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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,045 records · Page 58
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

A correlation of scale model and flight aeroacoustic data for the Space Shuttle vehicle

A correlation is presented between aeroacoustic data acquired in the early Space Shuttle flights and in the various scale model tests from which the Shuttle vibroacoustic design environments were derived. These are the external acoustic data on the vehicle elements at liftoff, during the transonic and maximum dynamic pressure period of ascent flight, and during spent SRB reentry. The maximum external acoustic environment on the Shuttle elements in a given 1/3-octave frequency band comes from one of these critical flight regimes. The data correlation is seen to be good, testifying to adequate scale model measurement and test techniques. Some of the more salient features of the scale model test programs are described.

Dougherty, N. S.↗
NASA NTRS1938

Tests of Five Full-Scale Propellers in the Presence of a Radial and a Liquid-Cooled Engine Nacelle, Including Tests of Two Spinners

Wind-tunnel tests are reported of five 3-blade 10-foot propellers operating in front of a radial and a liquid-cooled engine nacelle. The range of blade angles investigated extended from 15 degrees to 45 degrees. Two spinners were tested in conjunction with the liquid-cooled engine nacelle. Comparisons are made between propellers having different blade-shank shapes, blades of different thickness, and different airfoil sections. The results show that propellers operating in front of the liquid-cooled engine nacelle had higher take-off efficiencies than when operating in front of the radial engine nacelle; the peak efficiency was higher only when spinners were employed. One spinner increased the propulsive efficiency of the liquid-cooled unit 6 percent for the highest blade-angle setting investigated and less for lower blade angles. The propeller having airfoil sections extending into the hub was superior to one having round blade shanks. The thick propeller having a Clark y section had a higher take-off efficiency than the thinner one, but its maximum efficiency was possibly lower. Of the three blade sections tested, Clark y, R.A.F. 6, and NACA 2400-34, the Clark y was superior for the high-speed condition, but the R.A.F. 6 excelled for the take-off condition.

Biermann, David↗
NASA NTRS1992

Static and fatigue testing of full-scale fuselage panels fabricated using a Therm-X(R) process

Large, curved, integrally stiffened composite panels representative of an aircraft fuselage structure were fabricated using a Therm-X process, an alternative concept to conventional two-sided hard tooling and contour vacuum bagging. Panels subsequently were tested under pure shear loading in both static and fatigue regimes to assess the adequacy of the manufacturing process, the effectiveness of damage tolerant design features co-cured with the structure, and the accuracy of finite element and closed-form predictions of postbuckling capability and failure load. Test results indicated the process yielded panels of high quality and increased damage tolerance through suppression of common failure modes such as skin-stiffener separation and frame-stiffener corner failure. Finite element analyses generally produced good predictions of postbuckled shape, and a global-local modelling technique yielded failure load predictions that were within 7% of the experimental mean.

Dinicola, Albert J.↗
NASA NTRS2000

Current and Future Rocket Propulsion Testing at NASA Stennis Space Center

Year 2000 has been an active one for large-scale propulsion testing at the NASA John C. Stennis Space Center. This paper highlights several of the current-year test programs conducted at the Stennis Space Center (SSC) including the X-33 Aerospike Engine, Ultra Low Cost Engine (ULCE) program, and the Hybrid Sounding Rocket (HYSR) program. Future directions in propulsion test are also introduced including the development of a large-scale Rocket Based Combined Cycle (RBCC) test facility.

Ryan, H. M.↗
NASA NTRS2000

Research on the F/A-18E/F Using a 22%-Dynamically-Scaled Drop Model

Research on the F/A-18E/F configuration was conducted using a 22%-dynamically-scaled drop model to study flight dynamics in the subsonic regime. Several topics were investigated including longitudinal response, departure/spin resistance, developed spins and recoveries, and the failing leaf mode. Comparisons to full-scale flight test results were made and show the drop model strongly correlates to the airplane even under very dynamic conditions. The capability to use the drop model to expand on the information gained from full-scale flight testing is also discussed. Finally, a preliminary analysis of an unusual inclined spinning motion, dubbed the "cartwheel", is presented here for the first time.

