN finite element program for the prediction of aircraft interior noise is presented. Some refinements of the method, which reduce the amount of computation required for large, complex structures, are discussed. Also, further improvements are proposed and preliminary comparisons with structural and acoustic modal data obtained for a large, composite cylinder are presented.

  16. NASTRAN application for the prediction of aircraft interior noise

    NASA Technical Reports Server (NTRS)

    Marulo, Francesco; Beyer, Todd B.

    1987-01-01

    The application of a structural-acoustic analogy within the NASTRAN finite element program for the prediction of aircraft interior noise is presented. Some refinements of the method, which reduce the amount of computation required for large, complex structures, are discussed. Also, further improvements are proposed and preliminary comparisons with structural and acoustic modal data obtained for a large, composite cylinder are presented.

  17. Interior noise levels of two propeller-driven light aircraft

    NASA Technical Reports Server (NTRS)

    Catherines, J. J.; Mayes, W. H.

    1975-01-01

    The relationships between aircraft operating conditions and interior noise and the degree to which ground testing can be used in lieu of flight testing for performing interior noise research were studied. The results show that the noise inside light aircraft is strongly influenced by the rotational speed of the engine and propeller. Both the overall noise and low frequency spectra levels were observed to decrease with increasing high speed rpm operations during flight. This phenomenon and its significance is not presently understood. Comparison of spectra obtained in flight with spectra obtained on the ground suggests that identification of frequency components and relative amplitude of propeller and engine noise sources may be evaluated on stationary aircraft.

  18. Optimum Noise Reduction Methods for the Interior of Vehicles and Aircraft Cabins

    NASA Astrophysics Data System (ADS)

    Tavossi, Ph. D., Hasson M.

    The most effective methods of noise reduction in vehicles and Aircraft cabins are investigated. The first goal is to determine the optimal means of noise mitigation without change in external shape of the vehicle, or aircraft cabin exterior such as jet engine or fuselage design, with no significant added weight. The second goal is to arrive at interior designs that can be retrofitted to the existing interiors, to reduce overall noise level for the passengers. The physical phenomena considered are; relaxation oscillations, forced vibrations with non-linear damping and sub-harmonic resonances. The negative and positive damping coefficients and active noise cancelations methods are discussed. From noise power-spectrum for a prototype experimental setup, the most energetic vibration modes are determined, that require the highest damping. The proposed technique will utilize the arrangement of uniformly distributed open Helmholtz resonators, with sound absorbing surface. They are tuned to the frequencies that correspond to the most energetic noise levels. The resonators dissipate noise energy inside the vehicle, or aircraft cabin, at the peak frequencies of the noise spectrum, determined for different vehicle or aircraft cabin, interior design models.

  19. Transmission loss characteristics of aircraft sidewall systems to control cabin interior noise

    NASA Astrophysics Data System (ADS)

    Yesil, Oktay; Serati, Paul M.; Hofbeck, Eric V.; Glover, Billy M.

    We have explored the possibility of using new, light weight, and acoustically effective materials on aircraft interiors to control noise. The sidewall system elements were evaluated for increased TL in the laboratory. Measured TL for a given configuration, relative to a baseline, was used as an indication of the TL change to be expected for modifications. Test data were in good agreement with the predicted levels. The TL contributions due to all sidewall components were important for interior cabin noise control. Polyimide foam insulation was inferior to fiberglass in the mid-frequency range; however, foam was a better performer at high frequencies. Fiberglass/polyimide foam composite blankets, with less weight, provided noise reductions similar to fiberglass. 'Premium' fiberglass was slightly better performer than the standard fiberglass. Solid fiberglass interior trim panel provided adequate noise performance. Production-type trim attachment design could be improved to control flanking path for sound transmission.

  20. About sound mufflers sound-absorbing panels aircraft engine

    NASA Astrophysics Data System (ADS)

    Dudarev, A. S.; Bulbovich, R. V.; Svirshchev, V. I.

    2016-10-01

    The article provides a formula for calculating the frequency of sound absorbed panel with a perforated wall. And although the sound absorbing structure is a set of resonators Helmholtz, not individual resonators should be considered in acoustic calculations, and all the perforated wall panel. The analysis, showing how the parameters affect the size and sound-absorbing structures in the absorption rate.

  1. Experiments of multichannel least-square methods for sound field reproduction inside aircraft mock-up: Objective evaluations

    NASA Astrophysics Data System (ADS)

    Gauthier, P.-A.; Camier, C.; Lebel, F.-A.; Pasco, Y.; Berry, A.; Langlois, J.; Verron, C.; Guastavino, C.

    2016-08-01

    Sound environment reproduction of various flight conditions in aircraft mock-ups is a valuable tool for the study, prediction, demonstration and jury testing of interior aircraft sound quality and annoyance. To provide a faithful reproduced sound environment, time, frequency and spatial characteristics should be preserved. Physical sound field reproduction methods for spatial sound reproduction are mandatory to immerse the listener's body in the proper sound fields so that localization cues are recreated at the listener's ears. Vehicle mock-ups pose specific problems for sound field reproduction. Confined spaces, needs for invisible sound sources and very specific acoustical environment make the use of open-loop sound field reproduction technologies such as wave field synthesis (based on free-field models of monopole sources) not ideal. In this paper, experiments in an aircraft mock-up with multichannel least-square methods and equalization are reported. The novelty is the actual implementation of sound field reproduction with 3180 transfer paths and trim panel reproduction sources in laboratory conditions with a synthetic target sound field. The paper presents objective evaluations of reproduced sound fields using various metrics as well as sound field extrapolation and sound field characterization.

  2. Annoyance resulting from intrusion of aircraft sounds upon various activities

    NASA Technical Reports Server (NTRS)

    Gunn, W. J.; Shepherd, W. T.; Fletcher, J. L.

    1975-01-01

    An experiment was conducted in which subjects were engaged in TV viewing, telephone listening, or reverie (no activity) for a 1/2-hour session. During the session, they were exposed to a series of recorded aircraft sounds at the rate of one flight every 2 minutes. Within each session, four levels of flyover noise, separated by dB increments, were presented several times in a Latin Square balanced sequence. The peak level of the noisiest flyover in any session was fixed at 95, 90, 85, 75, or 70 dBA. At the end of the test session, subjects recorded their responses to the aircraft sounds, using a bipolar scale which covered the range from very pleasant to extremely annoying. Responses to aircraft noises were found to be significantly affected by the particular activity in which the subjects were engaged. Not all subjects found the aircraft sounds to be annoying.

  3. Flight Test of ASAC Aircraft Interior Noise Control System

    NASA Technical Reports Server (NTRS)

    Palumbo, Dan; Cabell, Ran; Cline, John; Sullivan, Brenda

    1999-01-01

    A flight test is described in which an active structural/acoustic control system reduces turboprop induced interior noise on a Raytheon Aircraft Company 1900D airliner. Control inputs to 21 inertial force actuators were computed adaptively using a transform domain version of the multichannel filtered-X LMS algorithm to minimize the mean square response of 32 microphones. A combinatorial search algorithm was employed to optimize placement of the force actuators on the aircraft frame. Both single frequency and multi-frequency results are presented. Reductions of up to 15 dB were obtained at the blade passage frequency (BPF) during single frequency control tests. Simultaneous reductions of the BPF and next 2 harmonics of 10 dB, 2.5 dB and 3.0 dB, were obtained in a multi-frequency test.

  4. Acoustic Source Localization in Aircraft Interiors Using Microphone Array Technologies

    NASA Technical Reports Server (NTRS)

    Sklanka, Bernard J.; Tuss, Joel R.; Buehrle, Ralph D.; Klos, Jacob; Williams, Earl G.; Valdivia, Nicolas

    2006-01-01

    Using three microphone array configurations at two aircraft body stations on a Boeing 777-300ER flight test, the acoustic radiation characteristics of the sidewall and outboard floor system are investigated by experimental measurement. Analysis of the experimental data is performed using sound intensity calculations for closely spaced microphones, PATCH Inverse Boundary Element Nearfield Acoustic Holography, and Spherical Nearfield Acoustic Holography. Each method is compared assessing strengths and weaknesses, evaluating source identification capability for both broadband and narrowband sources, evaluating sources during transient and steady-state conditions, and quantifying field reconstruction continuity using multiple array positions.

  5. Development of assembly techniques for fire resistant aircraft interior panels

    NASA Technical Reports Server (NTRS)

    Lee, S. C. S.

    1978-01-01

    Ten NASA Type A fire resistant aircraft interior panels were fabricated and tested to develop assembly techniques. These techiques were used in the construction of a full scale lavatory test structure for flame propagation testing. The Type A panel is of sandwich construction consisting of Nomex honeycomb filled with quinone dioxime foam, and bismaleimide/glass face sheets bonded to the core with polyimide film adhesive. The materials selected and the assembly techniques developed for the lavatory test structure were designed for obtaining maximum fire containment with minimum smoke and toxic emission.

  6. Fire-Retardant Decorative Inks For Aircraft Interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Nir, Z.; Mikroyannidis, J. A.

    1988-01-01

    Report describes testing of commercial and experimental fire retardants for incorporation into acrylic printing inks used on aircraft-interior sandwich panels. Films of acrylic ink containing fire-retardant additives prepared by casting on glass plates. Solvent evaporated in vacuum, cast films cured at 80 to 100 degree C for 30 minutes in air-circulating oven. Thermochemical properties of films examined by thermogravimetric analysis and differential scanning calorimetry (DSC). Samples of inks cast on sheets of polyvinylfloride (PVF), and their limiting oxygen indices and smoke evolution measured.

  7. Fire-retardant decorative inks for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Nir, Z.; Mikroyannidis, J. A.; Kourtides, D. A.

    1984-01-01

    Commercial and experimental fire retardants were screened for possible use wiith acrylic printing inks on aircraft interior sandwich panels. The fire retardants were selected according to their physical properties and thermostabilities. Thermostabilities were determined by thermogravimetric analysis and differential scanning calorimetry. A criterion was then established for selecting the more stable agent. Results show that some of the bromine-containing fire retardants are more thermostable than the acrylic ink, alone, used as a control. Also, the bromine-containing fire retardants yield even better limiting oxygen index values when tested after adding carboxy-terminated butadiene acrylonitrile (CTBN) rubber.

  8. Development of fire resistant, nontoxic aircraft interior materials

    NASA Technical Reports Server (NTRS)

    Haley, G.; Silverman, B.; Tajima, Y.

    1976-01-01

    All available newly developed nonmetallic polymers were examined for possible usage in developing fire resistant, nontoxic nonmetallic parts or assemblies for aircraft interiors. Specifically, feasibility for the development of clear films for new decorative laminates, compression moldings, injection molded parts, thermoformed plastic parts, and flexible foams were given primary considerations. Preliminary data on the flame resistant characteristics of the materials were obtained. Preliminary toxicity data were generated from samples of materials submitted from the contractor. Preliminary data on the physical characteristics of various thermoplastic materials to be considered for either compression molded, injection molded, or thermoformed parts were obtained.

  9. Possibilities to improve the aircraft interior comfort experience.

    PubMed

    Vink, P; Bazley, C; Kamp, I; Blok, M

    2012-03-01

    Comfort plays an increasingly important role in the interior design of airplanes. Although ample research has been conducted on airplane design technology, only a small amount of public scientific information is available addressing the passenger's opinion. In this study, more than 10,000 internet trip reports and 153 passenger interviews were used to gather opinions about aspects which need to be improved in order to design a more comfortable aircraft interior. The results show clear relationships between comfort and legroom, hygiene, crew attention and seat/personal space. Passengers rate the newer planes significantly better than older ones, indicating that attention to design for comfort has proven effective. The study also shows that rude flight attendants and bad hygiene reduce the comfort experience drastically and that a high comfort rating is related to higher "fly again" values.

  10. Aircraft Interior Noise Control Using Distributed Piezoelectric Actuators

    NASA Technical Reports Server (NTRS)

    Sun, Jian Q.

    1996-01-01

    Developing a control system that can reduce the noise and structural vibration at the same time is an important task. This talk presents one possible technical approach for accomplishing this task. The target application of the research is for aircraft interior noise control. The emphasis of the present approach is not on control strategies, but rather on the design of actuators for the control system. In the talk, a theory of distributed piezoelectric actuators is introduced. A uniform cylindrical shell is taken as a simplified model of fuselage structures to illustrate the effectiveness of the design theory. The actuators developed are such that they can reduce the tonal structural vibration and interior noise in a wide range of frequencies. Extensive computer simulations have been done to study various aspects of the design theory. Experiments have also been conducted and the test results strongly support the theoretical development.

  11. Annoyance response to simulated advanced turboprop aircraft interior noise containing tonal beats

    NASA Technical Reports Server (NTRS)

    Leatherwood, Jack D.

    1987-01-01

    A study is done to investigate the effects on subjective annoyance of simulated advanced turboprop (ATP) interior noise environments containing tonal beats. The simulated environments consisted of low-frequency tones superimposed on a turbulent-boundary-layer noise spectrum. The variables used in the study included propeller tone frequency (100 to 250 Hz), propeller tone levels (84 to 105 dB), and tonal beat frequency (0 to 1.0 Hz). Results indicated that propeller tones within the simulated ATP environment resulted in increased annoyance response that was fully predictable in terms of the increase in overall sound pressure level due to the tones. Implications for ATP aircraft include the following: (1) the interior noise environment with propeller tones is more annoying than an environment without tones if the tone is present at a level sufficient to increase the overall sound pressure level; (2) the increased annoyance due to the fundamental propeller tone frequency without harmonics is predictable from the overall sound pressure level; and (3) no additional noise penalty due to the perception of single discrete-frequency tones and/or beats was observed.

  12. Fire-retardant decorative inks for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Nir, Z.; Mikroyannidis, J. A.

    1985-01-01

    Commercial and experimental fire retardants were screened as potential fire retardants for acrylic printing inks used on aircraft interior sandwich panels. The fire retardants are selected according to their physical properties and their thermostabilities. A criterion for selecting a more stable fire retardant is established. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are used to determine thermostabilities. Results show that the fire retardant formulations are more thermally stable than the acrylic ink control. It is determined that an ink formulation containing a brominated phenol and carboxy-terminated butadiene acrylonitrile which has been modified with a brominated polymeric additive (BPA), yields the highest limiting oxygen index (LOI) of all the compounds tested. All of the fire-retardant formulations have a higher oxygen index than the baseline acrylic ink.

  13. BOREAS AFM-04 Twin Otter Aircraft Sounding Data

    NASA Technical Reports Server (NTRS)

    MacPherson, J. Ian; Desjardins, Raymond L.; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-4 team used the National Research Council, Canada (NRC) Twin Otter aircraft to make sounding measurements through the boundary layer. These measurements included concentrations of carbon dioxide and ozone, atmospheric pressure, dry bulb temperature, potential temperature, dewpoint temperature, calculated mixing ratio, and wind speed and direction. Aircraft position, heading, and altitude were also recorded. Data were collected at both the Northern Study Area (NSA) and the Southern Study Area (SSA) in 1994 and 1996. These data are stored in tabular ASCII files. The Twin Otter aircraft sounding data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files also are available on a CD-ROM (see document number 20010000884).

  14. The Influences of Lamination Angles on the Interior Noise Levels of an Aircraft

    NASA Technical Reports Server (NTRS)

    Fernholz, Christian M.; Robinson, Jay H.

    1996-01-01

    The feasibility of reducing the interior noise levels of an aircraft passenger cabin through optimization of the composite lay up of the fuselage is investigated. MSC/NASTRAN, a commercially available finite element code, is used to perform the dynamic analysis and subsequent optimization of the fuselage. The numerical calculation of sensitivity of acoustic pressure to lamination angle is verified using a simple thin, cylindrical shell with point force excitations as noise sources. The thin shell used represents a geometry similar to the fuselage and analytic solutions are available for the cylindrical thin shell equations of motion. Optimization of lamination angle for the reduction of interior noise is performed using a finite element model of an actual aircraft fuselage. The aircraft modeled for this study is the Beech Starship. Point forces simulate the structure borne noise produced by the engines and are applied to the fuselage at the wing mounting locations. These forces are the noise source for the optimization problem. The acoustic pressure response is reduced at a number of points in the fuselage and over a number of frequencies. The objective function is minimized with the constraint that it be larger than the maximum sound pressure level at the response points in the passenger cabin for all excitation frequencies in the range of interest. Results from the study of the fuselage model indicate that a reduction in interior noise levels is possible over a finite frequency range through optimal configuration of the lamination angles in the fuselage. Noise reductions of roughly 4 dB were attained. For frequencies outside the optimization range, the acoustic pressure response may increase after optimization. The effects of changing lamination angle on the overall structural integrity of the airframe are not considered in this study.

  15. Laboratory study of the effects of sidewall treatment, source directivity and temperature on the interior noise of a light aircraft fuselage

    NASA Technical Reports Server (NTRS)

    Heitman, K. E.; Mixson, J. S.

    1986-01-01

    This paper describes a laboratory study of add-on {coustic treatments for a twin-engine, propeller-driven aircraft fuselage. The sound source was a pneumatic-driver, with attached horn to simulate propeller noise distribution, powered by a white noise signal. Treatments included a double-wall, production-line treatment and various fiberglass and lead-vinyl treatments. Insertion losses, space-averaged across six interior microphone positions, were used to evaluate the treatments. In addition, the effects of sound source angle and ambient temperature on interior sound pressure level are presented. The sound source angle is shown to have a significant effect on one-third octave band localized sound pressure level. While changes in ambient temperature are shown to have little effect on one-third octave band localized sound pressure level, the change in narrowband localized sound pressure level may be dramatic.

  16. Aircraft interior noise reduction by alternate resonance tuning

    NASA Technical Reports Server (NTRS)

    Gottwald, James A.; Bliss, Donald B.

    1990-01-01

    The focus is on a noise control method which considers aircraft fuselages lined with panels alternately tuned to frequencies above and below the frequency that must be attenuated. An interior noise reduction called alternate resonance tuning (ART) is described both theoretically and experimentally. Problems dealing with tuning single paneled wall structures for optimum noise reduction using the ART methodology are presented, and three theoretical problems are analyzed. The first analysis is a three dimensional, full acoustic solution for tuning a panel wall composed of repeating sections with four different panel tunings within that section, where the panels are modeled as idealized spring-mass-damper systems. The second analysis is a two dimensional, full acoustic solution for a panel geometry influenced by the effect of a propagating external pressure field such as that which might be associated with propeller passage by a fuselage. To reduce the analysis complexity, idealized spring-mass-damper panels are again employed. The final theoretical analysis presents the general four panel problem with real panel sections, where the effect of higher structural modes is discussed. Results from an experimental program highlight real applications of the ART concept and show the effectiveness of the tuning on real structures.

  17. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... AND RESTRICTED AREA REGULATIONS § 334.410 Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations. (a) Target areas—(1) North Landing River (Currituck Sound...°31′00″, longitude 76°01′40″. (2) Northern part of Currituck Sound. Beginning at a point bearing...

  18. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Albemarle Sound, Pamlico Sound... AND RESTRICTED AREA REGULATIONS § 334.410 Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations. (a) Target areas—(1) North Landing River (Currituck...

  19. BOREAS AFM-03-NCAR Electra 1994 Aircraft Sounding Data

    NASA Technical Reports Server (NTRS)

    Lenschow, Donald H.; Oncley, Steven P.; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Airborne Fluxes and Meteorology (AFM)-3 team used the National Center for Atmospheric Research's (NCAR) Electra aircraft to make sounding measurements to study the planetary boundary layer using in situ and remote-sensing measurements. Measurements were made of wind speed and direction, air pressure and temperature, potential temperature, dewpoint, mixing ratio of H, O, CO, concentration, and ozone concentration. Twenty-five research missions were flown over the Northern Study Area (NSA), Southern Study Area (SSA), and the transect during BOREAS Intensive Field Campaigns (IFCs) 1, 2, and 3 during 1994. All missions had from four to ten soundings through the top of the planetary boundary layer. This sounding data set contains all of the in situ vertical profiles through the boundary layer top that were made (with the exception of 'porpoise' maneuvers). Data were recorded in one-second time intervals. These data are stored in tabular ASCII files. The NCAR Electra 1994 aircraft sounding data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  20. Interior and exterior fuselage noise measured on NASA's C-8a augmentor wing jet-STOL research aircraft

    NASA Technical Reports Server (NTRS)

    Shovlin, M. D.

    1977-01-01

    Interior and exterior fuselage noise levels were measured on NASA's C-8A Augmentor Wing Jet-STOL Research Aircraft in order to provide design information for the Quiet Short-Haul Research Aircraft (QSRA), which will use a modified C-8A fuselage. The noise field was mapped by 11 microphones located internally and externally in three areas: mid-fuselage, aft fuselage, and on the flight deck. Noise levels were recorded at four power settings varying from takeoff to flight idle and were plotted in one-third octave band spectra. The overall sound pressure levels of the external noise field were compared to previous tests and found to correlate well with engine primary thrust levels. Fuselage values were 145 + or - 3 dB over the aircraft's normal STOL operating range.

  1. Unmanned Aircraft Systems for Monitoring Department of the Interior Lands

    NASA Astrophysics Data System (ADS)

    Hutt, M. E.; Quirk, B.

    2013-12-01

    Unmanned Aircraft Systems (UAS) technology is quickly evolving and will have a significant impact on Earth science research. The U.S. Geological Survey (USGS) is conducting an operational test and evaluation of UAS to see how this technology supports the mission of the Department of the Interior (DOI). Over the last 4 years, the USGS, working with many partners, has been actively conducting proof of concept UAS operations, which are designed to evaluate the potential of UAS technology to support the mandated DOI scientific, resource and land management missions. UAS technology is being made available to monitor environmental conditions, analyze the impacts of climate change, respond to natural hazards, understand landscape change rates and consequences, conduct wildlife inventories and support related land management and law enforcement missions. Using small UAS (sUAS), the USGS is able to tailor solutions to meet project requirements by obtaining very high resolution video data, acquiring thermal imagery, detecting chemical plumes, and generating digital terrain models at a fraction of the cost of conventional surveying methods. UAS technology is providing a mechanism to collect timely remote sensing data at a low cost and at low risk over DOI lands that can be difficult to monitor and consequently enhances our ability to provide unbiased scientific information to better enable decision makers to make informed decisions. This presentation describes the UAS technology and infrastructure being employed, the application projects already accomplished, lessons learned and future of UAS within the DOI. We fully expect that by 2020 UAS will emerge as a primary platform for all DOI remote sensing applications. Much like the use of Internet technology, Geographic Information Systems (GIS) and Global Positioning Systems (GPS), UAS have the potential of enabling the DOI to be better stewards of the land.

  2. BOREAS AFM-2 Wyoming King Air 1994 Aircraft Sounding Data

    NASA Technical Reports Server (NTRS)

    Kelly, Robert D.; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS AFM-2 team used the University of Wyoming King Air aircraft during IFCs 1, 2, and 3 in 1994 to collected pass-by-pass fluxes (and many other statistics) for the large number of level (constant altitude), straight-line passes used in a variety of flight patterns over the SSA and NSA and areas along the transect between these study areas. The data described here form a second set, namely soundings that were incorporated into nearly every research flight by the King Air in 1994. These soundings generally went from near the surface to above the inversion layer. Most were flown immediately after takeoff or immediately after finishing the last flux pattern of that particular day's flights. The parameters that were measured include wind direction, wind speed, west wind component (u), south wind component (v), static pressure, air dry bulb temperature, potential temperature, dewpoint, temperature, water vapor mixing ratio, and CO2 concentration. Data on the aircraft's location, attitude, and altitude during data collection are also provided. These data are stored in tabular ASCH files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  3. Analysis of interior noise ground and flight test data for advanced turboprop aircraft applications

    NASA Technical Reports Server (NTRS)

    Simpson, M. A.; Tran, B. N.

    1991-01-01

    Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight tests with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

  4. A trade-off analysis design tool. Aircraft interior noise-motion/passenger satisfaction model

    NASA Technical Reports Server (NTRS)

    Jacobson, I. D.

    1977-01-01

    A design tool was developed to enhance aircraft passenger satisfaction. The effect of aircraft interior motion and noise on passenger comfort and satisfaction was modelled. Effects of individual aircraft noise sources were accounted for, and the impact of noise on passenger activities and noise levels to safeguard passenger hearing were investigated. The motion noise effect models provide a means for tradeoff analyses between noise and motion variables, and also provide a framework for optimizing noise reduction among noise sources. Data for the models were collected onboard commercial aircraft flights and specially scheduled tests.

  5. Study of thermal stability and degradation of fire resistant candidate polymers for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Hsu, M. T. S.

    1976-01-01

    The thermochemistry of bismaleimide resins and phenolphthalein polycarbonate was studied. Both materials are fire-resistant polymers and may be suitable for aircraft interiors. The chemical composition of the polymers has been determined by nuclear magnetic resonance and infrared spectroscopy and by elemental analysis. Thermal properties of these polymers have been characterized by thermogravimetric analyses. Qualitative evaluation of the volatile products formed in pyrolysis under oxidative and non-oxidative conditions has been made using infrared spectrometry. The residues after pyrolysis were analyzed by elemental analysis. The thermal stability of composite panel and thermoplastic materials for aircraft interiors was studied by thermogravimetric analyses.

  6. Evaluation of piezoceramic actuators for control of aircraft interior noise

    NASA Technical Reports Server (NTRS)

    Silcox, Richard J.; Lefebvre, Sylvie; Metcalf, Vern L.; Beyer, Todd B.; Fuller, Chris R.

    1992-01-01

    Results of an experiment to evaluate piezoceramic actuators as the control actuator for active control of interior noise in a large-scale fuselage model are presented. Control was demonstrated for tonal excitation using a time domain least mean squares algorithm. A maximum of four actuator channels and six error signals were used. The actuators were employed for control of noise at frequencies where interior cavity modes were the dominant response and for driven acoustic responses where a structure resonance was dominant. Global reductions of 9 to 12 dB were obtained for the cases examined. The most effective configuration of skin-mounted actuators was found to be a pure in-plane forcing function as opposed to a bending excitation. The frame-mounted actuators were found to be equally effective as the skin-mounted actuators. However, both configurations resulted in local regions of unacceptably high vibration response in the structure.

  7. Active control of turbulent boundary layer sound transmission into a vehicle interior

    NASA Astrophysics Data System (ADS)

    Caiazzo, A.; Alujević, N.; Pluymers, B.; Desmet, W.

    2016-09-01

    In high speed automotive, aerospace, and railway transportation, the turbulent boundary layer (TBL) is one of the most important sources of interior noise. The stochastic pressure distribution associated with the turbulence is able to excite significantly structural vibration of vehicle exterior panels. They radiate sound into the vehicle through the interior panels. Therefore, the air flow noise becomes very influential when it comes to the noise vibration and harshness assessment of a vehicle, in particular at low frequencies. Normally, passive solutions, such as sound absorbing materials, are used for reducing the TBL-induced noise transmission into a vehicle interior, which generally improve the structure sound isolation performance. These can achieve excellent isolation performance at higher frequencies, but are unable to deal with the low-frequency interior noise components. In this paper, active control of TBL noise transmission through an acoustically coupled double panel system into a rectangular cavity is examined theoretically. The Corcos model of the TBL pressure distribution is used to model the disturbance. The disturbance is rejected by an active vibration isolation unit reacting between the exterior and the interior panels. Significant reductions of the low-frequency vibrations of the interior panel and the sound pressure in the cavity are observed.

  8. Sound propagation elements in evaluation of en route noise of advanced turbofan aircraft

    NASA Technical Reports Server (NTRS)

    Sutherland, Louis C.; Wesler, John

    1990-01-01

    Cruise noise from an advanced turboprop aircraft is reviewed on the basis of available wind tunnel data to estimate the aircraft noise signature at the source. Available analytical models are used to evaluate the sound levels at the ground. The analysis allows reasonable estimates to be made of the community noise levels that might be generated during cruise by such aircraft, provides the basis for preliminary comparisons with available data on noise of existing aircraft during climb and helps to identify the dominant elements of the sound propagation models applicable to this situation.

  9. Sound propagation elements in evaluation of en route noise of advanced turbofan aircraft

    NASA Astrophysics Data System (ADS)

    Sutherland, Louis C.; Wesler, John

    1990-04-01

    Cruise noise from an advanced turboprop aircraft is reviewed on the basis of available wind tunnel data to estimate the aircraft noise signature at the source. Available analytical models are used to evaluate the sound levels at the ground. The analysis allows reasonable estimates to be made of the community noise levels that might be generated during cruise by such aircraft, provides the basis for preliminary comparisons with available data on noise of existing aircraft during climb and helps to identify the dominant elements of the sound propagation models applicable to this situation.

  10. A research program to reduce the interior noise in general aviation aircraft, index and summary

    NASA Technical Reports Server (NTRS)

    Morgan, L.; Jackson, K.; Roskam, J.

    1985-01-01

    This report is an index of the published works from NASA Grant NSG 1301, entitled A Research Program to Reduce the Interior Noise in General Aviation Aircraft. Included are a list of all published reports and papers, a compilation of test specimen characteristics, and summaries of each published work.

  11. The response of smoke detectors to pyrolysis and combustion products from aircraft interior materials

    NASA Technical Reports Server (NTRS)

    Mckee, R. G.; Alvares, N. J.

    1976-01-01

    The following projects were completed as part of the effort to develop and test economically feasible fire-resistant materials for interior furnishings of aircraft as well as detectors of incipient fires in passenger and cargo compartments: (1) determination of the sensitivity of various contemporary gas and smoke detectors to pyrolysis and combustion products from materials commonly used in aircraft interiors and from materials that may be used in the future, (2) assessment of the environmental limitations to detector sensitivity and reliability. The tests were conducted on three groups of materials by exposure to the following three sources of exposure: radiant and Meeker burner flame, heated coil, and radiant source only. The first test series used radiant heat and flame exposures on easily obtainable test materials. Next, four materials were selected from the first group and exposed to an incandescent coil to provide the conditions for smoldering combustion. Finally, radiant heat exposures were used on advanced materials that are not readily available.

  12. Interior noise control prediction study for high-speed propeller-driven aircraft

    NASA Technical Reports Server (NTRS)

    Rennison, D. C.; Wilby, J. F.; Marsh, A. H.; Wilby, E. G.

    1979-01-01

    An analytical model was developed to predict the noise levels inside propeller-driven aircraft during cruise at M = 0.8. The model was applied to three study aircraft with fuselages of different size (wide body, narrow body and small diameter) in order to determine the noise reductions required to achieve the goal of an A-weighted sound level which does not exceed 80 dB. The model was then used to determine noise control methods which could achieve the required noise reductions. Two classes of noise control treatments were investigated: add-on treatments which can be added to existing structures, and advanced concepts which would require changes to the fuselage primary structure. Only one treatment, a double wall with limp panel, provided the required noise reductions. Weight penalties associated with the treatment were estimated for the three study aircraft.

  13. The relative fire resistance of select thermoplastic materials. [for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.

    1978-01-01

    The relative thermal stability, flammability, and related thermochemical properties of some thermoplastic materials currently used in aircraft interiors as well as of some candidate thermoplastics were investigated. Currently used materials that were evaluated include acrylonitrile butadiene styrene, bisphenol A polycarbonate, polyphenylene oxide, and polyvinyl fluoride. Candidate thermoplastic materials evaluated include: 9,9-bis(4-hydroxyphenyl)fluorene polycarbonate-poly(dimethylsiloxane) block polymer, chlorinated polyvinylchloride homopolymer, phenolphthalein polycarbonate, polyethersulfone, polyphenylene sulfide, polyarylsulfone, and polyvinylidene fluoride.

  14. A study of interior noise levels, noise sources and transmission paths in light aircraft

    NASA Technical Reports Server (NTRS)

    Hayden, R. E.; Murray, B. S.; Theobald, M. A.

    1983-01-01

    The interior noise levels and spectral characteristics of 18 single-and twin-engine propeller-driven light aircraft, and source-path diagnosis of a single-engine aircraft which was considered representative of a large part of the fleet were studied. The purpose of the flight surveys was to measure internal noise levels and identify principal noise sources and paths under a carefully controlled and standardized set of flight procedures. The diagnostic tests consisted of flights and ground tests in which various parts of the aircraft, such as engine mounts, the engine compartment, exhaust pipe, individual panels, and the wing strut were instrumented to determine source levels and transmission path strengths using the transfer function technique. Predominant source and path combinations are identified. Experimental techniques are described. Data, transfer function calculations to derive source-path contributions to the cabin acoustic environment, and implications of the findings for noise control design are analyzed.

  15. Active control of counter-rotating open rotor interior noise in a Dornier 728 experimental aircraft

    NASA Astrophysics Data System (ADS)

    Haase, Thomas; Unruh, Oliver; Algermissen, Stephan; Pohl, Martin

    2016-08-01

    The fuel consumption of future civil aircraft needs to be reduced because of the CO2 restrictions declared by the European Union. A consequent lightweight design and a new engine concept called counter-rotating open rotor are seen as key technologies in the attempt to reach this ambitious goals. Bearing in mind that counter-rotating open rotor engines emit very high sound pressures at low frequencies and that lightweight structures have a poor transmission loss in the lower frequency range, these key technologies raise new questions in regard to acoustic passenger comfort. One of the promising solutions for the reduction of sound pressure levels inside the aircraft cabin are active sound and vibration systems. So far, active concepts have rarely been investigated for a counter-rotating open rotor pressure excitation on complex airframe structures. Hence, the state of the art is augmented by the preliminary study presented in this paper. The study shows how an active vibration control system can influence the sound transmission of counter-rotating open rotor noise through a complex airframe structure into the cabin. Furthermore, open questions on the way towards the realisation of an active control system are addressed. In this phase, an active feedforward control system is investigated in a fully equipped Dornier 728 experimental prototype aircraft. In particular, the sound transmission through the airframe, the coupling of classical actuators (inertial and piezoelectric patch actuators) into the structure and the performance of the active vibration control system with different error sensors are investigated. It can be shown that the active control system achieves a reduction up to 5 dB at several counter-rotating open rotor frequencies but also that a better performance could be achieved through further optimisations.

  16. Reduction of interior sound fields in flexible cylinders by active vibration control

    NASA Technical Reports Server (NTRS)

    Jones, J. D.; Fuller, C. R.

    1988-01-01

    The mechanisms of interior sound reduction through active control of a thin flexible shell's vibrational response are presently evaluated in view of an analytical model. The noise source is a single exterior acoustic monopole. The active control model is evaluated for harmonic excitation; the results obtained indicate spatially-averaged noise reductions in excess of 20 dB over the source plane, for acoustic resonant conditions inside the cavity.

  17. Development of an annoyance model based upon elementary auditory sensations for steady-state aircraft interior noise containing tonal components

    NASA Technical Reports Server (NTRS)

    Angerer, James R.; Mccurdy, David A.; Erickson, Richard A.

    1991-01-01

    The purpose of this investigation was to develop a noise annoyance model, superior to those already in use, for evaluating passenger response to sounds containing tonal components which may be heard within current and future commercial aircraft. The sound spectra investigated ranged from those being experienced by passengers on board turbofan powered aircraft now in service to those cabin noise spectra passengers may experience within advanced propeller-driven aircraft of the future. A total of 240 sounds were tested in this experiment. Sixty-six of these 240 sounds were steady state, while the other 174 varied temporally due to tonal beating. Here, the entire experiment is described, but the analysis is limited to those responses elicited by the 66 steady-state sounds.

  18. Re-engining - The sound case for aircraft noise reduction

    NASA Astrophysics Data System (ADS)

    Goddard, K.

    1991-06-01

    The paper reviews the history of legislation to reduce jet-powered aircraft noise, particularly in the U.S.A. Recently introduced legislation is discussed and the paper goes on to explain the fundamental advantage of re-engining as a means of reducing aircraft noise. Th Rolls-Royce Tay engine is introduced and the two re-engine programs already launched are described. The expected large reductions in noise level which result from re-engining are illustrated. The paper concludes with a discussion on new programs, on the current airline business scene and on some aspects of the economics of re-engining.

  19. Design and test of aircraft engine isolators for reduced interior noise

    NASA Technical Reports Server (NTRS)

    Unruh, J. F.; Scheidt, D. C.

    1982-01-01

    Improved engine vibration isolation was proposed to be the most weight and cost efficient retrofit structure-borne noise control measure for single engine general aviation aircraft. A study was carried out the objectives: (1) to develop an engine isolator design specification for reduced interior noise transmission, (2) select/design candidate isolators to meet a 15 dB noise reduction design goal, and (3) carry out a proof of concept evaluation test. Analytical model of the engine, vibration isolators and engine mount structure were coupled to an empirical model of the fuselage for noise transmission evaluation. The model was used to develop engine isolator dynamic properties design specification for reduced noise transmission. Candidate isolators ere chosen from available product literature and retrofit to a test aircraft. A laboratory based test procedure was then developed to simulate engine induced noise transmission in the aircraft for a proof of concept evaluation test. Three candidate isolator configurations were evaluated for reduced structure-borne noise transmission relative to the original equipment isolators.

  20. Effects of sound level fluctuations on annoyance caused by aircraft-flyover noise

    NASA Technical Reports Server (NTRS)

    Mccurdy, D. A.

    1979-01-01

    A laboratory experiment was conducted to determine the effects of variations in the rate and magnitude of sound level fluctuations on the annoyance caused by aircraft-flyover noise. The effects of tonal content, noise duration, and sound pressure level on annoyance were also studied. An aircraft-noise synthesis system was used to synthesize 32 aircraft-flyover noise stimuli representing the factorial combinations of 2 tone conditions, 2 noise durations, 2 sound pressure levels, 2 level fluctuation rates, and 2 level fluctuation magnitudes. Thirty-two test subjects made annoyance judgements on a total of 64 stimuli in a subjective listening test facility simulating an outdoor acoustic environment. Variations in the rate and magnitude of level fluctuations were found to have little, if any, effect on annoyance. Tonal content, noise duration, sound pressure level, and the interaction of tonal content with sound pressure level were found to affect the judged annoyance significantly. The addition of tone corrections and/or duration corrections significantly improved the annoyance prediction ability of noise rating scales.

  1. Active Control of Turbulent Boundary Layer Induced Sound Radiation from Multiple Aircraft Panels

    NASA Technical Reports Server (NTRS)

    Gibbs, Gary P.; Cabell, Randolph H.

    2002-01-01

    The objective of this work is to experimentally investigate active structural acoustic control of turbulent boundary layer (TBL) induced sound radiation from multiple panels on an aircraft sidewall. One possible approach for controlling sound radiation from multiple panels is a multi-input/multi-output scheme which considers dynamic coupling between the panels. Unfortunately, this is difficult for more than a few panels, and is impractical for a typical aircraft which contains several hundred such panels. An alternative is to implement a large number of independent control systems. Results from the current work demonstrate the feasibility of reducing broadband radiation from multiple panels utilizing a single-input/single-output (SISO) controller per bay, and is the first known demonstration of active control of TBL induced sound radiation on more than two bays simultaneously. The paper compares sound reduction for fully coupled control of six panels versus independent control on each panel. An online adaptive control scheme for independent control is also demonstrated. This scheme will adjust for slow time varying dynamic systems such as fuselage response changes due to aircraft pressurization, etc.

  2. Aircraft panel with sensorless active sound power reduction capabilities through virtual mechanical impedances

    NASA Astrophysics Data System (ADS)

    Boulandet, R.; Michau, M.; Micheau, P.; Berry, A.

    2016-01-01

    This paper deals with an active structural acoustic control approach to reduce the transmission of tonal noise in aircraft cabins. The focus is on the practical implementation of the virtual mechanical impedances method by using sensoriactuators instead of conventional control units composed of separate sensors and actuators. The experimental setup includes two sensoriactuators developed from the electrodynamic inertial exciter and distributed over an aircraft trim panel which is subject to a time-harmonic diffuse sound field. The target mechanical impedances are first defined by solving a linear optimization problem from sound power measurements before being applied to the test panel using a complex envelope controller. Measured data are compared to results obtained with sensor-actuator pairs consisting of an accelerometer and an inertial exciter, particularly as regards sound power reduction. It is shown that the two types of control unit provide similar performance, and that here virtual impedance control stands apart from conventional active damping. In particular, it is clear from this study that extra vibrational energy must be provided by the actuators for optimal sound power reduction, mainly due to the high structural damping in the aircraft trim panel. Concluding remarks on the benefits of using these electrodynamic sensoriactuators to control tonal disturbances are also provided.

  3. Optimizing an Actuator Array for the Control of Multi-Frequency Noise in Aircraft Interiors

    NASA Technical Reports Server (NTRS)

    Palumbo, D. L.; Padula, S. L.

    1997-01-01

    Techniques developed for selecting an optimized actuator array for interior noise reduction at a single frequency are extended to the multi-frequency case. Transfer functions for 64 actuators were obtained at 5 frequencies from ground testing the rear section of a fully trimmed DC-9 fuselage. A single loudspeaker facing the left side of the aircraft was the primary source. A combinatorial search procedure (tabu search) was employed to find optimum actuator subsets of from 2 to 16 actuators. Noise reduction predictions derived from the transfer functions were used as a basis for evaluating actuator subsets during optimization. Results indicate that it is necessary to constrain actuator forces during optimization. Unconstrained optimizations selected actuators which require unrealistically large forces. Two methods of constraint are evaluated. It is shown that a fast, but approximate, method yields results equivalent to an accurate, but computationally expensive, method.

  4. Hybrid Active-Passive Systems for Control of Aircraft Interior Noise

    NASA Technical Reports Server (NTRS)

    Fuller, Chris R.; Palumbo, Dan (Technical Monitor)

    2002-01-01

    It was proposed to continue with development and application in the two active-passive areas of Active Tuned Vibration Absorbers (ATVA) and smart foam applied to the reduction of interior noise in aircraft. In general the work was focused on making both techniques more efficient, practical and robust thus increasing their application potential. The work was also concerned with demonstrating the potential of these two technologies under realistic implementations as well as understanding the fundamental physics of the systems. The proposed work consisted of a three-year program and was tightly coordinated with related work being carried out in the Structural Acoustics Branch at NASA LaRC. The work was supervised and coordinated through all phases by Prof Chris Fuller of Va Tech.

  5. Characterization of flammability properties of some thermoplastic and thermoset resins. [for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.

