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  1. EVALUATION OF A STRAIN-GAGE LOAD CALIBRATION ON A LOW-ASPECT-RATIO WING STRUCTURE AT ELEVATED TEMPERATURE
    Authors: Lawrence F. Reardon
    Report Number: NASA-TP-2921
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The environmental aspect of elevated temperature and its relationship to the science of strain gage calibrations of aircraft structures are addressed. A section of a wing designed for a high-speed aircraft structure was used to study this problem. This structure was instrumented with strain gages calibrated at both elevated and room temperatures. Load equations derived from a high-temperature load calibration were compared with equations derived from an identical load calibration at room temperature. The implications of the high temperature load calibration were studied from the viewpoint of applicability and necessity. Load equations derived from the room temperature load calibration resulted in generally lower equation standard errors than equations derived from the elevated temperature load calibration. A distributed load was applied to the structure at elevated temperature and strain gage outputs were measured. This applied load was then calculated using equations derived from both the room temperature and elevated temperature calibration data. It was found that no significant differences between the two equation systems existed in terms of computing this applied distributed load, as long as the thermal shifts resulting from thermal stresses could be identified. This identification requires a heating of the structure. Therefore, it is concluded that for this structure, a high temperature load calibration is not required. However, a heating of the structure is required to determine thermal shifts.
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    Subject Category: 39
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    Report Date: June 1989
    No. Pages: 39
    Keywords:      Aircraft configurations; Aircraft structures; Calibrating; High temperature environments; Load tests.


  2. APPLICATION OF FRACTURE MECHANICS AND HALF-CYCLE METHOD TO THE PREDICTION OF FATIGUE LIFE OFB-52 AIRCRAFT PYLON COMPONENTS
    Authors: W. L. Ko, A. L. Carter, W. W. Totton and J. M. Ficke
    Report Number: NASA-TM-88277
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Stress intensity levels at various parts of the NASA B-52 carrier aircraft pylon were examined for the case when the pylon store was the space shuttle solid rocket booster drop test vehicle. Eight critical stress points were selected for the pylon fatigue analysis. Using fracture mechanics and the half-cycle theory (directly or indirectly) for the calculations of fatigue-crack growth ,the remaining fatigue life (number of flights left) was estimated for each critical part. It was found that the two rear hooks had relatively short fatigue life and that the front hook had the shortest fatigue life of all the parts analyzed. The rest of the pylon parts were found to be noncritical because of their extremely long fatigue life associated with the low operational stress levels.
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    Subject Category: 39
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    Report Date: September 1989
    No. Pages: 80
    Keywords:      B-52 aircraft; Crack propagation; Fatigue life; Fracture mechanics; Pylons.


  3. PRELIMINARY FLIGHT-DETERMINED SUBSONIC LIFT AND DRAG CHARACTERISTICS OF THE X-29AFORWARD-SWEPT-WING AIRPLANE
    Authors: John W. Hicks and Thomas Huckabone
    Report Number: NASA-TM-100409
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The X-29A subsonic lift and drag characteristics determined, met, or exceeded predictions, particularly with respect to the drag polar shapes. Induced drag levels were as great as 20 percent less than wind tunnel estimates, particularly at coefficients of lift above 0.8. Drag polar shape comparisons with other modern fighter aircraft showed the X-29A to have a better overall aircraft aerodynamic Oswald efficiency factor for the same aspect ratio. Two significant problems arose in the data reduction and analysis process. These included uncertainties in angle of attack upwash calibration and effects of maneuver dynamics on drag levels. The latter problem resulted from significantly improper control surface automatic camber control scheduling. Supersonic drag polar results were not obtained during this phase because of a lack of engine instrumentation to measure afterburner fuel flow.
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    Subject Category: 05
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    Report Date: August 1989
    No. Pages: 43
    Keywords:      Aerodynamic drag; Flight tests; Lift; Subsonic flow; Swept forward wings.


  4. A THREE-NODE C DEG ELEMENT FOR ANALYSIS OF LAMINATED COMPOSITE SANDWICH SHELLS
    Authors: C. Wayne Martin and K. K. Gupta
    Report Number: NASA-TM-4125
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A three-node flat shell element with C deg rotation fields has been developed for analysis of arbitrary composite shells. The element may consist of any number of orthotropic layers, each layer having different material properties and angular orientation. The formulation includes coupling between bending and extension, which is essential for analysis of unsymmetric laminates. Shearing deflections are included, since laminated and sandwich construction frequently results in shear stiffness much smaller than bending stiffness. Formulation of the element is straightforward, and calculation of its stiffness matrix is simple and fast. Convergence of solutions with mesh refinement is uniform for both thin and thick shells and is insensitive to element shape, although not as rapid as some other elements that lack one or more capabilities of the newly developed element. An experimental verification of the shall element is reported in the appendix.
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    Subject Category: 39
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    Report Date: June 1989
    No. Pages: 16
    Keywords:      Computer programs; Laminates; Plates (structural members); Shear properties; Shells (structural forms).


