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  1. FLIGHT CHARACTERISTICS OF THE AD-1 OBLIQUE-WING RESEARCH AIRCRAFT , Technical Paper
    Authors: Alex G. Sim and Robert E. Curry
    Report Number: NASA-TP-2223
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The AD-1 is a low-speed oblique-wing research airplane. This report reviews the vehicle's basic flight characteristics, including many aerodynamic, stability, and control effects that are unique to an oblique-wing configuration. These effects include the change in sideforce with angle of attack, moment changes with angle of attack and load factor, initial stall on the trailing wing, and inertial coupling caused by a roll-pitch cross product of inertia. An assessment of the handling qualities includes pilot ratings and comments. Ratings were generally satisfactory through 30 deg of wing sweep but degraded with increased sweep. A piloted simulation study indicated that a basic rate feedback control system could be used to improve the handling qualities at higher wing sweeps.
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    Subject Category: 08
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    Report Date: March 1985
    No. Pages: 29
    Keywords:      Aerodynamic configurations; Flight characteristics; Low speed; Oblique wings; Research aircraft.


  2. EFFECTS OF INLET DISTORTION ON A STATIC PRESSURE PROBE MOUNTED ON THE ENGINE HUB IN AN F-15 AIRPLANE , Technical Paper
    Authors: D. L. Hughes, L. P. Myers and K. G. Mackall
    Report Number: NASA-TP-2411
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An inlet static pressure (PS2) probe was mounted on the hub of an F100 engine in an F-15 airplane. Flight test results showed that for low distortion conditions, the ratio of engine-face total pressure to static pressure agreed well with previous altitude facility data. Off-schedule operation of the inlet third ramp angle caused increased distortion of the inlet airflow during steady-state flight conditions. Data are shown for inlet third ramp excursions leading to engine stall. The relationships of inlet face total to static pressure ratio as a function of several distortion descriptors are also described.
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    Subject Category: 07
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    Report Date: January 1985
    No. Pages: 23
    Keywords:      Aircraft engines; Engine failure; F-15 aircraft; Inlet flow; Static pressure.


  3. IN-FLIGHT SURFACE OIL-FLOW PHOTOGRAPHS WITH COMPARISONS TO PRESSURE DISTRIBUTION AND BOUNDARY-LAYER DATA , Technical Paper
    Authors: Robert R. Meyer, Jr. and Lisa A. Jennett
    Report Number: NASA-TP-2395
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Upper surface oil-flow photographs were obtained at transonic speeds on an F-111 transonic aircraft technology (TACT) aircraft, which had been fitted with a natural laminar-flow airfoil section. The oil-flow photographs were interpreted with regard to shock and boundary-layer characteristics and compared to results obtained from pressure distributions and boundary-layer measurements. Results indicated that flow phenomena (such as shock location and strength) and chord location of boundary-layer characteristics (such as transition location) could be correctly identified from the oil-flow photographs.
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    Subject Category: 02
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    Report Date: April 1985
    No. Pages: 27
    Keywords:      Boundary layer flow; Flow visualization; In-flight monitoring; Oils; Photography.


  4. F-8 REFUELING BOOM GROUND VIBRATION TEST
    Authors: Michael W. Kehoe
    Report Number: NASA-TM-84914
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A ground vibration test was conducted on a simulated refueling boom mounted on an F-8 airplane. The ground vibration test was conduted to determine if the refueling boom modal frequencies were close to the airplane frequencies. The data presented in this report include modal frequencies, mode shape data, and structural damping coefficients.
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    Subject Category: 05
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    Report Date: January 1985
    No. Pages: 50
    Keywords:      Ground vibration test; Vibration; Modal analysis


  5. MACH NUMBER AND FLOW-FIELD CALIBRATION AT THE ADVANCED DESIGN PROPELLERLOCATION ON THE JETSTAR AIRPLANE , Technical Memorandum
    Authors: L. D. Webb
    Report Number: NASA-TM-84923
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Advanced design propellers on a JetStar aircraft were tested at NASA Ames Research Center's Dryden Flight Research Facility. A calibration of the flow field at the test location to obtain local Mach number and flow direction was performed. A pitot-static probe and flow direction vane installation was installed and tested at Mach 0.3 to 0.8 and altitudes from 3000 m (10,000 ft) to 9100 m (30,000 ft). Local Mach number and flow direction relationships were obtained and related to their noseboom counterparts. Effects of varying angles of sideslip to + or - 3 deg. were investigated.
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    Subject Category: 02
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    Report Date: December 1985
    No. Pages: 21
    Keywords:      Design analysis; Flow distribution; Propellers; Turbojet engines; Wind tunnel tests.


  6. STRESS ANALYSES OF B-52 PYLON HOOKS , Technical Memorandum
    Authors: W. L. Ko and L. S. Schuster
    Report Number: NASA-TM-84924
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The NASTRAN finite element computer program was used in the two dimensional stress analysis of B-52 carrier aircraft pylon hooks: (1) old rear hook (which failed), (2) new rear hook (improved geometry), (3) new DAST rear hook (derated geometry), and (4) front hook. NASTRAN model meshes were generated by the aid of PATRAN-G computer program. Brittle limit loads for all the four hooks were established. The critical stress level calculated from NASTRAN agrees reasonably well with the values predicted from the fracture mechanics for the failed old rear hook.
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    Subject Category: 39
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    Report Date: October 1985
    No. Pages: 33
    Keywords:      B-52 aircraft; Fracture mechanics; Hooks; Pylons; Stress analysis.


