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Development and Conversion flight test of a Small Tiltrotor Unmanned Aerial Vehicle

JOURNAL OF AIRCRAFT 2010年第2期47卷 730-732页

作者： Choi, Seongwook Kang, Youngshin Chang, Sungho Koo, Samok Kim, Jai Moo Korea Aerosp Res Inst Smart UAV Dev Ctr Taejon 305333 South Korea

Sizing and performance analysis of the downscaled tiltrotor are presented in which simple codes based on blade element and momentum theory were used. The conversion corridor of the tiltrotor was predicted and the nacelle tilt angle and air speed were compared with flight-test results. The performance analysis code named SPAC (Smart UAV Performance Code) was developed and used for the performance estimation. The code has a capability to calculate the three modes of tiltrotor flight: hover, transition, and cruise. The hovering performance of the 1/2.5-scale proprotor was calculated and the result was used for investigation of the hovering capability as well as for the initial sizing of the rotor. The ground and flight tests were conducted using rate stability augmentation system and attitude stability and control augmentation system feedback. The flight test verified that the stability and control augmentation algorithm worked well in the flight control software.

关键词： flight test programme Tiltrotor UAV Airframes Aeroplane Aerodynamic Performance Stability and Control Augmentation System Rotor Systems flight Control System flight Control Computer

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EFFECTS OF SPIN AND MASS ADDITION ON HIGH-ANGLE-OF-ATTACK RE-ENTRY

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JOURNAL OF SPACECRAFT AND ROCKETS 1985年第1期22卷 68-73页

作者： MORRISON, AM FISCINA, C Naval Surface Weapons Center White Oak Silver Spring Maryland

A series of wind tunnel experiments has been conducted to investigate boundary layer and mass addition effects on the aerodynamics of typical re-entry configurations. Early investigators hypothesized that skewed circumferential mass addition distributions which might result from hypersonic ablation, at angle of attack, with spin could result in a Magnus-like side force and moment. The experiments described here were conducted in the Naval Surface Weapons Center Hypervelocity Research Tunnel at a Mach number of 18. Results of experiments in which both qualitative and quantitative simulations were carried out will be presented in the form of aerodynamic forces and moments in the pitch and yaw planes. This unique data base is a valuable tool in ongoing flowfield modeling/validation efforts. © American Institute of Aeronautics and Astronautics, Inc., 1985, All rights reserved.

关键词： Angle of Attack Stability Derivatives Boundary Layer Tunnel Flow Yaw Hypersonic Ablation Re Entry Vehicle Pressure Coefficient flight test programme Internal Flows

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PILOT PRODUCTION OF SUPERPLASTICALLY FORMED DIFFUSION BONDED T-38 MAIN LANDING GEAR DOORS

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JOURNAL OF AIRCRAFT 1985年第7期22卷 568-572页

作者： LEODOLTER, W Douglas Aircraft Company McDonnell Douglas Corporation Long Beach California

This paper discusses the engineering development effort, the preliminary and final airworthiness qualification of a test door, and the manufacture of 30 titanium main landing gear strut doors for the T-38 aircraft using superplastic forming and concurrent diffusion bonding (SPF/DB) as the principal fabrication method. The structural concept of the new door is a variable thickness sandwich panel having an internal core structure with rectangular cells. The tooling concept and fabrication steps, from sheet preparation to final assembly and nondestructive testing, are described, with particular emphasis on those elements that contribute most to the process reliability. Cost analyses indicated that fabrication costs are sensitive to the cost and utilization of the titanium material. Although acquisition costs for the SPF/DB doors are higher than those for the currently used aluminum honeycomb doors, significant life-cycle cost savings can be achieved. The discussion on costs deviates from the standard and highlights the implications from the time lag between front-end investments and later benefit accrual as a potential barrier for technology implementation. Since 1983, the titanium doors have been used on U.S. Air Force aircraft. © 1985 American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Aircraft Structures Pilot Manufacturing Cost Airworthiness Air Forces Nondestructive testing Life Cycle Costs Analysis Chemical Milling flight test programme Maximum Shear Stresses

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flight-test evaluation of stability augmentation steering system for aircraft ground handling

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2004年第1期27卷 41-51页

作者： Klyde, DH Reinsberg, JG Sanders, E Kokolios, A Syst Technol Inc Hawthorne CA 90250 USA Boeing Co St Louis MO 63166 USA USN Air Syst Command Patuxent River MD 20670 USA

A flight-test program was conducted to evaluate a newly developed stability augmentation steering system (SASS). Designed to improve the ground-handling characteristics of a U.S. Navy jet trainer, the SASS features a yaw-rate feedback that is used to set the heading attitude bandwidth as desired, while providing an essentially constant rudder pedal sensitivity variation with speed. flight-test, efforts were conducted to assess performance of two SASS configurations against the baseline aircraft configuration. Three pilots evaluated the ability of the aircraft to perform a runway offset capture-and-hold maneuver, essentially a lane change task, with and without braking. The task with braking was found to be the better separator in terms of pilot ratings for the two SASS configurations when compared to the baseline aircraft. The flight-test program found that the SASS significantly improved the ground handling of the aircraft.

