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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 1,441 records · Page 80
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Flight test results for a separate surface stability augmented Beech model 99

A flight evaluation of a Beech model 99 equipped with an attitude command control system incorporating separate surface stability augmentation (SSSA) was conducted to determine whether an attitude command control system could be implemented using separate surface controls, and to determine whether the handling and ride qualities of the aircraft were improved by the SSSA attitude command system. The results of the program revealed that SSSA is a viable approach to implementing attitude command and also that SSSA has the capability of performing less demanding augmentation tasks such as yaw damping, wing leveling, and pitch damping. The program also revealed that attitude command did improve the pilot rating and ride qualities of the airplane while flying an IFR mission in turbulence. Some disadvantages of the system included the necessity of holding aileron force in a banked turn and excessive stiffness in the pitch axis.

Jenks, G. E.↗
NASA NTRS2003

Estimation of Unsteady Aerodynamic Models from Flight Test Data

This report summarizes the activities in aerodynamic model estimation from flight data. In addition to public presentations at the AIAA Atmospheric Flight Mechanics Conferences, two presentations at Boeing-Seattle were made during personal trips. These are discussed in the following: 1. Methodology of Aerodynamic Model Estimation from Flight Data. 2. Applications of F-16XL aerodynamic modeling. 3. Modeling of turbulence response. 5. Presentations at Boeing-Seattle. 6. Recommendations. and 7. References.

Lan, C. Edward↗
NASA NTRS2011

Ares I-X Separation and Reentry Trajectory Analyses

The Ares I-X Flight Test Vehicle was launched on October 28, 2009 and was the first and only test flight of NASA s two-stage Ares I launch vehicle design. The launch was successful and the flight test met all of its primary and secondary objectives. This paper discusses the stage separation and reentry trajectory analysis that was performed in support of the Ares I-X test flight. Pre-flight analyses were conducted to assess the risk of stage recontact during separation, to evaluate the first stage flight dynamics during reentry, and to define the range safety impact ellipses of both stages. The results of these pre-flight analyses were compared with available flight data. On-board video taken during flight showed that the flight test vehicle successfully separated without any recontact. Reconstructed trajectory data also showed that first stage flight dynamics were well characterized by pre-flight Monte Carlo results. In addition, comparisons with flight data indicated that the complex interference aerodynamic models employed in the reentry simulation were effective in capturing the flight dynamics during separation. Finally, the splash-down locations of both stages were well within predicted impact ellipses.

Tartabini, Paul V.↗
NASA NTRS1992

Flight test results of the SHARE II monogroove heat pipe

The SHARE II (Space Station Heat Pipe Advanced Radiator Elements) flight experiment was flow in August 1991 on STS-43 in support of the Space Station Freedom (SSF) program. The flight experiment was designed to demonstrate startup and sustained microgravity operation of two 22 ft. long high capacity prototype SSF heat pipe radiator designs. The monogroove heat pipe radiator, one of the two heat pipe radiator designs flown on this experiment, is the subject of this paper. During the flight, the monogroove heat pipe, which contained 40 to 50 ppm of noncondensible gas to simulate end-of-life conditions, was shown to start up, vent bubbles as necessary, reprime under load, and operate successfully under all test conditions. The monogroove heat pipe operated under load for a total of 75 hours and achieved sustained heat transport of 50,000 watt-inches. This paper briefly describes the results of the previous SHARE flight experiment and the improvements made to the monogroove heat pipe as a result of that experiment. The test results of the SHARE II flight are discussed in detail. Based on the results of the SHARE II experiment, the monogroove heat pipe is ready for use in its intended application on SSF.

Brown, Richard F.↗
NASA NTRS1984

A flight test evaluation of the pilot interface with a digital advanced avionics system

A flight study was conducted to study pilot workload and the pilot interface with high levels of avionics capability and automation. The study was done in the context of general aviation, single-pilot IFR operations and utilized an experimental, digital, integrated avionics system. Results indicate that such advanced systems can provide improved information to the pilot and increased functional capability. The results also indicate that additional research is needed to increase the knowledge base required to design the pilot interfaces with highly capable systems. A CRT-based moving map display format tested provided excellent navigational situational awareness but was inferior to an HSI for manual path tracking. The complexity of navigation data management, autopilot management, and maintaining awareness of system status contributed to pilot workload and errors. Suggested guidelines for the design of the pilot/avionics interface for advanced avionics systems are given.

Hinton, D. A.↗
NASA NTRS1983

AFTI/F-16 flight test results and lessons

The advanced fighter technology integration (AFTI) F-16 aircraft is a highly complex digital flight control system integrated with advanced avionics and cockpit. The use of dissimilar backup modes if the primary system fails requires the designer to trade off system simplicity and capability. The tradeoff is evident in the AFTI/F-16 aircraft with its limited stability and fly by wire digital flight control systems when a generic software failure occurs the backup or normal mode must provide equivalent envelop protection during the transition to degraded flight control. The complexity of systems like the AFTI/F-16 system defines a second design issue, which is divided into two segments: (1) the effect on testing, (2) and the pilot's ability to act correctly in the limited time available for cockpit decisions. The large matrix of states possible with the AFTI/F-16 flight control system illustrates the difficulty of both testing the system and choosing real time pilot actions. The third generic issue is the possible reductions in the user's reliability expectations where false single channel information can be displayed at the pilot vehicle interface while the redundant set remains functional.