  7. FLOW FIELD SURVEY NEAR THE ROTATIONAL PLANE OF AN ADVANCED DESIGN PROPELLER ON A JETSTAR AIRPLANE , Technical Memorandum
    Authors: K. R. Walsh
    Report Number: NASA-TM-86037
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An investigation was conducted to obtain upper fuselage surface static pressures and boundary layer velocity profiles below the centerline of an advanced design propeller. This investigation documents the upper fuselage velocity flow field in support of the in-flight acoustic tests conducted on a JetStar airplane. Initial results of the boundary layer survey show evidence of an unusual flow disturbance, which is attributed to the two windshield wiper assemblies on the aircraft. The assemblies were removed, eliminating the disturbances from the flow field. This report presents boundary layer velocity profiles at altitudes of 6096 and 9144 m (20,000 and 30,000 ft) and Mach numbers from 0.6 to 0.8, and it investigated the effects of windshield wiper assemblies on these profiles. Because of the unconventional velocity profiles that were obtained with the assemblies mounted, classical boundary layer parameters, such as momentum and displacement thicknesses, are not presented. The effects of flight test variables (Mach number and angles of attack and sideslip) and an advanced design propeller on boundary layer profiles - with the wiper assemblies mounted and removed - are presented.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 02
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    Report Date: January 1985
    No. Pages: 29
    Keywords:      Aerodynamic characteristics; Boundary layers; Design analysis; Flow distribution; Fuselages.


  8. STRESS CONCENTRATION AROUND A SMALL CIRCULAR HOLE IN THE HIMAT COMPOSITEPLATE , Technical Memorandum
    Authors: W. L. Ko
    Report Number: NASA-TM-86038
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Anisotropic plate theory is used to calculate the anisotropic stress concentration factors for a composite plate (AS/3501-5 graphite/epoxy composite, single ply or laminated) containing a circular hole. This composite material is used on the highly maneuverable aircraft technology (HiMAT) vehicle. It is found that the anisotropic stress concentration factor could be greater or less than 3 (the stress concentration factor for isotropic materials), and that the locations of the maximum tangential stress points could shift with the change of fiber orientation with respect to the loading axis. The effect of hole size on the stress concentration factor is examined using the Point Stress Criterion and the Averaged Stress Criterion. The predicted stress concentration factors based on the two theories compared fairly well with the measured values for the hole size 0.3175 cm (1/8 in). It is also found that through the lamination process, the stress concentration factor could be reduced drastically, indicating an improvement in structural performance.
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    Subject Category: 24
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    Report Date: December 1985
    No. Pages: 18
    Keywords:      Anisotropic plates; Composite materials; Fiber orientation; Graphite-epoxy composites; Highly maneuverable aircraft.


  9. IMPACTS OF SPACE SHUTTLE THERMAL PROTECTION SYSTEM TILE ON F-15 AIRCRAFTVERTICAL TILE , Technical Memorandum
    Authors: W. L. Ko
    Report Number: NASA-TM-85904
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Impacts of the space shuttle thermal protection system (TPS) tile on the leading edge and the side of the vertical tail of the F-15 aircraft were analyzed under different TPS tile orientations. The TPS tile-breaking tests were conducted to simulate the TPS tile impacts. It was found that the predicted tile impact forces compare fairly well with the tile-breaking forces, and the impact forces exerted on the F-15 aircraft vertical tail were relatively low because a very small fraction of the tile kinetic energy was dissipated in the impact, penetration, and fracture of the tile. It was also found that the oblique impact of the tile on the side of the F-15 aircraft vertical tail was unlikely to dent the tail surface.
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    Subject Category: 16
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    Report Date: March 1985
    No. Pages: 24
    Keywords:      Computerized simulation; F-15 aircraft; Impact tolerances; Space shuttles; Thermal protection.


  10. MORE THAN YOU WANT TO KNOW ABOUT MAXIMUM LIKELIHOOD ESTIMATION , Technical Memorandum
    Authors: K. W. Iliff and R. E. Maine
    Report Number: NASA-TM-85905
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The maximum likelihood estimator has been used to extract stability and control derivatives from flight data for many years. Most of the literature on aircraft estimation concentrates on new developments and applications, assuming familiarity with basic estimation concepts. Some of these basic concepts are presented. The maximum likelihood estimator is briefly discussed and the aircraft equations of motion that the estimator uses. The basic concepts of minimization and estimation are examined for a simple computed aircraft example. The cost functions that are to be minimized during estimation are defined and discussed. Graphic representations of the cost functions are given to help illustrate the minimization process. Finally, the basic concepts are generalized, and estimation from flight data is discussed. Some of the major conclusions for the computed example are also developed for the analysis of flight data.
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    Subject Category: 08
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    Report Date: January 1985
    No. Pages: 26
    Keywords:      Cost analysis; Equations of motion; Maximum likelihood estimates; Parameter identification; Reliability.
    Notes: Presented at AIAA Atmospheric Flight Mech. Conf., Seattle, 21-23 Aug. 1984. Prepared in cooperation with NASA, Ames Research Center.