  5. MULTILAYER THEORY FOR DELAMINATION ANALYSIS OF A COMPOSITE CURVED BAR SUBJECTED TO ENDFORCES AND END MOMENTS
    Authors: William L. Ko and Raymond H. Jackson
    Report Number: NASA-TM-4139
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A composite test specimen in the shape of a semicircular curved bar subjected to bending offers an excellent stress field for studying the open-mode delamination behavior of laminated composite materials. This is because the open-mode delamination nucleates at the midspan of the curved bar. The classical anisotropic elasticity theory was used to construct a multilayer theory for the calculations of the stress and deformation fields induced in the multilayered composite semicircular curved bar subjected to end forces and end moments. The radial location and intensity of the open-mode delamination stress were calculated and were compared with the results obtained from the anisotropic continuum theory and from the finite element method. The multilayer theory gave more accurate predictions of the location and the intensity of the open-mode delamination stress than those calculated from the anisotropic continuum theory.
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    Subject Category: 24
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    Report Date: September 1989
    No. Pages: 29
    Keywords:      Bars; Bending; Composite materials; Delaminating; Loads (forces).
    Notes: Presented at the 5th International Conference on Composite Structures, Paisley, Scotland, 24-26 July 1989.


  6. GROUND VIBRATION TEST RESULTS OF A JETSTAR AIRPLANE USING IMPULSIVE SINE EXCITATION
    Authors: Michael W. Kehoe and David F. Voracek
    Report Number: NASA-TM-100448
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Structural excitation is important for both ground vibration and flight flutter testing. The structural responses caused by this excitation are analyzed to determine frequency, damping, and mode shape information. Many excitation waveforms have been used throughout the years. The use of impulsive sine (sin omega t)/omega t as an excitation waveform for ground vibration testing and the advantages of using this waveform for flight flutter testing are discussed. The ground vibration test results of a modified JetStar airplane using impulsive sine as an excitation waveform are compared with the test results of the same airplane using multiple-input random excitation. The results indicated that the structure was sufficiently excited using the impulsive sine waveform. Comparisons of input force spectrums, mode shape plots, and frequency and damping values for the two methods of excitation are presented.
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    Subject Category: 05
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    Report Date: February 1989
    No. Pages: 14
    Keywords:      C-140 aircraft; Excitation; Flight tests; Flutter analysis; Ground tests.
    Notes: Presented at the 7th International Modal Analysis Conference, Las Vegas, NV, 30 Jan. - 2 Feb. 1989.


  7. TECHNIQUES FOR OPTIMIZING HUMAN-MACHINE INFORMATION TRANSFER RELATED TO REAL-TIMEINTERACTIVE DISPLAY SYSTEMS
    Authors: Michael M. Granaas and Donald C. Rhea
    Report Number: NASA-TM-100450
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: In recent years the needs of ground-based researcher-analysts to access real-time engineering data in the form of processed information has expanded rapidly. Fortunately, the capacity to deliver that information has also expanded. The development of advanced display systems is essential to the success of a research test activity. Those developed at the National Aeronautics and Space Administration (NASA), Western Aeronautical Test Range (WATR), range from simple alphanumerics to interactive mapping and graphics. These unique display systems are designed not only to meet basic information display requirements of the user, but also to take advantage of techniques for optimizing information display. Future ground-based display systems will rely heavily not only on new technologies, but also on interaction with the human user and the associated productivity with that interaction. The psychological abilities and limitations of the user will become even more important in defining the difference between a usable and a useful display system. This paper reviews the requirements for development of real-time displays; the psychological aspects of design such as the layout, color selection, real-time response rate, and interactivity of displays; and an analysis of some existing WATR displays.
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    Subject Category: 53
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    Report Date: January 1989
    No. Pages: 16
    Keywords:      Display devices; Human factors engineering; Information management; Information systems; Man machine systems.
    Notes: Presented at the 27th AIAA Aerospace Sciences Meeting, Reno, NV, 9-12 Jan. 1989.