关键词： Stability Augmentation Steering Systems flight test programme Aircraft Ground Handling Pilot Rudder Runways Aircraft Configurations Indicated Airspeed Closed Loop System Power Spectral Density

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PRACTICAL flight test METHOD FOR DETERMINING RECIPROCATING-ENGINE COOLING REQUIREMENTS

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JOURNAL OF AIRCRAFT 1984年第12期21卷 936-942页

作者： WARD, DT MILEY, SJ Texas A&M University College Station Texas

A practical flight test procedure has been developed and verified for determining the cooling requirements for an installed air cooled reciprocating engine of any type The technique is based on a simple modification of the NACA cooling correlation method developed some 40 years ago for radial engines The modification involves replacing an empirically determined combustion gas temperature T_g with a measured exhaust gas temperature T_egt This latter parameter can be easily obtained utilizing cockpit instruments only The modification, therefore, reduces the need for extensive and expensive ground tests Data were collected in two separate flight test programs that verify the technique first with a rather completely instrumented airplane and later with minimal instrumentation and a minimal number of data points In both cases the data fits that comprise the correlation procedure were quite good Even the second tests with the sparse test matrix produced root mean square fit errors of less than 4% suggesting that the procedure provides consistent answers for practical flight test situations. © 1984 American Institute of Aeronautics and Astronautics, Inc., All rights reserved.

关键词： flight test programme Horizontally Opposed Engine Aeroplane Mass Flow Rate Air Cooled Engine Heat Transfer Landing Gear General Aviation Cockpit Instrumentation Airspeed

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Solar sail structural characterization test program

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JOURNAL OF SPACECRAFT AND ROCKETS 2007年第4期44卷 765-783页

作者： Gaspar, James L. Jones, Thomas W. Murphy, David M. NASA Langley Res Ctr Struct Dynam Branch Hampton VA 23681 USA ATK Space Syst & Sensors Solar Arrays & Deployables Goleta CA 93117 USA

The NASA in-space propulsion program sponsored intensive solar-sail technology and systems design, development, and hardware demonstration activities over the past three years. Efforts to validate an ATK Space Systems designed scalable solar sail system by functional demonstration in relevant environments, together with structural test-analysis correlation activities have recently been successfully completed. The tests spanned three phases of the program, with each phase lasting approximately I year;phase 1 focused on component tests of a mast segment and sail quadrant, phase 2 focused on a 10-m quadrant with two supporting masts, and phase 3 focused on a 20-m sail system with all four quadrants and masts. These tests were conducted for the purpose of validating analytical models that would be required by a flight test program to predict in-space performance. Specific tests included static shape testing using photogrammetry and modal vibration tests on the sail in a 1 torr vacuum environment using various excitation locations and techniques. The excitation methods were evaluated for their applicability to in-vacuum ground testing and their traceability to the development of on-orbit flight test techniques. The solar-sail masts were modal vibration tested in ambient atmospheric conditions and these results are also discussed.

关键词： Solar Sail Propulsion flight test programme Atmospheric Conditions Space Systems Design Dynamic Response Longerons Accelerometer Piezoelectric Stack Actuator Fiber Reinforced Composites Attitude Control System

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Adaptive Glide Slope Control for Parafoil and Payload Aircraft

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2013年第4期36卷 1019-1034页

作者： Ward, Michael Costello, Mark Georgia Inst Technol Guggenheim Sch Aerosp Engn Atlanta GA 30332 USA Georgia Inst Technol Guggenheim Sch Aerosp Engn Woodruff Sch Mech Engn Atlanta GA 30332 USA

The invention of the steerable, gliding, ram-air parafoil enabled the possibility of precision, autonomous aerial payload delivery. Research and development work on guided airdrop systems has focused primarily on evolutionary improvements to the guidance algorithm, although the navigation and control algorithms have changed little since the initial autonomous systems were developed. Recent work has demonstrated the potential for dramatic improvements in landing accuracy through the incorporation of canopy incidence variation to achieve glide slope control for parafoils. The current work presents the development of a control law to implement glide slope control on an autonomous airdrop system. Autonomous landings with the control law in both simulation and flight test demonstrate an improvement in landing accuracy by a factor of two, though the improvement can be even greater in especially windy conditions. Finally, the ability to perform in-flight system identification to adapt internal control mappings to match flight data and provide dramatic improvements in landing accuracy when there is a significant discrepancy between the assumed and actual flight characteristics is demonstrated in both simulation and flight test.