Croom, M.↗
NASA NTRS1995

Advanced Short Takeoff and Vertical Landing (ASTOVL) Concepts Tested

In this cooperative program between NASA, Lockheed Corporation, and the Advanced Research and Projects Agency (ARPA), an advanced short takeoff and vertical landing (ASTOVL) model was tested in the 9- by 15-Foot Low-Speed Wind Tunnel at the NASA Lewis Research Center. The 10-percent scaled model was tested over a range of headwind velocities from 25 to 120 kn. This inlet/forebody test was a key part of an important Department of Defense program investigation enabling technologies for future high-performance ASTOVL aircraft. The Lockheed concept is focused on a shaft-coupled lift fan system centered around Pratt & Whitney's F119 power plant. As envisioned, a conventional takeoff and landing version (CTOL) would replace the U.S. Air Force's F-16's. The ASTOVL version would eventually replace Marine and, possibly, British Harrier aircraft. The ASTOVL and CTOL versions are scheduled to begin their manufacturing development phases in 2000. The purpose of this test was to acquire data pertinent to the inlet-forebody model. The test was very successful. Both steady-state and dynamic data were obtained. This small-scale testing, which is directed at reducing risks, may greatly reduce the risks on a full-scale aircraft.

Source record↗
NASA NTRS1960

Large-Scale Wind-Tunnel Tests and Evaluation of the Low-Speed Performance of a 35 deg Sweptback Wing Jet Transport Model Equipped with a Blowing Boundary-Layer-Control Flap and Leading-Edge Slat

A wind-tunnel investigation was conducted to determine the effect of trailing-edge flaps with blowing-type boundary-layer control and leading-edge slats on the low-speed performance of a large-scale jet transport model with four engines and a 35 deg. sweptback wing of aspect ratio 7. Two spanwise extents and several deflections of the trailing-edge flap were tested. Results were obtained with a normal leading-edge and with full-span leading-edge slats. Three-component longitudinal force and moment data and boundary-layer-control flow requirements are presented. The test results are analyzed in terms of possible improvements in low-speed performance. The effect on performance of the source of boundary-layer-control air flow is considered in the analysis.

Hickey, David H.↗
NASA NTRSDate not supplied

Fundamental Test of a Hovering Rotor: Comprehensive Measurements for CFD Validation

A model-scale hover test of a 4-bladed, 11.08-ft diameter rotor was recently completed inside the National Full-Scale Aerodynamics Complex 80- by 120-Foot Wind Tunnel test section. The primary objective of the test was to acquire key experimental data for a hovering rotor of sufficient quality and quantity to allow validation of state-of-the-art analysis codes. A comprehensive measurement set has been acquired, including rotor performance, blade airloads, flow transition locations, blade deflections, and wake geometry for a range of tip Mach numbers and collective settings. The present paper provides an overview of the test, including detailed descriptions of the hardware, instrumentation, and measurement systems. In addition, the specific test objectives, approach, and sample results are presented. The full test database, as well as detailed rotor geometry information, will ultimately be shared openly on a NASA-sponsored website to serve as a benchmark validation dataset.

Hover↗
NASA NTRS1989

The development of a capability for aerodynamic testing of large-scale wing sections in a simulated natural rain environment

A research technique to obtain large-scale aerodynamic data in a simulated natural rain environment has been developed. A 10-ft chord NACA 64-210 wing section wing section equipped with leading-edge and trailing-edge high-lift devices was tested as part of a program to determine the effect of highly-concentrated, short-duration rainfall on airplane performance. Preliminary dry aerodynamic data are presented for the high-lift configuration at a velocity of 100 knots and an angle of attack of 18 deg. Also, data are presented on rainfield uniformity and rainfall concentration intensity levels obtained during the calibration of the rain simulation system.

Bezos, Gaudy M.↗
NASA NTRSDate not supplied

Aeroacoustic Testing of UAS-Scale Rotors for a Quadcopter in Hover and Forward Flight

A series of experiments was conducted in an anechoic chamber and wind tunnel to investigatethe noise and performance of an optimum hovering rotor design. The optimum hovering rotorexperimental data set presented in this paper provides the community with a rotor that istheoretically easier to model. Isolated rotors were tested in an anechoic hover chamber as wellas on a representative quadcopter vehicle. In the anechoic chamber, performance and acousticmeasurements were taken at various rotor speeds to compare to those of a commercial-off-the-shelf (COTS) rotor. In the wind tunnel, free-stream velocity, vehicle pitch, and rotor rotationrates were varied to achieve various hover and forward flight operating conditions. Previousinvestigation of a small quadcopter in the Low Speed Aeroacoustic Wind Tunnel (LSAWT) hadidentified possible broadband and interactional noise sources due to rotor airframe interactionand rotor-rotor interaction. These publications identified separation, turbulent boundary layertrailing edge, and bluntness vortex shedding as the main sources of self-generated airfoil noise.By replacing the COTS rotor with an optimum hovering rotor design, self-generated broadbandnoise was reduced for both hover and forward flight conditions for isolated rotor runs. However,the optimum rotors only reduced noise levels for full-vehicle hover conditions, and had little tono reduction in full-vehicle forward flight conditions.