  8. FLIGHT EVALUATION OF A PNEUMATIC SYSTEM FOR UNSTEADY PRESSURE MEASUREMENTS USINGCONVENTIONAL SENSORS
    Authors: Robert E. Curry and Glenn B. Gilyard
    Report Number: NASA-TM-4131
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A flight experiment was conducted to evaluate a pressure measurement system which uses pneumatic tubing and remotely located electronically scanned pressure transducer modules for in-flight unsteady aerodynamic studies. A parametric study of tubing length and diameter on the attenuation and lag of the measured signals was conducted. The hardware was found to operate satisfactorily at rates of up to 500 samples/sec per port in flight. The signal attenuation and lag due to tubing were shown to increase with tubing length, decrease with tubing diameter, and increase with altitude over the ranges tested. Measurable signal levels were obtained for even the longest tubing length tested, 4 ft, at frequencies up to 100 Hz. This instrumentation system approach provides a practical means of conducting detailed unsteady pressure surveys in flight.
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    Subject Category: 05
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    Report Date: August 1989
    No. Pages: 20
    Keywords:      Flight tests; Pneumatic equipment; Pressure measurement; Pressure sensors; Unsteady aerodynamics.
    Notes: Presented at the 4th AIAA Flight Test Conference, San Diego, CA, 18-20 May 1988.


  9. METHOD FOR EXPERIMENTAL DETERMINATION OF FLUTTER SPEED BY PARAMETER IDENTIFICATION
    Authors: E. Nissim and Glenn B. Gilyard
    Report Number: NASA-TP-2923
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A method for flight flutter testing is proposed which enables one to determine the flutter dynamic pressure from flights flown far below the flutter dynamic pressure. The method is based on the identification of the coefficients of the equations of motion at low dynamic pressures, followed by the solution of these equations to compute the flutter dynamic pressure. The initial results of simulated data reported in the present work indicate that the method can accurately predict the flutter dynamic pressure, as described. If no insurmountable difficulties arise in the implementation of this method, it may significantly improve the procedures for flight flutter testing.
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    Subject Category: 05
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    Report Date: June 1989
    No. Pages: 44
    Keywords:      Aeroelasticity; Dynamic pressure; Flight tests; Flutter; Parameter identification.


  10. A SMOKE GENERATOR SYSTEM FOR AERODYNAMIC FLIGHT RESEARCH
    Authors: David M. Richwine, Robert E. Curry and Gene V. Tracy
    Report Number: NASA-TM-4137
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A smoke generator system was developed for in-flight vortex flow studies on the F-18 high alpha research vehicle (HARV). The development process included conceptual design, a survey of existing systems, component testing, detailed design, fabrication, and functional flight testing. Housed in the forebody of the aircraft, the final system consists of multiple pyrotechnic smoke cartridges which can be fired simultaneously or in sequence. The smoke produced is ducted to desired locations on the aircraft surface. The smoke generator system (SGS) has been used successfully to identify vortex core and core breakdown locations as functions of flight condition. Although developed for a specific vehicle, this concept may be useful for other aerodynamic flight research which requires the visualization of local flows.
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    Subject Category: 05
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    Report Date: January 1989
    No. Pages: 26
    Keywords:      Flow distribution; Flow visualization; Smoke; Vortex breakdown; Vortices.


  11. THE AEROSPACE ENERGY SYSTEMS LABORATORY: HARDWARE AND SOFTWARE IMPLEMENTATION
    Authors: Richard D. Glover and Nora O'Neill-Rood
    Report Number: NASA-TM-101706
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: For many years NASA Ames Research Center, Dryden Flight Research Facility has employed automation in the servicing of flight critical aircraft batteries. Recently a major upgrade to Dryden's computerized Battery Systems Laboratory was initiated to incorporate distributed processing and a centralized database. The new facility, called the Aerospace Energy Systems Laboratory (AESL), is being mechanized with iAPX86 and iAPX286 hardware running iRMX86. The hardware configuration and software structure for the AESL are described.
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    Subject Category: 62
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    Report Date: July 1989
    No. Pages: 21
    Keywords:      Aircraft power supplies; Computer techniques; Distributed processing; Electric batteries; Test facilities.
    Notes: Presented at the 5th iRUG International Conference, Schaumberg, IL, 14-15 Nov. 1988.


  12. FLUTTER CLEARANCE OF THE F-18 HIGH-ANGLE-OF-ATTACK RESEARCH VEHICLE WITH EXPERIMENTAL WINGTIP INSTRUMENTATION PODS
    Authors: Lawrence C. Freudinger
    Report Number: NASA-TM-4148
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An F-18 aircraft was modified with wingtip instrumentation pods for use in NASA's high-angle-of-attack research program. Ground vibration and flight flutter testing were performed to clear an acceptable flight envelope for the aircraft. Flight test utilized atmospheric turbulence for structural excitation; the aircraft displayed no adverse aeroelastic trends within the envelope tested. The data presented in this report include mode shapes from the ground vibration and estimates of frequency and damping as a function of Mach number.
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    Subject Category: 05
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    Report Date: October 1989
    No. Pages: 21
    Keywords:      Angle of attack; Clearances; F-18 aircraft; Flutter; Wing tips.