关键词： Parafoil Air Vehicle flight test programme Adaptive Control Algorithm Control Algorithm flight Software Navigation Algorithm Autonomous Systems Airspeed GPS

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Strategy for developing air-breathing aerospace planes

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JOURNAL OF AIRCRAFT 1996年第2期33卷 377-385页

作者： Mehta, UB NASA Ames Research Center Moffett Field California 94035-1000

Hypersonic air-breathing propulsion, utilizing scramjets, can fundamentally change transatmospheric accelerators for transportation to and from low Earth orbits. The value and limitations of ground tests, flight tests, and computations are presented, and scramjet development requirements are discussed. Near-full-scale hypersonic propulsion flight tests are essential for developing a prototype hypersonic propulsion system, To determine how this development should be carried out, some technical and programmatic lessons learned from past programs are presented. A conceptual two-stage-to-orbit prototgpe/experimental aerospace plane is recommended as a means of providing access-to space and for developing hypersonic air-breathing propulsion.

关键词： Aerospace Plane flight test programme Single Stage to Orbit Propulsion System Supersonic Combustion Ramjet Freestream Mach Number Air Breathing Rockets Ramjet Engines Aerodynamic Flowfield Acquisition Costs

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UNSTEADY EULER ANALYSIS OF THE FLOWFIELD OF A PROPFAN AT AN ANGLE OF ATTACK

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JOURNAL OF PROPULSION AND POWER 1992年第1期8卷 136-143页

作者： NALLASAMY, M GROENEWEG, JF SVERDRUP TECHNOL INC BROOK PKOH 44142 NASA LEWIS RES CTRCLEVELANDOH 44135

The paper examines the effects of angle of attack of a propfan on the blade loading and details of the flowfield by solving the unsteady three-dimensional Euler equations. The configuration considered is the SR7L propeller at cruise condition and the inflow angles considered are 4.6, 1.6, and - 0.4 deg. The results indicate that the blade response is nearly sinusoidal at low inflow angles (1.6 and - 0.4 deg) and significant deviations from sinusoidal behavior occur at an inflow angle of 4.6 deg due to the presence of strong shocks on both suction and pressure surfaces of the blade. The detailed flow in the blade passages shows that a shock formed on the suction surface during the highly loaded portion of the revolution extends across the passage to the pressure surface. An increase in inflow angle results in an increase in blade loading on the down-going side and a decrease in loading on the up-going side.

关键词： Propfan Angle of Attack Blade Loading Propeller Blades Euler Equations Power Coefficient Transonic Flow Fuselages flight test programme Wind Tunnel tests

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HOVER ACOUSTIC CHARACTERISTICS OF THE XV-15 WITH ADVANCED TECHNOLOGY BLADES

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JOURNAL OF AIRCRAFT 1994年第4期31卷 737-744页

作者： CONNER, DA WELLMAN, JB NASA Langley Research Center Hampton Virginia 23681 NASA Ames Research Center Moffett Field California 94035

An experiment has been performed to investigate the far-field hover acoustic characteristics of the XV-15 aircraft with advanced technology blades (ATB). An extensive, high-quality, far-field acoustics data base was obtained for a rotor tip speed range of 645-771 ft/s. A 12-microphone, 500-ft radius semicircular array combined with two aircraft headings provided acoustic data over the full 360-deg azimuth about the aircraft with a resolution of 15 deg. Altitude variations provided data from near in-plane to 45 deg below the rotor tip path plane. Acoustic directivity characteristics in the lower hemisphere are explored through pressure time histories, narrow-band spectra, and contour plots. Directivity patterns were found to vary greatly with azimuth angle, especially in the forward quadrants. Sharp positive pressure pulses typical of blade-vortex interactions were found to propagate aft of the aircraft and were most intense at 45 deg below the rotor plane. Modest overall sound pressure levels were measured near in-plane indicating that thickness noise is not a major problem for this aircraft when operating in the hover mode with ATB. Rotor tip speed reductions reduced the average overall sound pressure level [dB (0.0002 dyne/cm2)] by nearly 8 dB in-plane, and by almost 5 dB at 12.6 deg below the rotor plane.

关键词： Overall Sound Pressure Level Band Spectra Blade Vortex Interaction Acoustic Measurement Rotor Blades Tiltrotor Aircraft flight test programme Rotor Systems Landing Gear GOES Satellites

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