  11. IDENTIFICATION OF DYNAMIC SYSTEMS, THEORY AND FORMULATION , Reference Publication
    Authors: R. E. Maine and K. W. Iliff
    Report Number: NASA-RP-1138
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The problem of estimating parameters of dynamic systems is addressed in order to present the theoretical basis of system identification and parameter estimation in a manner that is complete and rigorous, yet understandable with minimal prerequisites. Maximum likelihood and related estimators are highlighted. The approach used requires familiarity with calculus, linear algebra, and probability, but does not require knowledge of stochastic processes or functional analysis. The treatment emphasizes unification of the various areas in estimation in dynamic systems is treated as a direct outgrowth of the static system theory. Topics covered include basic concepts and definitions; numerical optimization methods; probability; statistical estimators; estimation in static systems; stochastic processes; state estimation in dynamic systems; output error, filter error, and equation error methods of parameter estimation in dynamic systems, and the accuracy of the estimates.
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    Subject Category: 66
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    Report Date: February 1985
    No. Pages: 138
    Keywords:      Maximum likelihood estimates; Optimization; Parameter identification; Probability theory; System identification.


  12. PREDICTED PERFORMANCE BENEFITS OF AN ADAPTIVE DIGITAL ENGINE CONTROL SYSTEMOF AN F-15 AIRPLANE , Technical Memorandum
    Authors: F. W. Burcham, Jr., L. P. Myers and R. J. Ray
    Report Number: NASA-TM-85916
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The highly integrated digital electronic control (HIDEC) program will demonstrate and evaluate the improvements in performance and mission effectiveness that result from integrating engine-airframe control systems. Currently this is accomplished on the NASA Ames Research Center's F-15 airplane. The two control modes used to implement the systems are an integrated flightpath management mode and in integrated adaptive engine control system (ADECS) mode. The ADECS mode is a highly integrated mode in which the airplane flight conditions, the resulting inlet distortion, and the available engine stall margin are continually computed. The excess stall margin is traded for thrust. The predicted increase in engine performance due to the ADECS mode is presented in this report.
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    Subject Category: 07
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    Report Date: January 1985
    No. Pages: 11
    Keywords:      Aircraft engines; Digital systems; Engine airframe integration; F-15 aircraft; Flight paths.
    Notes: Prepared in cooperation with NASA, Ames Research Center .


  13. FLUTTER CLEARANCE OF THE SCHWEIZER 1-36 DEEP-STALL SAILPLANE , Technical Memorandum
    Authors: M. W. Kehoe and J. F. Ellison
    Report Number: NASA-TM-85917
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A Schweizer 1-36 sailplane was modified for a controlled, deep-stall flight program. This modification allowed the horizontal stabilizer to pivot as much as 70 deg leading edge down. Ground vibration and flutter testing were accomplished on the sailplane with the horizontal stabilizer in the normal flight and deep-stall flight positions. Test results indicated satisfactory damping levels and trends for the structural modes of the sailplane. The modified sailplane was demonstrated to be free of aeroelastic instabilities to 83 KEAS with the horizontal stabilizer in the normal flight position and to 39 KEAS with the horizontal stabilizer in the deep-stall flight position. This flight envelope was adequate for the controlled, deep-stall flight experiments.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: August 1985
    No. Pages: 78
    Keywords:      Aerodynamic stalling; Flight control; Flutter analysis; Gliders; Stabilizers (fluid dynamics).


  14. GROUND-EFFECT ANALYSIS OF A JET TRANSPORT AIRPLANE , Technical Memorandum
    Authors: R. E. Curry and A. H. Bowers
    Report Number: NASA-TM-85920
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An analysis of the ground effect of a jet transport airplane has been made. Data were obtained from recent flight tests primarily using the constant angle-of-attack approach technique. Reasonable results were obtained for ground-effect pitching moment and lift increments. These were compared with data from other sources, including computations, wind tunnel, and previous flight test. A recommended ground-effect model was developed from the results. A brief simulator study was conducted to determine the sensitivity of a particular configuration to this ground-effect model and its associated uncertainty.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 02
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    Report Date: January 1985
    No. Pages: 12
    Keywords:      Flight tests; Ground effect (aerodynamics); Jet aircraft; Lift; Transport aircraft.
    Notes: Presented at the 23rd AIAA Aerospace Sci. Meeting, Reno, Nev., 14-17 Jan. 1985.


  15. THE WESTERN AERONAUTICAL TEST RANGE OF NASA AMES RESEARCH CENTER , Technical Memorandum
    Authors: Archie L. Moore
    Report Number: NASA-TM-85924
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An overview of the Western Aeronautical Test Range (WATR) of NASA Ames Research Center (ARC) is presented in this paper. The three WATR facilities are discussed, and three WATR elements - mission control centers, communications systems, real-time processing and display systems, and tracking systems - are reviewed. The relationships within the NASA WATR, with respect to the NASA aeronautics program, are also discussed.
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    Subject Category: 09
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    Report Date: January 1985
    No. Pages: 18
    Keywords:      Western Aeronautical Test Range; Real-time processing and display; Telemetry data; Mission control center
    Notes: This report was prepared as AIAA Paper 85-0316 for AIAA 23rd Aerospace Sciences Meeting, Reno, Nevada, Jan. 14-17, 1985.