  13. DEVELOPMENT AND USE OF INTERACTIVE DISPLAYS IN REAL-TIME GROUND SUPPORT RESEARCH FACILITIES
    Authors: Donald C. Rhea, Kevin R. Hammons, Jacqueline C. Malone and Michael C. Nesel
    Report Number: NASA-TM-101694
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The NASA Western Aeronautical Test Range (WATR) is one of the world's most advanced aeronautical research flight test support facilities. A variety of advanced and often unique real-time interactive displays has been developed for use in the mission control centers (MCC) to support research flight and ground testing. These displays consist of applications operating on systems described as real-time interactive graphics super workstations and real-time interactive PC/AT compatible workstations. This paper reviews these two types of workstations and the specific applications operating on each display system. The applications provide examples that demonstrate overall system capability applicable for use in other ground-based real-time research/test facilities.
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    Subject Category: 53
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    Report Date: January 1989
    No. Pages: 26
    Keywords:      Computer graphics; Display devices; Ground support systems; Real time operation; Test ranges.
    Notes: Presented at the AIAA 27th Aerospace Meeting, Reno, NV, 9-12 Jan. 1989.


  14. SIMULATION AT DRYDEN FLIGHT RESEARCH FACILITY FROM 1957 TO 1982
    Authors: John P. Smith, Lawrence J. Schilling and Charles A. Wagner
    Report Number: NASA-TM-101695
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The Dryden Flight Research Facility has been a leader in developing simulation as an integral part of flight test research. The history of that effort is reviewed, starting in 1957 and continuing to the present time. The contributions of the major program activities conducted at Dryden during this 25-year period to the development of a simulation philosophy and capability is explained.
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    Report Date: February 1989
    No. Pages: 14
    Keywords:      Computerized simulation; Flight safety; Flight simulation; Research aircraft; Test facilities.
    Notes: Presented at the SES/SFTE Simulation-Aircraft Test and Evaluation Symposium, Patuxent River, MD, 16-17 Mar. 1982.


  15. EFFECT OF CONTROL SURFACE MASS UNBALANCE ON THE STABILITY OF A CLOSED-LOOP ACTIVE CONTROL SYSTEM
    Authors: E. Nissim
    Report Number: NASA-TP-2952
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The effects on stability of inertial forces arising from closed-loop activation of mass-unbalanced control surfaces are studied analytically using inertial energy approach, similar to the aerodynamic energy approach used for flutter suppression. The limitations of a single control surface like a leading-edge (LE) control or a trailing-edge (TE) control are demonstrated and compared to the superior combined LE-TE mass unbalanced system. It is shown that a spanwise section for sensor location can be determined which ensures minimum sensitivity to the mode shapes of the aircraft. It is shown that an LE control exhibits compatibility between inertial stabilization and aerodynamic stabilization, and that a TE control lacks such compatibility. The results of the present work should prove valuable, both for the purpose of flutter suppression using mass unbalanced control surfaces, or for the stabilization of structural modes of large space structures by means of inertial forces.
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    Subject Category: 39
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    Report Date: October 1989
    No. Pages: 26
    Keywords:      Active control; Aerodynamic stability; Aerodynamics; Balance; Control surfaces.


  16. THE IMPLEMENTATION AND OPERATION OF A VARIABLE-RESPONSE ELECTRONIC THROTTLE CONTROL SYSTEMFOR A TF-104G AIRCRAFT
    Authors: Bradford Neal and Upal Sengupta
    Report Number: NASA-TM-101696
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: During some flight programs, researchers have encountered problems in the throttle response characteristics of high-performance aircraft. To study and to help solve these problems, the National Aeronautics and Space Administration Ames Research Center's Dryden Flight Research Facility (Ames-Dryden) conducted a study using a TF-104G airplane modified with a variable-response electronic throttle control system. Ames-Dryden investigated the effects of different variables on engine response and handling qualities. The system provided transport delay, lead and lag filters, second-order lags, command rate and position limits, and variable gain between the pilot's throttle command and the engine fuel controller. These variables could be tested individually or in combination. Ten research flights were flown to gather data on engine response and to obtain pilot ratings of the various system configurations. The results should provide design criteria for engine-response characteristics. The variable-response throttle components and how they were installed in the TF-104G aircraft are described. How the variable-response throttle was used in flight and some of the results of using this system are discussed.
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    Subject Category: 07
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    Report Date: December 1989
    No. Pages: 18
    Keywords:      Aircraft performance; Controllers; Electronic control; Engine control; Fighter control.