    1978-01-01

    The thermochemical and flammability properties of some thermally stable polymers considered for use in aircraft interiors are described. The properties studied include: (1) thermomechanical properties such as glass transition and melt temperature; (2) dynamic thermogravimetric analysis in anaerobic environment; (3) flammability properties such as oxygen index, flame spread, and smoke evolution; and (4) selected physical properties. The thermoplastic polymers evaluated included polyphenylene sulfide, polyaryl sulfone, 9,9-bis(4-hydroxyphenyl)-fluorene polycarbonate-poly(dimethylsiloxane) and polyether sulfone. The thermoset polymers evaluated included epoxy, bismaleimide, a modified phenolic and polyaromatic melamine resin. These resins were primarily used in the fabrication of glass reinforced prepregs for the construction of experimental panels. Test results and relative rankings of some of the flammability parameters are presented and the relationship of the molecular structure, char yield, and flammability properties of these polymers are discussed.

  6. Evaluation of analysis techniques for low frequency interior noise and vibration of commercial aircraft

    NASA Technical Reports Server (NTRS)

    Landmann, A. E.; Tillema, H. F.; Marshall, S. E.

    1989-01-01

    The application of selected analysis techniques to low frequency cabin noise associated with advanced propeller engine installations is evaluated. Three design analysis techniques were chosen for evaluation including finite element analysis, statistical energy analysis (SEA), and a power flow method using element of SEA (computer program Propeller Aircraft Interior Noise). An overview of the three procedures is provided. Data from tests of a 727 airplane (modified to accept a propeller engine) were used to compare with predictions. Comparisons of predicted and measured levels at the end of the first year's effort showed reasonable agreement leading to the conclusion that each technique had value for propeller engine noise predictions on large commercial transports. However, variations in agreement were large enough to remain cautious and to lead to recommendations for further work with each technique. Assessment of the second year's results leads to the conclusion that the selected techniques can accurately predict trends and can be useful to a designer, but that absolute level predictions remain unreliable due to complexity of the aircraft structure and low modal densities.

  7. Objective evaluation of interior trim effects on sound quality and noise reduction of a coupled plate cavity system

    NASA Astrophysics Data System (ADS)

    Egab, Laith; Wang, Xu

    2016-03-01

    In this study, the impedance mobility and psychoacoustic analysis methods are combined to develop a structural-acoustic model of a plate-cavity coupling system. The objective is to evaluate the effect of interior trim materials on sound loudness and sharpness of a plate-cavity coupling system. The impedance mobility method is applied to calculate the pressure frequency responses of the interior acoustic field for the plate-cavity coupling system. The sound pressure results calculated by the impedance mobility method are then directly used to calculate the psychoacoustic metrics using psychoacoustic analysis method. A good agreement was found between the experimental and analytical results. The results show that the interior trim has a large influence on the distribution of the sound loudness and sharpness inside the cavity in the middle and high frequency ranges.

  8. Behind Start of Take-Off Roll Aircraft Sound Level Directivity Study - Revision 1

    NASA Technical Reports Server (NTRS)

    Lau, Michael C.; Roof, Christopher J.; Fleming, Gregg G.; Rapoza, Amanda S.; Boeker, Eric R.; McCurdy, David A.; Shepherd, Kevin P.

    2015-01-01

    The National Aeronautics and Space Administration (NASA), Langley Research Center (LaRC) and the Environmental Measurement and Modeling Division of the Department of Transportation's Volpe National Transportation Systems Center (Volpe) conducted a noise measurement study to examine aircraft sound level directivity patterns behind the start-of-takeoff roll. The study was conducted at Washington Dulles International Airport (IAD) from October 4 through 20, 2004.

  9. A sound quality model for objective synthesis evaluation of vehicle interior noise based on artificial neural network

    NASA Astrophysics Data System (ADS)

    Wang, Y. S.; Shen, G. Q.; Xing, Y. F.

    2014-03-01

    Based on the artificial neural network (ANN) technique, an objective sound quality evaluation (SQE) model for synthesis annoyance of vehicle interior noises is presented in this paper. According to the standard named GB/T18697, firstly, the interior noises under different working conditions of a sample vehicle are measured and saved in a noise database. Some mathematical models for loudness, sharpness and roughness of the measured vehicle noises are established and performed by Matlab programming. Sound qualities of the vehicle interior noises are also estimated by jury tests following the anchored semantic differential (ASD) procedure. Using the objective and subjective evaluation results, furthermore, an ANN-based model for synthetical annoyance evaluation of vehicle noises, so-called ANN-SAE, is developed. Finally, the ANN-SAE model is proved by some verification tests with the leave-one-out algorithm. The results suggest that the proposed ANN-SAE model is accurate and effective and can be directly used to estimate sound quality of the vehicle interior noises, which is very helpful for vehicle acoustical designs and improvements. The ANN-SAE approach may be extended to deal with other sound-related fields for product quality evaluations in SQE engineering.

  10. Thermochemical characterization of some thermoplastic materials. [flammability and toxicity properties for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.; Hilado, C. J.

    1977-01-01

    The thermochemical and flammability characteristics of some typical thermoplastic materials currently in use or being considered for use in aircraft interiors are described. The properties studied included thermomechanical properties such as glass-transition and melt temperature, changes in polymer enthalpy, thermogravimetric analysis in anerobic and oxidative environments, oxygen index, smoke evolution, relative toxicity of the volatile products of pyrolysis, and selected physical properties. The generic polymers evaluated included acrylonitrile butadiene styrene, bisphenol A polycarbonate, 9,9 bis (4-hydroxyphenyl) fluorene polycarbonate-poly (dimethylsiloxane) block polymer, phenolphthalein-bisphenol A polycarbonate, phenolphthalein polycarbonate, polyether sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone, chlorinated polyvinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters, including molding characteristics of some of the advanced polymers, are described. Test results and relative rankings of some of the flammability, smoke, and toxicity properties are presented. Under these test conditions, some of the advanced polymers evaluated were significantly less flammable and toxic than or equivalent to polymers in current use.

  11. Decentralized Control of Sound Radiation from an Aircraft-Style Panel Using Iterative Loop Recovery

    NASA Technical Reports Server (NTRS)

    Schiller, Noah H.; Cabell, Randolph H.; Fuller, Chris R.

    2008-01-01

    A decentralized LQG-based control strategy is designed to reduce low-frequency sound transmission through periodically stiffened panels. While modern control strategies have been used to reduce sound radiation from relatively simple structural acoustic systems, significant implementation issues have to be addressed before these control strategies can be extended to large systems such as the fuselage of an aircraft. For instance, centralized approaches typically require a high level of connectivity and are computationally intensive, while decentralized strategies face stability problems caused by the unmodeled interaction between neighboring control units. Since accurate uncertainty bounds are not known a priori, it is difficult to ensure the decentralized control system will be robust without making the controller overly conservative. Therefore an iterative approach is suggested, which utilizes frequency-shaped loop recovery. The approach accounts for modeling error introduced by neighboring control loops, requires no communication between subsystems, and is relatively simple. The control strategy is validated using real-time control experiments performed on a built-up aluminum test structure representative of the fuselage of an aircraft. Experiments demonstrate that the iterative approach is capable of achieving 12 dB peak reductions and a 3.6 dB integrated reduction in radiated sound power from the stiffened panel.

  12. Analytical study of interior noise control by fuselage design techniques on high-speed, propeller-driven aircraft

    NASA Technical Reports Server (NTRS)

    Revell, J. D.; Balena, F. J.; Koval, L. R.

    1980-01-01

    The acoustical treatment mass penalties required to achieve an interior noise level of 80 dBA for high speed, fuel efficient propfan-powered aircraft are determined. The prediction method used is based on theory developed for the outer shell dynamics, and a modified approach for add-on noise control element performance. The present synthesis of these methods is supported by experimental data. Three different sized aircraft are studied, including a widebody, a narrowbody and a business sized aircraft. Noise control penalties are calculated for each aircraft for two kinds of noise control designs: add-on designs, where the outer wall structure cannot be changed, and advanced designs where the outer wall stiffness level and the materials usage can be altered. For the add-on designs, the mass penalties range from 1.7 to 2.4 percent of the takeoff gross weight (TOGW) of the various aircraft, similar to preliminary estimates. Results for advanced designs show significant reductions of the mass penalties. For the advanced aluminum designs the penalties are 1.5% of TOGW, and for an all composite aircraft the penalties range from 0.74 to 1.4% of TOGW.

  13. Sound Pressures and Correlations of Noise on the Fuselage of a Jet Aircraft in Flight

    NASA Technical Reports Server (NTRS)

    Shattuck, Russell D.

    1961-01-01

    Tests were conducted at altitudes of 10,000, 20,000, and 30,000 feet at speeds of Mach 0.4, 0.6, and O.8. It was found that the sound pressure levels on the aft fuselage of a jet aircraft in flight can be estimated using an equation involving the true airspeed and the free air density. The cross-correlation coefficient over a spacing of 2.5 feet was generalized with Strouhal number. The spectrum of the noise in flight is comparatively flat up to 10,000 cycles per second.

  14. Electromagnetic sounding of Moon's interior -a proposal for Luna-Globe project

    NASA Astrophysics Data System (ADS)

    Korepanov, Valery; Rokityansky, Igor; Dudkin, Fedir; Belyayev, Serhiy; Tereshin, Artem

    The Moon including its deep interior was intensively studied in the time interval 1959-1976, when the data from first lunar missions were recorded, processed and interpreted and the first model of the Moon interior was created. Data of lunar seismology and gravity as well as lunar geography and geology yield clear understanding that lunar crust and mantle are substantially not uniform laterally. Having quite few seismometers and magnetometers at the Moon, only spherically symmetric 1D model of seismic velocities and electrical conductivity was obtained. Next stage of the Moon exploration foresees landing of several robotic missions and it will be then possible to carry out at the Moon's surface geophysical experiments aimed at more careful study of the Moon interior structure. We propose to include in the next planned mission of Russian space program -Luna-Globe -the electromagnetic (EM) sounding of the Moon's mantle in order to clarify more in details its structure. For EM sounding, the spatial-temporal changes of interplanetary magnetic field carried by solar wind (mean intensity 5nT) as well as those of magnetic field in the Earth's magnetosphere tail (˜ 9nT) during its crossing by the Moon may be used. These values define the maximal level of the primary external magnetic field Be. Solar wind magnetic field induces in the Moon mostly poloidal field Bi due to eddy currents driven by variations of Be. For spherically symmetric 1D model, the higher is conductivity of a concentric internal lunar layer, the stronger eddy currents flow in it and the larger is contribution of the layer in Bi, of course, if skin depth is sufficient for this. Poloidal field from deep interior arrives to surface with geometrical attenuation. For example, field produced at Moon surface by currents in conducting layer at the depth R/2 (R = metricconverterProductID1738 km1738 km is Moon radius) attenuates and at the best will be equal to ˜0.1Bi. Practically it means that reliable

  15. ENERGY CONSERVATION AND GRAVITY WAVES IN SOUND-PROOF TREATMENTS OF STELLAR INTERIORS. PART I. ANELASTIC APPROXIMATIONS

    SciTech Connect

    Brown, Benjamin P.; Zweibel, Ellen G.; Vasil, Geoffrey M.

    2012-09-10

    Typical flows in stellar interiors are much slower than the speed of sound. To follow the slow evolution of subsonic motions, various sound-proof equations are in wide use, particularly in stellar astrophysical fluid dynamics. These low-Mach number equations include the anelastic equations. Generally, these equations are valid in nearly adiabatically stratified regions like stellar convection zones, but may not be valid in the sub-adiabatic, stably stratified stellar radiative interiors. Understanding the coupling between the convection zone and the radiative interior is a problem of crucial interest and may have strong implications for solar and stellar dynamo theories as the interface between the two, called the tachocline in the Sun, plays a crucial role in many solar dynamo theories. Here, we study the properties of gravity waves in stably stratified atmospheres. In particular, we explore how gravity waves are handled in various sound-proof equations. We find that some anelastic treatments fail to conserve energy in stably stratified atmospheres, instead conserving pseudo-energies that depend on the stratification, and we demonstrate this numerically. One anelastic equation set does conserve energy in all atmospheres and we provide recommendations for converting low-Mach number anelastic codes to this set of equations.

  16. Unmanned aircraft systems (UAS) activities at the Department of the Interior

    USGS Publications Warehouse

    Quirk, Bruce K.; Hutt, Michael E.

    2014-01-01

    The U.S. Department of the Interior (DOI) is responsible for protecting and managing the natural resources and heritage on almost 20% of the land in the United States. The DOI’s mission requires access to remotely sensed data over vast lands, including areas that are remote and potentially dangerous to access. Unmanned Aircraft Systems (UAS) technology has the potential to enable the DOI to be a better steward of the land by: (1) Improving natural hazard forecasting and the analysis of the impacts. (2) Improving the understanding of climate change to better plan for likely impacts. (3) Developing precipitation and evaporation forecasting to better manage water resources. (4) Monitoring Arctic ice change and its impacts on ecosystems, coasts, and transportation. (5) Increasing safety and effectiveness of wildland fire management. (6) Enhancing search and rescue capabilities. (7) Broadening the abilities to monitor environmental or landscape conditions and changes. (8) Better understanding and protecting the Nation’s ecosystems. The initial operational testing and evaluations performed by the DOI have proven that UAS technology can be used to support many of the Department’s activities. UAS technology provides scientists a way to look longer, closer and more frequently at some of Earth’s most remote areas—places that were previously too dangerous or expensive to monitor in detail. The flexibility of operations and relative low cost to purchase and operate Small Unmanned Aerial System (sUAS) enhances the ability to track long-term landscape and environmental change. The initial testing indicates the operational costs are approximately 10% of traditional manned aircraft. In addition, users can quickly assess landscape-altering events such as wildland fires, floods and volcanoes. UAS technology will allow the DOI to do more with less and in the process enhance the Department’s ability to provide unbiased scientific information to help stakeholders make

  17. Separation of airborne and structureborne noise radiated by plates constructed of conventional and composite materials with applications for prediction of interior noise paths in propeller driven aircraft. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1986-01-01

    The anticipated application of advanced turboprop propulsion systems and use of composite materials in primary structure is expected to increase the interior noise of future aircraft to unacceptability high levels. The absence of technically and economically feasible noise source-path diagnostic tools has been a primer obstacle in the development of efficient noise control treatments for propeller driven aircraft. A new diagnostic method which permits the separation and prediction of the fully coherent airborne and structureborne components of the sound radiated by plates or thin shells has been developed. Analytical and experimental studies of the proposed method were performed on plates constructed of both conventional and composite materials. The results of the study indicate that the proposed method can be applied to a variety of aircraft materials, could be used in flight, and has fewer encumbrances than the other diagnostic tools currently available. The study has also revealed that the noise radiation of vibrating plates in the low frequency regime due to combined airborne and structureborne inputs possesses a strong synergistic nature. The large influence of the interaction between the airborne and structureborne terms has been hitherto ignored by researchers of aircraft interior noise problems.

  18. Active control of aircraft engine inlet noise using compact sound sources and distributed error sensors

    NASA Technical Reports Server (NTRS)

    Burdisso, Ricardo (Inventor); Fuller, Chris R. (Inventor); O'Brien, Walter F. (Inventor); Thomas, Russell H. (Inventor); Dungan, Mary E. (Inventor)

    1996-01-01

    An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct and sealed on all edges to prevent leakage around the panel and to minimize the aerodynamic losses created by the addition of the panels. Each panel is driven by one or more piezoelectric force transducers mounted on the surface of the panel. The response of the panel to excitation is maximized when it is driven at its resonance; therefore, the panel is designed such that its fundamental frequency is near the tone to be canceled, typically 2000-4000 Hz.

  19. Active control of aircraft engine inlet noise using compact sound sources and distributed error sensors

    NASA Technical Reports Server (NTRS)

    Burdisso, Ricardo (Inventor); Fuller, Chris R. (Inventor); O'Brien, Walter F. (Inventor); Thomas, Russell H. (Inventor); Dungan, Mary E. (Inventor)

    1994-01-01

    An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct and sealed on all edges to prevent leakage around the panel and to minimize the aerodynamic losses created by the addition of the panels. Each panel is driven by one or more piezoelectric force transducers mounted on the surface of the panel. The response of the panel to excitation is maximized when it is driven at its resonance; therefore, the panel is designed such that its fundamental frequency is near the tone to be canceled, typically 2000-4000 Hz.

  20. Prediction of the interior noise levels of high-speed propeller-driven aircraft

    NASA Technical Reports Server (NTRS)

    Rennison, D. C.; Wilby, J. F.; Wilby, E. G.

    1980-01-01

    The theoretical basis for an analytical model developed to predict the interior noise levels of high-speed propeller-driven airplanes is presented. Particular emphasis is given to modeling the transmission of discrete tones through a fuselage element into a cavity, estimates for the mean and standard deviation of the acoustic power flow, the coupling between a non-homogeneous excitation and the fuselage vibration response, and the prediction of maximum interior noise levels. The model allows for convenient examination of the various roles of the excitation and fuselage structural characteristics on the fuselage vibration response and the interior noise levels, as is required for the design of model or prototype noise control validation tests.

  1. ENERGY CONSERVATION AND GRAVITY WAVES IN SOUND-PROOF TREATMENTS OF STELLAR INTERIORS. II. LAGRANGIAN CONSTRAINED ANALYSIS

    SciTech Connect

    Vasil, Geoffrey M.; Lecoanet, Daniel; Brown, Benjamin P.; Zweibel, Ellen G.; Wood, Toby S.

    2013-08-20

    The speed of sound greatly exceeds typical flow velocities in many stellar and planetary interiors. To follow the slow evolution of subsonic motions, various sound-proof models attempt to remove fast acoustic waves while retaining stratified convection and buoyancy dynamics. In astrophysics, anelastic models typically receive the most attention in the class of sound-filtered stratified models. Generally, anelastic models remain valid in nearly adiabatically stratified regions like stellar convection zones, but may break down in strongly sub-adiabatic, stably stratified layers common in stellar radiative zones. However, studying stellar rotation, circulation, and dynamos requires understanding the complex coupling between convection and radiative zones, and this requires robust equations valid in both regimes. Here we extend the analysis of equation sets begun in Brown et al., which studied anelastic models, to two types of pseudo-incompressible models. This class of models has received attention in atmospheric applications, and more recently in studies of white-dwarf supernova progenitors. We demonstrate that one model conserves energy but the other does not. We use Lagrangian variational methods to extend the energy conserving model to a general equation of state, and dub the resulting equation set the generalized pseudo-incompressible (GPI) model. We show that the GPI equations suitably capture low-frequency phenomena in both convection and radiative zones in stars and other stratified systems, and we provide recommendations for converting low-Mach number codes to this equation set.

  2. Corrosion protection of aerospace grade magnesium alloy Elektron 43(TM) for use in aircraft cabin interiors

    NASA Astrophysics Data System (ADS)

    Baillio, Sarah S.

    Magnesium alloys exhibit desirable properties for use in transportation technology. In particular, the low density and high specific strength of these alloys is of interest to the aerospace community. However, the concerns of flammability and susceptibility to corrosion have limited the use of magnesium alloys within the aircraft cabin. This work studies a magnesium alloy containing rare earth elements designed to increase resistance to ignition while lowering rate of corrosion. The microstructure of the alloy was documented using scanning electron microscopy. Specimens underwent salt spray testing and the corrosion products were examined using energy dispersive spectroscopy.

  3. On the reverse flow ceiling jet in pool fire-ventilation crossflow interactions in a simulated aircraft cabin interior

    NASA Technical Reports Server (NTRS)

    Kwack, E. Y.; Bankston, C. P.; Shakkottai, P.; Back, L. H.

    1989-01-01

    The behavior of the reverse flow ceiling jet against the ventilation flow from 0.58 to 0.87 m/s was investigated in a 1/3 scale model of a wide body aircraft interior. For all tests, strong reverse-flow ceiling jets of hot gases were detected well upstream of the fire. Both thicknesses of the reverse-flow ceiling jet and the smoke layer increased with the fire-crossflow parameter. The thickness of the smoke layer where the smoke flows along the main flow below the reverse-flow ceiling jet was almost twice that of the reverse-flow ceiling jet. Detailed spatial and time-varying temperatures of the gas in the test section were measured, and velocity profiles were also measured using a temperature compensated hot film.

  4. Interior noise prediction methodology: ATDAC theory and validation

    NASA Technical Reports Server (NTRS)

    Mathur, Gopal P.; Gardner, Bryce K.

    1992-01-01

    The Acoustical Theory for Design of Aircraft Cabins (ATDAC) is a computer program developed to predict interior noise levels inside aircraft and to evaluate the effects of different aircraft configurations on the aircraft acoustical environment. The primary motivation for development of this program is the special interior noise problems associated with advanced turboprop (ATP) aircraft where there is a tonal, low frequency noise problem. Prediction of interior noise levels requires knowledge of the energy sources, the transmission paths, and the relationship between the energy variable and the sound pressure level. The energy sources include engine noise, both airborne and structure-borne; turbulent boundary layer noise; and interior noise sources such as air conditioner noise and auxiliary power unit noise. Since propeller and engine noise prediction programs are widely available, they are not included in ATDAC. Airborne engine noise from any prediction or measurement may be input to this program. This report describes the theory and equations implemented in the ATDAC program.

  5. Study of the Earth's interior using measurements of sound velocities in minerals by ultrasonic interferometry

    SciTech Connect

    Li, Baosheng; Liebermann, Robert C.

    2014-07-29

    This paper reviews the progress of the technology of ultrasonic interferometry from the early 1950s to the present day. During this period of more than 60 years, sound wave velocity measurements have been increased from at pressures less than 1 GPa and temperatures less than 800 K to conditions above 25 GPa and temperatures of 1800 K. This is complimentary to other direct methods to measure sound velocities (such as Brillouin and impulsive stimulated scattering) as well as indirect methods (e.g., resonance ultrasound spectroscopy, static or shock compression, inelastic X-ray scattering). Newly-developed pressure calibration methods and data analysis procedures using a finite strain approach are described and applied to data for the major mantle minerals. The implications for the composition of the Earth’s mantle are discussed. The state-of-the-art ultrasonic experiments performed in conjunction with synchrotron X-radiation can provide simultaneous measurements of the elastic bulk and shear moduli and their pressure and temperature derivatives with direct determination of pressure. The current status and outlook/challenges for future experiments are summarized.

  6. Application of analysis techniques for low frequency interior noise and vibration of commercial aircraft

    NASA Technical Reports Server (NTRS)

    Landmann, A. E.; Tillema, H. F.; Macgregor, G. R.

    1992-01-01

    Finite element analysis (FEA), statistical energy analysis (SEA), and a power flow method (computer program PAIN) were used to assess low frequency interior noise associated with advanced propeller installations. FEA and SEA models were used to predict cabin noise and vibration and evaluate suppression concepts for structure-borne noise associated with the shaft rotational frequency and harmonics (less than 100 Hz). SEA and PAIN models were used to predict cabin noise and vibration and evaluate suppression concepts for airborne noise associated with engine radiated propeller tones. Both aft-mounted and wing-mounted propeller configurations were evaluated. Ground vibration test data from a 727 airplane modified to accept a propeller engine were used to compare with predictions for the aft-mounted propeller. Similar data from the 767 airplane was used for the wing-mounted comparisons.

  7. Experimental and numerical analysis of defects in composite panels used in business aircrafts interior

    NASA Astrophysics Data System (ADS)

    Ruiz, Edu; Courteau-Godmaire, H.; Fotsing, R.; Billotte, C.; Levesque, M.

    2016-05-01

    This paper provides an optical characterization and numerical prediction of local deformations appearing on the visible side of composite sandwich panels used for interior furniture of business airplanes. During manufacturing of furniture panels, metallic inserts are bonded inside the sandwich panel using an epoxy adhesive. Surface defects appear on the visible side of the panels due to curing of the adhesive, but also because of temperature gradients and humidity during manufacturing and in service. This paper presents an optical characterization based on deflectometry principle, that allows qualitative and quantitative analyses of the surface deformations in 3-dimensions. In addition, this paper presents a parametric model based on finite elements to predict the formation of surface defects using ABAQUS. A comparison is presented between the experimental observations and numerical predictions with good agreement between them.

  8. On the generation of sound by turbulent convection. I - A numerical experiment. [in solar interior

    NASA Technical Reports Server (NTRS)

    Bogdan, Thomas J.; Cattaneo, Fausto; Malagoli, Andrea

    1993-01-01

    Motivated by the problem of the origin of the solar p-modes, we study the generation of acoustic waves by turbulent convection. Our approach uses the results of high-resolution 3D simulations as the experimental basis for our investigation. The numerical experiment describes the evolution of a horizontally periodic layer of vigorously convecting fluid. The sound is measured by a procedure, based on a suitable linearization of the equations of compressible convection that allows the amplitude of the acoustic field to be determined. Through this procedure we identify unambiguously some 400 acoustic modes. The total energy of the acoustic field is found to be a fraction of a percent of the kinetic energy of the convection. The amplitudes of the observed modes depend weakly on (horizontal) wavenumber but strongly on frequency. The line widths of the observed modes typically exceed the natural linewidths of the modes as inferred from linear theory. This broadening appears to be related to the (stochastic) interaction between the modes and the underlying turbulence which causes abrupt, episodic events during which the phase coherence of the modes is lost.

  9. Structural sensing of interior sound for active control of noise in structural-acoustic cavities.

    PubMed

    Bagha, Ashok K; Modak, S V

    2015-07-01

    This paper proposes a method for structural sensing of acoustic potential energy for active control of noise in a structural-acoustic cavity. The sensing strategy aims at global control and works with a fewer number of sensors. It is based on the established concept of radiation modes and hence does not add too many states to the order of the system. Acoustic potential energy is sensed using a combination of a Kalman filter and a frequency weighting filter with the structural response measurements as the inputs. The use of Kalman filter also makes the system robust against measurement noise. The formulation of the strategy is presented using finite element models of the system including that of sensors and actuators so that it can be easily applied to practical systems. The sensing strategy is numerically evaluated in the framework of Linear Quadratic Gaussian based feedback control of interior noise in a rectangular box cavity with a flexible plate with single and multiple pairs of piezoelectric sensor-actuator patches when broadband disturbances act on the plate. The performance is compared with an "acoustic filter" that models the complete transfer function from the structure to the acoustic domain. The sensing performance is also compared with a direct estimation strategy.

  10. Engine isolation for structural-borne interior noise reduction in a general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Unruh, J. F.; Scheidt, D. C.

    1981-01-01

    Engine vibration isolation for structural-borne interior noise reduction is investigated. A laboratory based test procedure to simulate engine induced structure-borne noise transmission, the testing of a range of candidate isolators for relative performance data, and the development of an analytical model of the transmission phenomena for isolator design evaluation are addressed. The isolator relative performance test data show that the elastomeric isolators do not appear to operate as single degree of freedom systems with respect to noise isolation. Noise isolation beyond 150 Hz levels off and begins to decrease somewhat above 600 Hz. Coupled analytical and empirical models were used to study the structure-borne noise transmission phenomena. Correlation of predicted results with measured data show that (1) the modeling procedures are reasonably accurate for isolator design evaluation, (2) the frequency dependent properties of the isolators must be included in the model if reasonably accurate noise prediction beyond 150 Hz is desired. The experimental and analytical studies were carried out in the frequency range from 10 Hz to 1000 Hz.

  11. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... operations in the area described in paragraph (b) of this section, a cluster of flashing red lights at night and a large red flag by day will be displayed from the range observation tower located in the...′, 1,025 yards, from Currituck Sound Light 69; thence 86°, 6,000 yards; thence 193°, 4,425...

  12. 33 CFR 334.410 - Albemarle Sound, Pamlico Sound, and adjacent waters, NC; danger zones for naval aircraft operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... operations in the area described in paragraph (b) of this section, a cluster of flashing red lights at night and a large red flag by day will be displayed from the range observation tower located in the...′, 1,025 yards, from Currituck Sound Light 69; thence 86°, 6,000 yards; thence 193°, 4,425...

  13. Aircraft

    DOEpatents

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    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.

  14. Aircraft

    DOEpatents

    Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.

    1998-01-01

    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.

  15. Sound quality of supersonic aircraft noise as heard indoors and its impact on annoyance

    NASA Astrophysics Data System (ADS)

    Giacomoni, Clothilde

    Supersonic flight over inhabited territories of the United States has been banned by the Federal Aviation Association since 1973. While research has been conducted to determine the effects of sonic booms on the general population when heard outdoors, little work has been done on people's perception of sonic booms as heard indoors. A technique to simulate indoor sounds from an outdoor sound has been developed. Using this, subjective tests have been done to determine the best way to use this simulation (i.e. whether diotic or dichotic sounds should be used) and to determine which indoor room characteristics, if any, have an effect on the population's perception of annoyance when hearing sonic booms indoors. Two annoyance models based on sound metrics proposed by Marshall and Davies have also been explored, and it was observed that while these two models were proposed for outdoor sounds, they are also quite accurate in predicting annoyance to sonic booms when heard indoors.

  16. Aircraft noise-induced awakenings are more reasonably predicted from relative than from absolute sound exposure levels.

    PubMed

    Fidell, Sanford; Tabachnick, Barbara; Mestre, Vincent; Fidell, Linda

    2013-11-01

    Assessment of aircraft noise-induced sleep disturbance is problematic for several reasons. Current assessment methods are based on sparse evidence and limited understandings; predictions of awakening prevalence rates based on indoor absolute sound exposure levels (SELs) fail to account for appreciable amounts of variance in dosage-response relationships and are not freely generalizable from airport to airport; and predicted awakening rates do not differ significantly from zero over a wide range of SELs. Even in conjunction with additional predictors, such as time of night and assumed individual differences in "sensitivity to awakening," nominally SEL-based predictions of awakening rates remain of limited utility and are easily misapplied and misinterpreted. Probabilities of awakening are more closely related to SELs scaled in units of standard deviates of local distributions of aircraft SELs, than to absolute sound levels. Self-selection of residential populations for tolerance of nighttime noise and habituation to airport noise environments offer more parsimonious and useful explanations for differences in awakening rates at disparate airports than assumed individual differences in sensitivity to awakening.

  17. [Temporal and spatial distribution of ozone concentration by aircraft sounding over Beijing].

    PubMed

    Chen, Peng-Fei; Zhang, Qiang; Quan, Jian-Nong; Gao, Yang; Huang, Meng-Yu

    2012-12-01

    Based on the aircraft sounding volume fraction concentration data of ozone (O3), nitrogen oxides (NO, NO2) and other data in Beijing from 2007 to 2010, temporal and spatial evolution of ozone concentration from the ground surface to 3.5 km altitude were studied. Results show that: (1) Vertical profiles of monthly average O3 concentration were in good agreement, with increasing altitude, the concentrations were first increased and then decreased, and then remained almost constant, and there was a clear dividing line at 1.5 km altitude, the vertical gradient of the O3 concentration changed greatly below which, there were O3 high-value areas, which were influenced by human activities near the ground; the change of vertical gradient of O3 concentration was significantly reduced above 1.5 km altitude, this space was above the mixing layer, where the air mass movement was less affected by underlying surface, and the advection-diffusion played a crucial role in the local accumulation process of air pollutants. (2) Changes of O3 concentration showed clear seasonal characteristics, O3 concentration was lower in spring and autumn, but higher in summer. In the months studied, no significant difference in monthly average O3 concentration from July to September was detected (P > 0.05), but there was significant difference in other months (P < 0.01). (3) In summer days (daytime), the variations in the vertical profiles of hourly O3 concentration were consistent with those of the monthly O3 concentration. The O3 concentration was lower near the surface within 1.5 km in the morning (09:00-10:00), and higher in the afternoon (15:00-16:00), with the maximum discrepancy of about 60 x 10(-9) in the same altitude; there was minor difference in O3 concentration in altitude range of 1.5-3.5 km, generally fluctuating among 70 x 10(-9) -80 x 10(-9). (4) For the regional distribution of O3 concentration, higher concentration within 0-2 km appeared near the Fourth Ring Road of city center

  18. Thermoplastics for aircraft interiors

    NASA Technical Reports Server (NTRS)

    Silverman, B.

    1978-01-01

    The goal for this contract is the development of processes and techniques for molding thermally stable, fire retardant, low smoke emitting polymeric materials. Outlined in this presentation are: (1) the typical molding types; (2) a program schedule; (3) physical properties of molding types with the test methods to be used; (4) general properties of injection molding materials; and (5) preliminary materials selection.

  19. Impact of the chosen turbulent flow empirical model on the prediction of sound radiation and vibration by aircraft panels

    NASA Astrophysics Data System (ADS)

    Rocha, Joana

    2016-07-01

    A precise definition of the turbulent boundary layer excitation is required to accurately predict the sound radiation and surface vibration levels, produced by an aircraft panel excited turbulent flow during flight. Hence, any existing inaccuracy on turbulent boundary layer excitation models leads to an inaccurate prediction of the panel response. A number of empirical models have been developed over the years to provide the turbulent boundary layer wall pressure spectral density. However, different empirical models provide dissimilar predictions for the wall pressure spectral density. The objective of the present study is to investigate and quantify the impact of the chosen empirical model on the predicted radiated sound power, and on the predicted panel surface acceleration levels. This study provides a novel approach and a detailed analysis on the use of different turbulent boundary layer wall pressure empirical models, and impact on mathematical predictions. Closed-form mathematical relationships are developed, and recommendations are provided for the level of deviation and uncertainty associated to different models, in relation to a baseline model, both for panel surface acceleration and radiated sound power.

  20. First SNPP Cal/Val Campaign: Satellite and Aircraft Sounding Retrieval Intercomparison

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Liu, Xu; Larar, Allen M.; Tian, Jialin; Smith, William L.; Wu, Wan; Kizer, Susan; Goldberg, Mitch; Liu, Q.

    2015-01-01

    Satellite ultraspectral infrared sensors provide key data records essential for weather forecasting and climate change science. The Suomi National Polar-orbiting Partnership (SNPP) satellite Environmental Data Record (EDR) is retrieved from calibrated ultraspectral radiance so called Sensor Data Record (SDR). It is critical to understand the accuracy of retrieved EDRs, which mainly depends on SDR accuracy (e.g., instrument random noise and absolute accuracy), an ill-posed retrieval system, and radiative transfer model errors. There are few approaches to validate EDR products, e.g., some common methods are to rely on radiosonde measurements, ground-based measurements, and dedicated aircraft campaign providing in-situ measurements of atmosphere and/or employing similar ultraspectral interferometer sounders. Ultraspectral interferometer sounder aboard aircraft measures SDR to retrieve EDR, which is often used to validate satellite measurements of SDR and EDR. The SNPP Calibration/Validation Campaign was conducted during May 2013. The NASA high-altitude aircraft ER-2 that carried ultraspectral interferometer sounders such as the NASA Atmospheric Sounder Testbed-Interferometer (NAST-I) flew under the SNPP satellite that carries the Cross-track Infrared Sounder (CrIS). Here we inter-compare the EDRs produced with different retrieval algorithms from SDRs measured by the sensors from satellite and aircraft. The available dropsonde and radiosonde measurements together with the European Centre for Medium-Range Weather Forecasts (ECMWF) analysis were also used to draw the conclusion from this experiment.

  1. Analytical prediction of the interior noise for cylindrical models of aircraft fuselages for prescribed exterior noise fields. Phase 1: Development and validation of preliminary analytical models

    NASA Technical Reports Server (NTRS)

    Pope, L. D.; Rennison, D. C.; Wilby, E. G.

    1980-01-01

    The basic theoretical work required to understand sound transmission into an enclosed space (that is, one closed by the transmitting structure) is developed for random pressure fields and for harmonic (tonal) excitation. The analysis is used to predict the noise reducton of unpressurized unstiffened cylinder, and also the interior response of the cylinder given a tonal (plane wave) excitation. Predictions and measurements are compared and the transmission is analyzed. In addition, results for tonal (harmonic) mechanical excitation are considered.

  2. Interior Noise

    NASA Technical Reports Server (NTRS)

    Mixson, John S.; Wilby, John F.

    1991-01-01

    The generation and control of flight vehicle interior noise is discussed. Emphasis is placed on the mechanisms of transmission through airborne and structure-borne paths and the control of cabin noise by path modification. Techniques for identifying the relative contributions of the various source-path combinations are also discussed along with methods for the prediction of aircraft interior noise such as those based on the general modal theory and statistical energy analysis.

  3. A research to reduce interior noise in general aviation airplanes. General aviation interior noise study

    NASA Technical Reports Server (NTRS)

    Roskam, J.; Muirhead, V. U.; Smith, H. W.; Peschier, T. D.

    1977-01-01

    The construction, calibration, and properties of a facility for measuring sound transmission through aircraft type panels are described along with the theoretical and empirical methods used. Topics discussed include typical noise source, sound transmission path, and acoustic cabin properties and their effect on interior noise. Experimental results show an average sound transmission loss in the mass controlled frequency region comparable to theoretical predictions. The results also verify that transmission losses in the stiffness controlled region directly depend on the fundamental frequency of the panel. Experimental and theoretical results indicate that increases in this frequency, and consequently in transmission loss, can be achieved by applying pressure differentials across the specimen.

  4. Sound Generation in the Presence of Moving Surfaces with Application to Internally Generated Aircraft Engine Noise

    NASA Technical Reports Server (NTRS)

    Goldstein, Marvin E.; Envia, E.

    2002-01-01

    In many cases of technological interest solid boundaries play a direct role in the aerodynamic sound generation process and their presence often results in a large increase in the acoustic radiation. A generalized treatment of the emission of sound from moving boundaries is presented. The approach is similar to that of Ffowcs Williams and Hawkings (1969) but the effect of the surrounding mean flow is explicitly accounted for. The results are used to develop a rational framework for the prediction of internally generated aero-engine noise. The final formulas suggest some new noise sources that may be of practical significance.

  5. Analysis of Acoustic Modeling and Sound Propagation in Aircraft Noise Prediction

    NASA Technical Reports Server (NTRS)

    Plotkin, Kenneth J.; Shepherd, Kevin P. (Technical Monitor)

    2006-01-01

    An analysis has been performed of measured and predicted aircraft noise levels around Denver International Airport. A detailed examination was made of 90 straight-out departures that yielded good measurements on multiple monitors. Predictions were made with INM 5, INM 6 and the simulation model NMSIM. Predictions were consistently lower than measurements, less so for the simulation model than for the integrated models. Lateral directivity ("installation effect") patterns were seen which are consistent with other recent measurements. Atmospheric absorption was determined to be a significant factor in the underprediction. Calculations of atmospheric attenuation were made over a full year of upper air data at seven locations across the United States. It was found that temperature/humidity effects could cause variations of up to +/-4 dB, depending on season, for the sites examined. It was concluded that local temperature and humidity should be accounted for in aircraft noise modeling.

  6. Sound

    NASA Astrophysics Data System (ADS)

    Capstick, J. W.

    2013-01-01

    1. The nature of sound; 2. Elasticity and vibrations; 3. Transverse waves; 4. Longitudinal waves; 5. Velocity of longitudinal waves; 6. Reflection and refraction. Doppler's principle; 7. Interference. Beats. Combination tones; 8. Resonance and forced vibrations; 9. Quality of musical notes; 10. Organ pipes; 11. Rods. Plates. Bells; 12. Acoustical measurements; 13. The phonograph, microphone and telephone; 14. Consonance; 15. Definition of intervals. Scales. Temperament; 16. Musical instruments; 17. Application of acoustical principles to military purposes; Questions; Answers to questions; Index.

  7. A study of methods of prediction and measurement of the transmission of sound through the walls of light aircraft

    NASA Technical Reports Server (NTRS)

    Forssen, B.; Wang, Y. S.; Raju, P. K.; Crocker, M. J.

    1981-01-01

    The acoustic intensity technique was applied to the sound transmission loss of panel structures (single, composite, and stiffened). A theoretical model of sound transmission through a cylindrical shell is presented.

  8. Methods for designing treatments to reduce interior noise of predominant sources and paths in a single engine light aircraft

    NASA Technical Reports Server (NTRS)

    Hayden, Richard E.; Remington, Paul J.; Theobald, Mark A.; Wilby, John F.

    1985-01-01

    The sources and paths by which noise enters the cabin of a small single engine aircraft were determined through a combination of flight and laboratory tests. The primary sources of noise were found to be airborne noise from the propeller and engine casing, airborne noise from the engine exhaust, structureborne noise from the engine/propeller combination and noise associated with air flow over the fuselage. For the propeller, the primary airborne paths were through the firewall, windshield and roof. For the engine, the most important airborne path was through the firewall. Exhaust noise was found to enter the cabin primarily through the panels in the vicinity of the exhaust outlet although exhaust noise entering the cabin through the firewall is a distinct possibility. A number of noise control techniques were tried, including firewall stiffening to reduce engine and propeller airborne noise, to stage isolators and engine mounting spider stiffening to reduce structure-borne noise, and wheel well covers to reduce air flow noise.

  9. Indoor seismology by probing the Earth interior by using sound velocity measurements at high pressures and temperatures

    SciTech Connect

    Li,B.; Liebermann, R.

    2007-01-01

    The adiabatic bulk (K S) and shear (G) moduli of mantle materials at high pressure and temperature can be obtained directly by measuring compressional and shear wave velocities in the laboratory with experimental techniques based on physical acoustics. We present the application of the current state-of-the-art experimental techniques by using ultrasonic interferometry in conjunction with synchrotron x radiation to study the elasticity of olivine and pyroxenes and their high-pressure phases. By using these updated thermoelasticity data for these phases, velocity and density profiles for a pyrolite model are constructed and compared with radial seismic models. We conclude that pyrolite provides an adequate explanation of the major seismic discontinuities at 410- and 660-km depths, the gradient in the transition zone, as well as the velocities in the lower mantle, if the uncertainties in the modeling and the variations in different seismic models are considered. The characteristics of the seismic scaling factors in response to thermal anomalies suggest that anticorrelations between bulk sound and shear wave velocities, as well as the large positive density anomalies observed in the lower mantle, cannot be explained fully without invoking chemical variations.

  10. Indoor seismology by probing the Earth's interior by using sound velocity measurements at high pressures and temperatures.