  16. REMOTE CONTROL OF AN IMPACT DEMONSTRATION VEHICLE , Technical Memorandum
    Authors: P. F. Harney, J. B. Craft, Jr. and R. G. Johnson
    Report Number: NASA-TM-85925
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Uplink and downlink telemetry systems were installed in a Boeing 720 aircraft that was remotely flown from Rogers Dry Lake at Edwards Air Force Base and impacted into a designated crash site on the lake bed. The controlled impact demonstration (CID) program was a joint venture by the National Aeronautics and Space Administration (NASA) and the Federal Aviation Administration (FAA) to test passenger survivability using antimisting kerosene (AMK) to inhibit postcrash fires, improve passenger seats and restraints, and improve fire-retardent materials. The uplink telemetry system was used to remotely control the aircraft and activate onboard systems from takeoff until after impact. Aircraft systems for remote control, aircraft structural response, passenger seat and restraint systems, and anthropomorphic dummy responses were recorded and displayed by the downlink stems. The instrumentation uplink and downlink systems are described.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 06
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    Report Date: April 1985
    No. Pages: 12
    Keywords:      Command and control; Downlinking; Impact resistance; Remotely piloted vehicles; Telemetry.
    Notes: Presented at 31st Intern. Instrumentation Symp. of the Instrument Soc. of Am., San Diego, Calif., 6-9 May 1985.


  17. FORMULATION AND IMPLEMENTATION OF NONSTATIONARYADAPTIVE ESTIMATION ALGORITHM WITH APPLICATIONS TO AIR-DATARECONSTRUCTION , Technical Memorandum
    Authors: S. A. Whitmore
    Report Number: NASA-TM-86727
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The dynamics model and data sources used to perform air-data reconstruction are discussed, as well as the Kalman filter. The need for adaptive determination of the noise statistics of the process is indicated. The filter innovations are presented as a means of developing the adaptive criterion, which is based on the true mean and covariance of the filter innovations. A method for the numerical approximation of the mean and covariance of the filter innovations is presented. The algorithm as developed is applied to air-data reconstruction for the space shuttle, and data obtained from the third landing are presented. To verify the performance of the adaptive algorithm, the reconstruction is also performed using a constant covariance Kalman filter. The results of the reconstructions are compared, and the adaptive algorithm exhibits better performance.
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    Subject Category: 05
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    Report Date: May 1985
    No. Pages: 11
    Keywords:      Airspeed; Algorithms; Kalman filters; Space shuttles; Wind velocity.
    Notes: Presented at the IEEE Natl. Aerospace and Electron. Conf., Dayton, Ohio, 20-24 May 1985.


  18. APPLICATION OF FREQUENCY DOMAIN HANDLING QUALITIESCRITERIA TO THE LONGITUDINAL LANDING TASK , Technical Memorandum
    Authors: S. K. Sarrafian and B. G. Powers
    Report Number: NASA-TM-86728
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Under NASA sponsorship, an in-flight simulation of the longitudinal handling qualities of several configurations for the approach and landing tasks was performed on the USAF/AFWAL Total In-Flight Simulator by the Calspan Corporation. The basic configuration was a generic transport airplane with static instability. The control laws included proportional plus integral gain loops to produce pitch-rate and angle-of-attack feedback loops. The evaluation task was a conventional visual approach to a flared touchdown at a designated spot on the runway with a lateral offset. The general conclusions were that the existing criteria are based on pitch-attitude response and that these characteristics do not adequately discriminate between the good and bad configurations of this study. This paper describes the work that has been done to further develop frequency-based criteria in an effort to provide better correlation with the observed data.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 08
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    Report Date: August 1985
    No. Pages: 15
    Keywords:      Aircraft landing; Control systems design; Controllability; Feedback control; Transport aircraft.
    Notes: Presented at the AIAA Guidance, Navigation, and Control Conf., Snowmass, Colo., 19-21 Aug. 1985.


  19. A COMPARISON OF MEASURED AND CALCULATED THERMAL STRESSES IN A HYBRID METAL MATRIX COMPOSITE SPAR CAP ELEMENT , Technical Memorandum
    Authors: J. M. Jenkins, A. H. Taylor and I. F. Sakata
    Report Number: NASA-TM-86729
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A hybrid spar of titanium with an integrally brazed composite, consisting of an aluminum matrix reinforced with boron-carbide-coated fibers, was heated in an oven and the resulting thermal stresses were measured. Uniform heating of the spar in an oven resulted in thermal stresses arising from the effects of dissimilar materials and anisotropy of the metal matrix composite. Thermal stresses were calculated from a finite element structural model using anisotropic material properties deduced from constituent properties and rules of mixtures. Comparisons of calculated thermal stresses with measured thermal stresses on the spar are presented. It was shown that failure to account for anisotropy in the metal matrix composite elements would result in large errors in correlating measured and calculated thermal stresses. It was concluded that very strong material characterization efforts are required to predict accurate thermal stresses in anisotropic composite structures.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 39
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    Report Date: September 1985
    No. Pages: 20
    Keywords:      Finite element method; Longerons; Matrix methods; Thermal stresses; Titanium.


