Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “scaled testing”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

Prediction of flyover jet noise spectra from static tests

A scaling law is derived for predicting the flyover noise spectra of a single-stream shock-free circular jet from static experiments. The theory is based on the Lighthill approach to jet noise. Density terms are retained to include the effects of jet heating. The influence of flight on the turbulent flow field is considered by an experimentally supported similarity assumption. The resulting scaling laws for the difference between one-third-octave spectra and the overall sound pressure level compare very well with flyover experiments with a jet engine and with wind tunnel experiments with a heated model jet.

Michel, U.↗
NASA NTRSDate not supplied

A Summary of Test Results from a NASA Lift + Cruise eVTOL Crash Test

On November 9, 2022, the National Aeronautics and Space Administration (NASA) conducted a full-scale crash test of the NASA Lift+Cruise (LPC) reference vehicle at the NASA Langley Research Center Landing and Impact Research Facility (LandIR) under combined vertical and horizontal impact conditions to simulate a severe but survivable crash. The LPC test article is a carbon-composite skin/frame structure design, developed and fabricated for the cabin section only. The test utilized various configurations of seats and Anthropomorphic Test Devices (ATDs, a.k.a. crash test dummies) intended to encompass a variety of occupant conditions. In addition, an in-house developed energy absorbing subfloor was utilized for the evaluation of load attenuation. Overhead mass was simulated using attached lifting hardware and other systems were simulated using ballast mass. The test article impacted the ground with velocities of 38.1 ft/s horizontal and 31.4 ft/s vertical. During the first approximately 38 milliseconds (ms), the cabin section experienced a large amount of acceleration on the belly which was attenuated by the subfloor structures and seats. Over the next approximately 160 ms, the test article experienced failure in the a-, b- and c-pillars, leading to a partial collapse of the overhead structure. Test data was collected on the belly, floors, seats, overhead mass, and tail. In addition, there was high speed full-field digital image correlation analysis data collected on the port side skin surface. Collected ATD data showed that the ATDs seated in the energy absorbing seats experienced loads at limits below the those in current regulations. Even without an energy absorbing seat, the energy absorbing subfloors crushed as intended, and limited the load on the large 95 th percentile ATD to 10% over suggested limits. The collapse of the roof did affect the 95 th percentile ATD, which showed high neck loading values due to head contact, whereas survivable volume was maintained for the other ATDs. While the energy absorbing subfloor and energy absorbing seats both contributed to occupant load attenuation, further optimization is suggested to increase their robustness.

evtol↗
NASA NTRSDate not supplied

A Summary of Test Results from a NASA Lift + Cruise eVTOL Crash Test

On November 9, 2022, the National Aeronautics and Space Administration (NASA) conducted a full-scale crash test of the NASA Lift+Cruise (LPC) reference vehicle at the NASA Langley Research Center Landing and Impact Research Facility (LandIR) under combined vertical and horizontal impact conditions to simulate a severe but survivable crash. The LPC test article is a carbon-composite skin/frame structure design, developed and fabricated for the cabin section only. The test utilized various configurations of seats and Anthropomorphic Test Devices (ATDs, a.k.a. crash test dummies) intended to encompass a variety of occupant conditions. In addition, an in-house developed energy absorbing subfloor was utilized for the evaluation of load attenuation. Overhead mass was simulated using attached lifting hardware and other systems were simulated using ballast mass. The test article impacted the ground with velocities of 38.1 ft/s horizontal and 31.4 ft/s vertical. During the first approximately 38 milliseconds (ms), the cabin section experienced a large amount of acceleration on the belly which was attenuated by the subfloor structures and seats. Over the next approximately 160 ms, the test article experienced failure in the a-, b- and c-pillars, leading to a partial collapse of the overhead structure. Test data was collected on the belly, floors, seats, overhead mass, and tail. In addition, there was high speed full-field digital image correlation analysis data collected on the port side skin surface. Collected ATD data showed that the ATDs seated in the energy absorbing seats experienced loads at limits below the those in current regulations. Even without an energy absorbing seat, the energy absorbing subfloors crushed as intended, and limited the load on the large 95 th percentile ATD to 10% over suggested limits. The collapse of the roof did affect the 95 th percentile ATD, which showed high neck loading values due to head contact, whereas survivable volume was maintained for the other ATDs. While the energy absorbing subfloor and energy absorbing seats both contributed to occupant load attenuation, further optimization is suggested to increase their robustness.