    PubMed

    Li, Baosheng; Liebermann, Robert C

    2007-05-29

    The adiabatic bulk (K(S)) and shear (G) moduli of mantle materials at high pressure and temperature can be obtained directly by measuring compressional and shear wave velocities in the laboratory with experimental techniques based on physical acoustics. We present the application of the current state-of-the-art experimental techniques by using ultrasonic interferometry in conjunction with synchrotron x radiation to study the elasticity of olivine and pyroxenes and their high-pressure phases. By using these updated thermoelasticity data for these phases, velocity and density profiles for a pyrolite model are constructed and compared with radial seismic models. We conclude that pyrolite provides an adequate explanation of the major seismic discontinuities at 410- and 660-km depths, the gradient in the transition zone, as well as the velocities in the lower mantle, if the uncertainties in the modeling and the variations in different seismic models are considered. The characteristics of the seismic scaling factors in response to thermal anomalies suggest that anticorrelations between bulk sound and shear wave velocities, as well as the large positive density anomalies observed in the lower mantle, cannot be explained fully without invoking chemical variations.

  11. Numerical modeling and experimental validation of the acoustic transmission of aircraft's double-wall structures including sound package

    NASA Astrophysics Data System (ADS)

    Rhazi, Dilal

    In the field of aeronautics, reducing the harmful effects of acoustics constitutes a major concern at the international level and justifies the call for further research, particularly in Canada where aeronautics is a key economic sector, which operates in a context of global competition. Aircraft sidewall structure is usually of a double wall construction with a curved ribbed metallic skin and a lightweight composite or sandwich trim separated by a cavity filled with a noise control treatment. The latter is of a great importance in the transport industry, and continues to be of interest in many engineering applications. However, the insertion loss noise control treatment depends on the excitation of the supporting structure. In particular, Turbulent Boundary Layer is of interest to several industries. This excitation is difficult to simulate in laboratory conditions, given the prohibiting costs and difficulties associated with wind tunnel and in-flight tests. Numerical simulation is the only practical way to predict the response to such excitations and to analyze effects of design changes to the response to such excitation. Another kinds of excitations encountered in industrial are monopole, rain on the Roof and diffuse acoustic field. Deterministic methods can calculate in each point the spectral response of the system. Most known are numerical methods such as finite elements and boundary elements methods. These methods generally apply to the low frequency where modal behavior of the structure dominates. However, the high limit of calculation in frequency of these methods cannot be defined in a strict way because it is related to the capacity of data processing and to the nature of the studied mechanical system. With these challenges in mind, and with limitations of the main numerical codes on the market, the manufacturers have expressed the need for simple models immediately available as early as the stage of preliminary drafts. This thesis represents an attempt

  12. [Actuator placement for active sound and vibration control

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two refereed journal publications and ten talks given at conferences, seminars, and colloquia resulted from research supported by NASA. They are itemized in this report. The two publications were entitled "Reactive Tabu and Search Sensor Selection in Active Structural Acoustic Control Problems" and "Quelling Cabin Noise in Turboprop Aircraft via Active Control." The conference presentations covered various aspects of actuator placement, including location problems, for active sound and vibration control of cylinders, of commuter jets, of propeller driven or turboprop aircraft, and for quelling aircraft cabin or interior noise.

  13. Active Suppression Of Vibrations On Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio

    1995-01-01

    Method of active suppression of nonlinear and nonstationary vibrations developed to reduce sonic fatigue and interior noise in high-speed aircraft. Structure of aircraft exhibits periodic, chaotic, and random vibrations when forced by high-intensity sound from jet engines, shock waves, turbulence, and separated flows. Method of suppressing vibrations involves feedback control: Strain gauges or other sensors mounted in paths of propagation of vibrations on structure sense vibrations; outputs of sensors processed into control signal applied to actuator mounted on structure, inducing compensatory forces.

  14. Investigation of acoustic properties of a rigid foam with application to noise reduction in light aircraft

    NASA Technical Reports Server (NTRS)

    Holmer, C. I.

    1972-01-01

    A analytic model of sound transmission into an aircraft cabin was developed as well as test procedures which appropriately rank order properties which affect sound transmission. The proposed model agrees well with available data, and reveals that the pertinent properties of an aircraft cabin for sound transmission include: stiffness of cabin walls at low frequencies (as this reflects on impedance of the walls) and cabin wall transmission loss and interior absorption at mid and high frequencies. Below 315 Hz the foam contributes substantially to wall stiffness and sound transmission loss of typical light aircraft cabin construction, and could potentially reduce cabin noise levels by 3-5 db in this frequency range at a cost of about 0:2 lb/sq. ft. of treated cabin area. The foam was found not to have significant sound absorbing properties.

  15. Interior near-field acoustical holography in flight.

    PubMed

    Williams, E G; Houston, B H; Herdic, P C; Raveendra, S T; Gardner, B

    2000-10-01

    In this paper boundary element methods (BEM) are mated with near-field acoustical holography (NAH) in order to determine the normal velocity over a large area of a fuselage of a turboprop airplane from a measurement of the pressure (hologram) on a concentric surface in the interior of the aircraft. This work represents the first time NAH has been applied in situ, in-flight. The normal fuselage velocity was successfully reconstructed at the blade passage frequency (BPF) of the propeller and its first two harmonics. This reconstructed velocity reveals structure-borne and airborne sound-transmission paths from the engine to the interior space.

  16. Sound transmission class (STC) is not a good predictor of performance of insulated wood frame gypsum walls used as interior partitions in most North American homes

    NASA Astrophysics Data System (ADS)

    Godfrey, Richard D.; Alter, Harry; Berdan, Clarke

    2005-09-01

    Home owners say that insulating interior walls improves the acoustic environment. Based on STC alone, no perceptible difference is expected. To define ``improved,'' ethnographic and laboratory studies were conducted. Ethnographic studies in 33 homes, revealed owners want quieter, less reverberant environments, including rooms where added isolation is desired. Families lives are 24/7, leading to frustration that they cannot use their homes without disturbing others. Laboratory jury studies were conducted where 35 listeners rated the relative isolation of insulated and uninsulated walls. Noise sources included broadband and real home noises. Insulated walls were perceived to perform better than uninsulated walls in all cases. Noise control engineers know that STC is only a quick screening tool (actual sound transmission loss should be used to estimate noise reduction between rooms). This is what the jurors appeared to sense. Jury ratings and the midfrequency average SPL correlated reasonably well. The STC is determined by a structural resonance near 125 Hz. Above this band, insulation has a significant impact on transmission loss (perceptible, 6 dB average). A new rating system is needed that quantifies what actual listeners hear in quiet room environments. A model using some form of room criteria is suggested.

  17. INTERIOR VIEW OF EAST SIDE DOORS, FACING SOUTHEAST. Douglas ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF EAST SIDE DOORS, FACING SOUTHEAST. - Douglas Aircraft Company Long Beach Plant, Aircraft Wing & Fuselage Assembly Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  18. Optimization of aircraft interior panels

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A.; Roper, Willard D.

    1986-01-01

    Eight different graphite composite panels were fabricated using four different resin matrices. The resin matrices included Hercules 71775, a blend of vinylpolystyrpyridine and bismaleimide, H795, a bismaleimide, Cycom 6162, a phenolic, and PSP 6022M, a polystyrylpyridine. Graphite panels were fabricated using fabric or unidirectional tape. This report describes the processes for preparing these panels and some of their mechanical, thermal and flammability properties. Panel properties are compared with state-of-the-art epoxy fiberglass composite panels.

  19. Method for creating an aeronautic sound shield having gas distributors arranged on the engines, wings, and nose of an aircraft

    NASA Technical Reports Server (NTRS)

    Corda, Stephen (Inventor); Smith, Mark Stephen (Inventor); Myre, David Daniel (Inventor)

    2008-01-01

    The present invention blocks and/or attenuates the upstream travel of acoustic disturbances or sound waves from a flight vehicle or components of a flight vehicle traveling at subsonic speed using a local injection of a high molecular weight gas. Additional benefit may also be obtained by lowering the temperature of the gas. Preferably, the invention has a means of distributing the high molecular weight gas from the nose, wing, component, or other structure of the flight vehicle into the upstream or surrounding air flow. Two techniques for distribution are direct gas injection and sublimation of the high molecular weight solid material from the vehicle surface. The high molecular weight and low temperature of the gas significantly decreases the local speed of sound such that a localized region of supersonic flow and possibly shock waves are formed, preventing the upstream travel of sound waves from the flight vehicle.

  20. A study of methods to predict and measure the transmission of sound through the walls of light aircraft

    NASA Technical Reports Server (NTRS)

    Bernhard, R. J.; Bolton, J. S.

    1988-01-01

    The objectives are: measurement of dynamic properties of acoustical foams and incorporation of these properties in models governing three-dimensional wave propagation in foams; tests to measure sound transmission paths in the HP137 Jetstream 3; and formulation of a finite element energy model. In addition, the effort to develop a numerical/empirical noise source identification technique was completed. The investigation of a design optimization technique for active noise control was also completed. Monthly progress reports which detail the progress made toward each of the objectives are summarized.

  1. A study of methods to predict and measure the transmission of sound through the walls of light aircraft

    NASA Technical Reports Server (NTRS)

    Bernhard, R. J.; Bolton, J. S.; Gardner, B.; Mickol, J.; Mollo, C.; Bruer, C.

    1986-01-01

    Progress was made in the following areas: development of a numerical/empirical noise source identification procedure using bondary element techniques; identification of structure-borne noise paths using structural intensity and finite element methods; development of a design optimization numerical procedure to be used to study active noise control in three-dimensional geometries; measurement of dynamic properties of acoustical foams and incorporation of these properties in models governing three-dimensional wave propagation in foams; and structure-borne sound path identification by use of the Wigner distribution.

  2. Sound Transmission through a Cylindrical Sandwich Shell with Honeycomb Core

    NASA Technical Reports Server (NTRS)

    Tang, Yvette Y.; Robinson, Jay H.; Silcox, Richard J.

    1996-01-01

    Sound transmission through an infinite cylindrical sandwich shell is studied in the context of the transmission of airborne sound into aircraft interiors. The cylindrical shell is immersed in fluid media and excited by an oblique incident plane sound wave. The internal and external fluids are different and there is uniform airflow in the external fluid medium. An explicit expression of transmission loss is derived in terms of modal impedance of the fluids and the shell. The results show the effects of (a) the incident angles of the plane wave; (b) the flight conditions of Mach number and altitude of the aircraft; (c) the ratios between the core thickness and the total thickness of the shell; and (d) the structural loss factors on the transmission loss. Comparisons of the transmission loss are made among different shell constructions and different shell theories.

  3. Potential Subjective Effectiveness of Active Interior Noise Control in Propeller Airplanes

    NASA Technical Reports Server (NTRS)

    Powell, Clemans A.; Sullivan, Brenda M.

    2000-01-01

    Active noise control technology offers the potential for weight-efficient aircraft interior noise reduction, particularly for propeller aircraft. However, there is little information on how passengers respond to this type of interior noise control. This paper presents results of two experiments that use sound quality engineering practices to determine the subjective effectiveness of hypothetical active noise control (ANC) systems in a range of propeller aircraft. The two experiments differed by the type of judgments made by the subjects: pair comparisons based on preference in the first and numerical category scaling of noisiness in the second. Although the results of the two experiments were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference. The reductions in subjective response due to the ANC conditions were predicted with reasonable accuracy by reductions in measured loudness level. Inclusion of corrections for the sound quality characteristics of tonality and fluctuation strength in multiple regression models improved the prediction of the ANC effects.

  4. An analytical and experimental study of sound propagation and attenuation in variable-area ducts. [reducing aircraft engine noise

    NASA Technical Reports Server (NTRS)

    Nayfeh, A. H.; Kaiser, J. E.; Marshall, R. L.; Hurst, L. J.

    1978-01-01

    The performance of sound suppression techniques in ducts that produce refraction effects due to axial velocity gradients was evaluated. A computer code based on the method of multiple scales was used to calculate the influence of axial variations due to slow changes in the cross-sectional area as well as transverse gradients due to the wall boundary layers. An attempt was made to verify the analytical model through direct comparison of experimental and computational results and the analytical determination of the influence of axial gradients on optimum liner properties. However, the analytical studies were unable to examine the influence of non-parallel ducts on the optimum linear conditions. For liner properties not close to optimum, the analytical predictions and the experimental measurements were compared. The circumferential variations of pressure amplitudes and phases at several axial positions were examined in straight and variable-area ducts, hard-wall and lined sections with and without a mean flow. Reasonable agreement between the theoretical and experimental results was obtained.

  5. Analytical prediction of the interior noise for cylindrical models of aircraft fuselages for prescribed exterior noise fields. Phase 2: Models for sidewall trim, stiffened structures and cabin acoustics with floor partition

    NASA Technical Reports Server (NTRS)

    Pope, L. D.; Wilby, E. G.

    1982-01-01

    An airplane interior noise prediction model is developed to determine the important parameters associated with sound transmission into the interiors of airplanes, and to identify apropriate noise control methods. Models for stiffened structures, and cabin acoustics with floor partition are developed. Validation studies are undertaken using three test articles: a ring stringer stiffened cylinder, an unstiffened cylinder with floor partition, and ring stringer stiffened cylinder with floor partition and sidewall trim. The noise reductions of the three test articles are computed using the heoretical models and compared to measured values. A statistical analysis of the comparison data indicates that there is no bias in the predictions although a substantial random error exists so that a discrepancy of more than five or six dB can be expected for about one out of three predictions.

  6. Sound quality prediction of vehicle interior noise and mathematical modeling using a back propagation neural network (BPNN) based on particle swarm optimization (PSO)

    NASA Astrophysics Data System (ADS)

    Zhang, Enlai; Hou, Liang; Shen, Chao; Shi, Yingliang; Zhang, Yaxiang

    2016-01-01

    To better solve the complex non-linear problem between the subjective sound quality evaluation results and objective psychoacoustics parameters, a method for the prediction of the sound quality is put forward by using a back propagation neural network (BPNN) based on particle swarm optimization (PSO), which is optimizing the initial weights and thresholds of BP network neurons through the PSO. In order to verify the effectiveness and accuracy of this approach, the noise signals of the B-Class vehicles from the idle speed to 120 km h-1 measured by the artificial head, are taken as a target. In addition, this paper describes a subjective evaluation experiment on the sound quality annoyance inside the vehicles through a grade evaluation method, by which the annoyance of each sample is obtained. With the use of Artemis software, the main objective psychoacoustic parameters of each noise sample are calculated. These parameters include loudness, sharpness, roughness, fluctuation, tonality, articulation index (AI) and A-weighted sound pressure level. Furthermore, three evaluation models with the same artificial neural network (ANN) structure are built: the standard BPNN model, the genetic algorithm-back-propagation neural network (GA-BPNN) model and the PSO-back-propagation neural network (PSO-BPNN) model. After the network training and the evaluation prediction on the three models’ network based on experimental data, it proves that the PSO-BPNN method can achieve convergence more quickly and improve the prediction accuracy of sound quality, which can further lay a foundation for the control of the sound quality inside vehicles.

  7. An experimental investigation of the interior noise control effects of propeller synchrophasing

    NASA Technical Reports Server (NTRS)

    Jones, J. D.; Fuller, C. R.

    1986-01-01

    A simplified cylindrical model of an aircraft fuselage is used to investigate the mechanisms of interior noise suppression using synchrophasing techniques. This investigation allows isolation of important parameters to define the characteristics of synchrophasing. The optimum synchrophase angle for maximum noise reduction is found for several interior microphone positions with pure tone source excitation. Noise reductions of up to 30 dB are shown for some microphone positions, however, overall reductions are less. A computer algorithm is developed to decompose the cylinder vibration into modal components over a wide range of synchrophase angles. The circumferential modal response of the shell vibration is shown to govern the transmission of sound into the cylinder rather than localized transmission. As well as investigating synchrophasing, the interior sound field due to sources typical of propellers has been measured and discussed.

  8. Aircraft fire safety research

    NASA Technical Reports Server (NTRS)

    Botteri, Benito P.

    1987-01-01

    During the past 15 years, very significant progress has been made toward enhancing aircraft fire safety in both normal and hostile (combat) operational environments. Most of the major aspects of the aircraft fire safety problem are touched upon here. The technology of aircraft fire protection, although not directly applicable in all cases to spacecraft fire scenarios, nevertheless does provide a solid foundation to build upon. This is particularly true of the extensive research and testing pertaining to aircraft interior fire safety and to onboard inert gas generation systems, both of which are still active areas of investigation.

  9. Study of the damping characteristics of general aviation aircraft panels and development of computer programs to calculate the effectiveness of interior noise control treatment, part 1

    NASA Technical Reports Server (NTRS)

    Navaneethan, R.; Hunt, J.; Quayle, B.

    1982-01-01

    Tests were carried out on 20 inch x 20 inch panels at different test conditions using free-free panels, clamped panels, and panels as installed in the KU-FRL acoustic test facility. Tests with free-free panels verified the basic equipment set-up and test procedure. They also provided a basis for comparison. The results indicate that the effect of installed panels is to increase the damping ratio at the same frequency. However, a direct comparison is not possible, as the fundamental frequency of a free-free panel differs from the resonance frequency of the panel when installed. The damping values of panels installed in the test facility are closer to the damping values obtained with fixed-fixed panels. Effects of damping tape, stiffeners, and bonded and riveted edged conditions were also investigated. Progress in the development of a simple interior noise level control program is reported.

  10. 11. Interior view of communications compartment. View toward rear of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Interior view of communications compartment. View toward rear of aircraft. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  11. 10. Interior view of communications compartment. View toward front of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Interior view of communications compartment. View toward front of aircraft. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  12. 9. Interior view of electronics compartment. View toward rear of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Interior view of electronics compartment. View toward rear of aircraft. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  13. VIEW OF INTERIOR SPACE WITH MEZZANINE LEVEL IN BACKGROUND AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR SPACE WITH MEZZANINE LEVEL IN BACKGROUND AND SMALL QUENCH TANK IN FOREGROUND, FACING NORTHEAST. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  14. VIEW OF INTERIOR SPACE WITH SPRAY PAINT BOOTHS CENTER, FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR SPACE WITH SPRAY PAINT BOOTHS CENTER, FACING NORTHWEST. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Receiving & Storage Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  15. VIEW OF INTERIOR SPACE WITH VERSON HYDROPRESS IN FOREGROUND, FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR SPACE WITH VERSON HYDROPRESS IN FOREGROUND, FACING SOUTHWEST. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  16. DETAIL VIEW OF INTERIOR MAIN SPACE WITH SPAR MILL EQUIPMENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF INTERIOR MAIN SPACE WITH SPAR MILL EQUIPMENT IN FOREGROUND, FACING NORTH. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Sub-Assembly Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  17. INTERIOR VIEW OF EAST SIDE WALL AND DOOR, FACING EAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW OF EAST SIDE WALL AND DOOR, FACING EAST. - Douglas Aircraft Company Long Beach Plant, Aircraft Wing & Fuselage Assembly Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  18. VIEW OF INTERIOR SPACE WITH HUFFORD BULLDOZIER FORMING PRESS IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR SPACE WITH HUFFORD BULLDOZIER FORMING PRESS IN FOREGROUND, FACING NORTHWEST. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  19. VIEW OF INTERIOR SPACE WITH ANODIZING TANK AND LIQUID BIN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR SPACE WITH ANODIZING TANK AND LIQUID BIN STORAGE TANK IN FOREGROUND, FACING NORTH. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Receiving & Storage Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  20. VIEW OF INTERIOR SPACE WITH RECTANGULAR SHAPE STRETCH PRESS CONTAINMENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR SPACE WITH RECTANGULAR SHAPE STRETCH PRESS CONTAINMENT PIT IN BACKGROUND, FACING NORTH. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  1. VIEW OF INTERIOR SPACE WITH SQUARE SHAPE STRETCH PRESS CONTAINMENT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF INTERIOR SPACE WITH SQUARE SHAPE STRETCH PRESS CONTAINMENT PITS CENTER, FACING NORTH. - Douglas Aircraft Company Long Beach Plant, Aircraft Parts Shipping & Receiving Building, 3855 Lakewood Boulevard, Long Beach, Los Angeles County, CA

  2. Direct measurement of transmission loss of aircraft structures using the acoustic intensity approach

    NASA Technical Reports Server (NTRS)

    Wang, Y. S.; Crocker, M. J.

    1982-01-01

    A measurement technique is developed in order to obtain the sound transmission loss of an aircraft fuselage which obviates the need for the two-room transmission suite. The sound transmission paths were determined in tests on a light aircraft fuselage using a two-microphone acoustic intensity method for measuring the acoustic intensity transmitted to the interior when the fuselage was exposed to an external random incidence sound-field. The intensity transmitted through different sections of the fuselage can be estimated accurately using this new technique. Results of these tests show that the plexiglass window is the major transmission path in the high frequency range. In addition, the transmission losses through a single and a double layer window were predicted theoretically by using the Statistical Energy Analysis Model. Very good agreement is found between the predictions and the measurements.

  3. UHB demonstrator interior noise control flight tests and analysis

    NASA Technical Reports Server (NTRS)

    Simpson, M. A.; Druez, P. M.; Kimbrough, A. J.; Brock, M. P.; Burge, P. L.; Mathur, G. P.; Cannon, M. R.; Tran, B. N.

    1989-01-01

    The measurement and analysis of MD-UHB (McDonnell Douglas Ultra High Bypass) Demonstrator noise and vibration flight test data are described as they relate to passenger cabin noise. The analyses were done to investigate the interior noise characteristics of advanced turboprop aircraft with aft-mounted engines, and to study the effectiveness of selected noise control treatments in reducing passenger cabin noise. The UHB Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB engine. For these tests, the UHB engine was a General Electric Unducted Fan, with either 8x8 or 10x8 counter-rotating propeller configurations. Interior noise level characteristics were studied for several altitudes and speeds, with emphasis on high altitude (35,000 ft), high speed (0.75 Mach) cruise conditions. The effectiveness of several noise control treatments was evaluated based on cabin noise measurements. The important airborne and structureborne transmission paths were identified for both tonal and broadband sources using the results of a sound intensity survey, exterior and interior noise and vibration data, and partial coherence analysis techniques. Estimates of the turbulent boundary layer pressure wavenumber-frequency spectrum were made, based on measured fuselage noise levels.

  4. INTERIOR OF COLD STORAGE ROOM, SHOWING MOVABLE HANGING RACKS. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR OF COLD STORAGE ROOM, SHOWING MOVABLE HANGING RACKS. - Naval Air Station Barbers Point, Aircraft Storehouse, Between Midway & Card Streets at Enterprise Avenue intersection, Ewa, Honolulu County, HI

  5. Interior Design.

    ERIC Educational Resources Information Center

    Texas Tech Univ., Lubbock. Home Economics Curriculum Center.

    This document contains teacher's materials for an eight-unit secondary education vocational home economics course on interior design. The units cover period styles of interiors, furniture and accessories, surface treatments and lighting, appliances and equipment, design and space planning in home and business settings, occupant needs, acquisition…

  6. 7 CFR 3201.100 - Aircraft and boat cleaners.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Aircraft and boat cleaners. 3201.100 Section 3201.100... Designated Items § 3201.100 Aircraft and boat cleaners. (a) Definition. (1) Aircraft and boat cleaners are... interior and exterior of aircraft and/or boats. (2) Aircraft and boat cleaners for which Federal...

  7. Modeling of Sound Transmission through Shell Structures with Turbulent Boundary Layer Excitation

    NASA Technical Reports Server (NTRS)

    Tang, Yvette Y.; Silcox, Richard J.; Robinson, Jay H.

    1996-01-01

    The turbulent boundary layer (TBL) pressure field is an important source of cabin noise during cruise of high subsonic and supersonic commercial aircraft. The broadband character of this excitation field results in an interior noise spectrum that dominates the overall sound pressure level (SPL) and speech interference metrics in the forward and midcabins of many aircraft. In the authors' previous study, sound transmission through an aircraft fuselage, modeled by two concentric cylindrical sandwich shells and excited by a TBL statistical model was investigated analytically. An assessment of point and global structural vibration levels and resulting interior noise levels was obtained for different TBL models, flight conditions and fuselage structural designs. However, due to the complication of the shell structure, the important noise transmission mechanisms were difficult to discern. Previous experience has demonstrated that a fundamental understanding of the range of modes (or wavenumbers) generated by the TBL source both in the structure and the acoustic cavity is key to the development of both active and passive control technologies. In an initial effort to provide this insight, the objective of this paper is to develop an analytical model of sound transmission through a simple unstiffened cylindrical aluminum shell excited by a TBL pressure field. The description of the turbulent pressure field is based on the Corcos formulation for the cross-spectral density (CSD) of the pressure fluctuations. The coupled shell and interior and exterior acoustic equations are solved for the structural displacement and the interior acoustic response using a Galerkin approach to obtain analytical solutions. Specifically, this study compares the real part of the normalized CSD of the TBL excitation field, the structural displacement and the interior acoustic field. Further the modal compositions of the structural and cavity response are examined and some inference of the dominant

  8. Large Civil Tiltrotor (LCTR2) Interior Noise Predictions due to Turbulent Boundary Layer Excitation

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.

    2013-01-01

    The Large Civil Tiltrotor (LCTR2) is a conceptual vehicle that has a design goal to transport 90 passengers over a distance of 1800 km at a speed of 556 km/hr. In this study noise predictions were made in the notional LCTR2 cabin due to Cockburn/Robertson and Efimtsov turbulent boundary layer (TBL) excitation models. A narrowband hybrid Finite Element (FE) analysis was performed for the low frequencies (6-141 Hz) and a Statistical Energy Analysis (SEA) was conducted for the high frequency one-third octave bands (125- 8000 Hz). It is shown that the interior sound pressure level distribution in the low frequencies is governed by interactions between individual structural and acoustic modes. The spatially averaged predicted interior sound pressure levels for the low frequency hybrid FE and the high frequency SEA analyses, due to the Efimtsov turbulent boundary layer excitation, were within 1 dB in the common 125 Hz one-third octave band. The averaged interior noise levels for the LCTR2 cabin were predicted lower than the levels in a comparable Bombardier Q400 aircraft cabin during cruise flight due to the higher cruise altitude and lower Mach number of the LCTR2. LCTR2 cabin noise due to TBL excitation during cruise flight was found not unacceptable for crew or passengers when predictions were compared to an acoustic survey on a Q400 aircraft.

  9. 113. INTERIOR COMMUNICATIONS COMPARTMENT PORT LOOKING TO STARBOARD SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    113. INTERIOR COMMUNICATIONS COMPARTMENT - PORT LOOKING TO STARBOARD SHOWING MASTER GYRO AND INTERIOR COMMUNICATIONS SWITCHBOARD. - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

  10. 43 CFR 423.41 - Aircraft.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Aircraft. 423.41 Section 423.41 Public... Aircraft. (a) You must comply with any applicable Federal, State, and local laws, and with any additional... this part 423, with respect to aircraft landings, takeoffs, and operation on or in the proximity...

  11. 43 CFR 423.41 - Aircraft.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Aircraft. 423.41 Section 423.41 Public... Aircraft. (a) You must comply with any applicable Federal, State, and local laws, and with any additional... this part 423, with respect to aircraft landings, takeoffs, and operation on or in the proximity...

  12. 43 CFR 423.41 - Aircraft.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Aircraft. 423.41 Section 423.41 Public... Aircraft. (a) You must comply with any applicable Federal, State, and local laws, and with any additional... this part 423, with respect to aircraft landings, takeoffs, and operation on or in the proximity...

  13. 43 CFR 423.41 - Aircraft.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Aircraft. 423.41 Section 423.41 Public... Aircraft. (a) You must comply with any applicable Federal, State, and local laws, and with any additional... this part 423, with respect to aircraft landings, takeoffs, and operation on or in the proximity...

  14. 43 CFR 423.41 - Aircraft.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Aircraft. 423.41 Section 423.41 Public... Aircraft. (a) You must comply with any applicable Federal, State, and local laws, and with any additional... this part 423, with respect to aircraft landings, takeoffs, and operation on or in the proximity...

  15. Interior noise and vibration measurements on operational military helicopters and comparisons with various ride quality criteria

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Leatherwood, J. D.; Hollenbaugh, D. D.

    1983-01-01

    The results of physical measurements of the interior noise and vibration obtained within eight operational military helicopters are presented. The data were extensively analyzed and are presented in the following forms: noise and vibration spectra, overall root-mean-square acceleration levels in three linear axes, peak accelerations at dominant blade passage frequencies, acceleration exceedance data, and overall and ""A'' weighted sound pressure levels. Peak acceleration levels were compared to the ISO 1-hr reduced comfort and fatigue decreased proficiency boundaries and the NASA discomfort criteria. The ""A'' weighted noise levels were compared to the NASA annoyance criteria, and the overall noise spectra were compared to MIL-STD-1294 (""Acoustical Noise Limits in Helicopters''). Specific vibration components at blade passage frequencies for several aircraft exceeded both the ISO reduced comfort boundary and the NASA passenger discomfort criteria. The ""A'' weighted noise levels, corrected for SPH-4 helmet attenuation characteristics, exceeded the NASA annoyance threshold for several aircraft.

  16. Interior noise and vibration measurements on operational military helicopters and comparisons with various ride quality criteria

    NASA Astrophysics Data System (ADS)

    Clevenson, S. A.; Leatherwood, J. D.; Hollenbaugh, D. D.

    1983-08-01

    The results of physical measurements of the interior noise and vibration obtained within eight operational military helicopters are presented. The data were extensively analyzed and are presented in the following forms: noise and vibration spectra, overall root-mean-square acceleration levels in three linear axes, peak accelerations at dominant blade passage frequencies, acceleration exceedance data, and overall and ""A'' weighted sound pressure levels. Peak acceleration levels were compared to the ISO 1-hr reduced comfort and fatigue decreased proficiency boundaries and the NASA discomfort criteria. The ""A'' weighted noise levels were compared to the NASA annoyance criteria, and the overall noise spectra were compared to MIL-STD-1294 (""Acoustical Noise Limits in Helicopters''). Specific vibration components at blade passage frequencies for several aircraft exceeded both the ISO reduced comfort boundary and the NASA passenger discomfort criteria. The ""A'' weighted noise levels, corrected for SPH-4 helmet attenuation characteristics, exceeded the NASA annoyance threshold for several aircraft.

  17. Sound transmission loss of composite sandwich panels

    NASA Astrophysics Data System (ADS)

    Zhou, Ran

    Light composite sandwich panels are increasingly used in automobiles, ships and aircraft, because of the advantages they offer of high strength-to-weight ratios. However, the acoustical properties of these light and stiff structures can be less desirable than those of equivalent metal panels. These undesirable properties can lead to high interior noise levels. A number of researchers have studied the acoustical properties of honeycomb and foam sandwich panels. Not much work, however, has been carried out on foam-filled honeycomb sandwich panels. In this dissertation, governing equations for the forced vibration of asymmetric sandwich panels are developed. An analytical expression for modal densities of symmetric sandwich panels is derived from a sixth-order governing equation. A boundary element analysis model for the sound transmission loss of symmetric sandwich panels is proposed. Measurements of the modal density, total loss factor, radiation loss factor, and sound transmission loss of foam-filled honeycomb sandwich panels with different configurations and thicknesses are presented. Comparisons between the predicted sound transmission loss values obtained from wave impedance analysis, statistical energy analysis, boundary element analysis, and experimental values are presented. The wave impedance analysis model provides accurate predictions of sound transmission loss for the thin foam-filled honeycomb sandwich panels at frequencies above their first resonance frequencies. The predictions from the statistical energy analysis model are in better agreement with the experimental transmission loss values of the sandwich panels when the measured radiation loss factor values near coincidence are used instead of the theoretical values for single-layer panels. The proposed boundary element analysis model provides more accurate predictions of sound transmission loss for the thick foam-filled honeycomb sandwich panels than either the wave impedance analysis model or the

  18. Robust Feedback Control of Flow Induced Structural Radiation of Sound

    NASA Technical Reports Server (NTRS)

    Heatwole, Craig M.; Bernhard, Robert J.; Franchek, Matthew A.

    1997-01-01

    A significant component of the interior noise of aircraft and automobiles is a result of turbulent boundary layer excitation of the vehicular structure. In this work, active robust feedback control of the noise due to this non-predictable excitation is investigated. Both an analytical model and experimental investigations are used to determine the characteristics of the flow induced structural sound radiation problem. The problem is shown to be broadband in nature with large system uncertainties associated with the various operating conditions. Furthermore the delay associated with sound propagation is shown to restrict the use of microphone feedback. The state of the art control methodologies, IL synthesis and adaptive feedback control, are evaluated and shown to have limited success for solving this problem. A robust frequency domain controller design methodology is developed for the problem of sound radiated from turbulent flow driven plates. The control design methodology uses frequency domain sequential loop shaping techniques. System uncertainty, sound pressure level reduction performance, and actuator constraints are included in the design process. Using this design method, phase lag was added using non-minimum phase zeros such that the beneficial plant dynamics could be used. This general control approach has application to lightly damped vibration and sound radiation problems where there are high bandwidth control objectives requiring a low controller DC gain and controller order.

  19. The subjective evaluation of noise from light aircraft

    NASA Technical Reports Server (NTRS)

    Shepherd, K. P.

    1976-01-01

    A study was conducted in which subjects evaluated the sounds of a light aircraft and a motorcycle. Particular emphasis was placed on examining the duration of the sounds. Thirty subjects gave annoyance ratings to a total of 50 sounds, with peak levels between 65 and 85dB(A). It was found that aircraft and motorcycles have differing optimum duration corrections. The conventional duration correction used in the calculation of EPNL is far from being the optimum for light aircraft.

  20. Directional monitoring terminal for aircraft noise

    NASA Astrophysics Data System (ADS)

    Genescà, M.

    2016-07-01

    This paper presents a concept of an aircraft noise monitoring terminal (NMT) that reduces background noise and the influence of ground reflection, in comparison with a single microphone. Also, it automatically identifies aircraft sound events based on the direction of arrival of the sound rather than on the sound pressure level (or radar data). And moreover, it provides an indicator of the quality of the sound pressure level measurement, i.e. if it is possibly disturbed by extraneous sources. The performance of this NMT is experimentally tested under real conditions in a measurement site close to Zurich airport. The results show that the NMT unambiguously identifies the noise events generated by the target aircraft, correctly detects those aircraft noise events that may be disturbed by the presence of other sources, and offers a substantial reduction in background and ground reflected sound.

  1. Handbook of aircraft noise metrics

    NASA Technical Reports Server (NTRS)

    Bennett, R. L.; Pearsons, K. S.

    1981-01-01

    Information is presented on 22 noise metrics that are associated with the measurement and prediction of the effects of aircraft noise. Some of the instantaneous frequency weighted sound level measures, such as A-weighted sound level, are used to provide multiple assessment of the aircraft noise level. Other multiple event metrics, such as day-night average sound level, were designed to relate sound levels measured over a period of time to subjective responses in an effort to determine compatible land uses and aid in community planning. The various measures are divided into: (1) instantaneous sound level metrics; (2) duration corrected single event metrics; (3) multiple event metrics; and (4) speech communication metrics. The scope of each measure is examined in terms of its: definition, purpose, background, relationship to other measures, calculation method, example, equipment, references, and standards.

  2. Handbook of aircraft noise metrics

    NASA Astrophysics Data System (ADS)

    Bennett, R. L.; Pearsons, K. S.

    1981-03-01

    Information is presented on 22 noise metrics that are associated with the measurement and prediction of the effects of aircraft noise. Some of the instantaneous frequency weighted sound level measures, such as A-weighted sound level, are used to provide multiple assessment of the aircraft noise level. Other multiple event metrics, such as day-night average sound level, were designed to relate sound levels measured over a period of time to subjective responses in an effort to determine compatible land uses and aid in community planning. The various measures are divided into: (1) instantaneous sound level metrics; (2) duration corrected single event metrics; (3) multiple event metrics; and (4) speech communication metrics. The scope of each measure is examined in terms of its: definition, purpose, background, relationship to other measures, calculation method, example, equipment, references, and standards.

  3. Interior noise reduction by alternate resonance tuning

    NASA Technical Reports Server (NTRS)

    Bliss, Donald B.; Gottwald, James A.; Bryce, Jeffrey W.

    1987-01-01

    Existing interior noise reduction techniques for aircraft fuselages perform reasonably well at higher frequencies, but are inadequate at low frequencies, particularly with respect to the low blade passage harmonics with high forcing levels found in propeller aircraft. A method is studied which considers aircraft fuselages lined with panels alternately tuned to frequencies above and below the frequency that must be attenuated. Adjacent panel would oscillate at equal amplitude, to give equal acoustic source strength, but with opposite phase. Provided these adjacent panels are acoustically compact, the resulting cancellation causes the interior acoustic modes to be cut off, and therefore be nonpropagating and evanescent. This interior noise reduction method, called Alternate Resonance Tuning (ART), is being investigated theoretically and experimentally. Progress to date is discussed.

  4. Planetary Interiors

    NASA Technical Reports Server (NTRS)

    Banerdt, W. Bruce; Abercrombie, Rachel; Keddie, Susan; Mizutani, Hitoshi; Nagihara, Seiichi; Nakamura, Yosio; Pike, W. Thomas

    1996-01-01

    This report identifies two main themes to guide planetary science in the next two decades: understanding planetary origins, and understanding the constitution and fundamental processes of the planets themselves. Within the latter theme, four specific goals related to interior measurements addressing the theme. These are: (1) Understanding the internal structure and dynamics of at least one solid body, other than the Earth or Moon, that is actively convecting, (2) Determine the characteristics of the magnetic fields of Mercury and the outer planets to provide insight into the generation of planetary magnetic fields, (3) Specify the nature and sources of stress that are responsible for the global tectonics of Mars, Venus, and several icy satellites of the outer planets, and (4) Advance significantly our understanding of crust-mantle structure for all the solid planets. These goals can be addressed almost exclusively by measurements made on the surfaces of planetary bodies.

  5. Validation of an interior noise prediction model for a composite cylinder

    NASA Technical Reports Server (NTRS)

    Beyer, Todd B.; Grosveld, Ferdinand W.

    1987-01-01

    An acoustic modal analysis has been performed in the cavity of a composite cylinder model of an aircraft fuselage. The filament wound, composite shell is 12 feet long and 5.5 feet in diameter. A one-half-in. thick plywood floor is attached to the shell 69 deg from the vertical centerline through the bottom of the shell. The acoustic modal frequencies were obtained from a sound pressure level and phase survey conducted throughout the interior volume bounded by the floor, endcaps and stiffened shell, while being excited by white noise from a loudspeaker source. The measured acoustic resonance frequencies and mode shapes compare well with analytical predictions from the Propeller Aircraft Interior Noise (PAIN) model. Details of the theory and derivation of the acoustic characteristics have been included. Reverberation time measurements, using the integrated impulse technique, have been performed to determine acoustic loss factors. These measured loss factors have been input to the PAIN program in order to more accurately predict the space-averaged interior noise of the composite cylinder.

  6. Study of double wall panels for use in propeller driven aircraft

    NASA Technical Reports Server (NTRS)

    Atwal, M.; Bernhard, R.

    1984-01-01

    Propeller driven aircraft have exhibited high levels of interior noise. Most absorption materials are not effective at low frequencies where maximum noise levels occur. Two panels separated by an air gap are suggested as an alternative means of noise attenuation. This design produces an impedance mismatch where a sound wave travels backwards to the source. The higher the impedance, the higher the reflected soundwave intensity. Two aluminum panels with helium in between and two panels with one being perforated were investigated. Helium increases the transmission loss because of a greater impedance mismatch than air. The transmission loss of the unperforated panel is higher throughout the frequency range tested.

  7. Scaling aircraft noise perception.

    NASA Technical Reports Server (NTRS)

    Ollerhead, J. B.

    1973-01-01

    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.

  8. Effect of noise spectra and a listening task upon passenger annoyance in a helicopter interior noise environment

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Leatherwood, J. D.

    1979-01-01

    The effects of helicopter interior noise on passenger annoyance were studied. Both reverie and listening situations were studied as well as the relative effectiveness of several descriptors (i.e., overall sound pressure level, A-weighted sound pressure level, and speech interference level) for quantifying annoyance response for these situations. The noise stimuli were based upon recordings of the interior noise of a civil helicopter research aircraft. These noises were presented at levels ranging from approximately 68 to 86 dB(A) with various gear clash tones selectively attenuated to give a range of spectra. Results indicated that annoyance during a listening condition is generally higher than annoyance during a reverie condition for corresponding interior noise environments. Attenuation of the planetary gear clash tone results in increases in listening performance but has negligible effect upon annoyance for a given noise level. The noise descriptor most effective for estimating annoyance response under conditions of reverie and listening situations is shown to be the A-weighted sound pressure level.

  9. Human response to aircraft noise

    NASA Technical Reports Server (NTRS)

    Powell, Clemans A.; Fields, James M.

    1991-01-01

    The human auditory system and the perception of sound are discussed. The major concentration is on the annnoyance response and methods for relating the physical characteristics of sound to those psychosociological attributes associated with human response. Results selected from the extensive laboratory and field research conducted on human response to aircraft noise over the past several decades are presented along with discussions of the methodology commonly used in conducting that research. Finally, some of the more common criteria, regulations, and recommended practices for the control or limitation of aircraft noise are examined in light of the research findings on human response.

  10. Ultrasonic cleaning of interior surfaces

    DOEpatents

    Odell, D. MacKenzie C.

    1996-01-01

    An ultrasonic cleaning method for cleaning the interior surfaces of tubes. The method uses an ultrasonic generator and reflector each coupled to opposing ends of the open-ended, fluid-filled tube. Fluid-tight couplings seal the reflector and generator to the tube, preventing leakage of fluid from the interior of the tube. The reflector and generator are operatively connected to actuators, whereby the distance between them can be varied. When the distance is changed, the frequency of the sound waves is simultaneously adjusted to maintain the resonant frequency of the tube so that a standing wave is formed in the tube, the nodes of which are moved axially to cause cavitation along the length of the tube. Cavitation maximizes mechanical disruption and agitation of the fluid, dislodging foreign material from the interior surface.

  11. Ultrasonic cleaning of interior surfaces

    DOEpatents

    Odell, D. MacKenzie C.

    1994-01-01

    An ultrasonic cleaning apparatus for cleaning the interior surfaces of tubes. The apparatus includes an ultrasonic generator and reflector each coupled to opposing ends of the open-ended, fluid-filled tube. Fluid-tight couplings seal the reflector and generator to the tube, preventing leakage of fluid from the interior of the tube. The reflector and generator are operatively connected to actuators, whereby the distance between them can be varied. When the distance is changed, the frequency of the sound waves is simultaneously adjusted to maintain the resonant frequency of the tube so that a standing wave is formed in the tube, the nodes of which are moved axially to cause cavitation along the length of the tube. Cavitation maximizes mechanical disruption and agitation of the fluid, dislodging foreign material from the interior surface.