  20. EXTRACTION OF AERODYNAMIC PARAMETERS FOR AIRCRAFTAT EXTREME FLIGHT CONDITIONS , Technical Memorandum
    Authors: K. W. Iliff
    Report Number: NASA-TM-86730
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The maximum likelihood estimator has been used to extract stability and control derivatives from flight data for many years. Most of the literature on aircraft estimation concentrates on new developments and applications, assuming familiarity with basic concepts. This paper briefly discusses the maximum likelihood estimator and the aircraft equations of motion that the estimator uses. The current strength and limitations associated with obtaining flight-determined aerodynamic coefficients in extreme flight conditions is assessed. The importance of the careful combining of wind tunnel results (or calculations) and flight results and the thorough evaluation of the mathematical model is emphasized. The basic concepts of minimization and estimation are examined for a simple computed aircraft example, and the cost functions that are to be minimized during estimation are defined and discussed. Graphic representations of the cost functions are given to help illustrate the minimization process. Finally, the basic concepts are generalized, and estimation of stability and control derivatives from flight data is discussed.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 66
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    Report Date: May 1985
    No. Pages: 24
    Keywords:      Equations of motion; Flight conditions; Flight control; Maximum likelihood estimates; Parameter identification.
    Notes: Presented at the AGARD Symp. on Unsteady Aerodyn. Fundamentals and Appl. to Aircraft Dyn., Goettingen, West Germany, 6-9 May 1985.


  21. QUALIFICATION NEEDS FOR ADVANCED INTEGRATEDAIRCRAFT , Technical Memorandum
    Authors: D. A. Mackall
    Report Number: NASA-TM-86731
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: In an effort to achieve maximum aircraft performance, designers are integrating aircraft systems. The characteristics of aerodynamics, vehicle structure, and propulsion systems are being integrated and controlled through embedded, often flight critical, electronic systems. The qualification needs for such highly integrated aircraft systems are addressed. Based on flight experience with research aircraft, a set of test capabilities is described which allows for complete and efficient qualification of advanced integrated aircraft.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: January 1985
    No. Pages: 16
    Keywords:      Aircraft design; Aircraft performance; Electronic control; Flight tests; Qualifications.
    Notes: Presented at the AIAA Conf., Snowmass, Colo., 19-21 Aug. 1985.


  22. DEVELOPMENT OF A TEMPERATURE-COMPENSATEDHOT-FILM ANEMOMETER SYSTEM FOR BOUNDARY-LAYER TRANSITIONDETECTION ON HIGH-PERFORMANCE AIRCRAFT , Technical Memorandum
    Authors: H. R. Chiles and J. B. Johnson
    Report Number: NASA-TM-86732
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A hot-film constant-temperature anemometer (CTA) system was flight-tested and evaluated as a candidate sensor for determining boundary-layer transition on high-performance aircraft. The hot-film gage withstood an extreme flow environment characterized by shock waves and high dynamic pressures, although sensitivity to the local total temperature with the CTA indicated the need for some form of temperature compensation. A temperature-compensation scheme was developed and two CTAs were modified and flight-tested on the F-104/Flight Test Fixture (FTF) facility at a variety of Mach numbers and altitudes, ranging from 0.4 to 1.8 and 5,000 to 40,000 ft respectively.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 06
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    Report Date: August 1985
    No. Pages: 9
    Keywords:      Autonomy; Boundary layer transition; Dynamic pressure; Flight tests; Hot-film anemometers.
    Notes: Presented at the IEEE/CIASF Conf., Stanford, Calif., 26-28 Aug. 1985.


  23. FAULT DETECTION AND ACCOMMODATION TESTING ON ANF100 ENGINE IN AN F-15 AIRPLANE , Technical Memorandum
    Authors: L. P. Myers, J. L. Baer-Riedhart and M. D. Maxwell
    Report Number: NASA-TM-86735
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The fault detection and accommodation (FDA) methodology for digital engine-control systems may range from simple comparisons of redundant parameters to the more complex and sophisticated observer models of the entire engine system. Evaluations of the various FDA schemes are done using analytical methods, simulation, and limited-altitude-facility testing. Flight testing of the FDA logic has been minimal because of the difficulty of inducing realistic faults in flight. A flight program was conducted to evaluate the fault detection and accommodation capability of a digital electronic engine control in an F-15 aircraft. The objective of the flight program was to induce selected faults and evaluate the resulting actions of the digital engine controller. Comparisons were made between the flight results and predictions. Several anomalies were found in flight and during the ground test. Simulation results showed that the inducement of dual pressure failures was not feasible since the FDA logic was not designed to accommodate these types of failures.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 07
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    Report Date: July 1985
    No. Pages: 15
    Keywords:      Engine failure; F-15 aircraft; Failure analysis; Fault detection; Prediction analysis.
    Notes: Presented at AIAA/SAE/ASME 21st Joint Propulsion Conf., Monterey, Calif., 8-10 Jul. 1985.