evtol↗
NASA NTRS1991

Investigations of detail design issues for the high speed acoustic wind tunnel using a 60th scale model tunnel. Part 2: Tests with the closed circuit

This report summarizes the tests on the 1:60 scale model of the High Speed Acoustic Wind Tunnel (HSAWT) performed during the period June - August 1991. Throughout the testing the tunnel was operated in the 'closed circuit mode,' that is when the airflow was set up by an axial flow fan, which was located inside the tunnel circuit and was directly driven by a motor. The tests were first performed with the closed test section and were subsequently repeated with the open test section, the latter operating with the nozzle-diffuser at its optimum setting. On this subject, reference is made to the report (1) issued January 1991, under contract 17-GFY900125, which summarizes the result obtained with the tunnel operating in the 'open circuit mode.' The tests confirmed the viability of the tunnel design, and the flow distributions in most of the tunnel components were considered acceptable. There were found, however, some locations where the flow distribution requires improvement. This applies to the flow upstream of the fan where the flow was found skewed, thus affecting the flow downstream. As a result of this, the flow appeared separated at the end of the large diffuser at the outer side. All tests were performed at NASA LaRC.

Barna, P. Stephen↗
NASA NTRS1980

Large-scale wind-tunnel tests of inverting flaps on a STOL utility aircraft model

A unique inverting flap system was investigated on a large scale deflected slipstream model in the Ames 40 by 80 foot wind tunnel. The subject tests utilized 33% chord double-slotted flaps on a low aspect ratio wing that was fully immersed in the propeller slipstream. Evaluation of the flap effectiveness is aided by comparisons with the results of tests of other flap systems on the same twin propeller, twin tail boom STOL utility aircraft mode. No extreme or abrupt force or moment increments were encountered when the flaps were deflected through a wide range, corresponding to the complete retraction/extension spectrum. The lift and descent capability of the inverting flaps compared very favorably with that of the other flap systems that have been tested on this model, including some with much greater mechanical complexity. As expected, the flaps caused large nose down, pitching moment increments at the high lift settings; however, the trimmed characteristics are still competitive with those obtained from the more complicated flap systems. It is believed that these flaps may have promising potential application to the design of relatively simple STOL utility aircraft with improved performance capabilities. In addition, they may merit consideration as retrofits to existing aircraft with less effective flap systems.

Feistel, T. W.↗
NASA NTRS2010

Development and Operation of an Automatic Rotor Trim Control System for use During the UH-60 Individual Blade Control Wind Tunnel Test

A full-scale wind tunnel test to evaluate the effects of Individual Blade Control (IBC) on the performance, vibration, noise and loads of a UH-60A rotor was recently completed in the National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Foot Wind Tunnel [1]. A key component of this wind tunnel test was an automatic rotor trim control system that allowed the rotor trim state to be set more precisely, quickly and repeatably than was possible with the rotor operator setting the trim condition manually. The trim control system was also able to maintain the desired trim condition through changes in IBC actuation both in open- and closed-loop IBC modes, and through long-period transients in wind tunnel flow. This ability of the trim control system to automatically set and maintain a steady rotor trim enabled the effects of different IBC inputs to be compared at common trim conditions and to perform these tests quickly without requiring the rotor operator to re-trim the rotor. The trim control system described in this paper was developed specifically for use during the IBC wind tunnel test

Theodore, Colin R.↗
NASA NTRS1991

Investigations of detail design issues for the high speed acoustic wind tunnel using a 60th scale model tunnel. Part 1: Tests with open circuits