  12. Ultrasonic cleaning of interior surfaces

    DOEpatents

    MacKenzie, D.; Odell, C.

    1994-03-01

    An ultrasonic cleaning apparatus is described for cleaning the interior surfaces of tubes. The apparatus includes an ultrasonic generator and reflector each coupled to opposing ends of the open-ended, fluid-filled tube. Fluid-tight couplings seal the reflector and generator to the tube, preventing leakage of fluid from the interior of the tube. The reflector and generator are operatively connected to actuators, whereby the distance between them can be varied. When the distance is changed, the frequency of the sound waves is simultaneously adjusted to maintain the resonant frequency of the tube so that a standing wave is formed in the tube, the nodes of which are moved axially to cause cavitation along the length of the tube. Cavitation maximizes mechanical disruption and agitation of the fluid, dislodging foreign material from the interior surface. 3 figures.

  13. INTERIOR FROM WESTERN SECTION, THROUGH CENTRAL SECTION, TO EASTERN SECTION, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR FROM WESTERN SECTION, THROUGH CENTRAL SECTION, TO EASTERN SECTION, VIEW FACING NORTHEAST. - Naval Air Station Barbers Point, Aircraft Storehouse, Between Midway & Card Streets at Enterprise Avenue intersection, Ewa, Honolulu County, HI

  14. INTERIOR FROM MEZZANINE LEVEL OF CENTRAL SECTION, VIEW FACING WEST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR FROM MEZZANINE LEVEL OF CENTRAL SECTION, VIEW FACING WEST. - Naval Air Station Barbers Point, Aircraft Storehouse, Between Midway & Card Streets at Enterprise Avenue intersection, Ewa, Honolulu County, HI

  15. FEATURE 4, ARMCO HUT, INTERIOR , VIEW FACING NORTHWEST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FEATURE 4, ARMCO HUT, INTERIOR , VIEW FACING NORTHWEST. - Naval Air Station Barbers Point, Anti-Aircraft Battery Complex-ARMCO Hut, East of Coral Sea Road, northwest of Hamilton Road, Ewa, Honolulu County, HI

  16. Aircraft Contrails

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Captured in this scene is a series of aircraft contrails in a high traffic region over the northern Gulf of Mexico (27.0N, 85.5W). Contrails are caused by the hot engine exhaust of high flying aircraft interacting with moisture in the cold upper atmosphere and are common occurrances of high flying aircraft.

  17. 12. Interior view of battle staff compartment showing the general's ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Interior view of battle staff compartment showing the general's chair. View toward front of aircraft. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  18. Disturbance caused by aircraft noise

    NASA Technical Reports Server (NTRS)

    Josse, R.

    1980-01-01

    Noise pollution caused by the presence of airfields adjacent to residential areas is studied. Noise effects on the sleep of residents near airports and the degree of the residents noise tolerance are evaluated. What aircraft noises are annoying and to what extent the annoyance varies with sound level are discussed.

  19. 36 CFR 13.450 - Prohibition of aircraft use.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Subsistence § 13.450 Prohibition of aircraft use. (a) Notwithstanding the provisions 43 CFR 36.11(f) the use of aircraft for access to or from lands and waters within a... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Prohibition of aircraft...

  20. 36 CFR 13.450 - Prohibition of aircraft use.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Subsistence § 13.450 Prohibition of aircraft use. (a) Notwithstanding the provisions 43 CFR 36.11(f) the use of aircraft for access to or from lands and waters within a... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Prohibition of aircraft...

  1. 36 CFR 13.450 - Prohibition of aircraft use.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Subsistence § 13.450 Prohibition of aircraft use. (a) Notwithstanding the provisions 43 CFR 36.11(f) the use of aircraft for access to or from lands and waters within a... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Prohibition of aircraft...

  2. 36 CFR 13.450 - Prohibition of aircraft use.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Subsistence § 13.450 Prohibition of aircraft use. (a) Notwithstanding the provisions 43 CFR 36.11(f) the use of aircraft for access to or from lands and waters within a... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Prohibition of aircraft...

  3. 36 CFR 13.450 - Prohibition of aircraft use.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Subsistence § 13.450 Prohibition of aircraft use. (a) Notwithstanding the provisions 43 CFR 36.11(f) the use of aircraft for access to or from lands and waters within a... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Prohibition of aircraft...

  4. 38. INTERIOR VIEW, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING COMPLETE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. INTERIOR VIEW, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING COMPLETE SWITCH LEVER ASSEMBLAGE AND DISPLAY BOARD ON FRONT WALL - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  5. 35. END VIEW, INTERIOR, SHOWING SWITCHING LEVERS, BERK SWITCH TOWER, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    35. END VIEW, INTERIOR, SHOWING SWITCHING LEVERS, BERK SWITCH TOWER, SOUTH NORWALK - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  6. 36. INTERIOR VIEW, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING SWITCHING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. INTERIOR VIEW, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING SWITCHING LEVERS FROM OPERATOR'S POSITION - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  7. 42. INTERIOR VIEW, GREEN SWITCH TOWER, COS COB, SHOWING DETAIL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. INTERIOR VIEW, GREEN SWITCH TOWER, COS COB, SHOWING DETAIL OF SWITCH LEVERS - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  8. 37. OBLIQUE VIEW, INTERIOR, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. OBLIQUE VIEW, INTERIOR, BERK SWITCH TOWER, SOUTH NORWALK, SHOWING SWITCHING LEVERS - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  9. 41. INTERIOR VIEW, GREEN SWITCH TOWER, COS COB, SHOWING SWITCH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    41. INTERIOR VIEW, GREEN SWITCH TOWER, COS COB, SHOWING SWITCH LEVER ASSEMBLAGE AND DISPLAY BOARD - New York, New Haven & Hartford Railroad, Automatic Signalization System, Long Island Sound shoreline between Stamford & New Haven, Stamford, Fairfield County, CT

  10. 151. Interior of north addition to powerhouse, currently used as ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    151. Interior of north addition to powerhouse, currently used as a machine shop, looking east. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  11. 23. Interior view of SE corner of first floor of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. Interior view of SE corner of first floor of 1896 south section of building, showing windows and column. Camera pointed SE. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  12. 13. Interior view of individual work benches along west wall ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Interior view of individual work benches along west wall of north 1922 section of Building 59. Camera pointed NW. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  13. 15. Interior view of first floor aisle in 1904 middle ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Interior view of first floor aisle in 1904 middle section. Camera pointed south from near juncture with 1922 north section. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  14. 25. Interior view of third floor attic of 1904 middle ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    25. Interior view of third floor attic of 1904 middle section showing concrete roof and storage of wooden patterns for ship parts. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  15. Aircraft Design

    NASA Technical Reports Server (NTRS)

    Bowers, Albion H. (Inventor); Uden, Edward (Inventor)

    2016-01-01

    The present invention is an aircraft wing design that creates a bell shaped span load, which results in a negative induced drag (induced thrust) on the outer portion of the wing; such a design obviates the need for rudder control of an aircraft.

  16. Theoretical vibro-acoustic modeling of acoustic noise transmission through aircraft windows

    NASA Astrophysics Data System (ADS)

    Aloufi, Badr; Behdinan, Kamran; Zu, Jean

    2016-06-01

    In this paper, a fully vibro-acoustic model for sound transmission across a multi-pane aircraft window is developed. The proposed model is efficiently applied for a set of window models to perform extensive theoretical parametric studies. The studied window configurations generally simulate the passenger window designs of modern aircraft classes which have an exterior multi-Plexiglas pane, an interior single acrylic glass pane and a dimmable glass ("smart" glass), all separated by thin air cavities. The sound transmission loss (STL) characteristics of three different models, triple-, quadruple- and quintuple-paned windows identical in size and surface density, are analyzed for improving the acoustic insulation performances. Typical results describing the influence of several system parameters, such as the thicknesses, number and spacing of the window panes, on the transmission loss are then investigated. In addition, a comparison study is carried out to evaluate the acoustic reduction capability of each window model. The STL results show that the higher frequencies sound transmission loss performance can be improved by increasing the number of window panels, however, the low frequency performance is decreased, particularly at the mass-spring resonances.

  17. Sound Absorbers

    NASA Astrophysics Data System (ADS)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  18. Enhanced awakening probability of repetitive impulse sounds.

    PubMed

    Vos, Joos; Houben, Mark M J

    2013-09-01

    In the present study relations between the level of impulse sounds and the observed proportion of behaviorally confirmed awakening reactions were determined. The sounds (shooting sounds, bangs produced by door slamming or by container transshipment, aircraft landings) were presented by means of loudspeakers in the bedrooms of 50 volunteers. The fragments for the impulse sounds consisted of single or multiple events. The sounds were presented during a 6-h period that started 75 min after the subjects wanted to sleep. In order to take account of habituation, each subject participated during 18 nights. At equal indoor A-weighted sound exposure levels, the proportion of awakening for the single impulse sounds was equal to that for the aircraft sounds. The proportion of awakening induced by the multiple impulse sounds, however, was significantly higher. For obtaining the same rate of awakening, the sound level of each of the successive impulses in a fragment had to be about 15-25 dB lower than the level of one single impulse. This level difference was largely independent of the degree of habituation. Various explanations for the enhanced awakening probability are discussed. PMID:23967934

  19. Examining INM Accuracy Using Empirical Sound Monitoring and Radar Data

    NASA Technical Reports Server (NTRS)

    Miller, Nicholas P.; Anderson, Grant S.; Horonjeff, Richard D.; Kimura, Sebastian; Miller, Jonathan S.; Senzig, David A.; Thompson, Richard H.; Shepherd, Kevin P. (Technical Monitor)

    2000-01-01

    Aircraft noise measurements were made using noise monitoring systems at Denver International and Minneapolis St. Paul Airports. Measured sound exposure levels for a large number of operations of a wide range of aircraft types were compared with predictions using the FAA's Integrated Noise Model. In general it was observed that measured levels exceeded the predicted levels by a significant margin. These differences varied according to the type of aircraft and also depended on the distance from the aircraft. Many of the assumptions which affect the predicted sound levels were examined but none were able to fully explain the observed differences.

  20. Fire tests for airplane interior materials

    NASA Technical Reports Server (NTRS)

    Tustin, E. A.

    1980-01-01

    Large scale, simulated fire tests of aircraft interior materials were carried out in salvaged airliner fuselage. Two "design" fire sources were selected: Jet A fuel ignited in fuselage midsection and trash bag fire. Comparison with six established laboratory fire tests show that some laboratory tests can rank materials according to heat and smoke production, but existing tests do not characterize toxic gas emissions accurately. Report includes test parameters and test details.

  1. Technologies for Aircraft Noise Reduction

    NASA Technical Reports Server (NTRS)

    Huff, Dennis L.

    2006-01-01

    Technologies for aircraft noise reduction have been developed by NASA over the past 15 years through the Advanced Subsonic Technology (AST) Noise Reduction Program and the Quiet Aircraft Technology (QAT) project. This presentation summarizes highlights from these programs and anticipated noise reduction benefits for communities surrounding airports. Historical progress in noise reduction and technologies available for future aircraft/engine development are identified. Technologies address aircraft/engine components including fans, exhaust nozzles, landing gear, and flap systems. New "chevron" nozzles have been developed and implemented on several aircraft in production today that provide significant jet noise reduction. New engines using Ultra-High Bypass (UHB) ratios are projected to provide about 10 EPNdB (Effective Perceived Noise Level in decibels) engine noise reduction relative to the average fleet that was flying in 1997. Audio files are embedded in the presentation that estimate the sound levels for a 35,000 pound thrust engine for takeoff and approach power conditions. The predictions are based on actual model scale data that was obtained by NASA. Finally, conceptual pictures are shown that look toward future aircraft/propulsion systems that might be used to obtain further noise reduction.

  2. Radiometric sounding system

    SciTech Connect

    Whiteman, C.D.; Anderson, G.A.; Alzheimer, J.M.; Shaw, W.J.

    1995-04-01

    Vertical profiles of solar and terrestrial radiative fluxes are key research needs for global climate change research. These fluxes are expected to change as radiatively active trace gases are emitted to the earth`s atmosphere as a consequence of energy production and industrial and other human activities. Models suggest that changes in the concentration of such gases will lead to radiative flux divergences that will produce global warming of the earth`s atmosphere. Direct measurements of the vertical variation of solar and terrestrial radiative fluxes that lead to these flux divergences have been largely unavailable because of the expense of making such measurements from airplanes. These measurements are needed to improve existing atmospheric radiative transfer models, especially under the cloudy conditions where the models have not been adequately tested. A tethered-balloon-borne Radiometric Sounding System has been developed at Pacific Northwest Laboratory to provide an inexpensive means of making routine vertical soundings of radiative fluxes in the earth`s atmospheric boundary layer to altitudes up to 1500 m above ground level. Such vertical soundings would supplement measurements being made from aircraft and towers. The key technical challenge in the design of the Radiometric Sounding System is to develop a means of keeping the radiometers horizontal while the balloon ascends and descends in a turbulent atmospheric environment. This problem has been addressed by stabilizing a triangular radiometer-carrying platform that is carried on the tetherline of a balloon sounding system. The platform, carried 30 m or more below the balloon to reduce the balloon`s effect on the radiometric measurements, is leveled by two automatic control loops that activate motors, gears and pulleys when the platform is off-level. The sensitivity of the automatic control loops to oscillatory motions of various frequencies and amplitudes can be adjusted using filters.

  3. Preliminary Assessment of the Interior Noise Environment in the Large Civil Tiltrotor (LCTR2)

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Cabell, Randolph H.

    2011-01-01

    The second-generation Large Civil Tiltrotor (LCTR2) serves as a representative vehicle under the NASA Fundamental Aeronautics Program (FAP) Subsonic Rotary Wing (SRW) project with a design goal to transport 90 passengers over a distance of 1800 km at a speed of 550 km/hr. The tiltrotor combines the vertical lift capability of a helicopter with the speed, altitude, and range of a turboprop airplane. The blade-passage frequency of the four-bladed rotor is as low as 6.9 Hz during cruise conditions. The resulting low-frequency acoustic excitation and its harmonics, combined with the anticipated use of lightweight composite and sandwich materials for the fuselage sidewall, may pose a challenge to achieving acceptable interior noise levels. The objective of the present study is to perform a preliminary assessment of the expected interior noise environment in the LCTR2 cabin. The approach includes a combination of semi-empirical, analytical, and statistical energy analysis methods. Because the LCTR2 is a notional vehicle, the prediction approach was also applied to the XV-15 tiltrotor and Bombardier Q400 turobprop aircraft to compare predictions with publicly available experimental data. Guidance for the expected interior noise levels in the LCTR2 was obtained by considering both the predicted exterior noise levels and the transmission loss of a basic fuselage sidewall consisting of a skin, porous layer and a trim panel. Structural and acoustic resonances are expected to coincide with low order harmonics of the blade passage frequency. The estimated sound pressure levels in the LCTR2 may not be acceptable when evaluated against known characteristics of human response to low frequency sound.

  4. Sound Guard

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Lubrication technology originally developed for a series of NASA satellites has produced a commercial product for protecting the sound fidelity of phonograph records. Called Sound Guard, the preservative is a spray-on fluid that deposits a microscopically thin protective coating which reduces friction and prevents the hard diamond stylus from wearing away the softer vinyl material of the disc. It is marketed by the Consumer Products Division of Ball Corporation, Muncie, Indiana. The lubricant technology on which Sound Guard is based originated with NASA's Orbiting Solar Observatory (OSO), an Earth-orbiting satellite designed and built by Ball Brothers Research Corporation, Boulder, Colorado, also a division of Ball Corporation. Ball Brothers engineers found a problem early in the OSO program: known lubricants were unsuitable for use on satellite moving parts that would be exposed to the vacuum of space for several months. So the company conducted research on the properties of materials needed for long life in space and developed new lubricants. They worked successfully on seven OSO flights and attracted considerable attention among other aerospace contractors. Ball Brothers now supplies its "Vac Kote" lubricants and coatings to both aerospace and non-aerospace industries and the company has produced several hundred variations of the original technology. Ball Corporation expanded its product line to include consumer products, of which Sound Guard is one of the most recent. In addition to protecting record grooves, Sound Guard's anti-static quality also retards particle accumulation on the stylus. During comparison study by a leading U.S. electronic laboratory, a record not treated by Sound Guard had to be cleaned after 50 plays and the stylus had collected a considerable number of small vinyl particles. The Sound Guard-treated disc was still clean after 100 plays, as was its stylus.

  5. Aircraft cybernetics

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The use of computers for aircraft control, flight simulation, and inertial navigation is explored. The man-machine relation problem in aviation is addressed. Simple and self-adapting autopilots are described and the assets and liabilities of digital navigation techniques are assessed.

  6. Interior intrusion detection systems

    SciTech Connect

    Rodriguez, J.R.; Matter, J.C. ); Dry, B. )

    1991-10-01

    The purpose of this NUREG is to present technical information that should be useful to NRC licensees in designing interior intrusion detection systems. Interior intrusion sensors are discussed according to their primary application: boundary-penetration detection, volumetric detection, and point protection. Information necessary for implementation of an effective interior intrusion detection system is presented, including principles of operation, performance characteristics and guidelines for design, procurement, installation, testing, and maintenance. A glossary of sensor data terms is included. 36 figs., 6 tabs.

  7. Interior, building 810, view to west from approximately midhangar. Area ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior, building 810, view to west from approximately mid-hangar. Area of photo encompasses approximately 1/4 of the interior space, with the KC-10 tanker aircraft and the figures beneath it giving an idea of scale, 90mm lens plus electronic flash fill lightening. - Travis Air Force Base, B-36 Hangar, Between Woodskill Avenue & Ellis, adjacent to Taxiway V & W, Fairfield, Solano County, CA

  8. Optically measuring interior cavities

    DOEpatents

    Stone, Gary Franklin

    2008-12-21

    A method of measuring the three-dimensional volume or perimeter shape of an interior cavity includes the steps of collecting a first optical slice of data that represents a partial volume or perimeter shape of the interior cavity, collecting additional optical slices of data that represents a partial volume or perimeter shape of the interior cavity, and combining the first optical slice of data and the additional optical slices of data to calculate of the three-dimensional volume or perimeter shape of the interior cavity.

  9. Optically measuring interior cavities

    DOEpatents

    Stone, Gary Franklin

    2009-11-03

    A method of measuring the three-dimensional volume or perimeter shape of an interior cavity includes the steps of collecting a first optical slice of data that represents a partial volume or perimeter shape of the interior cavity, collecting additional optical slices of data that represents a partial volume or perimeter shape of the interior cavity, and combining the first optical slice of data and the additional optical slices of data to calculate of the three-dimensional volume or perimeter shape of the interior cavity.

  10. Advanced Study for Active Noise Control in Aircraft (ASANCA)

    NASA Technical Reports Server (NTRS)

    Borchers, Ingo U.; Emborg, Urban; Sollo, Antonio; Waterman, Elly H.; Paillard, Jacques; Larsen, Peter N.; Venet, Gerard; Goeransson, Peter; Martin, Vincent

    1992-01-01

    Aircraft interior noise and vibration measurements are included in this paper from ground and flight tests. In addition, related initial noise calculations with and without active noise control are conducted. The results obtained to date indicate that active noise control may be an effective means for reducing the critical low frequency aircraft noise.

  11. 36 CFR 2.17 - Aircraft and air delivery.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Aircraft and air delivery. 2.17 Section 2.17 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.17 Aircraft and air delivery. (a) The following...

  12. 75 FR 1404 - Denali National Park and Preserve Aircraft Overflights Advisory Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... National Park Service Denali National Park and Preserve Aircraft Overflights Advisory Council AGENCY: National Park Service, Interior. ACTION: Notice of renewal. SUMMARY: The Secretary of the Interior is giving notice of the renewal of the Denali National Park and Preserve Aircraft Overflights...

  13. Energy absorption studied to reduce aircraft crash forces

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The NASA/FAA aircraft safety reseach programs for general aviation aircraft are discussed. Energy absorption of aircraft subflooring and redesign of interior flooring are being studied. The testing of energy absorbing configurations is described. The three NASA advanced concepts performed at neary the maximum possible amount of energy absorption, and one of two minimum modifications concepts performed well. Planned full scale tests are described. Airplane seat concepts are being considered.

  14. Geophysical Sounding

    NASA Astrophysics Data System (ADS)

    Blake, E.

    1998-01-01

    Of the many geophysical remote-sensing techniques available today, a few are suitable for the water ice-rich, layered material expected at the north martian ice cap. Radio echo sounding has been used for several decades to determine ice thickness and internal structure. Selection of operating frequency is a tradeoff between signal attenuation (which typically increases with frequency and ice temperature) and resolution (which is proportional to wavelength). Antenna configuration and size will be additional considerations for a mission to Mars. Several configurations for ice-penetrating radar systems are discussed: these include orbiter-borne sounders, sounding antennas trailed by balloons and penetrators, and lander-borne systems. Lander-borne systems could include short-wave systems capable of resolving fine structure and layering in the upper meters beneath the lander. Spread-spectrum and deconvolution techniques can be used to increase the depth capability of a radar system. If soundings over several locations are available (e.g., with balloons, rovers, or panning short-wave systems), then it will be easier to resolve internal layering, variations in basal reflection coefficient (from which material properties may be inferred), and the geometry of nonhorizontal features. Sonic sounding has a long history in oil and gas exploration. It is, however, unlikely that large explosive charges, or even swept-frequency techniques such as Vibroseis, would be suitable for a Polar lander -- these systems are capable of penetrating several kilometers of material at frequencies of 10-200 Hz, but the energy required to generate the sound waves is large and potentially destructive. The use of audio-frequency and ultrasonic sound generated by piezoelectric crystals is discussed as a possible method to explore layering and fine features in the upper meters of the ice cap. Appropriate choice of transducer(s) will permit operation over a range of fixed or modulated frequencies

  15. Effects of changed aircraft noise exposure on experiential qualities of outdoor recreational areas.

    PubMed

    Krog, Norun Hjertager; Engdahl, Bo; Tambs, Kristian

    2010-10-01

    The literature indicates that sound and visual stimuli interact in the impression of landscapes. This paper examines the relationship between annoyance with sound from aircraft and annoyance with other area problems (e.g., careless bicycle riding, crowding, etc.), and how changes in noise exposure influence the perceived overall recreational quality of outdoor recreational areas. A panel study (telephone interviews) conducted before and after the relocation of Norway's main airport in 1998 examined effects of decreased or increased noise exposure in nearby recreational areas (n = 591/455). Sound from aircraft annoyed the largest proportion of recreationists, except near the old airport after the change. The decrease in annoyance with sound from aircraft was accompanied by significant decreases in annoyance with most of the other area problems. Near the new airport annoyance with most factors beside sound from aircraft increased slightly, but not significantly. A relationship between aircraft noise annoyance and perceived overall recreational quality of the areas was found.

  16. 14 CFR 91.205 - Powered civil aircraft with standard category U.S. airworthiness certificates: Instrument and...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC... paragraph (c) of this section; (2) Night vision goggles; (3) Interior and exterior aircraft lighting...

  17. 6. LOOKING WESTSOUTHWEST INTO THE INTERIOR OF THE AR8 STORAGE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. LOOKING WEST-SOUTHWEST INTO THE INTERIOR OF THE AR-8 STORAGE BAY. - Edwards Air Force Base, South Base, Rammed Earth Aircraft Dispersal Revetments, Western Shore of Rogers Dry Lake, Boron, Kern County, CA

  18. On INM's Use of Corrected Net Thrust for the Prediction of Jet Aircraft Noise

    NASA Technical Reports Server (NTRS)

    McAninch, Gerry L.; Shepherd, Kevin P.

    2011-01-01

    The Federal Aviation Administration s (FAA) Integrated Noise Model (INM) employs a prediction methodology that relies on corrected net thrust as the sole correlating parameter between aircraft and engine operating states and aircraft noise. Thus aircraft noise measured for one set of atmospheric and aircraft operating conditions is assumed to be applicable to all other conditions as long as the corrected net thrust remains constant. This hypothesis is investigated under two primary assumptions: (1) the sound field generated by the aircraft is dominated by jet noise, and (2) the sound field generated by the jet flow is adequately described by Lighthill s theory of noise generated by turbulence.

  19. Sound Solutions

    ERIC Educational Resources Information Center

    Starkman, Neal

    2007-01-01

    Poor classroom acoustics are impairing students' hearing and their ability to learn. However, technology has come up with a solution: tools that focus voices in a way that minimizes intrusive ambient noise and gets to the intended receiver--not merely amplifying the sound, but also clarifying and directing it. One provider of classroom audio…

  20. Sound Pollution-Another Urban Problem

    ERIC Educational Resources Information Center

    Breysse, Peter A.

    1970-01-01

    Suggests that sound pollution constitutes a severe problem to the urban dweller. Excessive exposure of humans to noise produces both physical and psychological manifestations. Suggests that control of industrial, aircraft, and community noise must be recognized and accepted as a major factor in urban planning and development. Bibliography. (LC)

  1. Effect of the wake flow on the soundproofing of aircraft structures

    NASA Astrophysics Data System (ADS)

    Generalov, A. V.

    The effect of the wake flow on the soundproofing of aircraft structures is calculated analytically for a single-layer structure for zero and nonzero Mach numbers. The results obtained indicate that the wake flow contributes to the sound insulation of aircraft structures. The greatest benefit from the standpoint of sound insulation is achieved when the powerplant is located in the tail section of the aircraft.

  2. Virtual Reality of Sound Generated from Vibrating Structures

    NASA Astrophysics Data System (ADS)

    KIM, S. J.; SONG, J. Y.

    2002-11-01

    The advancement of virtual reality (VR) technology in cyberspace is amazing, but its development is mainly concentrated on the visual part. In this paper, the development of VR technology to produce sound based on the exact physics is studied. Our main concern is on the sound generated from vibrating structures. This may be useful, for example, in apprehending sound field characteristics of an aircraft cabin in design stage. To calculate sound pressure from curved surface of a structure, a new integration scheme is developed in boundary element method. Several example problems are solved to confirm our integration scheme. The pressure distributions on a uniformly driven sphere and cylinders are computed and compared with analytic solutions, and radiation efficiency of a vibrating plate under one-dimensional flow is also calculated. Also, to realize sound through computer simulation, two concepts, "structure-oriented analysis" and "human-oriented analysis", are proposed. Using these concepts, virtual sound field of an aircraft cabin is created.

  3. Application of subharmonics for active sound design of electric vehicles.

    PubMed

    Gwak, Doo Young; Yoon, Kiseop; Seong, Yeolwan; Lee, Soogab

    2014-12-01

    The powertrain of electric vehicles generates an unfamiliar acoustical environment for customers. This paper seeks optimal interior sound for electric vehicles based on psychoacoustic knowledge and musical harmonic theory. The concept of inserting a virtual sound, which consists of the subharmonics of an existing high-frequency component, is suggested to improve sound quality. Subjective evaluation results indicate that the impression of interior sound can be enhanced in this manner. Increased appeal is achieved through two designed stimuli, which proves the effectiveness of the method proposed.

  4. Application of subharmonics for active sound design of electric vehicles.

    PubMed

    Gwak, Doo Young; Yoon, Kiseop; Seong, Yeolwan; Lee, Soogab

    2014-12-01

    The powertrain of electric vehicles generates an unfamiliar acoustical environment for customers. This paper seeks optimal interior sound for electric vehicles based on psychoacoustic knowledge and musical harmonic theory. The concept of inserting a virtual sound, which consists of the subharmonics of an existing high-frequency component, is suggested to improve sound quality. Subjective evaluation results indicate that the impression of interior sound can be enhanced in this manner. Increased appeal is achieved through two designed stimuli, which proves the effectiveness of the method proposed. PMID:25480088

  5. 36 CFR 13.1004 - Aircraft use.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Aircraft use. 13.1004 Section 13.1004 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR NATIONAL PARK SYSTEM UNITS IN ALASKA Special Regulations-Gates of the Arctic National Park and...

  6. Evaluation of Materials and Concepts for Aircraft Fire Protection

    NASA Technical Reports Server (NTRS)

    Anderson, R. A.; Price, J. O.; Mcclure, A. H.; Tustin, E. A.

    1976-01-01

    Woven fiberglass fluted-core simulated aircraft interior panels were flame tested and structurally evaluated against the Boeing 747 present baseline interior panels. The NASA-defined panels, though inferior on a strength-to-weight basis, showed better structural integrity after flame testing, due to the woven fiberglass structure.

  7. Interior, building 1205, view to southeast showing roof truss system, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior, building 1205, view to southeast showing roof truss system, sliding main doors, and roll up door at center to allow clearance for aircraft tail assembly, 90 mm lens plus electronic flash fill lighting. - Travis Air Force Base, Readiness Maintenance Hangar, W Street, Air Defense Command Readiness Area, Fairfield, Solano County, CA

  8. 8. Interior of cockpit showing pilot consoles and flight engineer ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Interior of cockpit showing pilot consoles and flight engineer seat with instrument panel. View to east. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  9. 7. Interior of cockpit showing pilot and copilot seats with ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Interior of cockpit showing pilot and co-pilot seats with console and overhead instrument panels. View to northeast. - Offutt Air Force Base, Looking Glass Airborne Command Post, Looking Glass Aircraft, On Operational Apron covering northeast half of Project Looking Glass Historic District, Bellevue, Sarpy County, NE

  10. INTERIOR OF WESTERN SECTION, SHOWING WALL OF COLD STORAGE ROOM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR OF WESTERN SECTION, SHOWING WALL OF COLD STORAGE ROOM (IN BAYS 32 TO 34) AND ROLLING DOORS AT WEST END, VIEW FACING SOUTH-SOUTHWEST. - Naval Air Station Barbers Point, Aircraft Storehouse, Between Midway & Card Streets at Enterprise Avenue intersection, Ewa, Honolulu County, HI

  11. Aircraft noise and quality of life around Frankfurt Airport.

    PubMed

    Schreckenberg, Dirk; Meis, Markus; Kahl, Cara; Peschel, Christin; Eikmann, Thomas

    2010-09-01

    In a survey of 2,312 residents living near Frankfurt Airport aircraft noise annoyance and disturbances as well as environmental (EQoL) and health-related quality of life (HQoL) were assessed and compared with data on exposure due to aircraft, road traffic, and railway noise. Results indicate higher noise annoyance than predicted from general exposure-response curves. Beside aircraft sound levels source-related attitudes were associated with reactions to aircraft noise. Furthermore, aircraft noise affected EQoL in general, although to a much smaller extent. HQoL was associated with aircraft noise annoyance, noise sensitivity and partly with aircraft noise exposure, in particular in the subgroup of multimorbid residents. The results suggest a recursive relationship between noise and health, yet this cannot be tested in cross-sectional studies. Longitudinal studies would be recommendable to get more insight in the causal paths underlying the noise-health relationship.

  12. General Aviation Interior Noise. Part 1; Source/Path Identification

    NASA Technical Reports Server (NTRS)

    Unruh, James F.; Till, Paul D.; Palumbo, Daniel L. (Technical Monitor)

    2002-01-01

    There were two primary objectives of the research effort reported herein. The first objective was to identify and evaluate noise source/path identification technology applicable to single engine propeller driven aircraft that can be used to identify interior noise sources originating from structure-borne engine/propeller vibration, airborne propeller transmission, airborne engine exhaust noise, and engine case radiation. The approach taken to identify the contributions of each of these possible sources was first to conduct a Principal Component Analysis (PCA) of an in-flight noise and vibration database acquired on a Cessna Model 182E aircraft. The second objective was to develop and evaluate advanced technology for noise source ranking of interior panel groups such as the aircraft windshield, instrument panel, firewall, and door/window panels within the cabin of a single engine propeller driven aircraft. The technology employed was that of Acoustic Holography (AH). AH was applied to the test aircraft by acquiring a series of in-flight microphone array measurements within the aircraft cabin and correlating the measurements via PCA. The source contributions of the various panel groups leading to the array measurements were then synthesized by solving the inverse problem using the boundary element model.

  13. Studies in Interior Design

    ERIC Educational Resources Information Center

    Environ Planning Design, 1970

    1970-01-01

    Floor plans and photographs illustrate a description of the Samuel C. Williams Library at Stevens Institute of Technology, Hoboken, N.J. The unusual interior design allows students to take full advantage of the library's resources. (JW)

  14. 76. INTERIOR, FIRST FLOOR, WING 1200 WEST, INTERIOR DEPARTMENT MUSEUM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    76. INTERIOR, FIRST FLOOR, WING 1200 WEST, INTERIOR DEPARTMENT MUSEUM, LOBBY, BRONZE GRILL (4' x 5' negative; 8' x 10' print) - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC

  15. 77. INTERIOR, FIRST FLOOR, WING 1200 WEST, INTERIOR DEPARTMENT MUSEUM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    77. INTERIOR, FIRST FLOOR, WING 1200 WEST, INTERIOR DEPARTMENT MUSEUM, NATIONAL PARK SERVICE EXHIBIT - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC

  16. 78. INTERIOR, FIRST FLOOR, WING 1200 WEST, INTERIOR DEPARTMENT MUSEUM, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    78. INTERIOR, FIRST FLOOR, WING 1200 WEST, INTERIOR DEPARTMENT MUSEUM, MAIN AISLE, DETAIL OF LIGHT FIXTURE (4' x 5' negative; 8' x 10' print) - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC

  17. Educating with Aircraft Models

    ERIC Educational Resources Information Center

    Steele, Hobie

    1976-01-01

    Described is utilization of aircraft models, model aircraft clubs, and model aircraft magazines to promote student interest in aerospace education. The addresses for clubs and magazines are included. (SL)

  18. Jupiter: Atmospheric Sounding and Sensing of the Interior (JASSI)

    NASA Technical Reports Server (NTRS)

    Bolton, S. J.; Owen, T.; Gautier, D.; Gulkis, S.; Janssen, M.; Atreya, S.; Guillot, T.; Anderson, J.; Allison, M.; Lunine, J.

    2001-01-01

    The formation of the giant planets is one of the most fundamental questions in solar system exploration. Understanding the process that led to the creation of Jupiter is essential to understanding the nature of the primordial solar nebula, and the formation of our solar system and others currently being discovered. Data from Galileo combined with HST and Ulysses results validated our basic understanding of Jupiter as a giant planet whose gaseous envelope consists of solar nebula gas enriched in elements heavier than He by in falling icy planetesimals. However, the current Galileo Probe data set does not itself allow firm conclusions about the original planetesimal composition or the process of giant planet formation - we crucially need the O and N abundances that Galileo could not determine. We propose a new and simple concept capable of determining these abundance in Jupiter plus substantial gravity science. Additional information is contained in the original extended abstract.

  19. Assessment of burning characteristics of aircraft interior materials

    NASA Technical Reports Server (NTRS)

    Grand, A. F.; Valys, A. J.

    1981-01-01

    The performance of a series of seat cushion design constructions was compared based on their heat and smoke release characteristics. Tests were conducted in a room size calorimeter instrumented for measuring weight loss, rate of heat release, smoke and volatile decomposition products and the cumulative energy release. Baseline data were obtained from burn tests conducted on commercial airline salvage sets as a comparison with more advanced seat designs. A toxicological assessment of smoke and fire gases involved the exposure of test animals and their biological responses ascertained. Relative toxicological hazards of the combustion gases are discussed based on the animal response studies and the analysis of the combustion gases.

  20. Aircraft interior noise reduction by alternate resonance tuning

    NASA Technical Reports Server (NTRS)

    Bliss, Donald B.; Gottwald, James A.; Gustaveson, Mark B.; Burton, James R., III

    1988-01-01

    Model problem development and analysis continues with the Alternate Resonance Tuning (ART) concept. The various topics described are presently at different stages of completion: investigation of the effectiveness of the ART concept under an external propagating pressure field associated with propeller passage by the fuselage; analysis of ART performance with a double panel wall mounted in a flexible frame model; development of a data fitting scheme using a branch analysis with a Newton-Raphson scheme in multiple dimensions to determine values of critical parameters in the actual experimental apparatus; and investigation of the ART effect with real panels as opposed to the spring-mass-damper systems currently used in much of the theory.

  1. Residents' annoyance responses to aircraft noise events

    NASA Technical Reports Server (NTRS)

    Dempsey, T. K.; Stephens, D. G.; Fields, J. M.; Shepherd, K. P.

    1983-01-01

    In a study conducted in the vicinity of Salt Lake City International Airport, community residents reported their annoyance with individual aircraft flyovers during rating sessions conducted in their homes. Annoyance ratings were obtained at different times of the day. Aircraft noise levels were measured, and other characteristics of the aircraft were noted by trained observers. Metrics commonly used for assessing aircraft noise were compared, but none performed significantly better than A-weighted sound pressure level. A significant difference was found between the ratings of commercial jet aircraft and general aviation propeller aircraft, with the latter being judged less annoying. After the effects of noise level were accounted for, no significant differences were found between the ratings of landings and takeoffs. Aircraft noise annoyance reactions are stronger in lowered ambient noise conditions. This is consistent with the theory that reduced nighttime and evening ambient levels could create different reactions at different times of day. After controlling for ambient noise in a multiple regression analysis, no significant differences were found between the ratings of single events obtained during the three time periods: morning, afternoon, and evenings.

  2. Chasing Sounds

    PubMed Central

    Neiworth, Julie J

    2012-01-01

    Prior work with Wright and others demonstrated that rhesus monkeys recognized the relative relationships of notes in common melodies. As an extension of tests of pattern similarities, tamarins were habituated to 3-sound unit patterns in an AAB or ABB form that were human phonemes, piano notes, or monkey calls. The subjects were tested with novel sounds in each category constructed either to match the prior pattern or to violate the prior habituated pattern. The monkeys attended significantly more to a violation of their habituated pattern to a new pattern when human phonemes were used, and there was a trend difference in attention toward pattern violations with melodies. Monkey call patterns generated a variety of behavioral responses, were less likely to show habituation, and did not generate a strong attention reaction to changes in the patterns. Monkeys can extract abstract rules and patterns from auditory stimuli but the stimuli, by their nature, may generate competing responses which block processing of abstract regularities. PMID:23219981

  3. Active sound attenuation across a double wall structure

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Shepherd, Kevin P.

    1991-01-01

    The possibility of achieving significant local and global sound attenuation across a flat double wall is demonstrated. It is also shown that sound can be prevented from entering the interior of a cabinlike environment. The approach used is unlike established active noise control techniques.

  4. 12. VIEW LOOKING WEST OF INTERIOR OF SCREEN HOUSE OVER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW LOOKING WEST OF INTERIOR OF SCREEN HOUSE OVER BRACKISH COOLING WATER INTAKE FLUME. PARTIALLY RAISED SCREEN IS SHOWN AT LOWER LEFT OF PHOTOGRAPH. THE REMAINS OF A COAL CRUSHER AND ELEVATOR STRUCTURE ARE SHOWN AT THE LEFT TOP BACKGROUND OF THE PHOTOGRAPH. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  5. 16. Interior view on first floor in 1904 middle section, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Interior view on first floor in 1904 middle section, east side, showing various machinery, including Post Lathe (Bull Lathe) with Large wheel and smaller lathe on left. Camera pointed S on east side building. See photos WA-116-A-17 through WA-116-A-20. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  6. 11. Interior view of first floor of 1922 north section, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Interior view of first floor of 1922 north section, showing east wall and windows at far north end of building. Camera pointed E. Rear of building is partially visible on far left. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  7. 24. Interior view of third floor attic of 1896 south ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    24. Interior view of third floor attic of 1896 south section of building. Note steel truss supports and wooden roof. Top floor round window in seen from outside in photo WA-116-A-2. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  8. 12. Interior view of first floor aisle in 1922 north ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. Interior view of first floor aisle in 1922 north section. Camera is pointed south from rear of building. Post at far left is also seen on right in photo WA-116-A-11. - Puget Sound Naval Shipyard, Pattern Shop, Farragut Avenue, Bremerton, Kitsap County, WA

  9. Aircraft Electric Secondary Power

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Technologies resulted to aircraft power systems and aircraft in which all secondary power is supplied electrically are discussed. A high-voltage dc power generating system for fighter aircraft, permanent magnet motors and generators for aircraft, lightweight transformers, and the installation of electric generators on turbine engines are among the topics discussed.

  10. World commercial aircraft accidents

    SciTech Connect

    Kimura, C.Y.

    1993-01-01

    This report is a compilation of all accidents world-wide involving aircraft in commercial service which resulted in the loss of the airframe or one or more fatality, or both. This information has been gathered in order to present a complete inventory of commercial aircraft accidents. Events involving military action, sabotage, terrorist bombings, hijackings, suicides, and industrial ground accidents are included within this list. Included are: accidents involving world commercial jet aircraft, world commercial turboprop aircraft, world commercial pistonprop aircraft with four or more engines and world commercial pistonprop aircraft with two or three engines from 1946 to 1992. Each accident is presented with information in the following categories: date of the accident, airline and its flight numbers, type of flight, type of aircraft, aircraft registration number, construction number/manufacturers serial number, aircraft damage, accident flight phase, accident location, number of fatalities, number of occupants, cause, remarks, or description (brief) of the accident, and finally references used. The sixth chapter presents a summary of the world commercial aircraft accidents by major aircraft class (e.g. jet, turboprop, and pistonprop) and by flight phase. The seventh chapter presents several special studies including a list of world commercial aircraft accidents for all aircraft types with 100 or more fatalities in order of decreasing number of fatalities, a list of collision accidents involving commercial aircrafts, and a list of world commercial aircraft accidents for all aircraft types involving military action, sabotage, terrorist bombings, and hijackings.

  11. Comparison ofdvanced turboprop interior noise control ground and flight test data

    NASA Technical Reports Server (NTRS)

    Simpson, Myles A.; Tran, Boi N.

    1992-01-01

    Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight sts with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

  12. Trends in Interior Environments.

    ERIC Educational Resources Information Center

    Hovey, Robyn

    2000-01-01

    Examines how an understanding of interior design trends can help planners address their present and future furniture needs. Examines how new types of construction and their associated concerns are requiring new approaches from the facility designers and manufacturers of product solutions. (GR)

  13. Interiors That Stand Out

    ERIC Educational Resources Information Center

    American School & University, 2008

    2008-01-01

    "It's what's on the inside that counts"--at least when it comes to "American School & University's" (AS&U's) annual Educational Interiors Showcase competition. Each May, "AS&U" assembles at its Overland Park, Kansas headquarters a jury made up of education and architectural professionals from across the country to pore over an array of exceptional…

  14. Interior of the Earth

    NASA Technical Reports Server (NTRS)

    Phillips, R. J.