  24. DEVELOPMENT OF CONTROL LAWS FOR A FLIGHT TEST MANEUVER AUTOPILOT FOR AN F-15 AIRCRAFT , Technical Memorandum
    Authors: G. S. Alag and E. L. Duke
    Report Number: NASA-TM-86736
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An autopilot can be used to provide precise control to meet the demanding requirements of flight research maneuvers with high-performance aircraft. The development of control laws within the context of flight test maneuver requirements is discussed. The control laws are developed using eigensystem assignment and command generator tracking. The eigenvalues and eigenvectors are chosen to provide the necessary handling qualities, while the command generator tracking enables the tracking of a specified state during the maneuver. The effectiveness of the control laws is illustrated by their application to an F-15 aircraft to ensure acceptable aircraft performance during a maneuver.
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    Subject Category: 08
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    Report Date: August 1985
    No. Pages: 9
    Keywords:      Aircraft control; Aircraft maneuvers; Automatic pilots; Control theory; Controllability.


  25. DEVELOPMENT AND VALIDATION OF A GENERAL PURPOSELINEARIZATION PROGRAM FOR RIGID AIRCRAFT MODELS , Technical Memorandum
    Authors: E. L. Duke and R. F. Antoniewicz
    Report Number: NASA-TM-86737
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A FORTRAN program that provides the user with a powerful and flexible tool for the linearization of aircraft models is discussed. The program LINEAR numerically determines a linear systems model using nonlinear equations of motion and a user-supplied, nonlinear aerodynamic model. The system model determined by LINEAR consists of matrices for both the state and observation equations. The program has been designed to allow easy selection and definition of the state, control, and observation variables to be used in a particular model. Also, included in the report is a comparison of linear and nonlinear models for a high performance aircraft.
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    Subject Category: 08
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    Report Date: August 1985
    No. Pages: 14
    Keywords:      Aircraft models; Computer programs; Computerized simulation; FORTRAN; Linearization.
    Notes: Presented at the AIAA Guidance, Navigation, and Control Conf., Snowmass, Colo., 19-21 Aug. 1985.


  26. FLIGHT TEST EXPERIENCE AND CONTROLLED IMPACT OF ALARGE, FOUR-ENGINE, REMOTELY PILOTED AIRPLANE , Technical Memorandum
    Authors: R. W. Kempel and T. W. Horton
    Report Number: NASA-TM-86738
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: A controlled impact demonstration (CID) program using a large, four engine, remotely piloted transport airplane was conducted. Closed loop primary flight control was performed from a ground based cockpit and digital computer in conjunction with an up/down telemetry link. Uplink commands were received aboard the airplane and transferred through uplink interface systems to a highly modified Bendix PB-20D autopilot. Both proportional and discrete commands were generated by the ground pilot. Prior to flight tests, extensive simulation was conducted during the development of ground based digital control laws. The control laws included primary control, secondary control, and racetrack and final approach guidance. Extensive ground checks were performed on all remotely piloted systems. However, manned flight tests were the primary method of verification and validation of control law concepts developed from simulation. The design, development, and flight testing of control laws and the systems required to accomplish the remotely piloted mission are discussed.
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    Subject Category: 08
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    Report Date: August 1985
    No. Pages: 17
    Keywords:      Control systems design; Crashworthiness; Feedback control; Flight control; Flight tests.
    Notes: Presented at the SFTE 16th Ann. Symp., Seattle, 29 Jul. - 2 Aug. 1985.


  27. DESIGN OF AN EXPERT-SYSTEM FLIGHT STATUS MONITOR , Technical Memorandum
    Authors: V. A. Regenie and E. L. Duke
    Report Number: NASA-TM-86739
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The modern advanced avionics in new high-performance aircraft strains the capability of current technology to safely monitor these systems for flight test prior to their generalized use. New techniques are needed to improve the ability of systems engineers to understand and analyze complex systems in the limited time available during crucial periods of the flight test. The Dryden Flight Research Facility of NASA's Ames Research Center is involved in the design and implementation of an expert system to provide expertise and knowledge to aid the flight systems engineer. The need for new techniques in monitoring flight systems and the conceptual design of an expert-system flight status monitor is discussed. The status of the current project and its goals are described.
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    Subject Category: 61
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    Report Date: August 1985
    No. Pages: 11
    Keywords:      Aircraft design; Aircraft reliability; Computer programs; Expert systems; Flight tests.
    Notes: Presented at the AIAA Guidance and Control Conf., Snowmass, Colo., 19-21 Aug. 1985. AIAA Paper 85-1908.


  28. FLIGHT EVALUATION OF A DIGITAL ELECTRONIC ENGINE CONTROL IN AN F-15 AIRPLANE , Journal Article
    Authors: F. W. Burcham, Jr., L. P. Myers and K. R. Walsh
    Report Number: H-1301
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: No abstract available.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 07
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    Report Date: December 1985
    No. Pages: 7
    Keywords:      Avionics; Digital systems; Electronic control; Engine control; F-15 aircraft.
    Notes: Journal of Aircraft (ISSN 0021-8669), vol. 22, Dec. 1985, p. 1072-1078.