Ishmael, S. D.↗
NASA NTRS2017

COBALT: Development of a Platform to Flight Test Lander GN&C Technologies on Suborbital Rockets

The NASA COBALT Project (CoOperative Blending of Autonomous Landing Technologies) is developing and integrating new precision-landing Guidance, Navigation and Control (GN&C) technologies, along with developing a terrestrial fight-test platform for Technology Readiness Level (TRL) maturation. The current technologies include a third- generation Navigation Doppler Lidar (NDL) sensor for ultra-precise velocity and line- of-site (LOS) range measurements, and the Lander Vision System (LVS) that provides passive-optical Terrain Relative Navigation (TRN) estimates of map-relative position. The COBALT platform is self contained and includes the NDL and LVS sensors, blending filter, a custom compute element, power unit, and communication system. The platform incorporates a structural frame that has been designed to integrate with the payload frame onboard the new Masten Xodiac vertical take-o, vertical landing (VTVL) terrestrial rocket vehicle. Ground integration and testing is underway, and terrestrial fight testing onboard Xodiac is planned for 2017 with two flight campaigns: one open-loop and one closed-loop.

Carson, John M., III↗
NASA NTRS1973

Review of drag measurements from flight tests of manned aircraft with comparisons to wind-tunnel predictions

In-flight studies of the overall and local components of drag of many types of aircraft were conducted. The primary goal of these studies was to evaluate wind-tunnel and semiempirical prediction methods. Some evaluations are presented in this paper which may be summarized by the following observations: Wind-tunnel predictions of overall vehicle drag can be accurately extrapolated to flight Reynolds numbers, provided that the base drag is removed and the boattail areas on the vehicle are small. The addition of ablated roughness to lifting body configurations causes larger losses in performance and stability than would be expected from the added friction drag due to the roughness. Successful measurements of skin friction have been made in flight to Mach numbers above 4. A reliable inflatable deceleration device was demonstrated in flight which effectively stabilizes and decelerates a lifting aircraft at supersonic speeds.

Pyle, J. S.↗
NASA NTRS1992

The Development of an Airborne Information Management System for Flight Test

An airborne information management system is being developed at the NASA Dryden Flight Research Facility. This system will improve the state of the art in management data acquisition on-board research aircraft. The design centers around highly distributable, high-speed microprocessors that allow data compression, digital filtering, and real-time analysis. This paper describes the areas of applicability, approach to developing the system, potential for trouble areas, and reasons for this development activity. System architecture (including the salient points of what makes it unique), design philosophy, and tradeoff issues are also discussed.

Liquid cooling↗
NASA NTRS1935

Flight Tests of a Balanced Split Flap with Particular Reference to Rapid Operation

The flight path of a small parasol monoplane equipped with a special type of balanced split flap was determined for a series of glides during which the time taken to deflect or retract the flap was varied from 1 to 15 seconds in order to study the effect of the time taken to complete a flap movement on the motion of an airplane between the start of a flap movement and the attainment of steady flight with the new flap setting. For flap movements accompanied by a change of lift characteristics, and consequently of velocity, there is an appreciable delay in obtaining a desired change in glide angle even though the flap is operated instantaneously. Immediate control of the glide path is obtained only when the speed is maintained during the flap movement. When the speed is changed, the deviation from the desired path during the transition increases in proportion to the rapidity with which the flap is moved so that, with a high-lift flap, abrupt retraction at speeds less than the minimum speed with the flap retracted may be dangerous if practiced close to the ground.

Soule, H A↗
NASA NTRS1965

Flight Tests Related to Jet-Transport Upset and Turbulent-Air Penetration

A flight program, utilizing a Convair 880 and a Boeing 720 airplane, was conducted in conjunction with wind-tunnel and simulator programs to study problems related to jet-transport upsets and operation in a turbulent environment. During the handling-qualities portion of the program the basic static stability of the airplanes was considered to be satisfactory and the lateral-directional damping was considered to be marginal without damper augmentation. An evaluation of the longitudinal control system indicated that this system can become marginal in effectiveness in the high Mach number and high dynamic-pressure range of the flight envelope. From the upset and recovery phase of the program it was apparent that retrimming the stabilizer and spoiler deployment were valuable tools in effecting a positive recovery; however, if these devices are to be used safely, it appears that a suitable g-meter should be provided in the cockpit because the high control forces in recovery tend to reduce the pilot's sensitivity to the actual acceleration loads. During the turbulence penetrations the pilot noted that the measured vibrations of 4 to 6 cps in the cockpit considerably disrupted their normal scan pattern and suggested that an improvement should be made in the seat cushion and restraint system. Also it was observed that the indicator needles on the flight instruments were quite stable in the turbulent environment.