    1984-01-01

    Basic questions regarding the interior of the Earth in the 1990's are discussed. Research problems in the areas of plate tectonics, the Earth mantle the Earth core, and continental structure are discussed. Observational requirements of the GRAVSAT satellite mission are discussed.

  15. Interior structure of Uranus

    SciTech Connect

    Hubbard, W.B.

    1984-10-01

    Key measurements are discussed which are diagnostic of Uranus interior structure and evolutionary history, and reviews their present status. Typical interior models have chondritic cores, but have the bulk of their mass in an envelope consisting of ice component, principally H2O. The total amount of free H2 in the planet cannot exceed approximately 1 to 2 earth masses. Measurements of the gravitational moments of Uranus are beginning to be accurate enough to constrain models, but are limited in utility by uncertainty in the rotation period. Discussed is evidence that the outermost planetary layers have a gravitationally significant quantity of denser material (ice component) in addition to H2 and He. The He/H ratio and the deuterium abundance in the atmosphere may be diagnostic of the planet's previous evolutionary history. It is argued that the planet's interior is likely to now be at a temperature approximately 10(3) deg K. Uranus interior with Neptune's in a number of ways, considering heat flow, degree of internal differentiation, and possible magnetic field.

  16. Planetary Interiors and Geodesy

    NASA Astrophysics Data System (ADS)

    Dehant, Veronique

    2013-04-01

    Lander and orbiter, even rover at the surface of planets or moons of the solar system help in determining their interior properties. First of all orbiters feel the gravity of the planet and its change. In particular, the tidal mass redistribution induces changes in the acceleration of the spacecraft orbiting around a planet. The Love number k2 has been determined for Venus, Mars and the Earth, as well as for Titan and will be deduced for instance for Mercury (MESSENGER and BepiColombo missions) and for the Galilean satellite from new missions such as JUICE (Jupiter Icy satellite Explorer). The properties of the interior can also be determined from the observation of the rotation of the celestial body. Radar observation from the Earth ground stations of Mercury has allowed Margo et al. (2012, JGR) to determine the moments of inertia of Mercury with an unprecedented accuracy. Rovers such as the MERs (Mars Exploration Rovers) allow as well to obtain the precession and nutation of Mars from which the moments of inertia of the planet and its core can be deduced. Future missions such as InSIGHT (Interior exploration using Seismic Investigations, Geodesy, and Heat Transport) will further help in the determination of Mars interior and evolution.

  17. Understanding Jupiter's interior

    NASA Astrophysics Data System (ADS)

    Militzer, Burkhard; Soubiran, François; Wahl, Sean M.; Hubbard, William

    2016-09-01

    This article provides an overview of how models of giant planet interiors are constructed. We review measurements from past space missions that provided constraints for the interior structure of Jupiter. We discuss typical three-layer interior models that consist of a dense central core and an inner metallic and an outer molecular hydrogen-helium layer. These models rely heavily on experiments, analytical theory, and first-principles computer simulations of hydrogen and helium to understand their behavior up to the extreme pressures ˜10 Mbar and temperatures ˜10,000 K. We review the various equations of state used in Jupiter models and compare them with shock wave experiments. We discuss the possibility that helium rain, core erosion, and double diffusive convection have affected the structure and evolution of giant planets. In July 2016 the Juno spacecraft entered orbit around Jupiter, promising high-precision measurements of the gravitational field that will allow us to test our understanding of gas giant interiors better than ever before.

  18. Interior Design in Architectural Education

    ERIC Educational Resources Information Center

    Gurel, Meltem O.; Potthoff, Joy K.

    2006-01-01

    The domain of interiors constitutes a point of tension between practicing architects and interior designers. Design of interior spaces is a significant part of architectural profession. Yet, to what extent does architectural education keep pace with changing demands in rendering topics that are identified as pertinent to the design of interiors?…

  19. Methods of sound simulation and applications in flight simulators

    NASA Technical Reports Server (NTRS)

    Gaertner, K. P.

    1980-01-01

    An overview of methods for electronically synthesizing sounds is presented. A given amount of hardware and computer capacity places an upper limit on the degree and fidelity of realism of sound simulation which is attainable. Good sound realism for aircraft simulators can be especially expensive because of the complexity of flight sounds and their changing patterns through time. Nevertheless, the flight simulator developed at the Research Institute for Human Engineering, West Germany, shows that it is possible to design an inexpensive sound simulator with the required acoustic properties using analog computer elements. The characteristics of the sub-sound elements produced by this sound simulator for take-off, cruise and approach are discussed.

  20. Method of sound synthesis

    DOEpatents

    Miner, Nadine E.; Caudell, Thomas P.

    2004-06-08

    A sound synthesis method for modeling and synthesizing dynamic, parameterized sounds. The sound synthesis method yields perceptually convincing sounds and provides flexibility through model parameterization. By manipulating model parameters, a variety of related, but perceptually different sounds can be generated. The result is subtle changes in sounds, in addition to synthesis of a variety of sounds, all from a small set of models. The sound models can change dynamically according to changes in the simulation environment. The method is applicable to both stochastic (impulse-based) and non-stochastic (pitched) sounds.

  1. Aircraft cabin noise prediction and optimization

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.

    1985-01-01

    Theoretical and experimental studies were conducted to determine the noise transmission into acoustic enclosures ranging from simple rectangular box models to full scale light aircraft in flight. The structural models include simple, stiffened, curved stiffened, and orthotropic panels and double wall windows. The theoretical solutions were obtained by model analysis. Transfer matrix and finite element procedures were utilized. Good agreement between theory and experiment has been achieved. An efficient acoustic add-on treatment was developed for interior noise control in a twin engine light aircraft.

  2. Interior of Callisto

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Cutaway view of the possible internal structure of Callisto. The surface of the satellite is a mosaic of images obtained in 1979 by NASA's Voyager spacecraft. The interior characteristics are inferred from gravity field and magnetic field measurements by NASA's Galileo spacecraft. Callisto's radius is 2403 km, larger than our Moon's radius. Callisto's interior is shown as a relatively uniform mixture of comparable amounts of ice and rock. The surface layer of Callisto is shown as white to indicate that it may differ from the underlying ice/rock layer in a variety of ways including, for example, the percentage of rock it contains.

    The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  3. Modeling of interior explosions

    NASA Astrophysics Data System (ADS)

    Zakharova, Y. V.; Fedorova, N. N.; Fedorov, A. V.

    2016-10-01

    The results of numerical simulation of an interior explosion are presented. The main purpose of the work is an investigation of shock-wave structure caused by explosion and estimation of pressure level on building walls. The numerical simulation was carried out by means of ANSYS AUTODYN software at normal atmospheric conditions with different mass of charge and internal geometry of room. The effect of mass charge and presence of vent area were shown. The calculation results are compared with published experimental data.

  4. Annoyance caused by aircraft en route noise

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.

    1992-01-01

    A laboratory experiment was conducted to quantify the annoyance response of people on the ground to enroute noise generated by aircraft at cruise conditions. The en route noises were ground level recordings of eight advanced turboprop aircraft flyovers and six conventional turbofan flyovers. The eight advanced turboprop enroute noises represented the NASA Propfan Test Assessment aircraft operating at different combinations of altitude, aircraft Mach number, and propeller tip speed. The conventional turbofan en route noises represented six different commercial airliners. The overall durations of the en route noises varied from approximately 40 to 160 sec. In the experiment, 32 subjects judged the annoyance of the en route noises as well as recordings of the takeoff and landing noises of each of 5 conventional turboprop and 5 conventional turbofan aircraft. Each of the noises was presented at three sound pressure levels to the subjects in an anechoic listening room. Analysis of the judgments found small differences in annoyance between three combinations of aircraft type and operation. Current tone and corrections did not significantly improve en route annoyance prediction. The optimum duration-correction magnitude for en route noise was approximately 1 dB per doubling of effective duration.

  5. Laboratory tests on an aircraft fuselage to determine the insertion loss of various acoustic add-on treatments

    NASA Technical Reports Server (NTRS)

    Heitman, K. E.; Mixson, J. S.

    1984-01-01

    This paper describes a laboratory study of add-on acoustic treatments for a propeller-driven light aircraft fuselage. The treatments included: no treatment (i.e., baseline fuselage); a production-type double-wall interior; and various amounts of high density fiberglass added to the baseline fuselage. The sound source was a pneumatic-driver with attached exponential horn, supplied with a broadband signal. Data were acquired at the approximate head positions of the six passenger seats. The results were analyzed on space-averaged narrowband, one-third octave band and overall insertion loss basis. In addition, insertion loss results for the different configurations at specific frequencies representing propeller tone spectra are presented. The propeller tone data includes not only the space-averaged insertion loss, but also the variation of insertion loss at these particular frequencies across the six microphone positions.

  6. Modeling Programs Increase Aircraft Design Safety

    NASA Technical Reports Server (NTRS)

    2012-01-01

    Flutter may sound like a benign word when associated with a flag in a breeze, a butterfly, or seaweed in an ocean current. When used in the context of aerodynamics, however, it describes a highly dangerous, potentially deadly condition. Consider the case of the Lockheed L-188 Electra Turboprop, an airliner that first took to the skies in 1957. Two years later, an Electra plummeted to the ground en route from Houston to Dallas. Within another year, a second Electra crashed. In both cases, all crew and passengers died. Lockheed engineers were at a loss as to why the planes wings were tearing off in midair. For an answer, the company turned to NASA s Transonic Dynamics Tunnel (TDT) at Langley Research Center. At the time, the newly renovated wind tunnel offered engineers the capability of testing aeroelastic qualities in aircraft flying at transonic speeds near or just below the speed of sound. (Aeroelasticity is the interaction between aerodynamic forces and the structural dynamics of an aircraft or other structure.) Through round-the-clock testing in the TDT, NASA and industry researchers discovered the cause: flutter. Flutter occurs when aerodynamic forces acting on a wing cause it to vibrate. As the aircraft moves faster, certain conditions can cause that vibration to multiply and feed off itself, building to greater amplitudes until the flutter causes severe damage or even the destruction of the aircraft. Flutter can impact other structures as well. Famous film footage of the Tacoma Narrows Bridge in Washington in 1940 shows the main span of the bridge collapsing after strong winds generated powerful flutter forces. In the Electra s case, faulty engine mounts allowed a type of flutter known as whirl flutter, generated by the spinning propellers, to transfer to the wings, causing them to vibrate violently enough to tear off. Thanks to the NASA testing, Lockheed was able to correct the Electra s design flaws that led to the flutter conditions and return the

  7. INTERIOR OF AIRLOCK FROM INTERIOR OF ALTITUDE CHAMBER R, FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR OF AIRLOCK FROM INTERIOR OF ALTITUDE CHAMBER R, FACING NORTHWEST - Cape Canaveral Air Force Station, Launch Complex 39, Altitude Chambers, First Street, between Avenue D and Avenue E, Cape Canaveral, Brevard County, FL

  8. 28. Interior view of telegrapher's bay, east wall, showing interior ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    28. Interior view of telegrapher's bay, east wall, showing interior finishes, framing, and furring over stonework - Bend Railroad Depot, 1160 Northeast Divion Street (At foot of Kearny Street), Bend, Deschutes County, OR

  9. 49. INTERIOR OF GILLEY ROOM: Interior view towards southeast of ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    49. INTERIOR OF GILLEY ROOM: Interior view towards southeast of the Gilley Room on the second floor of the powerhouse and ear barn. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  10. 3. INTERIOR VIEW OF PARTITIONS IN DRESSING ROOM; INTERIOR HALLWAY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. INTERIOR VIEW OF PARTITIONS IN DRESSING ROOM; INTERIOR HALLWAY FOR HYDROTHERAPY AREA AT RIGHT - Fort McCoy, Building No. T-1054, South side of South Tenth Avenue, Block 10, Sparta, Monroe County, WI

  11. Interior view of hallway showing interior door with transom on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior view of hallway showing interior door with transom on second floor, south wing; camera facing east. - Mare Island Naval Shipyard, Hospital Wards, Cedar Avenue, eat side between Fourteenth Avenue & Cossey Street, Vallejo, Solano County, CA

  12. Propulsion controlled aircraft computer

    NASA Technical Reports Server (NTRS)

    Cogan, Bruce R. (Inventor)

    2010-01-01

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

  13. Korotkoff Sounds.

    PubMed

    Shennan; Halligan

    1996-12-01

    We were interested in the historical perspective that Arabidze et al. [1] brought to the subject of Korotkoff's auscultatory method of measuring blood pressure. The original description by the Reverend Stephen Hales performing the very first blood pressure measurement (which was actually published in 1733) does not make reference to a column of water as the authors suggest [2]. Hales wrote: 'Then untying the Ligature on the Artery, the Blood rose in the Tube eight Feet three Inches.'. He goes on to state that, 'When it was at its full Height, it would rise and fall at and after each Pulse two, three, or four Inches, and sometimes it would fall twelve or fourteen Inches, and have there for a time the same vibrations up and down at and after each Pulse, as it had, when it was at its full Height; to which it would rise again, after forty or fifty Pulses'. We believe this fall of '12 or 14 in' to have been the first description of blood pressure variability, which has wrongly been attributed to respirations by subsequent authors [3]. The mare's pulse rate was described to be about 50 beats per minute; therefore an unanaesthetized horse would not be likely to have a respiration rate of once per minute. One further important point of error concerning the Korotkoff sounds is their reproducibility. We have demonstrated recently that phase IV is reproduced or identified poorly, both in adults and even during pregnancy, when it has been recommended to be used in favour of phase V. We have also demonstrated that phase I (systolic blood pressure) is perceived to be significantly clearer than phase V [4]. PMID:10226281

  14. 9. Credit PSR. Interior of Building 4305, looking east under ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Credit PSR. Interior of Building 4305, looking east under elliptical laminated wooden roof arches. Lower surfaces are ceilings of offices built within structure by the National Aeronautics and Space Adminstration (NASA) in 1977; cylindrical and rectangular ducts are for air conditioning. Suspended lighting fixtures date from building's original use as an aircraft hangar. - Edwards Air Force Base, North Base, Unicon Portable Hangar, First & C Streets, Boron, Kern County, CA

  15. Study of aircraft crashworthiness for fire protection

    NASA Technical Reports Server (NTRS)

    Cominsky, A.

    1981-01-01

    Impact-survivable postcrash fire accidents were surveyed. The data base developed includes foreign and domestic accidents involving airlines and jet aircraft. The emphasis was placed on domestic accidents, airlines, and jet aircraft due principally to availability of information. Only transport category aircraft in commercial service designed under FAR Part 25 were considered. A matrix was prepared to show the relationships between the accident characteristics and the fire fatalities. Typical postcrash fire scenaries were identified. Safety concepts were developed for three engineering categories: cabin interiors - cabin subsystems; power plant - engines and fuel systems; and structural mechanics - primary and secondary structures. The parameters identified for concept evaluation are cost, effectiveness, and societal concerns. Three concepts were selected for design definition and cost and effectiveness analysis: improved fire-resistant seat materials; anti-misting kerosene; and additional cabin emergency exits.

  16. Interior of the Moon

    NASA Technical Reports Server (NTRS)

    Weber, Renee C.

    2013-01-01

    A variety of geophysical measurements made from Earth, from spacecraft in orbit around the Moon, and by astronauts on the lunar surface allow us to probe beyond the lunar surface to learn about its interior. Similarly to the Earth, the Moon is thought to consist of a distinct crust, mantle, and core. The crust is globally asymmetric in thickness, the mantle is largely homogeneous, and the core is probably layered, with evidence for molten material. This chapter will review a range of methods used to infer the Moon's internal structure, and briefly discuss the implications for the Moon's formation and evolution.

  17. Simulation on a car interior aerodynamic noise control based on statistical energy analysis

    NASA Astrophysics Data System (ADS)

    Chen, Xin; Wang, Dengfeng; Ma, Zhengdong

    2012-09-01

    How to simulate interior aerodynamic noise accurately is an important question of a car interior noise reduction. The unsteady aerodynamic pressure on body surfaces is proved to be the key effect factor of car interior aerodynamic noise control in high frequency on high speed. In this paper, a detail statistical energy analysis (SEA) model is built. And the vibra-acoustic power inputs are loaded on the model for the valid result of car interior noise analysis. The model is the solid foundation for further optimization on car interior noise control. After the most sensitive subsystems for the power contribution to car interior noise are pointed by SEA comprehensive analysis, the sound pressure level of car interior aerodynamic noise can be reduced by improving their sound and damping characteristics. The further vehicle testing results show that it is available to improve the interior acoustic performance by using detailed SEA model, which comprised by more than 80 subsystems, with the unsteady aerodynamic pressure calculation on body surfaces and the materials improvement of sound/damping properties. It is able to acquire more than 2 dB reduction on the central frequency in the spectrum over 800 Hz. The proposed optimization method can be looked as a reference of car interior aerodynamic noise control by the detail SEA model integrated unsteady computational fluid dynamics (CFD) and sensitivity analysis of acoustic contribution.

  18. 11. Detail of the interior, looking through an interior doorway ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Detail of the interior, looking through an interior doorway toward the front and east window. Note: This photograph shows that the building had been converted to a residence following its use as a school. In addition, the hazardous condition of the structure's interior is evident. Two ceilings which are visible in the photograph, (the upper, probably original plastered ceiling, and a secondary, adapted ceiling) as well as ceiling joists in the southernmost rooms have collapsed. Because of the dangerous condition of the interior of the building, additional interior photography was not attempted at this time. - Perry Township School No. 3, Middle Mount Vernon & Eickhoff Roads, Evansville, Vanderburgh County, IN

  19. Making Sound Connections

    ERIC Educational Resources Information Center

    Deal, Walter F., III

    2007-01-01

    Sound provides and offers amazing insights into the world. Sound waves may be defined as mechanical energy that moves through air or other medium as a longitudinal wave and consists of pressure fluctuations. Humans and animals alike use sound as a means of communication and a tool for survival. Mammals, such as bats, use ultrasonic sound waves to…

  20. The Sound of Science

    ERIC Educational Resources Information Center

    Merwade, Venkatesh; Eichinger, David; Harriger, Bradley; Doherty, Erin; Habben, Ryan

    2014-01-01

    While the science of sound can be taught by explaining the concept of sound waves and vibrations, the authors of this article focused their efforts on creating a more engaging way to teach the science of sound--through engineering design. In this article they share the experience of teaching sound to third graders through an engineering challenge…

  1. Sounds Exaggerate Visual Shape

    ERIC Educational Resources Information Center

    Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

    2012-01-01

    While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

  2. The lunar interior

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.; Kovach, R. L.

    1972-01-01

    The compressional velocities are estimated for materials in the lunar interior and compared with lunar seismic results. The lower crust has velocities appropriate for basalts or anorthosites. The high velocities associated with the uppermost mantle imply high densities and a change in composition to a lighter assemblage at depths of the order of 120 km. Calcium and aluminum are probably important components of the upper mantle and are deficient in the lower mantle. Much of the moon may have accreted from material similar in composition to eucrites. The important mineral of the upper mantle is garnet; possible accessory minerals are kyanite, spinel, and rutile. If the seismic results stand up, the high velocity layer in the moon is more likely to be a high pressure form of anorthosite than eclogite, pyroxenite, or dunite. The thickness of the layer is of the order of 50 km. Cosmic abundances can be maintained if the lower mantle is ferromagnesium silicate with minimal amounts of calcium and aluminum. Achondrites such as eucrites and howardites have more of the required characteristics of the lunar interior than carbonaceous chondrites. A density inversion in the moon is a strong possibility.

  3. Unmanned aircraft systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Unmanned platforms have become increasingly more common in recent years for acquiring remotely sensed data. These aircraft are referred to as Unmanned Airborne Vehicles (UAV), Remotely Piloted Aircraft (RPA), Remotely Piloted Vehicles (RPV), or Unmanned Aircraft Systems (UAS), the official term used...

  4. X-1 aircraft in flight

    NASA Technical Reports Server (NTRS)

    1949-01-01

    The first of the rocket-powered research aircraft, the X-1 (originally designated the XS-1), was a bullet-shaped airplane that was built by the Bell Aircraft Company for the US Air Force and the National Advisory Committee for Aeronautics (NACA). The mission of the X-1 was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the 'sound barrier'. The first of the three X-1s was glide-tested at Pinecastle Field, FL, in early 1946. The first powered flight of the X-1 was made on Dec. 9, 1946, at Muroc Army Air Field (later redesignated Edwards Air Force Base) with Chalmers Goodlin, a Bell test pilot,at the controls. On Oct. 14, 1947, with USAF Captain Charles 'Chuck' Yeager as pilot, the aircraft flew faster than the speed of sound for the first time. Captain Yeager ignited the four-chambered XLR-11 rocket engines after being air-launched from under the bomb bay of a B-29 at 21,000 ft. The 6,000-lb thrust ethyl alcohol/liquid oxygen burning rockets, built by Reaction Motors, Inc., pushed him up to a speed of 700 mph in level flight. Captain Yeager was also the pilot when the X-1 reached its maximum speed of 957 mph. Another USAF pilot. Lt. Col. Frank Everest, Jr., was credited with taking the X-1 to its maximum altitude of 71,902 ft. Eighteen pilots in all flew the X-1s. The number three plane was destroyed in a fire before evermaking any powered flights. A single-place monoplane, the X-1 was 31 ft long, 10 ft high, and had a wingspan of 29 ft. It weighed 4,900 lb and carried 8,200 lb of fuel. It had a flush cockpit with a side entrance and no ejection seat. The following movie runs about 20 seconds, and shows several air-to-air views of X-1 Number 2 and its modified B-50 mothership. It begins with different angles of the X-1 in-flight while mated to the B-50's bomb bay, and ends showing the air-launch. The X-1 drops below the B-50, then accelerates away as the rockets ignite.

  5. A miniature robotic plane meteorological sounding system

    NASA Astrophysics Data System (ADS)

    Ma, Shuqing; Chen, Hongbin; Wang, Gai; Pan, Yi; Li, Qiang

    2004-12-01

    This article presents a miniature robotic plane meteorological sounding system (RPMSS), which consists of three major subsystems: a miniature robotic plane, an air-borne meteorological sounding and flight control system, and a ground-based system. Take-off and landing of the miniature aircraft are guided by radio control, and the flight of the robotic plane along a pre-designed trajectory is automatically piloted by an onboard navigation system. The observed meteorological data as well as all flight information are sent back in real time to the ground, then displayed and recorded by the ground-based computer. The ground-based subsystem can also transmit instructions to the air-borne control subsystem. Good system performance has been demonstrated by more than 300 hours of flight for atmospheric sounding.

  6. Aircraft landing gear systems

    NASA Technical Reports Server (NTRS)

    Tanner, John A. (Editor)

    1990-01-01

    Topics presented include the laboratory simulation of landing gear pitch-plane dynamics, a summary of recent aircraft/ground vehicle friction measurement tests, some recent aircraft tire thermal studies, and an evaluation of critical speeds in high-speed aircraft. Also presented are a review of NASA antiskid braking research, titanium matrix composite landing gear development, the current methods and perspective of aircraft flotation analysis, the flow rate and trajectory of water spray produced by an aircraft tire, and spin-up studies of the Space Shuttle Orbiter main gear tire.

  7. Understanding Io's Interior Structure from Electromagnetic Induction

    NASA Astrophysics Data System (ADS)

    Khurana, K. K.; Keszthelyi, L. P.; Jia, X.

    2015-12-01

    Io has long been suspected of a molten interior based on theoretical models of tidal dissipation in its interior. Extremely high temperature lava erupting on Io's surface would be consistent with an internal magma ocean but the highest reported eruption temperatures are questionable. Currently, the only direct evidence of a subsurface magma ocean in Io is the electromagnetic induction response observed by Galileo (Khurana et al. 2011, Science, 332, 1186). Using Jupiter's rotating magnetic field as a sounding signal, Khurana et al. (2011) provided evidence of a strong dipolar induction signature in Galileo's magnetometer data from four different flybys. They further showed that the signal is consistent with electromagnetic induction from large amounts of rock-melts in the asthenosphere of Io. Modeling showed that the induction response from a completely solid mantle model is inadequate to explain the magnetometer observations. However, a layer of asthenosphere >50 km in thickness with a melt fraction ≥20% is adequate to accurately match the observed magnetic field. Here we summarize our current knowledge of Io's interior from Galileo's induction measurements, and then outline a scheme to further infer properties of Io's interior, especially its internal temperature profile, by marrying the principles of thermodynamics with those of electromagnetism. In particular, we obtain guidance on stable mineral phases and their physical properties (such as density, melt state and electrical conductivity) from thermodynamic principles, whereas guidance on how the resulting internal conductivity profile affects the magnetic environment around Io is obtained from electromagnetic theory. We also explore how induction measurements can be obtained at multiple frequencies from a future mission and be used to constrain both the location and the thickness of the magma ocean. Finally, we explore the consequences of the global magma ocean on Io's physical properties such as the current

  8. 75 FR 65377 - Denali National Park and Preserve Aircraft Overflights Advisory Council; Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-22

    ... National Park Service Denali National Park and Preserve Aircraft Overflights Advisory Council; Meeting AGENCY: National Park Service, Interior. ACTION: Notice of meeting for the Denali National Park and Preserve Aircraft Overflights Advisory Council within the Alaska Region. SUMMARY: The National Park...

  9. Small transport aircraft technology

    NASA Technical Reports Server (NTRS)

    Williams, L. J.

    1983-01-01

    Information on commuter airline trends and aircraft developments is provided to upgrade the preliminary findings of a NASA-formed small transport aircraft technology (STAT) team, established to determine whether the agency's research and development programs could help commuter aircraft manufacturers solve technical problems related to passenger acceptance and use of 19- to 50-passenger aircraft. The results and conclusions of the full set of completed STAT studies are presented. These studies were performed by five airplane manufacturers, five engine manufacturers, and two propeller manufacturers. Those portions of NASA's overall aeronautics research and development programs which are applicable to commuter aircraft design are summarized. Areas of technology that might beneficially be expanded or initiated to aid the US commuter aircraft manufacturers in the evolution of improved aircraft for the market are suggested.

  10. Overview of Propulsion Systems for a Mars Aircraft

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Miller, Christopher J.; Reed, Brian D.; Kohout, Lisa L.; Loyselle, Patricia L.

    2001-01-01

    The capabilities and performance of an aircraft depends greatly on the ability of the propulsion system to provide thrust. Since the beginning of powered flight, performance has increased in step with advancements in aircraft propulsion systems. These advances in technology from combustion engines to jets and rockets have enabled aircraft to exploit our atmospheric environment and fly at altitudes near the Earth's surface to near orbit at speeds ranging from hovering to several times the speed of sound. One of the main advantages of our atmosphere for these propulsion systems is the availability of oxygen. Getting oxygen basically "free" from the atmosphere dramatically increases the performance and capabilities of an aircraft. This is one of the reasons our present-day aircraft can perform such a wide range of tasks. But this advantage is limited to Earth; if we want to fly an aircraft on another planetary body, such as Mars, we will either have to carry our own source of oxygen or use a propulsion system that does not require it. The Mars atmosphere, composed mainly of carbon dioxide, is very thin. Because of this low atmospheric density, an aircraft flying on Mars will most likely be operating, in aerodynamical terms, within a very low Reynolds number regime. Also, the speed of sound within the Martian environment is approximately 20 percent less than it is on Earth. The reduction in the speed of sound plays an important role in the aerodynamic performance of both the aircraft itself and the components of the propulsion system, such as the propeller. This low Reynolds number-high Mach number flight regime is a unique flight environment that is very rarely encountered here on Earth.

  11. Generating the sounds of silence

    SciTech Connect

    O'Conner, L.

    1994-04-01

    This article describes how digital-signal processors and repetitive- and random-noise algorithms have been linked to spur production of active control mufflers and headsets. Active and passive quieting systems are being developed to reduce noise from aircraft and other sources. High-level noise not only affects hearing, it can drive up blood pressure, disrupt sleep, and compromise the ability to work and learn. Although noise gets less attention than more conspicuous pollutants, public awareness over the unhealthy repercussions of loud noise is higher than ever. Recognizing public sensitivity over this topic, companies have begun producing active noise-control systems to reduce low-frequency sound--usually lower than 600 Hz--that often escapes established methods of passive quieting.

  12. Structural Acoustic Prediction and Interior Noise Control Technology

    NASA Technical Reports Server (NTRS)

    Mathur, G. P.; Chin, C. L.; Simpson, M. A.; Lee, J. T.; Palumbo, Daniel L. (Technical Monitor)

    2001-01-01

    This report documents the results of Task 14, "Structural Acoustic Prediction and Interior Noise Control Technology". The task was to evaluate the performance of tuned foam elements (termed Smart Foam) both analytically and experimentally. Results taken from a three-dimensional finite element model of an active, tuned foam element are presented. Measurements of sound absorption and sound transmission loss were taken using the model. These results agree well with published data. Experimental performance data were taken in Boeing's Interior Noise Test Facility where 12 smart foam elements were applied to a 757 sidewall. Several configurations were tested. Noise reductions of 5-10 dB were achieved over the 200-800 Hz bandwidth of the controller. Accelerometers mounted on the panel provided a good reference for the controller. Configurations with far-field error microphones outperformed near-field cases.

  13. Activities of the Institute of Sound and Vibration Research

    NASA Astrophysics Data System (ADS)

    Research in fluid dynamics, acoustics, automotive engineering, audiology, noise and vibration effects (on human beings), and structural response to noise and vibration was carried out. Aircraft noise, acoustics of flow duct systems and enclosures, acoustic modeling, sound propagation, and acoustic measurement techniques were studied. Auditory and vestibular functions and electrophysiology were investigated.

  14. The Insulation of Houses against Noise from Aircraft in Flight.

    ERIC Educational Resources Information Center

    Scholes, W. E.; Parkin, P. H.

    Three groups of traditional houses were insulated against aircraft noise by double glazing and installing sound attenuating ventilator units. For upper floor rooms of two story houses, overall insulations of 35-40 dB were obtainable, providing transmission through the roofs and down flues were also reduced. The noise levels caused by ventilator…

  15. 76 FR 30231 - Civil Supersonic Aircraft Panel Discussion

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ... the wave shape results in a softer sound that is quieter than the Concord sonic boom by a factor of 10... supersonic aircraft such as the Concorde in cruise produces a traditional jagged ``N-wave'' sonic boom pressure wave, resulting in a loud, jarring double boom on the ground as it passes by....

  16. Approach to interior design for passive direct gain solar homes

    SciTech Connect

    Kachadorian, C.C.

    1980-01-01

    In response to requests from buyers and builders of direct gain passive solar homes interior design criteria either specific to, or emphasized by, passive solar buildings are investigated. Problems of high sunlight penetration, secondary illumination, material selection, sound control and psychology are approached. Material deterioration, fading, glare, noise, and a sense of spacial confinement can be minimized, contributing to the appeal and saleability of passive solar homes.

  17. General Aviation Interior Noise. Part 2; In-Flight Source/Verification

    NASA Technical Reports Server (NTRS)

    Unruh, James F.; Till, Paul D.; Palumbo, Daniel L. (Technical Monitor)

    2002-01-01

    The technical approach made use of the Cessna Model 182E aircraft used in the previous effort as a test bed for noise control application. The present phase of the project reports on flight test results during application of various passive noise treatments in an attempt to verify the noise sources and paths for the aircraft. The data presented establishes the level of interior noise control that can be expected for various passive noise control applications within the aircraft cabin. Subsequent testing will address specific testing to demonstrate the technology available to meet a specified level of noise control by application of passive and/or active noise control technology.

  18. Solar interior structure and dynamics

    NASA Astrophysics Data System (ADS)

    Howe, Rachel

    2016-07-01

    Helioseismology allows us to probe the interior structure and dynamics of the Sun, and long-term observations allow us to follow their temporal variations. This review describes the important findings of recent years, covering the interior structure, the near-surface changes related to the solar cycle and possible deeper-seated variations, the interior rotation profile, and solar-cycle related changes in the zonal and meridional flows.

  19. The Sonic Altimeter for Aircraft

    NASA Technical Reports Server (NTRS)

    Draper, C S

    1937-01-01

    Discussed here are results already achieved with sonic altimeters in light of the theoretical possibilities of such instruments. From the information gained in this investigation, a procedure is outlined to determine whether or not a further development program is justified by the value of the sonic altimeter as an aircraft instrument. The information available in the literature is reviewed and condensed into a summary of sonic altimeter developments. Various methods of receiving the echo and timing the interval between the signal and the echo are considered. A theoretical discussion is given of sonic altimeter errors due to uncertainties in timing, variations in sound velocity, aircraft speed, location of the sending and receiving units, and inclinations of the flight path with respect to the ground surface. Plots are included which summarize the results in each case. An analysis is given of the effect of an inclined flight path on the frequency of the echo. A brief study of the acoustical phases of the sonic altimeter problem is carried through. The results of this analysis are used to predict approximately the maximum operating altitudes of a reasonably designed sonic altimeter under very good and very bad conditions. A final comparison is made between the estimated and experimental maximum operating altitudes which shows good agreement where quantitative information is available.

  20. Interior provinces in Alaska

    SciTech Connect

    Kirschner, C.E.; Fisher, M.A.; Bruns, T.R.; Stanley, R.G.

    1985-04-01

    Three types of interior provinces have been tested by exploratory drilling for their petroleum potential: three Tertiary nonmarine basins, two Jurassic and Cretaceous flysch and fold belts, and a Paleozoic thrust belt. Although the presence of hydrocarbons has not yet been demonstrated, the present data base is too limited to make a definitive assessment of hydrocarbon potential. During the 1983-84 field seasons, the authors acquired new gravity data and collected rock samples in and adjacent to the Yukon flats and the Nenana basins. These basins contain upper Tertiary, primarily nonmarine, sedimentary rock in extensional graben and half-graben complexes that are superimposed across preexisting terrane boundaries. The location and development of the basins result from strike-slip motion along the Tintina and Denali fault systems. Adjacent to the basins and within the fault systems are thick sections of nonmarine lower Tertiary coal-bearing rocks in deformed basin remnants. If these lower Tertiary rocks are present beneath the upper Tertiary fill, their greater depth and advanced maturation could enhance the hydrocarbon generative potential. Gravity modelling suggests the Tertiary fill is at least 3 km thick in the deeper parts of the basins and may be significantly thicker.

  1. An approach to aircraft seat comfort using interface pressure mapping.

    PubMed

    Ciaccia, Flavia Renata Dantas Alves Silva; Sznelwar, Laerte Idal

    2012-01-01

    The objective of the present study is to propose a method to dynamically evaluate discomfort of a passenger seat by measuring the interface pressure between the occupant and the seat during the performance of the most common activities of a typical flight. This article reports the results of resting and reading studies performed in a simulator that represents the interior of a commercial aircraft.

  2. Sound wave transmission (image)

    MedlinePlus

    When sounds waves reach the ear, they are translated into nerve impulses. These impulses then travel to the brain where they are interpreted by the brain as sound. The hearing mechanisms within the inner ear, can ...

  3. 15. Interior view, greenhouse, from the northwest. The greenhouse interior ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Interior view, greenhouse, from the northwest. The greenhouse interior was quite modest, the space between the floor of the lower level and the joists carrying the loft floor is only five-and-one-half feet. - John Bartram House & Garden, Greenhouse, 54th Street & LIndbergh Boulevard, Philadelphia, Philadelphia County, PA

  4. Hangar no. 2 interior detail of roof structures and interior ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Hangar no. 2 interior detail of roof structures and interior work spaces. Note concrete piers and cross bracing. Seen at trusses no. 42, 43, & 44. - Marine Corps Air Station Tustin, Southern Lighter Than Air Ship Hangar, Near intersection of Windmill Road & Johnson Street, Tustin, Orange County, CA

  5. 44. SECOND FLOOR 'ANNEX' INTERIOR VIEW TO SOUTHWEST: Interior ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. SECOND FLOOR 'ANNEX' - INTERIOR VIEW TO SOUTHWEST: Interior view towards southwest on second floor of the powerhouse 'annex.' Note the steel column and beam construction and the old shunt car formerly used to move cable cars around the yard. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  6. 45. INTERIOR VIEW TO SOUTHWEST ON SECOND FLOOR: Interior view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    45. INTERIOR VIEW TO SOUTHWEST ON SECOND FLOOR: Interior view towards southwest on second floor of main portion of the powerhouse and car barn. This space is used for repair and storage of cable cars. Note wooden trussed roof. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  7. 46. INTERIOR VIEW TO SOUTH ON SECOND FLOOR: Interior view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    46. INTERIOR VIEW TO SOUTH ON SECOND FLOOR: Interior view looking south along the east wall on the second floor of the powerhouse and car barn. Note the cable car truck in the foreground. - San Francisco Cable Railway, Washington & Mason Streets, San Francisco, San Francisco County, CA

  8. Sound attenuation by liners in a blown flap environment

    NASA Technical Reports Server (NTRS)

    Parthasarathy, S. P.; Vijayaraghavan, A.

    1980-01-01

    Sound propagation through a hot wall-jet flow over an absorbing wall is studied. The radiated sound field subject to the influence of flow convection and refraction is evaluated, and the nature of acoustic attenuation attributable to a sound absorbing liner is determined. Using a two-dimensional model, the noise field under the aircraft is also determined, and a slug-flow model is used to describe the influence of flow, density, and temperature on acoustic sources in jets. Results show significant changes in the radiated source due to the interference phenomenon, and a good absorber has the potential of changing the sound pressure range of variation to unity. A liner is also found to increase or decrease sound pressure, depending on the frequency.

  9. Raptors and aircraft

    USGS Publications Warehouse

    Smith, D.G.; Ellis, D.H.; Johnson, T.H.; Glinski, Richard L.; Pendleton, Beth Giron; Moss, Mary Beth; LeFranc, Maurice N.=; Millsap, Brian A.; Hoffman, Stephen W.

    1988-01-01

    Less than 5% of all bird strikes of aircraft are by raptor species, but damage to airframe structure or jet engine dysfunction are likely consequences. Beneficial aircraft-raptor interactions include the use of raptor species to frighten unwanted birds from airport areas and the use of aircraft to census raptor species. Many interactions, however, modify the raptor?s immediate behavior and some may decrease reproduction of sensitive species. Raptors may respond to aircraft stimuli by exhibiting alarm, increased heart rate, flushing or fleeing and occasionally by directly attacking intruding aircraft. To date, most studies reveal that raptor responses to aircraft are brief and do not limit reproduction; however, additional study is needed.

  10. Lightning effects on aircraft

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Direct and indirect effects of lightning on aircraft were examined in relation to aircraft design. Specific trends in design leading to more frequent lightning strikes were individually investigated. These trends included the increasing use of miniaturized, solid state components in aircraft electronics and electric power systems. A second trend studied was the increasing use of reinforced plastics and other nonconducting materials in place of aluminum skins, a practice that reduces the electromagnetic shielding furnished by a conductive skin.

  11. Effects of indoor rattle sounds on annoyance caused by sonic booms.

    PubMed

    Rathsam, Jonathan; Loubeau, Alexandra; Klos, Jacob

    2015-07-01

    To expand national air transportation capabilities, NASA's Commercial Supersonic Technology Project is working to make supersonic flight practical for commercial passengers. As an aid in designing and certifying quiet supersonic aircraft, a noise metric is sought that will correspond to indoor annoyance caused by sonic booms, including the effects of indoor rattle sounds. This study examines how well several common aircraft noise metrics predict indoor annoyance based on the indoor and outdoor sound fields. The results suggest notional community annoyance models that include the effects of indoor rattle sounds. PMID:26233059

  12. Designing fire safe interiors.

    PubMed

    Belles, D W

    1992-01-01

    Any product that causes a fire to grow large is deficient in fire safety performance. A large fire in any building represents a serious hazard. Multiple-death fires almost always are linked to fires that grow quickly to a large size. Interior finishes have large, continuous surfaces over which fire can spread. They are regulated to slow initial fire growth, and must be qualified for use on the basis of fire tests. To obtain meaningful results, specimens must be representative of actual installation. Variables--such as the substrate, the adhesive, and product thickness and density--can affect product performance. The tunnel test may not adequately evaluate some products, such as foam plastics or textile wall coverings, thermoplastic materials, or materials of minimal mass. Where questions exist, products should be evaluated on a full-scale basis. Curtains and draperies are examples of products that ignite easily and spread flames readily. The present method for testing curtains and draperies evaluates one fabric at a time. Although a fabric tested alone may perform well, fabrics that meet test standards individually sometimes perform poorly when tested in combination. Contents and furnishings constitute the major fuels in many fires. Contents may involve paper products and other lightweight materials that are easily ignited and capable of fast fire growth. Similarly, a small source may ignite many items of furniture that are capable of sustained fire growth. Upholstered furniture can reach peak burning rates in less than 5 minutes. Furnishings have been associated with many multiple-death fires.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. Fourth International Symposium on Long-Range Sound Propagation

    NASA Technical Reports Server (NTRS)

    Willshire, William L., Jr. (Compiler)

    1990-01-01

    Long range sound propagation is an aspect of many acoustical problems ranging from en route aircraft noise to the acoustic detection of aircraft. Over the past decade, the University of Mississippi and the Open University of England, together with a third institution, have held a symposium approx. every 2 years so that experts in the field of long range propagation could exchange information on current research, identify areas needing additional work, and coordinate activities as much as possible. The Fourth International Symposium on Long Range Sound Propagation was jointly sponsored by the University of Mississippi, the Open University of England, and NASA. Papers were given in the following areas: ground effects on propagation; infrasound propagation; and meteorological effects on sound propagation. A compilation of the presentations made at the symposium is presented along with a list of attendees, and the agenda.