  29. A CONSTANT ALTITUDE FLIGHT SURVEY METHOD FORMAPPING ATMOSPHERIC AMBIENT PRESSURES AND SYSTEMATICRADAR ERRORS , Technical Memorandum
    Authors: T. J. Larson and L. J. Ehernberger
    Report Number: NASA-TM-86733
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The flight test technique described uses controlled survey runs to determine horizontal atmospheric pressure variations and systematic altitude errors that result from space positioning measurements. The survey data can be used not only for improved air data calibrations, but also for studies of atmospheric structure and space positioning accuracy performance. The examples presented cover a wide range of radar tracking conditions for both subsonic and supersonic flight to an altitude of 42,000 ft.
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    Subject Category: 05
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    Report Date: June 1985
    No. Pages: 11
    Keywords:      Aerial reconaissance; Altitude; Atmospheric pressure; Errors; Mapping.
    Notes: Presented at IEEE Natl. Aerospace and Electron. Conf., Dayton, Ohio, 20-24 May 1985.


  30. WATER TUNNEL FLOW VISUALIZATION USING A LASER , Technical Memorandum
    Authors: C. Beckner and R. E. Curry
    Report Number: NASA-TM-86743
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Laser systems for flow visualization in water tunnels (similar to the vapor screen technique used in wind tunnels) can provide two-dimensional cross-sectional views of complex flow fields. This parametric study documents the practical application of the laser-enhanced visualization (LEV) technique to water tunnel testing. Aspects of the study include laser power levels, flow seeding (using flourescent dyes and embedded particulates), model preparation, and photographic techniques. The results of this study are discussed to provide potential users with basic information to aid in the design and setup of an LEV system.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 09
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    Report Date: October 1985
    No. Pages: 16
    Keywords:      Flow visualization; Fluorescence; Laser applications; Two dimensional flow; Water tunnel tests
    Notes: Presented at the 3rd AIAA Appl. Aerodyn. Conf., Colorado Springs, 14-16 Oct. 1985.


  31. IN-FLIGHT EVALUATION OF PURE TIME DELAYS IN PITCHAND ROLL , Conference Paper
    Authors: D. T. Berry
    Report Number: H-1308
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An in-flight investigation of the effect of pure time delays in pitch and roll was undertaken. The evaluation tasks consisted of low lift-to-drag-ratio landings of various levels of difficulty and formation flying. The results indicate that the effect of time delay is strongly dependent on the task. In the pitch axis, in calm air, spot landings from a lateral offset were most strongly influenced by time delay. In the roll axis, in calm air, formation flying was most strongly influenced by time delay. However, when landings were made in turbulence, flying qualities in pitch were only slightly degraded, whereas in roll they were severely degraded.
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    Subject Category: 08
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    Report Date: January 1985
    No. Pages: 8
    Keywords:      Aircraft landing; Attitude control; Flight tests; Pilot induced oscillation; Pitching moments.
    Notes: IN: Guidance, Navigation and Control Conference, Snowmass, CO, August 19-21, 1985, Technical Papers (A85-45876 22-08). New York, AIAA, 1985, p. 39-46.


  32. EXPERT SYSTEMS DEVELOPMENT AND APPLICATION , Technical Memorandum
    Authors: E. L. Duke and V. A. Regenie
    Report Number: NASA-TM-86746
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: Current research in the application of expert systems to problems in the flight research environment is discussed. In what is anticipated to be a broad research area, a real time expert system flight status monitor has been identified as the initial project. This real time expert system flight status monitor is described in terms of concept, application, development, and schedule.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: October 1985
    No. Pages: 8
    Keywords:      Avionics; Computer programming; Expert systems; Flight control; Flight tests.
    Notes: Presented at the IEEE Symp. on Expert Systems in Govt., McLean, Va., 23-25 Oct. 1985.


  33. PERFORMANCE IMPROVEMENTS OF A HIGHLY INTEGRATEDDIGITAL ELECTRONIC CONTROL SYSTEM FOR AN F-15 AIRPLANE , Technical Memorandum
    Authors: T. W. Putnam, F. W. Burcham, Jr., M. G. Andries and J. B. Kelly
    Report Number: NASA-TM-86748
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The NASA highly integrated digital electronic control (HIDEC) program is structured to conduct flight research into the benefits of integrating an aircraft flight control system with the engine control system. A brief description of the HIDEC system installed on an F-15 aircraft is provided. The adaptive engine control system (ADECS) mode is described in detail, together with simulation results and analyses that show the significant excess thrust improvements achievable with the ADECS mode. It was found that this increased thrust capability is accompanied by reduced fan stall margin and can be realized during flight conditions where engine face distortion is low. The results of analyses and simulations also show that engine thrust response is improved and that fuel consumption can be reduced. Although the performance benefits that accrue because of airframe and engine control integration are being demonstrated on an F-15 aircraft, the principles are applicable to advanced aircraft such as the advanced tactical fighter and advanced tactical aircraft.
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    Subject Category: 07
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    Report Date: August 1985
    No. Pages: 14
    Keywords:      Control systems design; Digital systems; Electronic control; Engine control; F-15 aircraft.
    Notes: Presented at the AIAA Guidance and Control Conf., Snowmass, Colo., 19-21 Aug. 1985. AIAA Paper 85-1876.


  34. IDENTIFICATION OF UNSTEADY AERODYNAMICS ANDAEROELASTIC INTEGRO-DIFFERENTIAL SYSTEMS , Technical Memorandum
    Authors: N. K. Gupta and K. W. Iliff
    Report Number: NASA-TM-86749
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The problem of estimating integro-differential models based on test or simulation data is dealt with. The identification techniques proposed for estimating parameters in models described by differential equations need to be considerably extended to deal with the integral terms. Conditions under which the integral terms may be approximated by algebraic values are discussed. The integro-differential models discussed are related to indicial models proposed by aerodynamicists to describe unsteady flow.
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    Subject Category: 66
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    Report Date: August 1985
    No. Pages: 32
    Keywords:      Differential equations; Estimates; Mathematical Models; Unsteady aerodynamics; Unsteady flow.