  17. A KNOWLEDGE-BASED SYSTEM DESIGN/INFORMATION TOOL FOR AIRCRAFT FLIGHT CONTROL SYSTEMS
    Authors: Dale A. Mackall and James G. Allen
    Report Number: NASA-TM-101704
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Research aircraft have become increasingly dependent on advanced control systems to accomplish program goals. These aircraft are integrating multiple disciplines to improve performance and satisfy research objectives. This integration is being accomplished through electronic control systems. Because of the number of systems involved and the variety of engineering disciplines, systems design methods and information management have become essential to program success. The primary objective of the system design/information tool for aircraft flight control system is to help transfer flight control system design knowledge to the flight test community. By providing all of the design information and covering multiple disciplines in a structured, graphical manner, flight control systems can more easily be understood by the test engineers. This will provide the engineers with the information needed to thoroughly ground test the system and thereby reduce the likelihood of serious design errors surfacing in flight. The secondary objective is to apply structured design techniques to all of the design domains. By using the techniques in the top level system design down through the detailed hardware and software designs, it is hoped that fewer design anomalies will result. The flight test experiences of three highly complex, integrated aircraft programs are reviewed: the X-29 forward-swept wing, the advanced fighter technology integration (AFTI) F-16, and the highly maneuverable aircraft technology (HiMAT) program. Significant operating anomalies and the design errors which cause them, are examined to help identify what functions a system design/information tool should provide to assist designers in avoiding errors.
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    Subject Category: 62
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    Report Date: October 1989
    No. Pages: 19
    Keywords:      Airborne/spaceborne computers; Aircraft control; Artificial intelligence; Computer systems design; Control systems design.
    Notes: Presented at the 7th AIAA Computers in Aerospace Conference, Monterey, CA, 4-6 Oct. 1989.


  18. A DESIGN PROCEDURE FOR THE HANDLING QUALITIES OPTIMIZATION OF THE X-29A AIRCRAFT
    Authors: John T. Bosworth and Timothy H. Cox
    Report Number: NASA-TM-4142
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A design technique for handling qualities improvement was developed for the X-29A aircraft. As with any new aircraft, the X-29A control law designers were presented with a relatively high degree of uncertainty in their mathematical models. The presence of uncertainties, and the high level of static instability of the X-29A caused the control law designers to stress stability and robustness over handling qualities. During flight test, the mathematical models of the vehicle were validated or corrected to match the vehicle dynamic behavior. The updated models were then used to fine tune the control system to provide fighter-like handling characteristics. A design methodology was developed which works within the existing control system architecture to provide improved handling qualities and acceptable stability with a minimum of cost in both implementation as well as software verification and validation.
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    Subject Category: 08
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    Report Date: September 1989
    No. Pages: 21
    Keywords:      Aircraft design; Control systems design; Controllability; Optimization; X-29A aircraft.
    Notes: Presented at the Guidance, Navigation, and Control Conference, Boston, MA, 14-16 Aug. 1989.


  19. MODELING OF AERODYNAMIC FORCES IN THE LAPLACE DOMAIN WITH MINIMUM NUMBER OFAUGMENTED STATES FOR THE DESIGN OF ACTIVE FLUTTER SUPPRESSION SYSTEMS
    Authors: E. Nissim
    Report Number: H-1552
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A method is proposed by which an aeroservoelastic problem is brought to a state-space form with a minimum number of augmented aerodynamic terms. The examples treated in this work relate to NASA's Drone for Aerodynamic and Structural Testing-Aerodynamic Research Wing 1 (DAST-ARW1) and to the YF-17 fighter model. It is shown that in all cases considered, the method yields a very good accuracy regarding the flutter parameters and the dynamic behavior of the systems, using only two augmented aerodynamic states. The method should prove useful in the design of lower order control laws based on optimal control theory.
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    Report Date: January 1989
    No. Pages: 21
    Keywords:      Active control; Aerodynamic loads; Control systems design; Flutter; Optimal control.
    Notes: IN: AIAA Guidance, Navigation and Control Conference, Boston, MA, Aug. 14-16, 1989, Technical Papers. Part 1. Washington, DC, American Institute of Aeronautics and Astronautics, 1989, p. 332-352.