  14. Hypersonic aircraft design

    NASA Technical Reports Server (NTRS)

    Alkamhawi, Hani; Greiner, Tom; Fuerst, Gerry; Luich, Shawn; Stonebraker, Bob; Wray, Todd

    1990-01-01

    A hypersonic aircraft is designed which uses scramjets to accelerate from Mach 6 to Mach 10 and sustain that speed for two minutes. Different propulsion systems were considered and it was decided that the aircraft would use one full scale turbofan-ramjet. Two solid rocket boosters were added to save fuel and help the aircraft pass through the transonic region. After considering aerodynamics, aircraft design, stability and control, cooling systems, mission profile, and landing systems, a conventional aircraft configuration was chosen over that of a waverider. The conventional design was chosen due to its landing characteristics and the relative expense compared to the waverider. Fuel requirements and the integration of the engine systems and their inlets are also taken into consideration in the final design. A hypersonic aircraft was designed which uses scramjets to accelerate from Mach 6 to Mach 10 and sustain that speed for two minutes. Different propulsion systems were considered and a full scale turbofan-ramjet was chosen. Two solid rocket boosters were added to save fuel and help the aircraft pass through the transonic reqion. After the aerodynamics, aircraft design, stability and control, cooling systems, mission profile, landing systems, and their physical interactions were considered, a conventional aircraft configuration was chosen over that of a waverider. The conventional design was chosen due to its landing characteristics and the relative expense compared to the waverider. Fuel requirements and the integration of the engine systems and their inlets were also considered in the designing process.

  15. Priming Gestures with Sounds

    PubMed Central

    Lemaitre, Guillaume; Heller, Laurie M.; Navolio, Nicole; Zúñiga-Peñaranda, Nicolas

    2015-01-01

    We report a series of experiments about a little-studied type of compatibility effect between a stimulus and a response: the priming of manual gestures via sounds associated with these gestures. The goal was to investigate the plasticity of the gesture-sound associations mediating this type of priming. Five experiments used a primed choice-reaction task. Participants were cued by a stimulus to perform response gestures that produced response sounds; those sounds were also used as primes before the response cues. We compared arbitrary associations between gestures and sounds (key lifts and pure tones) created during the experiment (i.e. no pre-existing knowledge) with ecological associations corresponding to the structure of the world (tapping gestures and sounds, scraping gestures and sounds) learned through the entire life of the participant (thus existing prior to the experiment). Two results were found. First, the priming effect exists for ecological as well as arbitrary associations between gestures and sounds. Second, the priming effect is greatly reduced for ecologically existing associations and is eliminated for arbitrary associations when the response gesture stops producing the associated sounds. These results provide evidence that auditory-motor priming is mainly created by rapid learning of the association between sounds and the gestures that produce them. Auditory-motor priming is therefore mediated by short-term associations between gestures and sounds that can be readily reconfigured regardless of prior knowledge. PMID:26544884

  16. Human Factors In Aircraft Automation

    NASA Technical Reports Server (NTRS)

    Billings, Charles

    1995-01-01

    Report presents survey of state of art in human factors in automation of aircraft operation. Presents examination of aircraft automation and effects on flight crews in relation to human error and aircraft accidents.

  17. Interior of Spacewedge #3

    NASA Technical Reports Server (NTRS)

    1996-01-01

    during the Army phase was not called a Spacewedge but simply a Wedge. The Spacewedge was a flattened biconical airframe joined to a ram-air parafoil with a custom harness. In the manual control mode, the vehicle was flown using a radio uplink. In its autonomous mode, it was controlled using a small computer that received input from onboard sensors. Selected sensor data was recorded onto several onboard data loggers. Two Spacewedge shapes were used for four airframes representing generic hypersonic vehicle configurations. Spacewedge vehicles were 48 inches long, 30 inches wide, and 21 inches high. Their basic weight was 120 pounds, although different configurations weighed from 127 to 184 pounds. Potential uses for Spacewedge-based technology include deployable, precision, autonomous landing systems, such as the one deployed by the X-38 crew return vehicle; planetary probes; booster recovery systems; autonomous gliding parachute systems on military aircraft ejection seats; offset delivery of military cargoes; and delivery of humanitarian aid to hard-to-reach locations. Dryden employees involved with the Spacewedge program included R. Dale Reed, who originated the concept of conducting a subscale flight test at Dryden and participated in the actual testing. Alexander Sim managed the flight project and participated in its documentation. James Murray served as the principal Dryden investigator and as the lead for all systems integration for Phases I and II (the Spacewedge phases).

  18. Technology for the Sound of Music

    NASA Technical Reports Server (NTRS)

    1994-01-01

    In the early 1960s during an industry recession, Kaman Aircraft lost several defense contracts. Forced to diversify, the helicopter manufacturer began to manufacture acoustic guitars. Kaman's engineers used special vibration analysis equipment based on aerospace technology. While a helicopter's rotor system is highly susceptible to vibration, which must be reduced or "dampened," vibration enhances a guitar's sound. After two years of vibration analysis Kaman produced an instrument, which is very successful. The Ovation guitar is made of fiberglass. It is stronger than the traditional rosewood and manufactured with adapted aircraft techniques such as jigs and fixtures, reducing labor and assuring quality and cost control. Kaman Music Corporation now has annual sales of $100 million.

  19. General Aviation Aircraft Reliability Study

    NASA Technical Reports Server (NTRS)

    Pettit, Duane; Turnbull, Andrew; Roelant, Henk A. (Technical Monitor)

    2001-01-01

    This reliability study was performed in order to provide the aviation community with an estimate of Complex General Aviation (GA) Aircraft System reliability. To successfully improve the safety and reliability for the next generation of GA aircraft, a study of current GA aircraft attributes was prudent. This was accomplished by benchmarking the reliability of operational Complex GA Aircraft Systems. Specifically, Complex GA Aircraft System reliability was estimated using data obtained from the logbooks of a random sample of the Complex GA Aircraft population.

  20. Analysis of sound absorption of tuck spacer fabrics to reduce automotive noise

    NASA Astrophysics Data System (ADS)

    Dias, Tilak; Monaragala, Ravindra; Needham, Peter; Lay, Edward

    2007-08-01

    Textiles are widely used in the automotive industry to provide both comfort to the passengers and an aesthetic appearance to the automotive interior. They can also be used to reduce automotive interior noise, which can make automotive travel safer and more comfortable. Knitted fabrics are used widely in automotive upholstery; however, the sound absorbency of a single layer of a knitted fabric is inadequate for the reduction of automotive interior noise. This paper investigates the sound absorbency of a novel knitted spacer fabric, which can be used in automotive upholstery and has the potential for greater sound absorbency than a conventional plain knitted fabric and its derivatives. The spacer fabric is modelled as a porous sound absorber and its sound absorbency is studied with regard to its structural parameters.

  1. Computer program to predict aircraft noise levels

    NASA Technical Reports Server (NTRS)

    Clark, B. J.

    1981-01-01

    Methods developed at the NASA Lewis Research Center for predicting the noise contributions from various aircraft noise sources were programmed to predict aircraft noise levels either in flight or in ground tests. The noise sources include fan inlet and exhaust, jet, flap (for powered lift), core (combustor), turbine, and airframe. Noise propagation corrections are available for atmospheric attenuation, ground reflections, extra ground attenuation, and shielding. Outputs can include spectra, overall sound pressure level, perceived noise level, tone-weighted perceived noise level, and effective perceived noise level at locations specified by the user. Footprint contour coordinates and approximate footprint areas can also be calculated. Inputs and outputs can be in either System International or U.S. customary units. The subroutines for each noise source and propagation correction are described. A complete listing is given.

  2. Cable Tensiometer for Aircraft

    NASA Technical Reports Server (NTRS)

    Nunnelee, Mark (Inventor)

    2008-01-01

    The invention is a cable tensiometer that can be used on aircraft for real-time, in-flight cable tension measurements. The invention can be used on any aircraft cables with high precision. The invention is extremely light-weight, hangs on the cable being tested and uses a dual bending beam design with a high mill-volt output to determine tension.

  3. Lightning protection of aircraft

    NASA Technical Reports Server (NTRS)

    Fisher, F. A.; Plumer, J. A.

    1977-01-01

    The current knowledge concerning potential lightning effects on aircraft and the means that are available to designers and operators to protect against these effects are summarized. The increased use of nonmetallic materials in the structure of aircraft and the constant trend toward using electronic equipment to handle flight-critical control and navigation functions have served as impetus for this study.

  4. Civil aircraft accident investigation.

    PubMed

    Haines, Daniel

    2013-01-01

    This talk reviews some historic aircraft accidents and some more recent. It reflects on the division of accident causes, considering mechanical failures and aircrew failures, and on aircrew training. Investigation results may lead to improved aircraft design, and to appropriate crew training. PMID:24057309

  5. 18. INTERIOR SURFACE OF THE SHORT SOUTH WALL OF AR9, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. INTERIOR SURFACE OF THE SHORT SOUTH WALL OF AR-9, WITH THE MORE RECENT CONCRETE BLOCK CONTROL ROOM AT THE LEFT AND ASSOCIATED CONCRETE PAVING IN THE FOREGROUND. - Edwards Air Force Base, South Base, Rammed Earth Aircraft Dispersal Revetments, Western Shore of Rogers Dry Lake, Boron, Kern County, CA

  6. Smoke toxicity of common aircraft carpets.

    PubMed

    Dressler, D P; Skornik, W A; Bloom, S B; Dougherty, J D

    1975-09-01

    The smoke toxicity of three carpets commonly available for use in commercial aircraft was determined by ignition in a specially designed smoke apparatus. Rats were exposed for 15 min to three different fuel loads, on a weight-to-volume basis. Evaluation was by mortality, time of useful function (TUF), and unconsciousness. No deaths were noted with carpets A or C at 64 mg/l or 128 mg/l fuel load concentration; at 256 mg/l, 42% mortality resulted from carpet A and 4.5% with carpet C. Exposure to carpet B resulted in a mortality of 4.3%, 72.5%, and 100% at the three concentrations. The TUF data and time of unconsciousness correlated closely with the results of the mortality, but were much more sensitive. These studies indicate that a potential severe hazard exists with some types of carpet, and further research is needed to identify and eliminate these materials from aircraft interiors. PMID:1164351

  7. Why aircraft disinsection?

    PubMed Central

    Gratz, N. G.; Steffen, R.; Cocksedge, W.

    2000-01-01

    A serious problem is posed by the inadvertent transport of live mosquitoes aboard aircraft arriving from tropical countries where vector-borne diseases are endemic. Surveys at international airports have found many instances of live insects, particularly mosquitoes, aboard aircraft arriving from countries where malaria and arboviruses are endemic. In some instances mosquito species have been established in countries in which they have not previously been reported. A serious consequence of the transport of infected mosquitoes aboard aircraft has been the numerous cases of "airport malaria" reported from Europe, North America and elsewhere. There is an important on-going need for the disinsection of aircraft coming from airports in tropical disease endemic areas into nonendemic areas. The methods and materials available for use in aircraft disinsection and the WHO recommendations for their use are described. PMID:10994283

  8. Aircraft operations management manual

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The NASA aircraft operations program is a multifaceted, highly diverse entity that directly supports the agency mission in aeronautical research and development, space science and applications, space flight, astronaut readiness training, and related activities through research and development, program support, and mission management aircraft operations flights. Users of the program are interagency, inter-government, international, and the business community. This manual provides guidelines to establish policy for the management of NASA aircraft resources, aircraft operations, and related matters. This policy is an integral part of and must be followed when establishing field installation policy and procedures covering the management of NASA aircraft operations. Each operating location will develop appropriate local procedures that conform with the requirements of this handbook. This manual should be used in conjunction with other governing instructions, handbooks, and manuals.

  9. Hypersonic reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Bulk, Tim; Chiarini, David; Hill, Kevin; Kunszt, Bob; Odgen, Chris; Truong, Bon

    1992-01-01

    A conceptual design of a hypersonic reconnaissance aircraft for the U.S. Navy is discussed. After eighteen weeks of work, a waverider design powered by two augmented turbofans was chosen. The aircraft was designed to be based on an aircraft carrier and to cruise 6,000 nautical miles at Mach 4;80,000 feet and above. As a result the size of the aircraft was only allowed to have a length of eighty feet, fifty-two feet in wingspan, and roughly 2,300 square feet in planform area. Since this is a mainly cruise aircraft, sixty percent of its 100,000 pound take-off weight is JP fuel. At cruise, the highest temperature that it will encounter is roughly 1,100 F, which can be handled through the use of a passive cooling system.

  10. 22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL AND TEST LAB FOR UNIT NO. 2 GREY IRON DISAMATIC. SAND CASTING TECHNICIAN, ROY BATES, TESTS THE WEIGHT OF THE SAND, DRYS IT, AND WEIGHT IT AGAINST STANDARDS TO CALCULATE THE CORRECT MOISTURE NEEDED FOR DIFFERENT MOLDS. THE SAND MIX VARY WITH THE SIZE AND COMPOSITION OF THE CASTING. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  11. Spectral Characteristics of Wake Vortex Sound During Roll-Up

    NASA Technical Reports Server (NTRS)

    Booth, Earl R., Jr. (Technical Monitor); Zhang, Yan; Wang, Frank Y.; Hardin, Jay C.

    2003-01-01

    This report presents an analysis of the sound spectra generated by a trailing aircraft vortex during its rolling-up process. The study demonstrates that a rolling-up vortex could produce low frequency (less than 100 Hz) sound with very high intensity (60 dB above threshold of human hearing) at a distance of 200 ft from the vortex core. The spectrum then drops o rapidly thereafter. A rigorous analytical approach has been adopted in this report to derive the spectrum of vortex sound. First, the sound pressure was solved from an alternative treatment of the Lighthill s acoustic analogy approach [1]. After the application of Green s function for free space, a tensor analysis was applied to permit the removal of the source term singularity of the wave equation in the far field. Consequently, the sound pressure is expressed in terms of the retarded time that indicates the time history and spacial distribution of the sound source. The Fourier transformation is then applied to the sound pressure to compute its spectrum. As a result, the Fourier transformation greatly simplifies the expression of the vortex sound pressure involving the retarded time, so that the numerical computation is applicable with ease for axisymmetric line vortices during the rolling-up process. The vortex model assumes that the vortex circulation is proportional to the time and the core radius is a constant. In addition, the velocity profile is assumed to be self-similar along the aircraft flight path, so that a benchmark vortex velocity profile can be devised to obtain a closed form solution, which is then used to validate the numerical calculations for other more realistic vortex profiles for which no closed form solutions are available. The study suggests that acoustic sensors operating at low frequency band could be profitably deployed for detecting the vortex sound during the rolling-up process.

  12. Convective Overshoot in Stellar Interior

    NASA Astrophysics Data System (ADS)

    Zhang, Q. S.

    2015-07-01

    In stellar interiors, the turbulent thermal convection transports matters and energy, and dominates the structure and evolution of stars. The convective overshoot, which results from the non-local convective transport from the convection zone to the radiative zone, is one of the most uncertain and difficult factors in stellar physics at present. The classical method for studying the convective overshoot is the non-local mixing-length theory (NMLT). However, the NMLT bases on phenomenological assumptions, and leads to contradictions, thus the NMLT was criticized in literature. At present, the helioseismic studies have shown that the NMLT cannot satisfy the helioseismic requirements, and have pointed out that only the turbulent convection models (TCMs) can be accepted. In the first part of this thesis, models and derivations of both the NMLT and the TCM were introduced. In the second part, i.e., the work part, the studies on the TCM (theoretical analysis and applications), and the development of a new model of the convective overshoot mixing were described in detail. In the work of theoretical analysis on the TCM, the approximate solution and the asymptotic solution were obtained based on some assumptions. The structure of the overshoot region was discussed. In a large space of the free parameters, the approximate/asymptotic solutions are in good agreement with the numerical results. We found an important result that the scale of the overshoot region in which the thermal energy transport is effective is 1 HK (HK is the scale height of turbulence kinetic energy), which does not depend on the free parameters of the TCM. We applied the TCM and a simple overshoot mixing model in three cases. In the solar case, it was found that the temperature gradient in the overshoot region is in agreement with the helioseismic requirements, and the profiles of the solar lithium abundance, sound speed, and density of the solar models are also improved. In the low-mass stars of open

  13. Fire resistant films for aircraft applications

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.

    1983-01-01

    Alternative sandwich panel decorative films were investigated as replacements for the polyvinyl fluoride currently used in aircraft interiors. Candidate films were studied for flammability, smoke emission, toxic gas emission, flame spread, and suitability as a printing surface for the decorative acrylic ink system. Several of the candidate films tested were flame modified polyvinyl fluoride, polyvinylidene fluoride, polyimide, polyamide, polysulfone, polyphenylsulfone, polyethersulfone, polybenzimidazole, polycarbonate, polyparabanic acid, polyphosphazene, polyetheretherketon, and polyester. The films were evaluated as pure films only, films silk-screened with an acrylic ink, and films adhered to a phenolic fiberglass substrate. Films which exhibited the highest fire resistant properties included PEEK polyetheretherketon, Aramid polyamide, and ISO-BPE polyester.

  14. How Technology Influences Interior Design.

    ERIC Educational Resources Information Center

    McDavitt, Tish

    1999-01-01

    Examines telecommunication technology's influences on interior school design and effective learning, and discusses how to implement this technology into the school. Building the infrastructure to support telecommunications in an educational setting and the importance of effective lighting are discussed. (GR)

  15. Interior of building 16 section, view north of machine shop, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Interior of building 16 section, view north of machine shop, showing shrink-fitting a bearing sleeve onto a section of the propeller shaft for the aircraft carrier John F. Kennedy. The lathe on the extreme left of the photograph was used to machine bearing sleeves to final dimensions. This work, in August 1994, was the final major machine shop job done for the U.S. Navy. Photograph by Robert Stewart, August 1994. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Machine Shops, League Island, Philadelphia, Philadelphia County, PA

  16. Predicting visibility of aircraft.

    PubMed

    Watson, Andrew; Ramirez, Cesar V; Salud, Ellen

    2009-05-20

    Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration.

  17. Predicting Visibility of Aircraft

    PubMed Central

    Watson, Andrew; Ramirez, Cesar V.; Salud, Ellen

    2009-01-01

    Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration. PMID:19462007

  18. Acoustical comfort of vehicles: A combination of sound and vibration

    NASA Astrophysics Data System (ADS)

    Genuit, Klaus; Schutte-Fortkamp, Brigitte; Fiebig, Andre

    2005-09-01

    As vehicles become more and more quiet, the customer's sensitivity to acoustical comfort increases. The acoustical comfort is not independent of the vibrations the driver can feel in the seat and at the steering. The passenger of a vehicle must be regarded as part of a vibro-acoustic system. Correspondingly, the subjective judgement which passengers make about their impression of levels of acoustic comfort encompasses both sound and vibration. Achievement in this field depends on obtaining knowledge about the interaction between sound and vibration and how these factors impact subjective evaluation. To save time and money prediction tools for the estimation of sound and vibration contributions into the vehicle cabin are very important in order to simulate the final comfort with respect to sound and vibration. Based on the binaural transfer path analysis in combination with the binaural transfer path synthesis a sound and vibration reproduction in a so-called SoundCar can be realized with a very good simulation of a real situation of a car. First research tests completed for the European research project OBELICS (Objective Evaluation of Interior Car Sound) have shown that the use of SoundCar may result in more reliable sound characteristic and quality evaluation.

  19. Aircraft noise and speech intelligibility in an outdoor living space.

    PubMed

    Alvarsson, Jesper J; Nordström, Henrik; Lundén, Peter; Nilsson, Mats E

    2014-06-01

    Studies of effects on speech intelligibility from aircraft noise in outdoor places are currently lacking. To explore these effects, first-order ambisonic recordings of aircraft noise were reproduced outdoors in a pergola. The average background level was 47 dB LA eq. Lists of phonetically balanced words (LAS max,word = 54 dB) were reproduced simultaneously with aircraft passage noise (LAS max,noise = 72-84 dB). Twenty individually tested listeners wrote down each presented word while seated in the pergola. The main results were (i) aircraft noise negatively affects speech intelligibility at sound pressure levels that exceed those of the speech sound (signal-to-noise ratio, S/N < 0), and (ii) the simple A-weighted S/N ratio was nearly as good an indicator of speech intelligibility as were two more advanced models, the Speech Intelligibility Index and Glasberg and Moore's [J. Audio Eng. Soc. 53, 906-918 (2005)] partial loudness model. This suggests that any of these indicators is applicable for predicting effects of aircraft noise on speech intelligibility outdoors.

  20. 30 CFR 250.224 - What information on support vessels, offshore vehicles, and aircraft you will use must accompany...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND... Exploration Plans (ep) § 250.224 What information on support vessels, offshore vehicles, and aircraft you will... aircraft you will use to support your exploration activities. The description of vessels and...

  1. D-558-2 Aircraft on lakebed

    NASA Technical Reports Server (NTRS)

    1955-01-01

    Viewed in this 1955 photograph is the NACA High Speed Flight Station D-558-2 #2 (144) Skyrocket, an all-rocket powered vehicle. The Skyrocket is parked on Rogers Dry Lakebed at Edwards Air Force Base. This aircraft, NACA 144/Navy 37974, was the first to reach Mach 2 (see project description). The Douglas D-558-2 'Skyrockets' were among the early transonic research airplanes like the X-1, X-4, X-5, and X-92A. Three of the single-seat, swept-wing aircraft flew from 1948 to 1956 in a joint program involving the National Advisory Committee for Aeronautics (NACA), with its flight research done at the NACA's Muroc Flight Test Unit in Calif., redesignated in 1949 the High-Speed Flight Research Station (HSFRS); the Navy-Marine Corps; and the Douglas Aircraft Co. The HSFRS became the High-Speed Flight Station in 1954 and is now known as the NASA Dryden Flight Research Center. The Skyrocket made aviation history when it became the first airplane to fly twice the speed of sound. The 2 in the aircraft's designation referred to the fact that the Skyrocket was the phase-two version of what had originally been conceived as a three-phase program, with the phase-one aircraft having straight wings. The third phase, which never came to fruition, would have involved constructing a mock-up of a combat-type aircraft embodying the results from the testing of the phase one and two aircraft. Douglas pilot John F. Martin made the first flight at Muroc Army Airfield (later renamed Edwards Air Force Base) in Calif. on February 4, 1948. The goals of the program were to investigate the characteristics of swept-wing aircraft at transonic and supersonic speeds with particular attention to pitch-up (uncommanded rotation of the nose of the airplane upwards)--a problem prevalent in high-speed service aircraft of that era, particularly at low speeds during take-off and landing and in tight turns. The three aircraft gathered a great deal of data about pitch-up and the coupling of lateral (yaw) and

  2. OVRhyp, Scramjet Test Aircraft

    NASA Technical Reports Server (NTRS)

    Aslan, J.; Bisard, T.; Dallinga, S.; Draper, K.; Hufford, G.; Peters, W.; Rogers, J.

    1990-01-01

    A preliminary design for an unmanned hypersonic research vehicle to test scramjet engines is presented. The aircraft will be launched from a carrier aircraft at an altitude of 40,000 feet at Mach 0.8. The vehicle will then accelerate to Mach 6 at an altitude of 100,000 feet. At this stage the prototype scramjet will be employed to accelerate the vehicle to Mach 10 and maintain Mach 10 flight for 2 minutes. The aircraft will then decelerate and safely land.

  3. Aircraft compass characteristics

    NASA Technical Reports Server (NTRS)

    Peterson, John B; Smith, Clyde W

    1937-01-01

    A description of the test methods used at the National Bureau of Standards for determining the characteristics of aircraft compasses is given. The methods described are particularly applicable to compasses in which mineral oil is used as the damping liquid. Data on the viscosity and density of certain mineral oils used in United States Navy aircraft compasses are presented. Characteristics of Navy aircraft compasses IV to IX and some other compasses are shown for the range of temperatures experienced in flight. Results of flight tests are presented. These results indicate that the characteristic most desired in a steering compass is a short period and, in a check compass, a low overswing.

  4. Loftin Collection - Boeing Aircraft

    NASA Technical Reports Server (NTRS)

    1933-01-01

    Either a F2B-1 or F3B-1, both aircraft were built by Boeing and both were powered by Pratt and Whitney Wasp engines. These fighters were intended for Navy shipboard use. Boeing F3B-1: While most Boeing F3B-1s served the U. S. Navy aircraft carriers the Lexington and the Saratoga, this example flew in NACA hands at the Langley Memorial Aeronautical Laboratory in the late 1920's. Also known as the Boeing Model 77, the aircraft was the next to last F3B-1 build in November 1928.

  5. Some fighter aircraft trends

    NASA Technical Reports Server (NTRS)

    Spearman, L.

    1985-01-01

    Some basic trends in fighters are traced from the post World II era. Beginning with the first operational jet fighter, the P-80, the characteristics of subsequent fighter aircraft are examined for performance, mission capability, effectiveness, and cost. Characteristics presented include: power loading, wing loading, maximum speed, rate of climb, turn rate, weight and weight distribution, cost and cost distribution. The characteristics of some USSR aircraft are included for comparison. The trends indicate some of the rationale for certain fighter designs and some likely characteristics to be sought in future fighter aircraft designs.

  6. Lightning hazards to aircraft

    NASA Technical Reports Server (NTRS)

    Corn, P. B.

    1978-01-01

    Lightning hazards and, more generally, aircraft static electricity are discussed by a representative for the Air Force Flight Dynamics Laboratory. An overview of these atmospheric electricity hazards to aircraft and their systems is presented with emphasis on electrical and electronic subsystems. The discussion includes reviewing some of the characteristics of lightning and static electrification, trends in weather and lightning-related mishaps, some specific threat mechanisms and susceptible aircraft subsystems and some of the present technology gaps. A roadmap (flow chart) is presented to show the direction needed to address these problems.

  7. Tropospheric sampling with aircraft

    SciTech Connect

    Daum, P.H.; Springston, S.R.

    1991-03-01

    Aircraft constitute a unique environment which places stringent requirements on the instruments used to measure the concentrations of atmospheric trace gases and aerosols. Some of these requirements such as minimization of size, weight, and power consumption are general; others are specific to individual techniques. This review presents the basic principles and considerations governing the deployment of trace gas and aerosol instrumentation on an aircraft. An overview of common instruments illustrates these points and provides guidelines for designing and using instruments on aircraft-based measurement programs.

  8. Sounds of a Star

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Acoustic Oscillations in Solar-Twin "Alpha Cen A" Observed from La Silla by Swiss Team Summary Sound waves running through a star can help astronomers reveal its inner properties. This particular branch of modern astrophysics is known as "asteroseismology" . In the case of our Sun, the brightest star in the sky, such waves have been observed since some time, and have greatly improved our knowledge about what is going on inside. However, because they are much fainter, it has turned out to be very difficult to detect similar waves in other stars. Nevertheless, tiny oscillations in a solar-twin star have now been unambiguously detected by Swiss astronomers François Bouchy and Fabien Carrier from the Geneva Observatory, using the CORALIE spectrometer on the Swiss 1.2-m Leonard Euler telescope at the ESO La Silla Observatory. This telescope is mostly used for discovering exoplanets (see ESO PR 07/01 ). The star Alpha Centauri A is the nearest star visible to the naked eye, at a distance of a little more than 4 light-years. The new measurements show that it pulsates with a 7-minute cycle, very similar to what is observed in the Sun . Asteroseismology for Sun-like stars is likely to become an important probe of stellar theory in the near future. The state-of-the-art HARPS spectrograph , to be mounted on the ESO 3.6-m telescope at La Silla, will be able to search for oscillations in stars that are 100 times fainter than those for which such demanding observations are possible with CORALIE. PR Photo 23a/01 : Oscillations in a solar-like star (schematic picture). PR Photo 23b/01 : Acoustic spectrum of Alpha Centauri A , as observed with CORALIE. Asteroseismology: listening to the stars ESO PR Photo 23a/01 ESO PR Photo 23a/01 [Preview - JPEG: 357 x 400 pix - 96k] [Normal - JPEG: 713 x 800 pix - 256k] [HiRes - JPEG: 2673 x 3000 pix - 2.1Mb Caption : PR Photo 23a/01 is a graphical representation of resonating acoustic waves in the interior of a solar-like star. Red and blue

  9. Antecedents and analogues - Experimental aircraft

    NASA Technical Reports Server (NTRS)

    Smith, R. H.

    1978-01-01

    The paper reviews the development of experimental aircraft from 1953 to the present. Consideration is given to the X-series experimental aircraft, to X-15 (the first aerospace plane), to the transition of experimental aircraft to high-speed flight, to XB-70 research, to lifting body research aircraft, and to current high-speed flight research.

  10. Report on the general design of commercial aircraft

    NASA Technical Reports Server (NTRS)

    Warner, Edward P

    1922-01-01

    Given here are evaluations of six different European aircraft from the point of view of a passenger. The aircraft discussed are the DH 34, the Handley-Page W8B, the Farman Goliath, the Potez IX, the Spad 33 (Berline), and the Fokker F.III. The airplanes were evaluated with regard to seating comfort, ventilation, noise, seating arrangements, cabin doors, baggage accommodation, interior arrangement of cabins, pilot's position and communication with the pilot, pilot accommodations, view from the cabin, safety, and lavatory accommodations.

  11. Cabin Noise Control for Twin Engine General Aviation Aircraft

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.; Slazak, M.

    1982-01-01

    An analytical model based on modal analysis was developed to predict the noise transmission into a twin-engine light aircraft. The model was applied to optimize the interior noise to an A-weighted level of 85 dBA. To achieve the required noise attenuation, add-on treatments in the form of honeycomb panels, damping tapes, acoustic blankets, septum barriers and limp trim panels were added to the existing structure. The added weight of the noise control treatment is about 1.1 percent of the total gross take-off weight of the aircraft.

  12. Depreciation of aircraft

    NASA Technical Reports Server (NTRS)

    Warner, Edward P

    1922-01-01

    There is a widespread, and quite erroneous, impression to the effect that aircraft are essentially fragile and deteriorate with great rapidity when in service, so that the depreciation charges to be allowed on commercial or private operation are necessarily high.

  13. Advanced hypersonic aircraft design

    NASA Technical Reports Server (NTRS)

    Utzinger, Rob; Blank, Hans-Joachim; Cox, Craig; Harvey, Greg; Mckee, Mike; Molnar, Dave; Nagy, Greg; Petersen, Steve

    1992-01-01

    The objective of this design project is to develop the hypersonic reconnaissance aircraft to replace the SR-71 and to complement existing intelligence gathering devices. The initial design considerations were to create a manned vehicle which could complete its mission with at least two airborne refuelings. The aircraft must travel between Mach 4 and Mach 7 at an altitude of 80,000 feet for a maximum range of 12,000 nautical miles. The vehicle should have an air breathing propulsion system at cruise. With a crew of two, the aircraft should be able to take off and land on a 10,000 foot runway, and the yearly operational costs were not to exceed $300 million. Finally, the aircraft should exhibit stealth characteristics, including a minimized radar cross-section (RCS) and a reduced sonic boom. The technology used in this vehicle should allow for production between the years 1993 and 1995.

  14. Aircraft Engine Emissions. [conference

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A conference on a aircraft engine emissions was held to present the results of recent and current work. Such diverse areas as components, controls, energy efficient engine designs, and noise and pollution reduction are discussed.

  15. The Aircraft Morphing Program

    NASA Technical Reports Server (NTRS)

    Wlezien, R. W.; Horner, G. C.; McGowan, A. R.; Padula, S. L.; Scott, M. A.; Silcox, R. J.; Simpson, J. O.

    1998-01-01

    In the last decade smart technologies have become enablers that cut across traditional boundaries in materials science and engineering. Here we define smart to mean embedded actuation, sensing, and control logic in a tightly coupled feedback loop. While multiple successes have been achieved in the laboratory, we have yet to see the general applicability of smart devices to real aircraft systems. The NASA Aircraft Morphing program is an attempt to couple research across a wide range of disciplines to integrate smart technologies into high payoff aircraft applications. The program bridges research in seven individual disciplines and combines the effort into activities in three primary program thrusts. System studies are used to assess the highest- payoff program objectives, and specific research activities are defined to address the technologies required for development of smart aircraft systems. In this paper we address the overall program goals and programmatic structure, and discuss the challenges associated with bringing the technologies to fruition.

  16. Laminar Flow Aircraft Certification

    NASA Technical Reports Server (NTRS)

    Williams, Louis J. (Compiler)

    1986-01-01

    Various topics telative to laminar flow aircraft certification are discussed. Boundary layer stability, flaps for laminar flow airfoils, computational wing design studies, manufacturing requirements, windtunnel tests, and flow visualization are among the topics covered.

  17. Aircraft electromagnetic compatibility

    NASA Technical Reports Server (NTRS)

    Clarke, Clifton A.; Larsen, William E.

    1987-01-01

    Illustrated are aircraft architecture, electromagnetic interference environments, electromagnetic compatibility protection techniques, program specifications, tasks, and verification and validation procedures. The environment of 400 Hz power, electrical transients, and radio frequency fields are portrayed and related to thresholds of avionics electronics. Five layers of protection for avionics are defined. Recognition is given to some present day electromagnetic compatibility weaknesses and issues which serve to reemphasize the importance of EMC verification of equipment and parts, and their ultimate EMC validation on the aircraft. Proven standards of grounding, bonding, shielding, wiring, and packaging are laid out to help provide a foundation for a comprehensive approach to successful future aircraft design and an understanding of cost effective EMC in an aircraft setting.

  18. Solar thermal aircraft

    DOEpatents

    Bennett, Charles L.

    2007-09-18

    A solar thermal powered aircraft powered by heat energy from the sun. A heat engine, such as a Stirling engine, is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller. The heat engine has a thermal battery in thermal contact with it so that heat is supplied from the thermal battery. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  19. Aircraft parameter estimation

    NASA Technical Reports Server (NTRS)

    Iliff, Kenneth W.

    1987-01-01

    The aircraft parameter estimation problem is used to illustrate the utility of parameter estimation, which applies to many engineering and scientific fields. Maximum likelihood estimation has been used to extract stability and control derivatives from flight data for many years. This paper presents some of the basic concepts of aircraft parameter estimation and briefly surveys the literature in the field. The maximum likelihood estimator is discussed, and the basic concepts of minimization and estimation are examined for a simple simulated aircraft example. The cost functions that are to be minimized during estimation are defined and discussed. Graphic representations of the cost functions are given to illustrate the minimization process. Finally, the basic concepts are generalized, and estimation from flight data is discussed. Some of the major conclusions for the simulated example are also developed for the analysis of flight data from the F-14, highly maneuverable aircraft technology (HiMAT), and space shuttle vehicles.

  20. Poetry Pages. Sound Effects.

    ERIC Educational Resources Information Center

    Fina, Allan de

    1992-01-01

    Explains how elementary teachers can help students understand onomatopoeia, suggesting that they define onomatopoeia, share examples of it, read poems and have students discuss onomatopoeic words, act out common household sounds, write about sound effects, and create choral readings of onomatopoeic poems. Two appropriate poems are included. (SM)

  1. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  2. Sounding rocket lessons learned

    NASA Technical Reports Server (NTRS)

    Wessling, Francis C.; Maybee, George W.

    1991-01-01

    Programmatic, applicatory, developmental, and operational aspects of sounding rocket utilization for materials processing studies are discussed. Lessons learned through the experience of 10 sounding rocket missions are described. Particular attention is given to missions from the SPAR, Consort, and Joust programs. Successful experiments on Consort include the study of polymer membranes and resins, biological processes, demixing of immiscible liquids, and electrodeposition.

  3. Breaking the Sound Barrier

    ERIC Educational Resources Information Center

    Brown, Tom; Boehringer, Kim

    2007-01-01

    Students in a fourth-grade class participated in a series of dynamic sound learning centers followed by a dramatic capstone event--an exploration of the amazing Trashcan Whoosh Waves. It's a notoriously difficult subject to teach, but this hands-on, exploratory approach ignited student interest in sound, promoted language acquisition, and built…

  4. The Bosstown Sound.

    ERIC Educational Resources Information Center

    Burns, Gary

    Based on the argument that (contrary to critical opinion) the musicians in the various bands associated with Bosstown Sound were indeed talented, cohesive individuals and that the bands' lack of renown was partially a result of ill-treatment by record companies and the press, this paper traces the development of the Bosstown Sound from its…

  5. D-558-2 Aircraft on lakebed

    NASA Technical Reports Server (NTRS)

    1954-01-01

    Viewed in this 1954 photograph is the NACA High Speed Flight Research Station's D-558-2 #2 (144), an all rocket powered Skyrocket. Like the X-1, the D-558-2 had a fuselage shaped like a .50 caliber bullet. Unlike both the X-1 and the D-558-1, it had swept wings. To accommodate them required a completely different design than that used for the earlier straight-wing D-558-1. The Douglas D-558-2 'Skyrockets' were among the early transonic research airplanes like the X-1, X-4, X-5, and X-92A. Three of the single-seat, swept-wing aircraft flew from 1948 to 1956 in a joint program involving the National Advisory Committee for Aeronautics (NACA), with its flight research done at the NACA's Muroc Flight Test Unit in Calif., redesignated in 1949 the High-Speed Flight Research Station (HSFRS); the Navy-Marine Corps; and the Douglas Aircraft Co. The HSFRS became the High-Speed Flight Station in 1954 and is now known as the NASA Dryden Flight Research Center. The Skyrocket made aviation history when it became the first airplane to fly twice the speed of sound. The 2 in the aircraft's designation referred to the fact that the Skyrocket was the phase-two version of what had originally been conceived as a three-phase program, with the phase-one aircraft having straight wings. The third phase, which never came to fruition, would have involved constructing a mock-up of a combat-type aircraft embodying the results from the testing of the phase one and two aircraft. Douglas pilot John F. Martin made the first flight at Muroc Army Airfield (later renamed Edwards Air Force Base) in Calif. on February 4, 1948. The goals of the program were to investigate the characteristics of swept-wing aircraft at transonic and supersonic speeds with particular attention to pitch-up (uncommanded rotation of the nose of the airplane upwards)--a problem prevalent in high-speed service aircraft of that era, particularly at low speeds during take-off and landing and in tight turns. The three aircraft

  6. Alternative jet aircraft fuels

    NASA Technical Reports Server (NTRS)

    Grobman, J.

    1979-01-01

    Potential changes in jet aircraft fuel specifications due to shifts in supply and quality of refinery feedstocks are discussed with emphasis on the effects these changes would have on the performance and durability of aircraft engines and fuel systems. Combustion characteristics, fuel thermal stability, and fuel pumpability at low temperature are among the factors considered. Combustor and fuel system technology needs for broad specification fuels are reviewed including prevention of fuel system fouling and fuel system technology for fuels with higher freezing points.

  7. Numerical investigation of sound transmission through double wall cylinders with respect to active noise control

    NASA Astrophysics Data System (ADS)

    Coats, T. J.; Silcox, R. J.; Lester, H. C.

    Market pressure for more fuel efficient air travel has led to increased use of turboprop and higher bypass turbofan engines. The low frequency components of propeller, jet and boundary layer noise are difficult to attenuate with conventional passive techniques. Weight and geometric restrictions for sound absorbing meterials limit the amount and type of treatment that may be applied. An active noise control (ANC) method is providing to be an attractive alternative. The approach taken in this paper uses a numerical finite/boundary element method (FEM/BEM) that may be easilty adapted to arbitrary geometries. A double walled cylinder is modeled using commercially available software. The outer shell is modeled as an aluminum cylinder, similar to that of aircraft skins. The inner shell is modeled as a composite material representative of a lightweight, stiff trim panel. Two different inner shell materials are used. The first is representative of current trim structure, the second a much stiffer composite. The primary source is generated by an exterior acoustic monopole. Control fields are generated using normal force inputs to the inner cylindrical shell. A linear least mean square (LMS) algorithm is used to determine amplitudes of control forces that minimize the interior acoustic field. Coupling of acoustic and structural modes and noise reductions are discussed for each of the inner shell materials.

  8. Variational Principle for Planetary Interiors

    NASA Astrophysics Data System (ADS)

    Zeng, Li; Jacobsen, Stein B.

    2016-09-01

    In the past few years, the number of confirmed planets has grown above 2000. It is clear that they represent a diversity of structures not seen in our own solar system. In addition to very detailed interior modeling, it is valuable to have a simple analytical framework for describing planetary structures. The variational principle is a fundamental principle in physics, entailing that a physical system follows the trajectory, which minimizes its action. It is alternative to the differential equation formulation of a physical system. Applying the variational principle to the planetary interior can beautifully summarize the set of differential equations into one, which provides us some insight into the problem. From this principle, a universal mass-radius relation, an estimate of the error propagation from the equation of state to the mass-radius relation, and a form of the virial theorem applicable to planetary interiors are derived.

  9. Aeroacoustics. [analysis of properties of sound generated by aerodynamic forces

    NASA Technical Reports Server (NTRS)

    Goldstein, M., E.

    1974-01-01

    An analysis was conducted to determine the properties of sound generated by aerodynamic forces or motions originating in a flow, such as the unsteady aerodynamic forces on propellers or by turbulent flows around an aircraft. The acoustics of moving media are reviewed and mathematical models are developed. Lighthill's acoustic analogy and the application to turbulent flows are analyzed. The effects of solid boundaries are calculated. Theories based on the solution of linearized vorticity and acoustic field equations are explained. The effects of nonuniform mean flow on the generation of sound are reported.

  10. X-1 research aircraft landing on lakebed

    NASA Technical Reports Server (NTRS)

    1947-01-01

    The first of the rocket-powered research aircraft, the X-1 (originally designated the XS-1), was a bullet-shaped airplane that was built by the Bell Aircraft Company for the US Air Force and the National Advisory Committee on Aeronautics (NACA). The mission of the X-1 was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the 'sound barrier'. The first of the three X-1s was glide-tested at Pinecastle Air Force Base, FL, in early 1946. The first powered flight of the X-1 was made on Dec. 9, 1946, at Edwards Air Force Base with Chalmers Goodlin, a Bell test pilot, at the controls. On Oct. 14, 1947, with USAF Captain Charles 'Chuck' Yeager as pilot, the aircraft flew faster than the speed of sound for the first time. Captain Yeager ignited the four-chambered XLR-11 rocket engines after being air-launched from under the bomb bay of a B-29 at 21,000 ft. The 6,000-lbthrust ethyl alcohol/liquid oxygen burning rockets, built by Reaction Motors, Inc., pushed him up to a speed of 700 mph in level flight. Captain Yeager was also the pilot when the X-1 reached its maximum speed of 957 mph. Another USAF pilot. Lt. Col. Frank Everest, Jr., was credited with taking the X-1 to its maximum altitude of 71,902 ft. Eighteen pilots in all flew the X-1s. The number three plane was destroyed in a fire before ever making any powered flights. A single-place monoplane, the X-1 was 31 ft long, 10 ft high, and had a wingspan of 29 ft. It weighed 4,900 lb and carried 8,200 lb of fuel. It had a flush cockpit with a side entrance and no ejection seat. This roughly 30-second video clip shows the X-1 landing on Rogers Dry Lakebed followed by the safety chase aircraft.