This report summarizes the tests on the 1:60 scale model of the High Speed Acoustic Wind Tunnel (HSAWT) performed during the period of November 1989 to December 1990. Throughout the testing the tunnel was operated in the 'open circuit mode', that is when the airflow was induced by a powerful exhaust fan located outside the tunnel circuit. The tests were first performed with the closed test section and were subsequently repeated with the open test section. While operating with the open test section, a novel device, called the 'nozzle-diffuser,' was also tested in order to establish its usefulness of increasing pressure recovery in the first diffuser. The tests established the viability of the tunnel design. The flow distribution in each tunnel component was found acceptable and pressure recovery in the diffusers were found satisfactory. The diffusers appeared to operate without flow separation. All tests were performed at NASA LaRC.

Barna, P. Stephen↗
NASA NTRS1974

Results of transonic wind tunnel tests on an 0.015-scale space shuttle mated vehicle model (67-ots) in the LaRC 8 foot TPT (IA41)

Wind tunnel tests were conducted to obtain aerodynamic force data for Mach numbers from 0.60 to 1.20. Data were obtained for an alpha range of -10 deg to +10 deg (beta = 0 deg beta = 5 deg) and beta range of -10 deg to +10 deg (alpha = 0 deg). Longitudinal and lateral-directional stability and control data were obtained for tank alone, tank plus SRB's, tank plus Orbiter, and mated configuration of tank + Orbiter + SRB's. Also, single-component rudder hinge moment data were obtained at rudder deflections of 0 and -20 deg for each Mach number tested. Plots of aerodynamic coefficients vs. Mach number are presented, using data from both test IA41 and tests LRC-UPWT-1056, 1073 (IA42A/B) for Mach numbers of 1.60 to 4.63. The model tested in IA42A/B was the same model as tested in IA41.

Hardin, R.↗
NASA NTRS2005

Impact of Scaled Technology on Radiation Testing and Hardening

This presentation gives a brief overview of some of the radiation challenges facing emerging scaled digital technologies with implications on using consumer grade electronics and next generation hardening schemes. Commercial semiconductor manufacturers are recognizing some of these issues as issues for terrestrial performance. Looking at means of dealing with soft errors. The thinned oxide has indicated improved TID tolerance of commercial products hardened by "serendipity" which does not guarantee hardness or say if the trend will continue. This presentation also focuses one reliability implications of thinned oxides.

LaBel, Kenneth A.↗
NASA NTRS1971

Full-scale wind-tunnel tests of a small unpowered jet aircraft with a T-tail

The aerodynamic characteristics of a full scale executive type jet transport aircraft with a T-tail were investigated in a 40 x 80 ft (12.2 by 24.4 meter) wind tunnel (subsonic). Static, longitudinal, and lateral stability, and control characteristics were determined at angles of attack from -2 deg to +42 deg. The aircraft wing had 13 deg of sweep and an aspect ratio of 5.02. The aircraft was tested power off with various wing leading- and trailing-edge high lift devices. The basic configuration was tested with and without such components as engine nacelles, wing tip tanks, and empannage. Hinge-moment data were obtained and downwash angles in the horizontal-tail plane location were calculated. The data were obtained at Reynolds numbers of 4.1 million and 8.7 million based on mean aerodynamic chord. The model had static longitudinal stability through initial stall. Severe tail buffet occurred near the angle of attack for maximum lift. Above initial stall the aircraft had pronounced pitch-up, characteristic of T-tail configurations. A stable trim point was possible at angles of attack between 30 deg and 40 deg (depending on c.g. location and flap setting). Hinge-moment data showed no regions with adverse effects on stick force. Comparisons of wind-tunnel data and flight-test are presented.