Andrews, William H.↗
NASA NTRS2015

Flight Testing a Real-Time Hazard Detection System for Safe Lunar Landing on the Rocket-Powered Morpheus Vehicle

The Hazard Detection System (HDS) is a component of the ALHAT (Autonomous Landing and Hazard Avoidance Technology) sensor suite, which together provide a lander Guidance, Navigation and Control (GN&C) system with the relevant measurements necessary to enable safe precision landing under any lighting conditions. The HDS consists of a stand-alone compute element (CE), an Inertial Measurement Unit (IMU), and a gimbaled flash LIDAR sensor that are used, in real-time, to generate a Digital Elevation Map (DEM) of the landing terrain, detect candidate safe landing sites for the vehicle through Hazard Detection (HD), and generate hazard-relative navigation (HRN) measurements used for safe precision landing. Following an extensive ground and helicopter test campaign, ALHAT was integrated onto the Morpheus rocket-powered terrestrial test vehicle in March 2014. Morpheus and ALHAT then performed five successful free flights at the simulated lunar hazard field constructed at the Shuttle Landing Facility (SLF) at Kennedy Space Center, for the first time testing the full system on a lunar-like approach geometry in a relevant dynamic environment. During these flights, the HDS successfully generated DEMs, correctly identified safe landing sites and provided HRN measurements to the vehicle, marking the first autonomous landing of a NASA rocket-powered vehicle in hazardous terrain. This paper provides a brief overview of the HDS architecture and describes its in-flight performance.

Avoidance↗
NASA NTRS1976

Survivable flight control system fly-by-wire development and flight test

Results from an intensive FBW advanced development effort indicate significant improvements in overall flight control system performance, reliability, safety and maintainability. Additionally, the strong and credible FBW technology base developed as a result paved the way for further exploitation through the application of advanced concepts such as control configured vehicles and multi-mode controls.

Hunter, J. E.↗
NASA NTRS1976

Flight test design for efficient extraction of aircraft parameters

This paper considers the design of flight control inputs which result in a minimization of the nonuniqueness problem of parameter identification due to statistical correlation. The performance index for the control design is taken as a linear weighted sum of the squares of the correlation coefficients of the aerodynamic stability and control derivatives as computed from the Cramer-Rao lower bound matrix. An optimal input design is demonstrated for an F-8 aircraft with supercritical wing. Reduced correlations are noted and corresponding estimates and confidence levels presented.

Wells, W. R.↗
NASA NTRS2012

Results from Navigator GPS Flight Testing for the Magnetospheric MultiScale Mission

The recent delivery of the first Goddard Space Flight Center (GSFC) Navigator Global Positioning System (GPS) receivers to the Magnetospheric MultiScale (MMS) mission spacecraft is a high water mark crowning a decade of research and development in high-altitude space-based GPS. Preceding MMS delivery, the engineering team had developed receivers to support multiple missions and mission studies, such as Low Earth Orbit (LEO) navigation for the Global Precipitation Mission (GPM), above the constellation navigation for the Geostationary Operational Environmental Satellite (GOES) proof-of-concept studies, cis-Lunar navigation with rapid re-acquisition during re-entry for the Orion Project and an orbital demonstration on the Space Shuttle during the Hubble Servicing Mission (HSM-4).

Lulich, Tyler D.↗
NASA NTRS1976

Business jet approach noise abatement techniques - Flight test results

Operational techniques for reducing approach noise from business jet aircraft were evaluated in flight by measuring the noise generated by five such aircraft during modified approaches. Approaches with 4-deg glide slopes were approximately 4.0 EPNdB quieter than approaches with standard 3-deg glide slopes. Noise reductions for low-drag 3-deg approaches varied widely among the airplanes tested; the fleet-weighted reduction was 8.5 EPNdB. Two-segment approaches resulted in noise reductions of 7.0 EPNdB to 8.5 EPNdB 3 nautical miles and 5 nautical miles from touchdown. Pilot workload increased progressively for the 4-deg, low-drag 3-deg, and two-segment approach.

Putnam, T. W.↗
NASA NTRS1982

Simulated space flight testing of commercial terrestrial silicon cells

Low cost silicon solar cells manufactured for the terrestrial market are examined for possible space flight use. The results of preliminary space environmental testing are reported and discussed. In addition, a number of possible obstacles to the use of these cells is examined. It is concluded that the terrestrial industry could provide an extremely low cost and reliable cell for space use.

Stella, P. M.↗
NASA NTRS1992

Subsonic flight test evaluation of a propulsion system parameter estimation process for the F100 engine

An adaptive-performance-seeking control system which optimizes the quasi-steady-state performance of the F-15 propulsion system is discussed. This paper presents flight- and ground-test evaluations of the propulsion system parameter-estimation process used by the performance seeking control system. The estimator consists of a compact propulsion system model and an extended Kalman filter. The extended Kalman filter estimates five engine component deviation parameters from measured inputs. The compact model uses measurements and Kalman-filter estimates as inputs to predict unmeasured propulsion parameters such as net propulsive force and fan stall margin. The ability to track trends and estimate absolute values of propulsion system parameters was demonstrated. For example, thrust stand results show a good correlation especially in trends between the performance seeking control estimated and measured thrust.

Orme, John S.↗