  11. A Lightweight Loudspeaker for Aircraft Communications and Active Noise Control

    NASA Technical Reports Server (NTRS)

    Warnaka, Glenn E.; Kleinle, Mark; Tsangaris, Parry; Oslac, Michael J.; Moskow, Harry J.

    1992-01-01

    A series of new, lightweight loudspeakers for use on commercial aircraft has been developed. The loudspeakers use NdFeB magnets and aluminum alloy frames to reduce the weight. The NdFeB magnet is virtually encapsulated by steel in the new speaker designs. Active noise reduction using internal loudspeakers was demonstrated to be effective in 1983. A weight, space, and cost efficient method for creating the active sound attenuating fields is to use the existing cabin loudspeakers for both communication and sound attenuation. This will require some additional loudspeaker design considerations.

  12. Structureborne noise control in advanced turboprop aircraft

    NASA Astrophysics Data System (ADS)

    Loeffler, Irvin J.

    1987-01-01

    Structureborne noise is discussed as a contributor to propeller aircraft interior noise levels that are nonresponsive to the application of a generous amount of cabin sidewall acoustic treatment. High structureborne noise levels may jeopardize passenger acceptance of the fuel-efficient high-speed propeller transport aircraft designed for cruise at Mach 0.65 to 0.85. These single-rotation tractor and counter-rotation tractor and pusher propulsion systems will consume 15 to 30 percent less fuel than advanced turbofan systems. Structureborne noise detection methodologies and the importance of development of a structureborne noise sensor are discussed. A structureborne noise generation mechanism is described in which the periodic components or propeller swirl produce periodic torques and forces on downstream wings and airfoils that are propagated to the cabin interior as noise. Three concepts for controlling structureborne noise are presented: (1) a stator row swirl remover, (2) selection of a proper combination of blade numbers in the rotor/stator system of a single-rotation propeller, and the rotor/rotor system of a counter-rotation propeller, and (3) a tuned mechanical absorber.

  13. The sound manifesto

    NASA Astrophysics Data System (ADS)

    O'Donnell, Michael J.; Bisnovatyi, Ilia

    2000-11-01

    Computing practice today depends on visual output to drive almost all user interaction. Other senses, such as audition, may be totally neglected, or used tangentially, or used in highly restricted specialized ways. We have excellent audio rendering through D-A conversion, but we lack rich general facilities for modeling and manipulating sound comparable in quality and flexibility to graphics. We need coordinated research in several disciplines to improve the use of sound as an interactive information channel. Incremental and separate improvements in synthesis, analysis, speech processing, audiology, acoustics, music, etc. will not alone produce the radical progress that we seek in sonic practice. We also need to create a new central topic of study in digital audio research. The new topic will assimilate the contributions of different disciplines on a common foundation. The key central concept that we lack is sound as a general-purpose information channel. We must investigate the structure of this information channel, which is driven by the cooperative development of auditory perception and physical sound production. Particular audible encodings, such as speech and music, illuminate sonic information by example, but they are no more sufficient for a characterization than typography is sufficient for characterization of visual information. To develop this new conceptual topic of sonic information structure, we need to integrate insights from a number of different disciplines that deal with sound. In particular, we need to coordinate central and foundational studies of the representational models of sound with specific applications that illuminate the good and bad qualities of these models. Each natural or artificial process that generates informative sound, and each perceptual mechanism that derives information from sound, will teach us something about the right structure to attribute to the sound itself. The new Sound topic will combine the work of computer

  14. 150 Passenger Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Bucovsky, Adrian; Romli, Fairuz I.; Rupp, Jessica

    2002-01-01

    It has been projected that the need for a short-range mid-sized, aircraft is increasing. The future strategy to decrease long-haul flights will increase the demand for short-haul flights. Since passengers prefer to meet their destinations quickly, airlines will increase the frequency of flights, which will reduce the passenger load on the aircraft. If a point-to-point flight is not possible, passengers will prefer only a one-stop short connecting flight to their final destination. A 150-passenger aircraft is an ideal vehicle for these situations. It is mid-sized aircraft and has a range of 3000 nautical miles. This type of aircraft would market U.S. domestic flights or inter-European flight routes. The objective of the design of the 150-passenger aircraft is to minimize fuel consumption. The configuration of the aircraft must be optimized. This aircraft must meet CO2 and NOx emissions standards with minimal acquisition price and operating costs. This report contains all the work that has been performed for the completion of the design of a 150 passenger commercial aircraft. The methodology used is the Technology Identification, Evaluation, and Selection (TIES) developed at Georgia Tech Aerospace Systems Design laboratory (ASDL). This is an eight-step conceptual design process to evaluate the probability of meeting the design constraints. This methodology also allows for the evaluation of new technologies to be implemented into the design. The TIES process begins with defining the problem with a need established and a market targeted. With the customer requirements set and the target values established, a baseline concept is created. Next, the design space is explored to determine the feasibility and viability of the baseline aircraft configuration. If the design is neither feasible nor viable, new technologies can be implemented to open up the feasible design space and allow for a plausible solution. After the new technologies are identified, they must be evaluated

  15. Sound field inside acoustically levitated spherical drop

    NASA Astrophysics Data System (ADS)

    Xie, W. J.; Wei, B.

    2007-05-01

    The sound field inside an acoustically levitated small spherical water drop (radius of 1mm) is studied under different incident sound pressures (amplitude p0=2735-5643Pa). The transmitted pressure ptr in the drop shows a plane standing wave, which varies mainly in the vertical direction, and distributes almost uniformly in the horizontal direction. The maximum of ptr is always located at the lowermost point of the levitated drop. Whereas the secondary maximum appears at the uppermost point if the incident pressure amplitude p0 is higher than an intermediate value (3044Pa), in which there exists a pressure nodal surface in the drop interior. The value of the maximum ptr lies in a narrow range of 2489-3173Pa, which has a lower limit of 2489Pa when p0=3044Pa. The secondary maximum of ptr is rather small and only remarkable at high incident pressures.

  16. The meaning of interior tomography.

    PubMed

    Wang, Ge; Yu, Hengyong

    2013-08-21

    The classic imaging geometry for computed tomography is for the collection of un-truncated projections and the reconstruction of a global image, with the Fourier transform as the theoretical foundation that is intrinsically non-local. Recently, interior tomography research has led to theoretically exact relationships between localities in the projection and image spaces and practically promising reconstruction algorithms. Initially, interior tomography was developed for x-ray computed tomography. Then, it was elevated to have the status of a general imaging principle. Finally, a novel framework known as 'omni-tomography' is being developed for a grand fusion of multiple imaging modalities, allowing tomographic synchrony of diversified features.

  17. Experimental active control of sound in the ATR 42

    NASA Astrophysics Data System (ADS)

    Paonessa, A.; Sollo, A.; Paxton, M.; Purver, M.; Ross, C. F.

    Passenger comfort is becoming day by day an important issue for the market of the regional turboprop aircraft and also for the future high speed propeller driven aircraft. In these aircraft the main contribution to the passenger annoyance is due to the propeller noise blade passing frequency (BPF) and its harmonics. In the recent past a detailed theoretical and experimental work has been done by Alenia Aeronautica in order to reduce the noise level in the ATR aircraft passenger cabin by means of conventional passive treatments: synchrophasing of propellers, dynamic vibration absorbers, structural reinforcements, damping materials. The application of these treatments has been introduced on production aircraft with a remarkable improvement of noise comfort but with a significant weight increase. For these reasons, a major technology step is required for reaching passenger comfort comparable to that of jet aircraft with the minimum weight increase. The most suitable approach to this problem has been envisaged in the active noise control which consists in generating an anti-sound field in the passenger cabin to reduce the noise at propeller BPF and its harmonics. The attenuation is reached by means of a control system which acquires information about the cabin noise distribution and the propeller speed during flight and simultaneously generates the signals to drive the speakers.

  18. Sound as artifact

    NASA Astrophysics Data System (ADS)

    Benjamin, Jeffrey L.

    A distinguishing feature of the discipline of archaeology is its reliance upon sensory dependant investigation. As perceived by all of the senses, the felt environment is a unique area of archaeological knowledge. It is generally accepted that the emergence of industrial processes in the recent past has been accompanied by unprecedented sonic extremes. The work of environmental historians has provided ample evidence that the introduction of much of this unwanted sound, or "noise" was an area of contestation. More recent research in the history of sound has called for more nuanced distinctions than the noisy/quiet dichotomy. Acoustic archaeology tends to focus upon a reconstruction of sound producing instruments and spaces with a primary goal of ascertaining intentionality. Most archaeoacoustic research is focused on learning more about the sonic world of people within prehistoric timeframes while some research has been done on historic sites. In this thesis, by way of a meditation on industrial sound and the physical remains of the Quincy Mining Company blacksmith shop (Hancock, MI) in particular, I argue for an acceptance and inclusion of sound as artifact in and of itself. I am introducing the concept of an individual sound-form, or sonifact , as a reproducible, repeatable, representable physical entity, created by tangible, perhaps even visible, host-artifacts. A sonifact is a sound that endures through time, with negligible variability. Through the piecing together of historical and archaeological evidence, in this thesis I present a plausible sonifactual assemblage at the blacksmith shop in April 1916 as it may have been experienced by an individual traversing the vicinity on foot: an 'historic soundwalk.' The sensory apprehension of abandoned industrial sites is multi-faceted. In this thesis I hope to make the case for an acceptance of sound as a primary heritage value when thinking about the industrial past, and also for an increased awareness and acceptance

  19. Quantification of advanced turboprop aircraft flyover noise annoyance

    NASA Technical Reports Server (NTRS)

    Mccurdy, D. A.

    1984-01-01

    A laboratory experiment was conducted to quantify the annoyance to advanced turboprop (propfan) aircraft flyover noise. A computer synthesis system was used to generate 45 realistic, time varying simulations of propeller aircraft flyover noise in which the tonal content was systematically varied to represent the factorial combinations of five fundamental frequencies, three frequency envelope shapes, and three tone-to-broadband noise ratios. In the experiment, 64 subjects judged the annoyance of recordings of the 45 synthesized flyover noises presented at three sound levels in a test facility which simulates the outdoor acoustic environment. Analyses of the judgements showed that frequency envelope shape did not significantly affect annoyance. The interaction of fundamental frequency with tone-to-broadband noise ratio did have a large and complex effect on annoyance. Duration corrected A-weighted sound pressure level with a modified tone correction predicted annoyance better than any other measurement procedure.

  20. Aircraft Engine Noise Scattering - A Discontinuous Spectral Element Approach

    NASA Technical Reports Server (NTRS)

    Stanescu, D.; Hussaini, M. Y.; Farassat, F.

    2002-01-01

    The paper presents a time-domain method for computation of sound radiation from aircraft engine sources to the far-field. The effects of nonuniform flow around the aircraft and scattering of sound by fuselage and wings are accounted for in the formulation. Our approach is based on the discretization of the inviscid flow equations through a collocation form of the Discontinuous Galerkin spectral element method. An isoparametric representation of the underlying geometry is used in order to take full advantage of the spectral accuracy of the method. Largescale computations are made possible by a parallel implementation based on message passing. Results obtained for radiation from an axisymmetric nacelle alone are compared with those obtained when the same nacelle is installed in a generic con.guration, with and without a wing.

  1. 149. Interior of Room B3, Air Compressor Room, showing a ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    149. Interior of Room B-3, Air Compressor Room, showing a ca. 1960s Worthington air compressor used to provide compressed air for powerhouse; air compressor powered by an electric motor; stairway (far left) leads to the generator room. Looking south. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  2. Engine-induced structural-borne noise in a general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Unruh, J. F.; Scheidt, D. C.; Pomerening, D. J.

    1979-01-01

    Structural borne interior noise in a single engine general aviation aircraft was studied to determine the importance of engine induced structural borne noise and to determine the necessary modeling requirements for the prediction of structural borne interior noise. Engine attached/detached ground test data show that engine induced structural borne noise is a primary interior noise source for the single engine test aircraft, cabin noise is highly influenced by responses at the propeller tone, and cabin acoustic resonances can influence overall noise levels. Results from structural and acoustic finite element coupled models of the test aircraft show that wall flexibility has a strong influence on fundamental cabin acoustic resonances, the lightweight fuselage structure has a high modal density, and finite element analysis procedures are appropriate for the prediction of structural borne noise.

  3. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place in the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of highly accurate and useful system.

  4. Seismic probes of solar interior magnetic structure.

    PubMed

    Hanasoge, Shravan; Birch, Aaron; Gizon, Laurent; Tromp, Jeroen

    2012-09-01

    Sun spots are prominent manifestations of solar magnetoconvection, and imaging their subsurface structure is an outstanding problem of wide physical importance. Travel times of seismic waves that propagate through these structures are typically used as inputs to inversions. Despite the presence of strongly anisotropic magnetic waveguides, these measurements have always been interpreted in terms of changes to isotropic wave speeds and flow-advection-related Doppler shifts. Here, we employ partial-differential-equation-constrained optimization to determine the appropriate parametrization of the structural properties of the magnetic interior. Seven different wave speeds fully characterize helioseismic wave propagation: the isotropic sound speed, a Doppler-shifting flow-advection velocity, and an anisotropic magnetic velocity. The structure of magnetic media is sensed by magnetoacoustic slow and fast modes and Alfvén waves, each of which propagates at a different wave speed. We show that even in the case of weak magnetic fields, significant errors may be incurred if these anisotropies are not accounted for in inversions. Translation invariance is demonstrably lost. These developments render plausible the accurate seismic imaging of magnetoconvection in the Sun. PMID:23005276

  5. Seismic probes of solar interior magnetic structure.

    PubMed

    Hanasoge, Shravan; Birch, Aaron; Gizon, Laurent; Tromp, Jeroen

    2012-09-01

    Sun spots are prominent manifestations of solar magnetoconvection, and imaging their subsurface structure is an outstanding problem of wide physical importance. Travel times of seismic waves that propagate through these structures are typically used as inputs to inversions. Despite the presence of strongly anisotropic magnetic waveguides, these measurements have always been interpreted in terms of changes to isotropic wave speeds and flow-advection-related Doppler shifts. Here, we employ partial-differential-equation-constrained optimization to determine the appropriate parametrization of the structural properties of the magnetic interior. Seven different wave speeds fully characterize helioseismic wave propagation: the isotropic sound speed, a Doppler-shifting flow-advection velocity, and an anisotropic magnetic velocity. The structure of magnetic media is sensed by magnetoacoustic slow and fast modes and Alfvén waves, each of which propagates at a different wave speed. We show that even in the case of weak magnetic fields, significant errors may be incurred if these anisotropies are not accounted for in inversions. Translation invariance is demonstrably lost. These developments render plausible the accurate seismic imaging of magnetoconvection in the Sun.

  6. Space station interior noise analysis program

    NASA Technical Reports Server (NTRS)

    Stusnick, E.; Burn, M.

    1987-01-01

    Documentation is provided for a microcomputer program which was developed to evaluate the effect of the vibroacoustic environment on speech communication inside a space station. The program, entitled Space Station Interior Noise Analysis Program (SSINAP), combines a Statistical Energy Analysis (SEA) prediction of sound and vibration levels within the space station with a speech intelligibility model based on the Modulation Transfer Function and the Speech Transmission Index (MTF/STI). The SEA model provides an effective analysis tool for predicting the acoustic environment based on proposed space station design. The MTF/STI model provides a method for evaluating speech communication in the relatively reverberant and potentially noisy environments that are likely to occur in space stations. The combinations of these two models provides a powerful analysis tool for optimizing the acoustic design of space stations from the point of view of speech communications. The mathematical algorithms used in SSINAP are presented to implement the SEA and MTF/STI models. An appendix provides an explanation of the operation of the program along with details of the program structure and code.

  7. Space station interior noise analysis program

    NASA Astrophysics Data System (ADS)

    Stusnick, E.; Burn, M.

    1987-02-01

    Documentation is provided for a microcomputer program which was developed to evaluate the effect of the vibroacoustic environment on speech communication inside a space station. The program, entitled Space Station Interior Noise Analysis Program (SSINAP), combines a Statistical Energy Analysis (SEA) prediction of sound and vibration levels within the space station with a speech intelligibility model based on the Modulation Transfer Function and the Speech Transmission Index (MTF/STI). The SEA model provides an effective analysis tool for predicting the acoustic environment based on proposed space station design. The MTF/STI model provides a method for evaluating speech communication in the relatively reverberant and potentially noisy environments that are likely to occur in space stations. The combinations of these two models provides a powerful analysis tool for optimizing the acoustic design of space stations from the point of view of speech communications. The mathematical algorithms used in SSINAP are presented to implement the SEA and MTF/STI models. An appendix provides an explanation of the operation of the program along with details of the program structure and code.

  8. Interior Design Trends in Libraries.

    ERIC Educational Resources Information Center

    Sager, Don, Ed.

    2000-01-01

    Four contributing authors discuss perspectives on current trends in library interior design. Articles include: "Trends in Library Furnishings: A Manufacturer's Perspective" (Andrea Johnson); "Libraries, Architecture, and Light: The Architect's Perspective" (Rick McCarthy); "The Library Administrator's Perspective" (Chadwick Raymond); and "The…

  9. Interior Design: Teacher's Instructional Guide.

    ERIC Educational Resources Information Center

    Hays, Tricia

    This teacher's instructional guide, which is part of a family and consumer sciences education series focusing on a broad range of employment opportunities, is intended to assist teachers responsible for teaching one- and two-year interior design programs for Texas high school students. The following are among the items included: (1) introductory…

  10. Interior Design: Challenges and Solutions.

    ERIC Educational Resources Information Center

    School Planning and Management, 1999

    1999-01-01

    Presents solutions to architectural challenges in school interior design; these solutions made the indoor environments more conducive and attractive for learning. Addresses four challenges: making a long corridor look less like a tunnel; maintaining tradition and minimizing cost in a new athletic facility; designing a kindergarten that is secure…

  11. Interior Design Factors in Library Facilities.

    ERIC Educational Resources Information Center

    Jackson, Patricia Ann

    When planning the interior of a library facility, the planning team of librarian, library consultant, architect, and interior design consultant must focus attention on the basic principles of interior design and the psychological needs of the user. Colors for an interior should be selected with careful regard to space, light, and emotional and…

  12. IDENTIFICATION OF AIRCRAFT HAZARDS

    SciTech Connect

    K.L. Ashley

    2005-03-23

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in the ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2004, Section 6.4.1). That determination was conservatively based on limited knowledge of flight data in the area of concern and on crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a Monitored Geologic Repository (MGR) at Yucca Mountain using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987, Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. NUREG-0800 is being used here as a reference because some of the same considerations apply. The intended use of this report is to provide inputs for further screening and analysis of the identified aircraft hazards based on the criteria that apply to Category 1 and 2 event sequence analyses as defined in 10 CFR 63.2 (see Section 4). The scope of this technical report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the MGR at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (see Section 7).

  13. High altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdo, Renee Anna; Moller, David

    1990-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000 plus feet, which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 feet for six hours at Mach 0.7, while carrying 3,000 lbs. of payload. In addition, the aircraft must have a minimum range of 6,000 miles. In consideration of the novel nature of this project, the pilot must be able to take control in the event of unforeseen difficulties. Three aircraft configurations were determined to be the most suitable - a joined-wing, a biplane, and a twin-boom conventional airplane. The performance of each configuration was analyzed to investigate the feasibility of the project.

  14. Aircraft control position indicator

    NASA Technical Reports Server (NTRS)

    Dennis, Dale V. (Inventor)

    1987-01-01

    An aircraft control position indicator was provided that displayed the degree of deflection of the primary flight control surfaces and the manner in which the aircraft responded. The display included a vertical elevator dot/bar graph meter display for indication whether the aircraft will pitch up or down, a horizontal aileron dot/bar graph meter display for indicating whether the aircraft will roll to the left or to the right, and a horizontal dot/bar graph meter display for indicating whether the aircraft will turn left or right. The vertical and horizontal display or displays intersect to form an up/down, left/right type display. Internal electronic display driver means received signals from transducers measuring the control surface deflections and determined the position of the meter indicators on each dot/bar graph meter display. The device allows readability at a glance, easy visual perception in sunlight or shade, near-zero lag in displaying flight control position, and is not affected by gravitational or centrifugal forces.

  15. Aircraft noise synthesis system

    NASA Technical Reports Server (NTRS)

    Mccurdy, David A.; Grandle, Robert E.

    1987-01-01

    A second-generation Aircraft Noise Synthesis System has been developed to provide test stimuli for studies of community annoyance to aircraft flyover noise. The computer-based system generates realistic, time-varying, audio simulations of aircraft flyover noise at a specified observer location on the ground. The synthesis takes into account the time-varying aircraft position relative to the observer; specified reference spectra consisting of broadband, narrowband, and pure-tone components; directivity patterns; Doppler shift; atmospheric effects; and ground effects. These parameters can be specified and controlled in such a way as to generate stimuli in which certain noise characteristics, such as duration or tonal content, are independently varied, while the remaining characteristics, such as broadband content, are held constant. The system can also generate simulations of the predicted noise characteristics of future aircraft. A description of the synthesis system and a discussion of the algorithms and methods used to generate the simulations are provided. An appendix describing the input data and providing user instructions is also included.

  16. Aircraft Operations Classification System

    NASA Technical Reports Server (NTRS)

    Harlow, Charles; Zhu, Weihong

    2001-01-01

    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.

  17. Identification of Aircraft Hazards

    SciTech Connect

    K. Ashley

    2006-12-08

    Aircraft hazards were determined to be potentially applicable to a repository at Yucca Mountain in ''Monitored Geological Repository External Events Hazards Screening Analysis'' (BSC 2005 [DIRS 174235], Section 6.4.1). That determination was conservatively based upon limited knowledge of flight data in the area of concern and upon crash data for aircraft of the type flying near Yucca Mountain. The purpose of this report is to identify specific aircraft hazards that may be applicable to a monitored geologic repository (MGR) at Yucca Mountain, using NUREG-0800, ''Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants'' (NRC 1987 [DIRS 103124], Section 3.5.1.6), as guidance for the inclusion or exclusion of identified aircraft hazards. The intended use of this report is to provide inputs for further screening and analysis of identified aircraft hazards based upon the criteria that apply to Category 1 and Category 2 event sequence analyses as defined in 10 CFR 63.2 [DIRS 176544] (Section 4). The scope of this report includes the evaluation of military, private, and commercial use of airspace in the 100-mile regional setting of the repository at Yucca Mountain with the potential for reducing the regional setting to a more manageable size after consideration of applicable screening criteria (Section 7).

  18. Interior design for passive solar homes

    NASA Astrophysics Data System (ADS)

    Breen, J. C.

    1981-07-01

    The increasing emphasis on refinement of passive solar systems brought recognition to interior design as an integral part of passive solar architecture. Interior design can be used as a finetuning tool minimizing many of the problems associated with passive solar energy use in residential buildings. In addition, treatment of interior space in solar model homes may be a prime factor in determining sales success. A new style of interior design is evolving in response to changes in building from incorporating passive solar design features. The psychology behind passive solar architecture is reflected in interiors, and selection of interior components increasingly depends on the functional suitably of various interior elements.

  19. Interior design for passive solar homes

    SciTech Connect

    Breen, J. C.

    1981-07-01

    The increasing emphasis on refinement of passive solar systems has brought recognition to interior design as an integral part of passive solar architecture. Interior design can be used as a finetuning tool minimizing many of the problems associated with passive solar energy use in residential buildings. In addition, treatment of interior space in solar model homes may be a prime factor in determining sales success. A new style of interior design is evolving in response to changes in building form incorporating passive solar design features. The psychology behind passive solar architecture is reflected in interiors, and selection of interior components increasingly depends on the functional suitability of various interior elements.

  20. Aircraft icing instrumentation: Unfilled needs. [rotary wing aircraft

    NASA Technical Reports Server (NTRS)

    Kitchens, P. F.

    1980-01-01

    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.

  1. Velocity of Sound

    ERIC Educational Resources Information Center

    Gillespie, A.

    1975-01-01

    Describes a method for the determination of the velocity of sound using a dual oscilloscope on which is displayed the sinusoidal input into a loudspeaker and the signal picked up by a microphone. (GS)

  2. Sound Visualization and Holography

    ERIC Educational Resources Information Center

    Kock, Winston E.

    1975-01-01

    Describes liquid surface holograms including their application to medicine. Discusses interference and diffraction phenomena using sound wave scanning techniques. Compares focussing by zone plate to holographic image development. (GH)

  3. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1979-01-01

    The second part of a three-part series, this article describes sound measurement, effects, and indoor learning activities. Thirty elementary school activities are described with appropriate grade levels specified. (Author/CS)

  4. New materials for manned spacecraft, aircraft, and other applications

    NASA Technical Reports Server (NTRS)

    Radnofsky, M. I.

    1971-01-01

    The application of fire resistant spacecraft materials to the interior design of commercial aircraft is discussed. The use of such materials for curtains, upholstery, carpets, decorative panels, cabinets, paper products, and oxygen lines is examined. It is concluded that the highest degree of nonflammability can be obtained with inorganic fibers such as asbestos and fiber glass. The application of various chemical compounds for specific purposes is presented.

  5. The Sounds of Sentences: Differentiating the Influence of Physical Sound, Sound Imagery, and Linguistically Implied Sounds on Physical Sound Processing.

    PubMed

    Dudschig, Carolin; Mackenzie, Ian Grant; Strozyk, Jessica; Kaup, Barbara; Leuthold, Hartmut

    2016-10-01

    Both the imagery literature and grounded models of language comprehension emphasize the tight coupling of high-level cognitive processes, such as forming a mental image of something or language understanding, and low-level sensorimotor processes in the brain. In an electrophysiological study, imagery and language processes were directly compared and the sensory associations of processing linguistically implied sounds or imagined sounds were investigated. Participants read sentences describing auditory events (e.g., "The dog barks"), heard a physical (environmental) sound, or had to imagine such a sound. We examined the influence of the 3 sound conditions (linguistic, physical, imagery) on subsequent physical sound processing. Event-related potential (ERP) difference waveforms indicated that in all 3 conditions, prime compatibility influenced physical sound processing. The earliest compatibility effect was observed in the physical condition, starting in the 80-110 ms time interval with a negative maximum over occipital electrode sites. In contrast, the linguistic and the imagery condition elicited compatibility effects starting in the 180-220 ms time window with a maximum over central electrode sites. In line with the ERPs, the analysis of the oscillatory activity showed that compatibility influenced early theta and alpha band power changes in the physical, but not in the linguistic and imagery, condition. These dissociations were further confirmed by dipole localization results showing a clear separation between the source of the compatibility effect in the physical sound condition (superior temporal area) and the source of the compatibility effect triggered by the linguistically implied sounds or the imagined sounds (inferior temporal area). Implications for grounded models of language understanding are discussed. PMID:27473463

  6. The Sounds of Sentences: Differentiating the Influence of Physical Sound, Sound Imagery, and Linguistically Implied Sounds on Physical Sound Processing.

    PubMed

    Dudschig, Carolin; Mackenzie, Ian Grant; Strozyk, Jessica; Kaup, Barbara; Leuthold, Hartmut

    2016-10-01

    Both the imagery literature and grounded models of language comprehension emphasize the tight coupling of high-level cognitive processes, such as forming a mental image of something or language understanding, and low-level sensorimotor processes in the brain. In an electrophysiological study, imagery and language processes were directly compared and the sensory associations of processing linguistically implied sounds or imagined sounds were investigated. Participants read sentences describing auditory events (e.g., "The dog barks"), heard a physical (environmental) sound, or had to imagine such a sound. We examined the influence of the 3 sound conditions (linguistic, physical, imagery) on subsequent physical sound processing. Event-related potential (ERP) difference waveforms indicated that in all 3 conditions, prime compatibility influenced physical sound processing. The earliest compatibility effect was observed in the physical condition, starting in the 80-110 ms time interval with a negative maximum over occipital electrode sites. In contrast, the linguistic and the imagery condition elicited compatibility effects starting in the 180-220 ms time window with a maximum over central electrode sites. In line with the ERPs, the analysis of the oscillatory activity showed that compatibility influenced early theta and alpha band power changes in the physical, but not in the linguistic and imagery, condition. These dissociations were further confirmed by dipole localization results showing a clear separation between the source of the compatibility effect in the physical sound condition (superior temporal area) and the source of the compatibility effect triggered by the linguistically implied sounds or the imagined sounds (inferior temporal area). Implications for grounded models of language understanding are discussed.

  7. Alternative aircraft fuels technology

    NASA Technical Reports Server (NTRS)

    Grobman, J.

    1976-01-01

    NASA is studying the characteristics of future aircraft fuels produced from either petroleum or nonpetroleum sources such as oil shale or coal. These future hydrocarbon based fuels may have chemical and physical properties that are different from present aviation turbine fuels. This research is aimed at determining what those characteristics may be, how present aircraft and engine components and materials would be affected by fuel specification changes, and what changes in both aircraft and engine design would be required to utilize these future fuels without sacrificing performance, reliability, or safety. This fuels technology program was organized to include both in-house and contract research on the synthesis and characterization of fuels, component evaluations of combustors, turbines, and fuel systems, and, eventually, full-scale engine demonstrations. A review of the various elements of the program and significant results obtained so far are presented.

  8. Transport aircraft accident dynamics

    NASA Technical Reports Server (NTRS)

    Cominsky, A.

    1982-01-01

    A study was carried out of 112 impact survivable jet transport aircraft accidents (world wide) of 27,700 kg (60,000 lb.) aircraft and up extending over the last 20 years. This study centered on the effect of impact and the follow-on events on aircraft structures and was confined to the approach, landing and takeoff segments of the flight. The significant characteristics, frequency of occurrence and the effect on the occupants of the above data base were studied and categorized with a view to establishing typical impact scenarios for use as a basis of verifying the effectiveness of potential safety concepts. Studies were also carried out of related subjects such as: (1) assessment of advanced materials; (2) human tolerance to impact; (3) merit functions for safety concepts; and (4) impact analysis and test methods.

  9. Pathfinder aircraft in flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Pathfinder research aircraft's solar cell arrays are prominently displayed as it touches down on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, following a test flight. The solar arrays covered more than 75 percent of Pathfinder's upper wing surface, and provided electricity to power its six electric motors, flight controls, communications links and a host of scientific sensors. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  10. Pathfinder aircraft in flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The unique Pathfinder solar-powered flying wing, is shown during a checkout flight from the Dryden Flight Research Center, Edwards, California. This two-hour low-altitude flight over Rogers Dry Lake, Nov. 19, 1996, served to test aircraft systems and functional procedures, according to officials of AeroVironment, Inc., Pathfinder's developer and operator. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  11. Pathfinder aircraft in flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Pathfinder solar-powered research aircraft heads for landing on the bed of Rogers Dry Lake at the Dryden Flight Research Center, Edwards, California, after a successful test flight Nov. 19, 1996. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  12. Pathfinder aircraft in flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Pathfinder solar-powered research aircraft is silhouetted against a clear blue sky as it soars aloft during a checkout flight from the Dryden Flight Research Center, Edwards, California, November, 1996. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  13. Pathfinder aircraft flight

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Pathfinder research aircraft's wing structure is clearly defined as it soars under a clear blue sky during a test flight from Dryden Flight Research Center, Edwards, California, in November of 1996. Pathfinder was a lightweight, solar-powered, remotely piloted flying wing aircraft used to demonstrate the use of solar power for long-duration, high-altitude flight. Its name denotes its mission as the 'Pathfinder' or first in a series of solar-powered aircraft that will be able to remain airborne for weeks or months on scientific sampling and imaging missions. Solar arrays covered most of the upper wing surface of the Pathfinder aircraft. These arrays provided up to 8,000 watts of power at high noon on a clear summer day. That power fed the aircraft's six electric motors as well as its avionics, communications, and other electrical systems. Pathfinder also had a backup battery system that could provide power for two to five hours, allowing for limited-duration flight after dark. Pathfinder flew at airspeeds of only 15 to 20 mph. Pitch control was maintained by using tiny elevators on the trailing edge of the wing while turns and yaw control were accomplished by slowing down or speeding up the motors on the outboard sections of the wing. On September 11, 1995, Pathfinder set a new altitude record for solar-powered aircraft of 50,567 feet above Edwards Air Force Base, California, on a 12-hour flight. On July 7, 1997, it set another, unofficial record of 71,500 feet at the Pacific Missile Range Facility, Kauai, Hawaii. In 1998, Pathfinder was modified into the longer-winged Pathfinder Plus configuration. (See the Pathfinder Plus photos and project description.)

  14. Aircraft engines. II

    SciTech Connect

    Smith, M.G. Jr.

    1988-01-01

    An account is given of the design features and prospective performance gains of ultrahigh bypass subsonic propulsion configurations and various candidate supersonic commercial aircraft powerplants. The supersonic types, whose enhanced thermodynamic cycle efficiency is considered critical to the economic viability of a second-generation SST, are the variable-cycle engine, the variable stream control engine, the turbine-bypass engine, and the supersonic-throughflow fan. Also noted is the turboramjet concept, which will be applicable to hypersonic aircraft whose airframe structure materials can withstand the severe aerothermodynamic conditions of this flight regime.

  15. Aircraft surface coatings

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Liquid, spray on elastomeric polyurethanes are selected and investigated as best candidates for aircraft external protective coatings. Flight tests are conducted to measure drag effects of these coatings compared to paints and a bare metal surface. The durability of two elastometric polyurethanes are assessed in airline flight service evaluations. Laboratory tests are performed to determine corrosion protection properties, compatibility with aircraft thermal anti-icing systems, the effect of coating thickness on erosion durability, and the erosion characteristics of composite leading edges-bare and coated. A cost and benefits assessment is made to determine the economic value of various coating configurations to the airlines.

  16. Alternative aircraft fuels

    NASA Technical Reports Server (NTRS)

    Longwell, J. P.; Grobman, J. S.

    1977-01-01

    The efficient utilization of fossil fuels by future jet aircraft may necessitate the broadening of current aviation turbine fuel specifications. The most significant changes in specifications would be an increased aromatics content and a higher final boiling point in order to minimize refinery energy consumption and costs. These changes would increase the freezing point and might lower the thermal stability of the fuel, and could cause increased pollutant emissions, increased combustor liner temperatures, and poorer ignition characteristics. The effects that broadened specification fuels may have on present-day jet aircraft and engine components and the technology required to use fuels with broadened specifications are discussed.

  17. Solar powered aircraft

    SciTech Connect

    Phillips, W.H.

    1983-11-15

    A cruciform wing structure for a solar powered aircraft is disclosed. Solar cells are mounted on horizontal wing surfaces. Wing surfaces with spanwise axis perpendicular to surfaces maintain these surfaces normal to the sun's rays by allowing aircraft to be flown in a controlled pattern at a large bank angle. The solar airplane may be of conventional design with respect to fuselage, propeller and tail, or may be constructed around a core and driven by propeller mechanisms attached near the tips of the airfoils.

  18. Solar powered aircraft

    NASA Technical Reports Server (NTRS)

    Phillips, W. H. (Inventor)

    1983-01-01

    A cruciform wing structure for a solar powered aircraft is disclosed. Solar cells are mounted on horizontal wing surfaces. Wing surfaces with spanwise axis perpendicular to surfaces maintain these surfaces normal to the Sun's rays by allowing aircraft to be flown in a controlled pattern at a large bank angle. The solar airplane may be of conventional design with respect to fuselage, propeller and tail, or may be constructed around a core and driven by propeller mechanisms attached near the tips of the airfoils.

  19. Aircraft Laminar Flow Control

    NASA Technical Reports Server (NTRS)

    Joslin, Ronald D.

    1998-01-01

    Aircraft laminar flow control (LFC) from the 1930's through the 1990's is reviewed and the current status of the technology is assessed. Examples are provided to demonstrate the benefits of LFC for subsonic and supersonic aircraft. Early studies related to the laminar boundary-layer flow physics, manufacturing tolerances for laminar flow, and insect-contamination avoidance are discussed. LFC concept studies in wind-tunnel and flight experiments are the major focus of the paper. LFC design tools are briefly outlined for completeness.

  20. Optical communications for transport aircraft

    NASA Technical Reports Server (NTRS)

    Stengel, Robert

    1994-01-01

    Optical communications for transport aircraft are discussed. The problem involves: increasing demand for radio-frequency bands from an enlarging pool of users (aircraft, ground and sea vehicles, fleet operators, traffic control centers, and commercial radio and television); desirability of providing high-bandwidth dedicated communications to and from every aircraft in the National Airspace System; need to support communications, navigation, and surveillance for a growing number of aircraft; and improved meteorological observations by use of probe aircraft. The solution involves: optical signal transmission support very high data rates; optical transmission of signals between aircraft, orbiting satellites, and ground stations, where unobstructed line-of-sight is available; conventional radio transmissions of signals between aircraft and ground stations, where optical line-of-sight is unavailable; and radio priority given to aircraft in weather.

  1. Aircraft community noise impact studies

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The objectives of the study are to: (1) conduct a program to determine the community noise impact of advanced technology engines when installed in a supersonic aircraft, (2) determine the potential reduction of community noise by flight operational techniques for the study aircraft, (3) estimate the community noise impact of the study aircraft powered by suppressed turbojet engines and by advanced duct heating turbofan engines, and (4) compare the impact of the two supersonic designs with that of conventional commercial DC-8 aircraft.

  2. Interiors of Enceladus and Rhea

    NASA Technical Reports Server (NTRS)

    Rappaport, N. J.; Iess, L.; Tortora, P.; Lunine, J. I.; Armstrong, J. W.; Asmar, S. W.; Somenzi, L.; Zingoni, F.

    2006-01-01

    Measurement method and data set: Gravity field parameters determined by means of range rate measurements over multiple arcs across flyby. Optical imaging not required when reliable a priori estimates of spacecraft state vector are available. Interior of Enceladus: Density of 1605 +/-14 kg/cu m, higher than pre-Cassini estimates, requires a substantial amount of rock to warmer interior to enhance likelihood of differentiation of water from rock-metal. Assume no porosity. Assuming Io s mean density for the rock-metal component, one finds its fractional mass to be 0.52+/-0.06. There is evidence that Enceladus may be differentiated: a) Areas devoid of craters must be geologically young. b) Systems of ridges, fractures, and groove indicate that the surface has been tectonically altered. c) Viscous relaxation of craters has occurred, and d) The plumes near the South pole indicate venting of subsurface volatiles.

  3. Planetary Interior in the Laboratory

    SciTech Connect

    Chau, R; Bastea, M; Mitchell, A C; Minich, R W; Nellis, W J

    2003-01-31

    In the three years of this project, we have provided a complete database of the electrical conductivity of planetary materials to 180 GPa. The electrical conductivities of these planetary materials now provide a basis for future modeling of planets taking into account full magnetohydrodynamics. By using a full magnetohydrodynamics simulation, the magnetic fields of the planets can then be taken into account. Moreover, the electrical conductivities of the planetary materials have given us insight into the structure and nature of these dense fluids. We showed that simple monoatomic fluids such as hydrogen, nitrogen, and oxygen at planetary interior conditions undergo a common metallization process which can be explained on a simple basis of their radial charge density distributions. This model also shows that the metallization process is actually rather common and likely to take place in a number of materials such as carbon monoxide which is also present within planetary objects. On the other hand, we have also showed that a simple two component fluid like water and methane take on much different behaviors than say nitrogen due to the chemical interactions within these systems. The dynamics of an even more complex system, ''synthetic Uranus'' are still being analyzed but suggest that on some levels the behavior is very simple, i.e. the electrical conductivity is essentially the same as water, but the local dynamics are very complex. This project has shed much light on the nature of electrical transport within planetary interiors but also has shown that understanding chemical processes in the complex fluids within planetary interiors to be very important. Understanding those local interactions and processes is required to gain further insight into planetary interiors.

  4. Bibliography for aircraft parameter estimation

    NASA Technical Reports Server (NTRS)

    Iliff, Kenneth W.; Maine, Richard E.

    1986-01-01

    An extensive bibliography in the field of aircraft parameter estimation has been compiled. This list contains definitive works related to most aircraft parameter estimation approaches. Theoretical studies as well as practical applications are included. Many of these publications are pertinent to subjects peripherally related to parameter estimation, such as aircraft maneuver design or instrumentation considerations.

  5. Commercial aircraft wake vortices

    NASA Astrophysics Data System (ADS)

    Gerz, Thomas; Holzäpfel, Frank; Darracq, Denis

    2002-04-01

    This paper discusses the problem of wake vortices shed by commercial aircraft. It presents a consolidated European view on the current status of knowledge of the nature and characteristics of aircraft wakes and of technical and operational procedures of minimizing and predicting the vortex strength and avoiding wake encounters. Methodological aspects of data evaluation and interpretation, like the description of wake ages, the characterization of wake vortices, and the proper evaluation of wake data from measurement and simulation, are addressed in the first part. In the second part an inventory of our knowledge is given on vortex characterization and control, prediction and monitoring of vortex decay, vortex detection and warning, vortex encounter models, and wake-vortex safety assessment. Each section is concluded by a list of questions and required actions which may help to guide further research activities. The primary objective of the joint international efforts in wake-vortex research is to avoid potentially hazardous wake encounters for aircraft. Shortened aircraft separations under appropriate meteorological conditions, whilst keeping or even increasing the safety level, is the ultimate goal. Reduced time delays on the tactical side and increased airport capacities on the strategic side will be the benefits of these ambitious ventures for the air transportation industry and services.

  6. Robots for Aircraft Maintenance

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Marshall Space Flight Center charged USBI (now Pratt & Whitney) with the task of developing an advanced stripping system based on hydroblasting to strip paint and thermal protection material from Space Shuttle solid rocket boosters. A robot, mounted on a transportable platform, controls the waterjet angle, water pressure and flow rate. This technology, now known as ARMS, has found commercial applications in the removal of coatings from jet engine components. The system is significantly faster than manual procedures and uses only minimal labor. Because the amount of "substrate" lost is minimal, the life of the component is extended. The need for toxic chemicals is reduced, as is waste disposal and human protection equipment. Users of the ARMS work cell include Delta Air Lines and the Air Force, which later contracted with USBI for development of a Large Aircraft Paint Stripping system (LARPS). LARPS' advantages are similar to ARMS, and it has enormous potential in military and civil aircraft maintenance. The technology may also be adapted to aircraft painting, aircraft inspection techniques and paint stripping of large objects like ships and railcars.