Soderman, P. T.↗
NASA NTRS1984

Fuel savings potential of the NASA Advanced Turboprop Program

The NASA Advanced Turboprop (ATP) Program is directed at developing new technology for highly loaded, multibladed propellers for use at Mach 0.65 to 0.85 and at altitudes compatible with the air transport system requirements. Advanced turboprop engines offer the potential of 15 to 30 percent savings in aircraft block fuel relative to advanced turbofan engines (50 to 60 percent savings over today's turbofan fleet). The concept, propulsive efficiency gains, block fuel savings and other benefits, and the program objectives through a systems approach are described. Current program status and major accomplishments in both single rotation and counter rotation propeller technology are addressed. The overall program from scale model wind tunnel tests to large scale flight tests on testbed aircraft is discussed.

Whitlow, J. B., Jr.↗
NASA NTRS2009

Integrated Resilient Aircraft Control Project Full Scale Flight Validation

Objective: Provide validation of adaptive control law concepts through full scale flight evaluation. Technical Approach: a) Engage failure mode - destabilizing or frozen surface. b) Perform formation flight and air-to-air tracking tasks. Evaluate adaptive algorithm: a) Stability metrics. b) Model following metrics. Full scale flight testing provides an ability to validate different adaptive flight control approaches. Full scale flight testing adds credence to NASA's research efforts. A sustained research effort is required to remove the road blocks and provide adaptive control as a viable design solution for increased aircraft resilience.

Bosworth, John T.↗
NASA NTRS1976

A low speed wind tunnel test of a 0.050 scale model of shuttle orbiter (model 089B) to investigate the longitudinal and lateral directional effects of canard and tail configurational modifications in the LTV LSWT (MA14)

A low speed wind tunnel test was conducted to determine the effects of 6 canard configurations on the 0.050 scale model of shuttle orbiter 089B. In addition, two horizontal tail configurations were tested at two positions on the model as were two wing configurations. Since this test was restricted to 103 runs, only a limited number of permutations of the configurational changes could be tested. The testing was done in the 15 by 20 foot section of the LSWT and consisted of pitch polars, one yawed polar and several yaw runs. The pitch polars encompassed an alpha range from 0 to 28 deg; the yawed polar was run at beta = +2 degrees and the yaw runs covered a beta range from -6 to +6 deg at angles-of-attack of 0, 4, 10, 16, and 20 deg.

Chambliss, E. B.↗
NASA NTRS1990

The acoustic results of a United Technologies scale model helicopter rotor tested at DNW

In a major cooperative program between U.S. Government agencies (represented by the U.S. Army Aeroflightdynamics Directorate and NASA Ames and Langley Research Centers) and United Technologies Corp., a 1/6 geometrically and aeroelastically scaled UTC model helicopter rotor was tested in the open-jet anechoic test section of the Duits-Nederlandse Windtunnel in the Netherlands. As the fourth entry under the Aerodynamic and Acoustic Testing of Model Rotors Program, several comprehensive acoustic and aerodynamic databases were obtained relating the important aerodynamic phenomena to both the near- and far-field acoustic radiation. In particular, high speed impulsive noise and blade-vortex interaction are of primary interest. This paper provides an initial summary of the acoustic measurements acquired for some of the different configurations tested. A review of the baseline swept tip rotor acoustic characteristics in the regimes of high speed forward flight, where high speed impulsive noise dominates, and low speed descent, where severe blade vortex interaction noise occurs, is presented. The trends of these primary noise sources are studied as the first step in validating the data for release and application.

Liu, Sandy R.↗
NASA NTRS1999

Overview of the Testing of a Small-Scale Proprotor

This paper presents an overview of results from the wind tunnel test of a 1/4-scale V-22 proprotor in the Duits-Nederlandse Windtunnel (DNW) in The Netherlands. The small-scale proprotor was tested on the isolated rotor configuration of the Tilt Rotor Aeroacoustic Model (TRAM). The test was conducted by a joint team from NASA Ames, NASA Langley, U.S. Army Aeroflightdynamics Directorate, and The Boeing Company. The objective of the test was to acquire a benchmark database for validating aeroacoustic analyses. Representative examples of airloads, acoustics, structural loads, and performance data are provided and discussed.

Young, Larry A.↗