  20. PRELIMINARY DEVELOPMENT OF AN INTELLIGENT COMPUTER ASSISTANT FOR ENGINE MONITORING
    Authors: James D. Disbrow, Eugene L. Duke and Ronald J. Ray
    Report Number: NASA-TM-101702
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: As part of the F-18 high-angle-of-attack vehicle program, an AI method was developed for the real time monitoring of the propulsion system and for the identification of recovery procedures for the F404 engine. The aim of the development program is to provide enhanced flight safety and to reduce the duties of the propulsion engineers. As telemetry data is received, the results are continually displayed in a number of different color graphical formats. The system makes possible the monitoring of the engine state and the individual parameters. Anomaly information is immediately displayed to the engineer.
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    Subject Category: 63
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    Report Date: August 1989
    No. Pages: 12
    Keywords:      Airborne/spaceborne computers; Aircraft engines; Computer graphics; Engine monitoring instruments; Expert systems.


  21. INITIAL FLIGHT TEST OF A GROUND DEPLOYED SYSTEM FOR FLYING QUALITIES ASSESSMENT
    Authors: Mary F. Shafer, Ruthard Koehler, Edward M. Wilson and David R. Levy
    Report Number: NASA-TM-101700
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: In order to provide a safe, repeatable, precise, high-gain flying qualities task a ground deployed system was developed and tested at the NASA Ames Research Center's Dryden Flight Research Facility. This system, the adaptable target lighting array system (ATLAS), is based on the German Aerospace Research Establishment's ground attack test equipment (GRATE). These systems provide a flying-qualities task, emulating the ground-attack task with ground deployed lighted targets. These targets light in an unpredictable sequence and the pilot has to aim the aircraft at whichever target is lighted. Two flight-test programs were used to assess the suitability of ATLAS. The first program used the United States Air Force (USAF) NT-33A variability stability aircraft to establish that ATLAS provided a task suitable for use in flying qualities research. A head-up display (HUD) tracking task was used for comparison. The second program used the X-29A forward-swept wing aircraft to demonstrate that the ATLAS task was suitable for assessing the flying qualities of a specific experimental aircraft. In this program, the ground-attack task was used for comparison. All pilots who used ATLAS found it be highly satisfactory and thought it to be superior to the other tasks used in flying qualities evaluations. It was recommended that ATLAS become a standard for flying qualities evaluations.
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    Subject Category: 08
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    Report Date: August 1989
    No. Pages: 10
    Keywords:      Deployment; Flight characteristics; Flight tests; Ground tests; Head-up displays.
    Notes: Presented at the AIAA Atmospheric Flight Mechanics Conference, Boston, MA, 14-16 Aug. 1989.


  22. MEASUREMENT EFFECTS ON THE CALCULATION OF IN-FLIGHT THRUST FOR AN F404 TURBOFAN ENGINE
    Authors: Timothy R. Conners
    Report Number: NASA-TM-4140
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A study was performed that investigates parameter measurement effects on calculated in-flight thrust for the General Electric F404-GE-400 afterburning turbofan engine which powered the X-29A forward-swept wing research aircraft. Net-thrust uncertainty and influence coefficients were calculated and are presented. Six flight conditions were analyzed at five engine power settings each. Results were obtained using the mass flow-temperature and area-pressure thrust calculation methods, both based on the commonly used gas generator technique. Thrust uncertainty was determined using a common procedure based on the use of measurement uncertainty and influence coefficients. The effects of data nonlinearity on the uncertainty calculation procedure were studied and results are presented. The advantages and disadvantages of using this particular uncertainty procedure are discussed. A brief description of the thrust-calculation technique along with the uncertainty calculation procedure is included.
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    Subject Category: 07
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    Report Date: September 1989
    No. Pages: 24
    Keywords:      Afterburning; In-flight monitoring; Research aircraft; Thrust measurement; Turbofan engines.
    Notes: Presented at the AIAA Joint Propulsion Conference, Monterey, CA, 10-14 Jul. 1989.


  23. INITIAL FLIGHT QUALIFICATION AND OPERATIONAL MAINTENANCE OF X-29A FLIGHT SOFTWARE
    Authors: Michael R. Earls and Joel R. Sitz
    Report Number: NASA-TM-101703
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A discussion is presented of some significant aspects of the initial flight qualification and operational maintenance of the flight control system softward for the X-29A technology demonstrator. Flight qualification and maintenance of complex, embedded flight control system software poses unique problems. The X-29A technology demonstrator aircraft has a digital flight control system which incorporates functions generally considered too complex for analog systems. Organizational responsibilities, software assurance issues, tools, and facilities are discussed.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: September 1989
    No. Pages: 28
    Keywords:      Computer programs; File maintenance (computers); Flight control; Program verification (computers); X-29 aircraft.
    Notes: Presented at the AIAA Guidance, Navigation and Control Conference, Boston, MA, 14-16 Aug. 1989.