  7. Aircraft to Medicine

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This video discusses how the technology of computer modeling can improve the design and durability of artificial joints for human joint replacement surgery. Also, ultrasound, originally used to detect structural flaws in aircraft, can also be used to quickly assess the severity of a burn patient's injuries, thus aiding the healing process.

  8. Aircraft mission analysis

    NASA Technical Reports Server (NTRS)

    Hauge, D. S.; Rosendaal, H. L.

    1979-01-01

    Aircraft missions, from low to hypersonic speeds, are analyzed rapidly using the FORTRAN IV program NSEG. Program employs approximate equations of motion that vary in form with type of flight segment. Takeoffs, accelerations, climbs, cruises, descents, decelerations, and landings are considered.

  9. Aircraft adaptive learning control

    NASA Technical Reports Server (NTRS)

    Lee, P. S. T.; Vanlandingham, H. F.

    1979-01-01

    The optimal control theory of stochastic linear systems is discussed in terms of the advantages of distributed-control systems, and the control of randomly-sampled systems. An optimal solution to longitudinal control is derived and applied to the F-8 DFBW aircraft. A randomly-sampled linear process model with additive process and noise is developed.

  10. Non-auditory health effects among air force crew chiefs exposed to high level sound.

    PubMed

    Jensen, Anker; Lund, Søren Peter; Lücke, Thorsten Høgh; Clausen, Ole Voldum; Svendsen, Jørgen Torp

    2009-01-01

    The possibility of non-auditory health effects in connection with occupational exposure to high level sound is supposed by some researchers, but is still debated. Crew chiefs on airfields are exposed to high-level aircraft sound when working close to aircraft with running engines. We compared their health status with a similar control group who were not subject to this specific sound exposure. Health records of 42 crew chiefs were compared to health records of 42 aircraft mechanics and 17 former crew chiefs. The specific sound exposure of crew chiefs was assessed. The number of reported disease cases was generally small, but generally slightly higher among mechanics than among crew chiefs. Diseases of the ear were more frequent among crew chiefs (not significant). Former crew chiefs reported fewer diseases of the ear and more airways infections (both significant). The sound exposure during launch was up to 144 dB (peak) and 124 dB (L(eq) ), but for limited time. The study did not reveal a higher disease frequency in general among crew chiefs. However, it did reveal a tendency to ear diseases, possibly due to their exposure to high-level sound.

  11. Sound modes in holographic superfluids

    SciTech Connect

    Herzog, Christopher P.; Yarom, Amos

    2009-11-15

    Superfluids support many different types of sound waves. We investigate the relation between the sound waves in a relativistic and a nonrelativistic superfluid by using hydrodynamics to calculate the various sound speeds. Then, using a particular holographic scalar gravity realization of a strongly interacting superfluid, we compute first, second, and fourth sound speeds as a function of the temperature. The relativistic low temperature results for second sound differ from Landau's well known prediction for the nonrelativistic, incompressible case.

  12. AVE-SESAME 1: 25-MB sounding data

    NASA Technical Reports Server (NTRS)

    Gerhard, M. L.; Fuelberg, H. E.; Williams, S. F.; Turner, R. E.

    1979-01-01

    Seven atmospheric variability experiments (AVE), two atmospheric variability and severe storms experiments (AVSSE), and six atmospheric variability experiment-severe environmental storm and mesoscale experiments (AVE-SESAME) conducted by NASA are discussed. The dates, observation times, and data reports for each of the experiments for which data was processed are listed. The AVE experiments were conducted primarily to study atmospheric variability with emphasis on spatial and temporal in atmospheric structure that can be detected from soundings taken at 3 hr intervals but not seen in soundings taken at 12 hr intervals. The AVSSE experiments were conducted to study atmospheric structure and variability associated with severe storms combining both rawinsonde and aircraft data to provide information on near storm environments. The method of processing is discussed, estimates of the rms errors in the data are presented, an example of contact data is given, and soundings are listed which exhibited abnormal characteristics.

  13. On categorizing sounds

    NASA Astrophysics Data System (ADS)

    Lockhead, Gregory R.

    1991-08-01

    Context is important when people judge sounds, or attributes of sounds, or other stimuli. It is shown how judgments depend on what sounds recently occurred (sequence effects), on how those sounds differ from one another (range effects), on the distribution of those differences (set effects), on what subjects are told about the situation (task effects), and on what subjects are told about their performance (feedback effects). Each of these factors determines the overall mean and variability of response times and response choices, which are the standard measures, when people judge attribute amounts. Trial-by-trial analysis of the data show these factors also determine performance on individual trials. Moreover, these momentary data cannot be predicted from the overall data. The opposite is not true; the averaged data can be predicted from the momentary details. These results are consistent with a model having two simple assumptions: successive sounds (not just their attributes) assimilate toward one another in memory, and judgments are based on comparisons of these remembered events. It is suggested that relations between attributes, rather than the magnitudes of the attributes themselves, are the basis for judgment.

  14. Meteor fireball sounds identified

    NASA Technical Reports Server (NTRS)

    Keay, Colin

    1992-01-01

    Sounds heard simultaneously with the flight of large meteor fireballs are electrical in origin. Confirmation that Extra/Very Low Frequency (ELF/VLF) electromagnetic radiation is produced by the fireball was obtained by Japanese researchers. Although the generation mechanism is not fully understood, studies of the Meteorite Observation and Recovery Project (MORP) and other fireball data indicate that interaction with the atmosphere is definitely responsible and the cut-off magnitude of -9 found for sustained electrophonic sounds is supported by theory. Brief bursts of ELF/VLF radiation may accompany flares or explosions of smaller fireballs, producing transient sounds near favorably placed observers. Laboratory studies show that mundane physical objects can respond to electrical excitation and produce audible sounds. Reports of electrophonic sounds should no longer be discarded. A catalog of over 300 reports relating to electrophonic phenomena associated with meteor fireballs, aurorae, and lightning was assembled. Many other reports have been cataloged in Russian. These may assist the full solution of the similar long-standing and contentious mystery of audible auroral displays.

  15. GPS Sounding Rocket Developments

    NASA Technical Reports Server (NTRS)

    Bull, Barton

    1999-01-01

    Sounding rockets are suborbital launch vehicles capable of carrying scientific payloads several hundred miles in altitude. These missions return a variety of scientific data including; chemical makeup and physical processes taking place In the atmosphere, natural radiation surrounding the Earth, data on the Sun, stars, galaxies and many other phenomena. In addition, sounding rockets provide a reasonably economical means of conducting engineering tests for instruments and devices used on satellites and other spacecraft prior to their use in more expensive activities. The NASA Sounding Rocket Program is managed by personnel from Goddard Space Flight Center Wallops Flight Facility (GSFC/WFF) in Virginia. Typically around thirty of these rockets are launched each year, either from established ranges at Wallops Island, Virginia, Poker Flat Research Range, Alaska; White Sands Missile Range, New Mexico or from Canada, Norway and Sweden. Many times launches are conducted from temporary launch ranges in remote parts of the world requi6ng considerable expense to transport and operate tracking radars. An inverse differential GPS system has been developed for Sounding Rocket. This paper addresses the NASA Wallops Island history of GPS Sounding Rocket experience since 1994 and the development of a high accurate and useful system.

  16. Thermodynamics and Interior Structure Measurements of Ocean Worlds

    NASA Astrophysics Data System (ADS)

    Vance, S.; Brown, J. M.; Bollengier, O.; Bills, B. G.; Castillo, J. C.; Choukroun, M.; Jackson, J. M.; Kedar, S.; Tsai, V. C.

    2015-12-01

    Extending thermodynamics of aqueous solutions to elevated salinity and pressure is key to understanding icy moon oceans. Such a project is intrinsically linked to future seismic investigations, which would offer the most comprehensive views into the deep interiors of planetary bodies. The InSight Mars mission and Europa Lander mission concept both identify seismology as a critical measurement to constrain interior structure and thermal state of astrobiological targets. By pinpointing the radial depths of compositional interfaces, seismology in a broad frequency range can address uncertainty in interior structures inferred from gravity and magnetometry studies, such as those planned for the NASA's Europa and ESA's JUICE missions. Seismology also offers information about fluid motions within or beneath ice, which complement magnetic studies; and can record the dynamics of ice layers, which would reveal mechanisms and spatiotemporal occurrence of crack formation and propagation. Investigating these in the future calls for detailed modeling of seismic sources and signatures. Thermodynamic measurements of sound velocities and elastic moduli can provide needed seismic model inputs, as well as associated densities, thermal expansion, heat capacities, and chemical potentials for modeling interior structure. Sound speed profiles built from our internal structure models for Ganymede (Vance et al. 2014), using thermodynamically consistent data (Shaw 1986, Vance and Brown 2013) point to needed research, both in developing thermodynamic data from new laboratory measurements and applying them to problems in planetary geophysics. Comparing these profiles with simulated electrical conductivities of MgSO4 along the geotherms illustrates how dual seismology-magnetometry investigations can infer ocean density structure and salinity. Electrical conductivities are based on measurements by Larionov (1984) and Huang and Papangelakis (2006), and extrapolation to 273 K by Hand and Chyba

  17. Turboprop cargo aircraft systems study

    NASA Technical Reports Server (NTRS)

    Muehlbauer, J. C.; Hewell, J. G., Jr.; Lindenbaum, S. P.; Randall, C. C.; Searle, N.; Stone, R. G., Jr.

    1981-01-01

    The effects of using advanced turboprop propulsion systems to reduce the fuel consumption and direct operating costs of cargo aircraft were studied, and the impact of these systems on aircraft noise and noise prints around a terminal area was determined. Parametric variations of aircraft and propeller characteristics were investigated to determine their effects on noiseprint areas, fuel consumption, and direct operating costs. From these results, three aircraft designs were selected and subjected to design refinements and sensitivity analyses. Three competitive turbofan aircraft were also defined from parametric studies to provide a basis for comparing the two types of propulsion.

  18. Braking performance of aircraft tires

    NASA Astrophysics Data System (ADS)

    Agrawal, Satish K.

    This paper brings under one cover the subject of aircraft braking performance and a variety of related phenomena that lead to aircraft hydroplaning, overruns, and loss of directional control. Complex processes involving tire deformation, tire slipping, and fluid pressures in the tire-runway contact area develop the friction forces for retarding the aircraft; this paper describes the physics of these processes. The paper reviews the past and present research efforts and concludes that the most effective way to combat the hazards associated with aircraft landings and takeoffs on contaminated runways is by measuring and displaying in realtime the braking performance parameters in the aircraft cockpit.

  19. An Overview of Virtual Acoustic Simulation of Aircraft Flyover Noise

    NASA Technical Reports Server (NTRS)

    Rizzi, Stephen A.

    2013-01-01

    Methods for testing human subject response to aircraft flyover noise have greatly advanced in recent years as a result of advances in simulation technology. Capabilities have been developed which now allow subjects to be immersed both visually and aurally in a three-dimensional, virtual environment. While suitable for displaying recorded aircraft noise, the true potential is found when synthesizing aircraft flyover noise because it allows the flexibility and freedom to study sounds from aircraft not yet flown. A virtual acoustic simulation method is described which is built upon prediction-based source noise synthesis, engineering-based propagation modeling, and empirically-based receiver modeling. This source-path-receiver paradigm allows complete control over all aspects of flyover auralization. With this capability, it is now possible to assess human response to flyover noise by systematically evaluating source noise reductions within the context of a system level simulation. Examples of auralized flyover noise and movie clips representative of an immersive aircraft flyover environment are made in the presentation.

  20. 78 FR 48715 - Proposed Information Collection; Comment Request: NPS Study of Value of Natural Sounds: A Pilot...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-09

    ... 4, 2011, we published a Federal Register notice (76 FR 6495) announcing that we would submit this... Sounds: A Pilot Study AGENCY: National Park Service, Interior. ACTION: Notice; request for comments... ``1024-SOUND''. Please also send a copy of your comments to Phadrea Ponds, Information...

  1. Monaural Sound Localization Revisited

    NASA Technical Reports Server (NTRS)

    Wightman, Frederic L.; Kistler, Doris J.

    1997-01-01

    Research reported during the past few decades has revealed the importance for human sound localization of the so-called 'monaural spectral cues.' These cues are the result of the direction-dependent filtering of incoming sound waves accomplished by the pinnae. One point of view about how these cues are extracted places great emphasis on the spectrum of the received sound at each ear individually. This leads to the suggestion that an effective way of studying the influence of these cues is to measure the ability of listeners to localize sounds when one of their ears is plugged. Numerous studies have appeared using this monaural localization paradigm. Three experiments are described here which are intended to clarify the results of the previous monaural localization studies and provide new data on how monaural spectral cues might be processed. Virtual sound sources are used in the experiments in order to manipulate and control the stimuli independently at the two ears. Two of the experiments deal with the consequences of the incomplete monauralization that may have contaminated previous work. The results suggest that even very low sound levels in the occluded ear provide access to interaural localization cues. The presence of these cues complicates the interpretation of the results of nominally monaural localization studies. The third experiment concerns the role of prior knowledge of the source spectrum, which is required if monaural cues are to be useful. The results of this last experiment demonstrate that extraction of monaural spectral cues can be severely disrupted by trial-to-trial fluctuations in the source spectrum. The general conclusion of the experiments is that, while monaural spectral cues are important, the monaural localization paradigm may not be the most appropriate way to study their role.

  2. Sounding rockets in Antarctica

    NASA Technical Reports Server (NTRS)

    Alford, G. C.; Cooper, G. W.; Peterson, N. E.

    1982-01-01

    Sounding rockets are versatile tools for scientists studying the atmospheric region which is located above balloon altitudes but below orbital satellite altitudes. Three NASA Nike-Tomahawk sounding rockets were launched from Siple Station in Antarctica in an upper atmosphere physics experiment in the austral summer of 1980-81. The 110 kg payloads were carried to 200 km apogee altitudes in a coordinated project with Arcas rocket payloads and instrumented balloons. This Siple Station Expedition demonstrated the feasibility of launching large, near 1,000 kg, rocket systems from research stations in Antarctica. The remoteness of research stations in Antarctica and the severe environment are major considerations in planning rocket launching expeditions.

  3. Eliciting Sound Memories.

    PubMed

    Harris, Anna

    2015-11-01

    Sensory experiences are often considered triggers of memory, most famously a little French cake dipped in lime blossom tea. Sense memory can also be evoked in public history research through techniques of elicitation. In this article I reflect on different social science methods for eliciting sound memories such as the use of sonic prompts, emplaced interviewing, and sound walks. I include examples from my research on medical listening. The article considers the relevance of this work for the conduct of oral histories, arguing that such methods "break the frame," allowing room for collaborative research connections and insights into the otherwise unarticulatable.

  4. Spectral analysis methods for vehicle interior vibro-acoustics identification

    NASA Astrophysics Data System (ADS)

    Hosseini Fouladi, Mohammad; Nor, Mohd. Jailani Mohd.; Ariffin, Ahmad Kamal

    2009-02-01

    Noise has various effects on comfort, performance and health of human. Sound are analysed by human brain based on the frequencies and amplitudes. In a dynamic system, transmission of sound and vibrations depend on frequency and direction of the input motion and characteristics of the output. It is imperative that automotive manufacturers invest a lot of effort and money to improve and enhance the vibro-acoustics performance of their products. The enhancement effort may be very difficult and time-consuming if one relies only on 'trial and error' method without prior knowledge about the sources itself. Complex noise inside a vehicle cabin originated from various sources and travel through many pathways. First stage of sound quality refinement is to find the source. It is vital for automotive engineers to identify the dominant noise sources such as engine noise, exhaust noise and noise due to vibration transmission inside of vehicle. The purpose of this paper is to find the vibro-acoustical sources of noise in a passenger vehicle compartment. The implementation of spectral analysis method is much faster than the 'trial and error' methods in which, parts should be separated to measure the transfer functions. Also by using spectral analysis method, signals can be recorded in real operational conditions which conduce to more consistent results. A multi-channel analyser is utilised to measure and record the vibro-acoustical signals. Computational algorithms are also employed to identify contribution of various sources towards the measured interior signal. These achievements can be utilised to detect, control and optimise interior noise performance of road transport vehicles.

  5. Creating Library Interiors: Planning and Design Considerations.

    ERIC Educational Resources Information Center

    Jones, Plummer Alston, Jr.; Barton, Phillip K.

    1997-01-01

    Examines design considerations for public library interiors: access; acoustical treatment; assignable and nonassignable space; building interiors: ceilings, clocks, color, control, drinking fountains; exhibit space: slotwall display, floor coverings, floor loading, furniture, lighting, mechanical systems, public address, copying machines,…

  6. Hyper-spectral Atmospheric Sounding. Appendixes 1

    NASA Technical Reports Server (NTRS)

    Smith, W. L.; Zhou, D. K.; Revercomb, H. E.; Huang, H. L.; Antonelli, P.; Mango, S. A.

    2002-01-01

    The Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS) is the first hyper-spectral remote sounding system to be orbited aboard a geosynchronous satellite. The GETS is designed to obtain revolutionary observations of the four dimensional atmospheric temperature, moisture, and wind structure as well as the distribution of the atmospheric trace gases, CO and O3. Although GIFTS will not be orbited until 2006-2008, a glimpse at the its measurement capabilities has been obtained by analyzing data from the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Airborne Sounder Test-bed-Interferometer (NAST-I) and Aqua satellite Atmospheric Infrared Sounder (AIRS). In this paper we review the GIFTS experiment and empirically assess measurement expectations based on meteorological profiles retrieved from the NAST aircraft and Aqua satellite AIRS spectral radiances.

  7. Empirical Prediction of Aircraft Landing Gear Noise

    NASA Technical Reports Server (NTRS)

    Golub, Robert A. (Technical Monitor); Guo, Yue-Ping

    2005-01-01

    This report documents a semi-empirical/semi-analytical method for landing gear noise prediction. The method is based on scaling laws of the theory of aerodynamic noise generation and correlation of these scaling laws with current available test data. The former gives the method a sound theoretical foundation and the latter quantitatively determines the relations between the parameters of the landing gear assembly and the far field noise, enabling practical predictions of aircraft landing gear noise, both for parametric trends and for absolute noise levels. The prediction model is validated by wind tunnel test data for an isolated Boeing 737 landing gear and by flight data for the Boeing 777 airplane. In both cases, the predictions agree well with data, both in parametric trends and in absolute noise levels.

  8. Effects of aircraft noise on human activities

    NASA Technical Reports Server (NTRS)

    Arnoult, M. D.; Gilfillan, L. G.

    1983-01-01

    The effects of aircrft noise on human activities was investigated by developing a battery of tasks (1) representative of a range of human activities and (2) sensitive to the disruptive effects of noise. The noise used were recordings of jet aircraft and helicopter sounds at three lvels of loudness--60, 70, and 80 dB(A). Experiment 1 investigated 12 different cognitive tasks, along with two intelligibility tasks included to validate that the noises were being effective. Interference with intelligibility was essentially the same as found in the research literature, but only inconsistent effects were found on either accuracy or latency of performance on the cognitive tasks. When the tasks were grouped into four categories (Intelligibility, Matching, Verbal, and Arithmetic), reliable differences in rated annoyingness of the noises were related to the task category and to the type of noise (jet or helicopter).

  9. High resolution non-contact interior profilometer

    DOEpatents

    Piltch, Martin S.; Patterson, R. Alan; Leeches, Gerald W.; Nierop, John Van; Teti, John J.

    2001-01-01

    Apparatus and method for inspecting the interior surfaces of devices such as vessels having a single entry port. Laser energy is launched into the vessel, and the light reflected from the interior surfaces is interfered with reference laser energy to produce an interference pattern. This interference pattern is analyzed to reveal information about the condition of the interior surfaces of the device inspected.

  10. Interior Design Research: A Human Ecosystem Model.

    ERIC Educational Resources Information Center

    Guerin, Denise A.

    1992-01-01

    The interior ecosystems model illustrates effects on the human organism of the interaction of the natural, behavioral, and built environment. Examples of interior lighting and household energy consumption show the model's flexibility for organizing study variables in interior design research. (SK)

  11. Market Aspects of an Interior Design Program.

    ERIC Educational Resources Information Center

    Gold, Judy E.

    A project was conducted to evaluate a proposed interior design program in order to determine the marketability (job availability in the field of interior design and home furnishings merchandising) and the feasibility (educational requirements for entrance into the interior design and home furnishings merchandising job market) of the program. To…

  12. State Skill Standards: Housing and Interior Design

    ERIC Educational Resources Information Center

    Nevada Department of Education, 2008

    2008-01-01

    Meeting the Housing and Interior Design Standards will provide students with skills for personal family life and towards becoming a professional in the interior design field. The mission of Housing and Interior Design education is to prepare students for family life, work life, and careers in the fashion industry by creating opportunities to…

  13. National Unmanned Aircraft Systems Project Office

    USGS Publications Warehouse

    Goplen, Susan E.; Sloan, Jeff L.

    2015-01-01

    The U.S. Geological Survey (USGS) National Unmanned Aircraft Systems (UAS) Project Office leads the implementation of UAS technology in the Department of the Interior (DOI). Our mission is to support the transition of UAS into DOI as a new cost-effective tool for collecting remote-sensing data to monitor environmental conditions, respond to natural hazards, recognize the consequences and benefits of land and climate change and conduct wildlife inventories. The USGS is teaming with all DOI agencies and academia as well as local, State, and Tribal governments with guidance from the Federal Aviation Administration and the DOI Office of Aviation Services (OAS) to lead the safe, efficient, costeffective and leading-edge adoption of UAS technology into the scientific research and operational activities of the DOI.

  14. Fire resistant films for aircraft applications

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.

    1983-01-01

    Alternative sandwich panel decorative films were investigated as replacements for the polyvinyl fluoride currently used in aircraft interiors. Candidate films were studied for flammability, smoke emission, toxic gas emission, flame spread, and suitability as a printing surface for the decorative acrylic ink system. Several of the candidate films tested were flame modified polyvinyl fluoride, polyvinylidene fluoride, polyimide, polyamide, polysulfone, polyphenylsulfone, polyethersulfone, polybenzimidazole, polycarbonate, polyparabanic acid, polyphosphazene, polyetheretherketon, and polyester. The films were evaluated as pure films only, films silk-screened with an acrylic ink, and films adhered to a phenolic fiberglass substrate. Films which exhibited the highest fire resistant properties included PEEK polyetheretherketon, Aramid polyamide, and ISO-BPE polyester. Previously announced in STAR as N83-22320

  15. Materials research for aircraft fire safety

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.; Bricker, R. W.

    1976-01-01

    The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high-temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of the state-of-the-art and the advanced bismaleimide composites are detailed.

  16. Air pollution from aircraft

    NASA Technical Reports Server (NTRS)

    Heywood, J. B.; Fay, J. A.; Chigier, N. A.

    1979-01-01

    Forty-one annotated abstracts of reports generated at MIT and the University of Sheffield are presented along with summaries of the technical projects undertaken. Work completed includes: (1) an analysis of the soot formation and oxidation rates in gas turbine combustors, (2) modelling the nitric oxide formation process in gas turbine combustors, (3) a study of the mechanisms causing high carbon monoxide emissions from gas turbines at low power, (4) an analysis of the dispersion of pollutants from aircraft both around large airports and from the wakes of subsonic and supersonic aircraft, (5) a study of the combustion and flow characteristics of the swirl can modular combustor and the development and verification of NO sub x and CO emissions models, (6) an analysis of the influence of fuel atomizer characteristics on the fuel-air mixing process in liquid fuel spray flames, and (7) the development of models which predict the stability limits of fully and partially premixed fuel-air mixtures.

  17. Aircraft turbofan noise

    NASA Technical Reports Server (NTRS)

    Groeneweg, J. F.; Rice, E. J.

    1983-01-01

    Turbofan noise generation and suppression in aircraft engines are reviewed. The chain of physical processes which connect unsteady flow interactions with fan blades to far field noise is addressed. Mechanism identification and description, duct propagation, radiation and acoustic suppression are discussed. The experimental technique of fan inflow static tests are discussed. Rotor blade surface pressure and wake velocity measurements aid in the determination of the types and strengths of the generation mechanisms. Approaches to predicting or measuring acoustic mode content, optimizing treatment impedance to maximize attenuation, translating impedance into porous wall structure and interpreting far field directivity patterns are illustrated by comparisons of analytical and experimental results. The interdependence of source and acoustic treatment design to minimize far field noise is emphasized. Area requiring further research are discussed and the relevance of aircraft turbofan results to quieting other turbomachinery installations is addressed.

  18. Autonomous aircraft initiative study

    NASA Technical Reports Server (NTRS)

    Hewett, Marle D.

    1991-01-01

    The results of a consulting effort to aid NASA Ames-Dryden in defining a new initiative in aircraft automation are described. The initiative described is a multi-year, multi-center technology development and flight demonstration program. The initiative features the further development of technologies in aircraft automation already being pursued at multiple NASA centers and Department of Defense (DoD) research and Development (R and D) facilities. The proposed initiative involves the development of technologies in intelligent systems, guidance, control, software development, airborne computing, navigation, communications, sensors, unmanned vehicles, and air traffic control. It involves the integration and implementation of these technologies to the extent necessary to conduct selected and incremental flight demonstrations.

  19. Project report: Aircraft

    SciTech Connect

    Wuebbles, D.J.; Baughcum, S.; Metwally, M.; Seals, R.

    1994-04-01

    Analyses of scenarios of past and possible future emissions are an important aspect of assessing the potential environmental effects from aircraft, including the proposed high speed civil transport (HSCT). The development of a detailed three-dimensional database that accurately represents the integration of all aircraft emissions along realistic flight paths for such scenarios requires complex computational modeling capabilities. Such a detailed data set is required for the scenarios evaluated in this interim assessment. Within the NASA High-Speed Research Program, the Emissions Scenarios Committee provides a forum for identifying the required scenarios and evaluating the resulting database being developed with the advanced emissions modeling capabilities at the Boeing Company and McDonnell Douglas Corporation.

  20. Aircraft engine pollution reduction.

    NASA Technical Reports Server (NTRS)

    Rudey, R. A.

    1972-01-01

    The effect of engine operation on the types and levels of the major aircraft engine pollutants is described and the major factors governing the formation of these pollutants during the burning of hydrocarbon fuel are discussed. Methods which are being explored to reduce these pollutants are discussed and their application to several experimental research programs are pointed out. Results showing significant reductions in the levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen obtained from experimental combustion research programs are presented and discussed to point out potential application to aircraft engines. An experimental program designed to develop and demonstrate these and other advanced, low pollution combustor design methods is described. Results that have been obtained to date indicate considerable promise for reducing advanced engine exhaust pollutants to levels significantly below current engines.

  1. Energy efficient aircraft engines

    NASA Technical Reports Server (NTRS)

    Chamberlin, R.; Miller, B.

    1979-01-01

    The three engine programs that constitute the propulsion portion of NASA's Aircraft Energy Efficiency Program are described, their status indicated, and anticipated improvements in SFC discussed. The three engine programs are (1) Engine Component Improvement--directed at current engines, (2) Energy Efficiency Engine directed at new turbofan engines, and (3) Advanced Turboprops--directed at technology for advanced turboprop--powered aircraft with cruise speeds to Mach 0.8. Unique propulsion system interactive ties to the airframe resulting from engine design features to reduce fuel consumption are discussed. Emphasis is placed on the advanced turboprop since it offers the largest potential fuel savings of the three propulsion programs and also has the strongest interactive ties to the airframe.

  2. Aircraft turbofan noise

    NASA Astrophysics Data System (ADS)

    Groeneweg, J. F.; Rice, E. J.

    1987-01-01

    Turbofan noise generation and suppression in aircraft engines are reviewed. The chain of physical processes which connect unsteady flow interactions with fan blades to far field noise is addressed. Mechanism identification and description, duct propagation, radiation, and acoustic suppression are discussed. The experimental techniques of fan inflow static tests are discussed. Rotor blade surface pressure and wake velocity measurements aid in the determination of the types and strengths of the generation mechanisms. Approaches to predicting or measuring acoustic mode content, optimizing treatment impedance to maximize attenuation, translating impedance into porous wall structure, and interpreting far field directivity patterns are illustrated by comparisons of analytical and experimental results. The interdependence of source and acoustic treatment design to minimize far field noise is emphasized. Areas requiring further research are discussed, and the relevance of aircraft turbofan results to quieting other turbomachinery installation is addressed.

  3. Aircraft turbofan noise

    NASA Astrophysics Data System (ADS)

    Groeneweg, J. F.; Rice, E. J.

    1983-03-01

    Turbofan noise generation and suppression in aircraft engines are reviewed. The chain of physical processes which connect unsteady flow interactions with fan blades to far field noise is addressed. Mechanism identification and description, duct propagation, radiation and acoustic suppression are discussed. The experimental technique of fan inflow static tests are discussed. Rotor blade surface pressure and wake velocity measurements aid in the determination of the types and strengths of the generation mechanisms. Approaches to predicting or measuring acoustic mode content, optimizing treatment impedance to maximize attenuation, translating impedance into porous wall structure and interpreting far field directivity patterns are illustrated by comparisons of analytical and experimental results. The interdependence of source and acoustic treatment design to minimize far field noise is emphasized. Area requiring further research are discussed and the relevance of aircraft turbofan results to quieting other turbomachinery installations is addressed.

  4. Laser detection of sound

    NASA Astrophysics Data System (ADS)

    Vignola, Joseph F.

    1991-05-01

    A prototype laser Doppler anemometry (LDA) system has been constructed to detect and measure underwater sound. The technique is based on measuring the Doppler shift of laser light scattered from small particles in colloidal suspension in water. These particles move with the sound wave and thus a measure of their velocity is a measure of the acoustic particle velocity. Experiments have been conducted using this system to measure the acoustic particle displacements in a standing wave tube. A study has been made from both theoretical and experimental perspectives of the performance characteristics and practical limitations of making such measurements. A computer simulation was used to study the effects of physical parameters of the prototype system such as laser power, system geometry, and particle size. Because several authors have suggested that Brownian motion of the scattering particle might limit the system's ability to make such measurements, particular interest has been focused on this question. It has been shown both experimentally and theoretically that Brownian motion does not limit the ability to measure acoustic particle velocity. The emphasis on practical consideration will lead to the development of a laboratory tool that can be used to make non-invasive measurements that can not be made with conventional types of pressure sensors such as a conventional microscope or hydroplane. Examples of such situations are the sound field in the vicinity of a radiating body where there is no simple relationship between acoustic pressure and acoustic particle velocity and sound velocity measurements near an air-water interface.

  5. Laser Detection of Sound

    NASA Astrophysics Data System (ADS)

    Vignola, Joseph F.

    1991-02-01

    A prototype laser Doppler anemometry (LDA) system has been constructed to detect and measure underwater sound. The technique is based on measuring the Doppler shift of laser light scattered from small particles in colloidal suspension in water. These particles move with the sound wave and thus a measure of their velocity is a measure of the acoustic particle velocity. Experiments have been conducted using this system to measure acoustic particle displacements in a standing wave tube. A study has been made from both theoretical and experimental perspectives of the performance characteristics and practical limitations of making such measurements. A computer simulation was used to study the effects of physical parameters of the prototype system such as the laser power, system geometry and particle size. Because several authors have suggested that Brownian motion of the scattering particle might limit the system's ability to make such measurements, particular interest has been focused on this question. It has been shown both experimentally and theoretically that Brownian motion does not limit the ability to measure acoustic particle velocity. The emphasis on practical consideration will lead to the development of a laboratory tool that can be used to make non-invasive measurements that can not be made with conventional types of pressure sensors such as a conventional microscope or hydroplane. Examples of such situations are the sound field in the vicinity of a radiating body where there is no simple relationship between acoustic pressure and acoustic particle velocity and sound velocity measurements near an air-water interface.

  6. Exploring Noise: Sound Pollution.

    ERIC Educational Resources Information Center

    Rillo, Thomas J.

    1980-01-01

    This article is the last of a three-part series dealing with sound measurement, effects, pollution, and indoor/door learning activities. This section focuses on outdoor activities and equipment that students can make to assist them in data collection. (Author/SA)

  7. Exploring Sound with Insects

    ERIC Educational Resources Information Center

    Robertson, Laura; Meyer, John R.

    2010-01-01

    Differences in insect morphology and movement during singing provide a fascinating opportunity for students to investigate insects while learning about the characteristics of sound. In the activities described here, students use a free online computer software program to explore the songs of the major singing insects and experiment with making…

  8. Creative Sound Dramatics

    ERIC Educational Resources Information Center

    Hendrix, Rebecca; Eick, Charles

    2014-01-01

    Sound propagation is not easy for children to understand because of its abstract nature, often best represented by models such as wave drawings and particle dots. Teachers Rebecca Hendrix and Charles Eick wondered how science inquiry, when combined with an unlikely discipline like drama, could produce a better understanding among their…

  9. Sounds Like Fun.

    ERIC Educational Resources Information Center

    Lucas, Linda M.

    1991-01-01

    Presents hands-on science activities that help students learn the concepts of hearing and sound while allowing students to practice science process skills. Students investigate the use of alternative phonograph speakers and needles and apply the knowledge learned to the construction of one-string banjos. (MDH)

  10. Interior order expands minerals management

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    In a surprise move on May 10, Secretary of the Interior James G. Watt ordered the consolidation of all leasing and resource management functions for the outer continental shelf (OCS) into the Minerals Management Service (MMS). Among those programs shifted to MMS are ‘all functions in direct support of the OCS program’ in the Geologic Division and in the Office of the Assistant Director for Resource Programs of the U.S. Geological Survey (USGS), including oil and gas resources, energy-related hazards, and marine geology investigations. It is unclear whether research associated with the OCS leasing functions will be considered ‘direct support’ and what will happen to the research if it is so considered.Also to be shuttled to MMS are the oil-spill trajectory functions of the Office of Earth Sciences Applications and all the functions of the Office of Policy Analysis relating to the OCS that had been transferred from the Department of Energy as a result of the Interior and Related Agencies Appropriations Act.

  11. Mercury's Interior Structure and Geodesy

    NASA Astrophysics Data System (ADS)

    van Hoolst, T.

    2004-12-01

    Interior structure models of Mercury have been calculated with particular focus on the core. Mercury has a very large core, compared to the other terrestrial planets, thought to consist mainly of iron and an unknown amount of sulfur. Thermal evolution models, high pressure data on iron alloys, and the magnetic measurements of Mariner 10 point to a core structure as for the Earth, with a solid inner core and a liquid outer core. We have considered a plausible range in sulfur concentration for the core and constructed Mercury models in different phases of its core evolution, from entirely liquid to entirely solid cores. Data on core material relevant for the pressures and temperatures in Mercury's core is used, and we investigate the effects of sulfur dissolving in the solid inner core. Several geodesy experiments have the potential of providing insight into Mercury's deep interior. Precise measurements of Mercury's obliquity and libration in longitude, along with the harmonic degree 2 gravitational field coefficients will determine both the polar principal moment of inertia of the entire planet and of the mantle, C and Cm, respectively. On the other hand, Mercury's solid body tides, which are the largest of the solar system planets, are very sensitive to the core properties, and will be observed by the MESSENGER and BepiColombo missions. We calculated the moments of inertia C and Cm and the tidal reaction of our Mercury models, and studied their sensitivity to several core parameters.

  12. Electrical Thermometers for Aircraft

    NASA Technical Reports Server (NTRS)

    Peterson, John B; Womack, S H J

    1937-01-01

    Electrical thermometers commonly used on aircraft are the thermoelectric type for measuring engine-cylinder temperatures, the resistance type for measuring air temperatures, and the superheat meters of thermoelectric and resistance types for use on airships. These instruments are described and their advantages and disadvantages enumerated. Methods of testing these instruments and the performance to be expected from each are discussed. The field testing of engine-cylinder thermometers is treated in detail.

  13. Active control of structurally-coupled sound fields in elastic cylinders by vibrational force inputs

    NASA Technical Reports Server (NTRS)

    Jones, J. D.; Fuller, C. R.

    1990-01-01

    Active control of structurally-coupled sound fields in elastic cylinders is analytically and experimentally studied. The primary (noise) field in the cylinder model is generated by the coupled dynamic response of the shell under loading by a single exterior acoustic source. Control of the interior sound field is achieved by applying vibrational force inputs directly to the shell wall. Action of the point controllers serve to increase the input impedance of select structural modes of the shell which are well-coupled to the interior acoustic cavity, thus substantially reducing sound transmission into the cavity. Spatially-averaged noise reductions in excess of 30 dB are demonstrated for acoustic resonant conditions within the cavity. Twin controller configurations are presented which demonstrate the ability to independently control orthogonal modes of the interior acoustic space. Benefits and drawbacks of this new methodology for noise control are discussed and clearly demonstrated.

  14. Controlled impact demonstration on-board (interior) photographic system

    NASA Technical Reports Server (NTRS)

    May, C. J.

    1986-01-01

    Langley Research Center (LaRC) was responsible for the design, manufacture, and integration of all hardware required for the photographic system used to film the interior of the controlled impact demonstration (CID) B-720 aircraft during actual crash conditions. Four independent power supplies were constructed to operate the ten high-speed 16 mm cameras and twenty-four floodlights. An up-link command system, furnished by Ames Dryden Flight Research Facility (ADFRF), was necessary to activate the power supplies and start the cameras. These events were accomplished by initiation of relays located on each of the photo power pallets. The photographic system performed beyond expectations. All four power distribution pallets with their 20 year old Minuteman batteries performed flawlessly. All 24 lamps worked. All ten on-board high speed (400 fps) 16 mm cameras containing good resolution film data were recovered.

  15. Application of stiffened cylinder analysis to ATP interior noise studies

    NASA Technical Reports Server (NTRS)

    Wilby, E. G.; Wilby, J. F.

    1983-01-01

    An analytical model developed to predict the interior noise of propeller driven aircraft was applied to experimental configurations for a Fairchild Swearingen Metro II fuselage exposed to simulated propeller excitation. The floor structure of the test fuselage was of unusual construction - mounted on air springs. As a consequence, the analytical model was extended to include a floor treatment transmission coefficient which could be used to describe vibration attenuation through the mounts. Good agreement was obtained between measured and predicted noise reductions when the foor treatment transmission loss was about 20 dB - a value which is consistent with the vibration attenuation provided by the mounts. The analytical model was also adapted to allow the prediction of noise reductions associated with boundary layer excitation as well as propeller and reverberant noise.

  16. 19 CFR 10.183 - Duty-free entry of civil aircraft, aircraft engines, ground flight simulators, parts, components...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Duty-free entry of civil aircraft, aircraft engines, ground flight simulators, parts, components, and... aircraft, aircraft engines, and ground flight simulators, including their parts, components, and... United States (HTSUS) by meeting the following requirements: (1) The aircraft, aircraft engines,...

  17. Sounds of Space

    NASA Astrophysics Data System (ADS)

    Gurnett, D. A.

    2005-12-01

    Starting in the early 1960s, spacecraft-borne plasma wave instruments revealed that space is filled with an astonishing variety of radio and plasma wave sounds, which have come to be called "sounds of space." For over forty years these sounds have been collected and played to a wide variety of audiences, often as the result of press conferences or press releases involving various NASA projects for which the University of Iowa has provided plasma wave instruments. This activity has led to many interviews on local and national radio programs, and occasionally on programs haviang world-wide coverage, such as the BBC. As a result of this media coverage, we have been approached many times by composers requesting copies of our space sounds for use in their various projects, many of which involve electronic synthesis of music. One of these collaborations led to "Sun Rings," which is a musical event produced by the Kronos Quartet that has played to large audiences all over the world. With the availability of modern computer graphic techniques we have recently been attempting to integrate some of these sound of space into an educational audio/video web site that illustrates the scientific principles involved in the origin of space plasma waves. Typically I try to emphasize that a substantial gas pressure exists everywhere in space in the form of an ionized gas called a plasma, and that this plasma can lead to a wide variety of wave phenomenon. Examples of some of this audio/video material will be presented.

  18. Noise Reduction in an Aircraft Fuselage Model Using Active Trim Panels

    NASA Technical Reports Server (NTRS)

    Silcox, Richard J.; Lyle, Karen H.

    1996-01-01

    An experiment was conducted to evaluate the use of force actuators on a model aircraft interior trim panel as the control element for active control of interior noise. The trim panel, designed specifically for this study, was constructed in three large identical sections and hard mounted to the ring frames of the primary structure. Piezoceramic actuators were bonded to the outer surface of the trim panels. Studies of the interior pressure response due to both the primary source alone and control sources alone were conducted as well as the control cases. A single acoustic loudspeaker, centered at the axial midpoint, generated the acoustic field to be controlled.

  19. Implementation of unmanned aircraft systems by the U.S. Geological Survey

    USGS Publications Warehouse

    Cress, J.J.; Sloan, J.L.; Hutt, M.E.

    2011-01-01

    The U.S. Geological Survey (USGS) Unmanned Aircraft Systems (UAS) Project Office is leading the implementation of UAS technology in anticipation of transforming the research methods and management techniques employed across the Department of the Interior. UAS technology is being made available to monitor environmental conditions, analyse the impacts of climate change, respond to natural hazards, understand landscape change rates and consequences, conduct wildlife inventories and support related land management missions. USGS is teaming with the Department of the Interior Aviation Management Directorate (AMD) to lead the safe and cost-effective adoption of UAS technology by the Department of the Interior Agencies and USGS scientists.

  20. Acoustic Performance of a Real-Time Three-Dimensional Sound-Reproduction System

    NASA Technical Reports Server (NTRS)

    Faller, Kenneth J., II; Rizzi, Stephen A.; Aumann, Aric R.

    2013-01-01

    The Exterior Effects Room (EER) is a 39-seat auditorium at the NASA Langley Research Center and was built to support psychoacoustic studies of aircraft community noise. The EER has a real-time simulation environment which includes a three-dimensional sound-reproduction system. This system requires real-time application of equalization filters to compensate for spectral coloration of the sound reproduction due to installation and room effects. This paper describes the efforts taken to develop the equalization filters for use in the real-time sound-reproduction system and the subsequent analysis of the system s acoustic performance. The acoustic performance of the compensated and uncompensated sound-reproduction system is assessed for its crossover performance, its performance under stationary and dynamic conditions, the maximum spatialized sound pressure level it can produce from a single virtual source, and for the spatial uniformity of a generated sound field. Additionally, application examples are given to illustrate the compensated sound-reproduction system performance using recorded aircraft flyovers