Nicole A Pettingill↗
NASA NTRS2011

Correlating CFD Simulation with Wind Tunnel Test for the Full-Scale UH-60A Airloads Rotor

Data from the recent UH-60A Airloads Test in the National Full-Scale Aerodynamics Complex 40- by 80- Foot Wind Tunnel at NASA Ames Research Center are presented and compared to predictions computed by a loosely coupled Computational Fluid Dynamics (CFD)/Comprehensive analysis. Primary calculations model the rotor in free-air, but initial calculations are presented including a model of the tunnel test section. The conditions studied include a speed sweep at constant lift up to an advance ratio of 0.4 and a thrust sweep at constant speed into deep stall. Predictions show reasonable agreement with measurement for integrated performance indicators such as power and propulsive but occasionally deviate significantly. Detailed analysis of sectional airloads reveals good correlation in overall trends for normal force and pitching moment but pitching moment mean often differs. Chord force is frequently plagued by mean shifts and an overprediction of drag on the advancing side. Locations of significant aerodynamic phenomena are predicted accurately although the magnitude of individual events is often missed.

Romandr, Ethan↗
NASA NTRS2013

Summary of Activities for Health Monitoring of Composite Overwrapped Pressure Vessels

This three-year project (FY12-14) will design and demonstrate the ability of new Magnetic Stress Gages for the measurement of stresses on the inner diameter of a Composite Overwrapped Pressure Vessel overwrap. The sensors are being tested at White Sands Testing Facility (WSTF) where the results will be correlated with a known nondestructive technique acoustic emission. The gages will be produced utilizing Meandering Winding Magnetometer (MWM) and/or MWM array eddy current technology. The ultimate goal is to utilize this technology for the health monitoring of Composite Overwrapped Pressure Vessels for all future flight programs. The first full-scale pressurization test was performed at WSTF in June 2012. The goals of this test were to determine adaptations of the magnetic stress gauge instrumentation that would be necessary to allow multiple sensors to monitor the vessel's condition simultaneously and to determine how the sensor response changes with sensor selection and orientation. The second full scale pressurization test was performed at WSTF in August 2012. The goals of this test were to monitor the vessel's condition with multiple sensors simultaneously, to determine the viability of the multiplexing units (MUX) for the application, and to determine if the sensor responses in different orientations are repeatable. For both sets of tests the vessel was pressured up to 6,000 psi to simulate maximum operating pressure. Acoustic events were observed during the first pressurization cycle. This suggested that the extended storage period prior to use of this bottle led to a relaxation of the residual stresses imparted during auto-frettage. The pressurization tests successfully demonstrated the use of multiplexers with multiple MWM arrays to monitor a vessel. It was discovered that depending upon the sensor orientation, the frequencies, and the sense element, the MWM arrays can provide a variety of complementary information about the composite overwrapped pressure vessel load conditions. For example, low frequency measurements can be used to monitor the overwrap thickness and changes associated with pressure level. High frequency data is dominated by the properties of the overwrap, including the fiber orientations and lay-up of the layers.

Russell, Rick↗
NASA NTRS1980

Tests of subgrid-scale models in strained turbulence

Strained and sheared turbulence is computed by direct simulation and it is shown that the results are in good qualitative agreement with experiments. It is found that after large amounts of strain have been applied to turbulence, the energy flow to the small scales is reduced and, in some cases, reversed. Eddy viscosity models are shown to be very poor in strained turbulence and, when they are used, the mean strain should not be included in them. Finally, new models proposed by Bardina et al. have been tested and found to offer considerable promise for the future.

Mcmillan, O. J.↗
NASA NTRS1974

Flutter tests (IS4) of the 0.0125-scale shuttle reflection plane model 30-OTS in the Langley Research Center 26-inch transonic blowdown tunnel test no. 547

A series of slab wing flutter models with rigid orbiter fuselage, external tank, and SRB models of the space shuttle were tested, in a reflection plane arrangement, in the NASA Langley Research Center's 26-inch Transonic Blowdown Tunnel. Model flutter boundaries were obtained for both a wing-alone configuration and a wing-with-orbiter, tank and SRB configuration. Additional test points were taken of the wing-with-orbiter configuration, as a correlation with the wing-alone condition. A description of the wind tunnel models and test procedures utilized in the experiment are provided.

Kotch, M. A.↗