  24. AFTI/F-111 AIRPLANE MISSION ADAPTIVE WING OPERATIONAL FLIGHT EVALUATION TECHNIQUE USINGUPLINKED PILOT COMMAND CUES
    Authors: Robert W. Kempel, Paul W. Phillips, C. Gordon Fullerton and John J. Bressina
    Report Number: H-1562
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: NASA and the USAF have conducted a program to investigate aircraft performance improvements utilizing a mission adaptive wing (MAW). The MAW was designed and developed for the AFTI/F-111 variable-sweep aircraft to provide a hydraulically driven, smooth, and continuous variable camber of the trailing and leading edges as a function of maneuvering requirements or of flight conditions. The remotely augmented vehicle facility (RAV) at the NASA DFRF, as utilized in the MAW investigations, is described. The RAV was a dedicated, ground based, general purpose facility capable of receiving a data stream downlinked from a test vehicle, processing this data stream in a digital computer, and transmitting processed data back to the test vehicle. It is shown that this method of flight testing provides a technique that can evaluate highly dynamic maneuvers.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: January 1989
    No. Pages: 19
    Keywords:      F-111 aircraft; Fighter aircraft; Flight tests; Fly by wire control; Mission adaptive wings.
    Notes: IN: Society of Flight Test Engineers, Annual Symposium, 20th, Reno, NV, Sept. 18-21, 1989, Proceedings (A91-20976 07-05). Lancaster, CA, Society of Flight Test Engineers, 1989, p. 3.6-1 to 3.6-19.


  25. AN IN-FLIGHT TECHNIQUE FOR WIND MEASUREMENT IN SUPPORT OF THE SPACE SHUTTLE PROGRAM
    Authors: Lisa J. Bjarke and L. J. Ehernberger
    Report Number: NASA-TM-4154
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A technique to use an aircraft to measure wind profiles in the altitude range of 1,500 to 18,200 m was demonstrated at NASA Ames-Dryden. This demonstration was initiated to determine if an aircraft could measure wind profiles in support of space shuttle launches. The Jimsphere balloon is currently the device used to measure pre-launch wind profiles for the space shuttle. However, it takes approximately an hour for the Jimsphere to travel through the altitudes of interest. If these wind instruments could be taken with an aircraft closer to launch in a more timely manner and with the same accuracy as a Jimsphere balloon, some uncertainties in the measurements could be removed. The aircraft used for this investigation was an F-104G which is capable of flight above 18,000 m. It had conventional research instrumentation to provide air data and flow angles along with a ring laser gyro inertial navigation system (INS) to provide inertial and Euler angle data. During the course of 17 flights, wind profiles were measured in 21 climbs and 18 descents. Preliminary comparisons between aircraft measured wind profiles and Jimsphere measured profiles show reasonable agreement (within 3 m/sec). Most large differences between the profiles can usually be explained by large spatial or time differences between the Jimsphere and aircraft measurements, the fact that the aircraft is not in a wings-level attitude, or INS shifts caused by aircraft maneuvering.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: November 1989
    No. Pages: 25
    Keywords:      Flight tests; In-flight monitoring; Spacecraft launching; Weather forecasting; Wind measurement.
    Notes: Presented at the Society of Flight Test Engineers 20th Annual Symposium, Reno, NV, 18-21 Sep. 1989


  26. A KNOWLEDGE-BASED FLIGHT STATUS MONITOR FOR REAL-TIME APPLICATION IN DIGITAL AVIONICS SYSTEMS
    Authors: E. L. Duke, J. D. Disbrow and G. F. Butler
    Report Number: NASA-TM-101710
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The Dryden Flight Research Facility of the National Aeronautics and Space Administration (NASA) Ames Research Center (Ames-Dryden) is the principal NASA facility for the flight testing and evaluation of new and complex avionics systems. To aid in the interpretation of system health and status data, a knowledge-based flight status monitor was designed. The monitor was designed to use fault indicators from the onboard system which are telemetered to the ground and processed by a rule-based model of the aircraft failure management system to give timely advice and recommendations in the mission control room. One of the important constraints on the flight status monitor is the need to operate in real time, and to pursue this aspect, a joint research activity between NASA Ames-Dryden and the Royal Aerospace Establishment (RAE) on real-time knowledge-based systems was established. Under this agreement, the original LISP knowledge base for the flight status monitor was reimplemented using the intelligent knowledge-based system toolkit, MUSE, which was developed under RAE sponsorship. Details of the flight status monitor and the MUSE implementation are presented.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 63
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    Report Date: October 1989
    No. Pages: 14
    Keywords:      Artificial intelligence; Avionics; Digital systems; Expert systems; Flight management systems.
    Notes: Presented at the MILCOMP'89 Conference, London, England, 26-28 Sep. 1989.