  35. NET THRUST CALCULATION SENSITIVITY OF AN AFTERBURNING TURBOFAN ENGINE TOVARIATIONS IN INPUT PARAMETERS , Conference Paper
    Authors: D. L. Hughes, R. J. Ray and J. T. Walton
    Report Number: H-1315
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: The calculated value of net thrust of an aircraft powered by a General Electric F404-GE-400 afterburning turbofan engine was evaluated for its sensitivity to various input parameters. The effects of a 1.0-percent change in each input parameter on the calculated value of net thrust with two calculation methods are compared. This paper presents the results of these comparisons and also gives the estimated accuracy of the overall net thrust calculation as determined from the influence coefficients and estimated parameter measurement accuracies.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 07
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    Report Date: October 1985
    No. Pages: 9
    Keywords:      Afterburning; Aircraft engines; In-flight monitoring; Influence coefficient; Thrust measurement.
    Notes: AIAA, AHS, and ASEE, Aircraft Design Systems and Operations Meeting, Colorado Springs, CO, Oct. 14-16, 1985. 9 p.


  36. DESCRIPTION OF AN EXPERIMENTAL EXPERT SYSTEM FLIGHT STATUS MONITOR , Technical Memorandum
    Authors: E. L. Duke and V. A. Regenie
    Report Number: NASA-TM-86791
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: This paper describes an experimental version of an expert system flight status monitor being developed at the Dryden Flight Research Facility of the NASA Ames Research Center. This experimental expert system flight status monitor (ESSFSM) is supported by a specialized knowledge acquisition tool that provides the user with a powerful and easy-to-use documentation and rule construction tool. The EESFSM is designed to be a testbed for concepts in rules, inference mechanisms, and knowledge structures to be used in a real-time expert system flight status monitor that will monitor the health and status of the flight control system of state-of-the-art, high-performance, research aircraft.
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    Subject Category: 05
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    Report Date: October 1985
    No. Pages: 11
    Keywords:      Avionics; Control systems design; Expert systems; Flight control; Flight tests.
    Notes: Presented at the 5th AIAA Computers in Aerospace Conf., Long Beach, Calif., 21-23 Oct. 1985.


  37. X-29 INITIAL FLIGHT TEST RESULTS , Conference Paper
    Authors: S. D. Ishmael and T. Wierzbanowski
    Report Number: H-1326
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: It is announced that the X-29 forward-swept-wing (FSW) aircraft has been built, with flight testing under way and proceeding smoothly. The X-29 is a single-seat, single-engine supersonic aircraft that blends an optimized FSW, a close-coupled near-coplar canard, an F-5A forward fuselage module employing two side-mounted engine inlets, and a new aft fuselage. An F404-GE-400 engine with afterburner provides about 16,000 lb of thrust. The X-29 was designed to be near neutrally stable in the supersonic region to minimize drag; it becomes highly unstable transonically and subsonically, which dictates the use of a computerized fly-by-wire flight control system capable of stabilizing the aircraft. The X-29 advanced technology demonstrator began flight testing on Dec. 14, 1984; by Sept. 26, 1985, its envelope had been expanded to 0.75 Mach, 350 knots estimated airspeed, and 30,000 feet altitude. The aircraft has flown with very few problems and aerodynamic, structural, and control system results have correlated well with predictions. Areas where prediction and performance are not so well correlated are noted.
    Distribution/Availability: Unclassified - Unlimited
    Subject Category: 05
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    Report Date: September 1985
    No. Pages: 19
    Keywords:      Aerodynamics; Aircraft control; Aircraft performance; Flight tests; X-29 aircraft.
    Notes: IN: Society of Experimental Test Pilots, Symposium, 29th, Beverly Hills, CA, September 25-28, 1985, Proceedings. Lancaster, CA, Society of Experimental Test Pilots, 1985, p. 95-113.


  38. DEVELOPMENT OF A FLIGHT TEST MANEUVER AUTOPILOT FOR AN F-15 AIRCRAFT , Technical Memorandum
    Authors: G. S. Alag and E. L. Duke
    Report Number: NASA-TM-86799
    Performing Organization: NASA Dryden Flight Research Center, Edwards, CA
    Abstract: An autopilot can be used to provide precise control to meet the demanding requirements of flight research maneuvers with high-performance aircraft. This paper presents the development of control laws for a flight test maneuver autopilot for an F-15 aircraft. A linear quadratic regulator approach is used to develop the control laws within the context of flight test maneuver requirements by treating the maneuver as a finite time tracking problem with regulation of state rates. Results are presented to show the effectiveness of the controller in insuring acceptable aircraft performance during a maneuver.
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    Subject Category: 08
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    Report Date: December 1985
    No. Pages: 8
    Keywords:      Control systems design; Control theory; F-15 aircraft; Flight tests; Maneuvers.
    Notes: Presented at the 24th IEEE Conf. on Decision and Control, 11 Dec. 1985.
 
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