  27. THE AEROSPACE ENERGY SYSTEMS LABORATORY: A BITBUS NETWORKING APPLICATION
    Authors: Richard D. Glover and Nora O'Neill-Rood
    Report Number: NASA-TM-4149
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The NASA Ames-Dryden Flight Research Facility developed a computerized aircraft battery servicing facility called the Aerospace Energy Systems Laboratory (AESL). This system employs distributed processing with communications provided by a 2.4-megabit BITBUS local area network. Customized handlers provide real time status, remote command, and file transfer protocols between a central system running the iRMX-II operating system and ten slave stations running the iRMX-I operating system. The hardware configuration and software components required to implement this BITBUS application are required.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 62
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    Report Date: November 1989
    No. Pages: 15
    Keywords:      Computer programs; Distributed processing; Electric batteries; Local area networks; Multiprocessing (computers).
    Notes: Presented at the iRUG 6th International Conference, Bethesda, MD, 13-14 Nov. 1989.


  28. AN IN-FLIGHT INVESTIGATION OF GROUND EFFECT ON A FORWARD-SWEPT WING AIRPLANE
    Authors: Robert E. Curry, Bryan J. Moulton and John Kresse
    Report Number: NASA-TM-101708
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A limited flight experiment was conducted to document the ground-effect characteristics of the X-29A research airplane. This vehicle has an aerodynamic platform which includes a forward-swept wing and close-coupled, variable incidence canard. The flight-test program obtained results for errors in the airdata measurement and for incremental normal force and pitching moment caused by ground effect. Correlations with wind-tunnel and computational analyses were made. The results are discussed with respect to the dynamic nature of the flight measurements, similar data from other configurations, and pilot comments. The ground-effect results are necessary to obtain an accurate interpretation of the vehicle's landing characteristics. The flight data can also be used in the development of many modern aircraft systems such as autoland and piloted simulations.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 02
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    Report Date: September 1989
    No. Pages: 14
    Keywords:      Aerodynamic characteristics; Flight tests; Ground effect (aerodynamics); In-flight monitoring; Swept forward wings.
    Notes: Presented at the AGARD Symposium on Aerodynamics of Combat Aircraft, Controls, and of Ground Effect, Madrid, Spain, 2-5 Oct. 1989.


  29. X-29A AIRCRAFT STRUCTURAL LOADS FLIGHT TESTING
    Authors: Robert Sim, Paul McCrosson, Robert Ryan and Joe Rivera
    Report Number: NASA-TM-101715
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The X-29A research and technology demonstrator aircraft has completed a highly successful multiphase flight test program. The primary research objective was to safely explore, evaluate, and validate a number of aerodynamic, structural, and flight control technologies, all highly integrated into the vehicle design. Most of these advanced technologies, particularly the forward-swept-wing platform, had a major impact on the structural design. Throughout the flight test program, structural loads clearance was an ongoing activity to provide a safe maneuvering envelope sufficient to accomplish the research objectives. An overview is presented of the technologies, flight test approach, key results, and lessons learned from the structural flight loads perspective. The overall design methodology was considered validated, but a number of structural load characteristics were either not adequately predicted or totally unanticipated prior to flight test. While conventional flight testing techniques were adequate to insure flight safety, advanced analysis tools played a key role in understanding some of the structural load characteristics, and in maximizing flight test productivity.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: December 1989
    No. Pages: 37
    Keywords:      Aerodynamic loads; Aircraft structures; Canard configurations; Flight tests; Structural design.
    Notes: Presented at the 20th Annual Society of Flight Test Engineers Symposium, Reno, NV, 18-21 Sep. 1989.


  30. RECENT EXPERIENCE WITH ELEVATED-TEMPERATURE FOIL STRAIN GAGES WITH APPLICATION TO THIN-GAGEMATERIALS
    Authors: Larry D. Hudson
    Report Number: H-1579
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The effects of thin-gage materials on high-temperature strain measurements are discussed. Apparent strain test were performed using facesheet coupons, honeycomb coupons, and the panel with strain gages in an installed condition. The apparent strain results differed in each of the cases. The apparent strain curves from the panel tests are expected to provide the best correlation with analysis, assuming that the thermal strains are insignificant or that the thermal strains derived from the analysis of the apparent strain test performed on the panel can be used to correct the apparent strain curves.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 35
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    Report Date: January 1989
    No. Pages: 14
    Keywords:      High temperature environments; Honeycomb structures; Space transportation system; Strain gages; Thermal protection.
    Notes: IN: Hostile environments and high temperature measurements; Proceedings of the Conference, Kansas City, MO, Nov. 6-8, 1989. Bethel, CT, Society for Experimental Mechanics, Inc., 1989, p. 68-81.
 
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