| Accurate Modeling of Stability and Control Properties for Fighter Aircraft from CFD |
Mar 2012 |
196 pages |
| Authors:
Jedediah H Butler; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
 | Difficulties in obtaining accurate Stability and Control (S&C) data for nonlinear regions in the flight envelope early in the design phase often lead to costly fixes late in the acquisition process. Work examined herein addresses this problem by utilizing recent advances in Computational Fluid Dynamics (CFD) to create a high-fidelity database before any parts have to be physically produced. In combination with CFD, System Identification (SID) is used to characterize ... |
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| Coupled Radiation-Gasdynamic Solution Method for Hypersonic Shock Layers in Thermochemical Nonequilibrium |
Dec 2011 |
175 pages |
| Authors:
Jr Martin Christopher L; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| The purpose of this research was to develop a highly accurate computational method for calculating the nonequilibrium radiative heat transfer within reentry shock layers. The nonequilibrium state of the flowfield was solved using the multispecies multitemperature nonequilibrium flow solver NH7AIR which is capable of separately tracking the vibrational energy of each diatomic species and the energy of the free electrons. The calculation of radiative heat transfer was performed by utilizing ... |
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| Study for Air Vehicles at High Speeds, Identifying the Potential Benefits to Transport Aircraft of a Continuously Variable Geometry Trailing-Edge Structure that can be Utilized for Aircraft Control, Trim, Load-Alleviation, and High Lift |
Aug 2011 |
133 pages |
| Authors:
Raj K Nangia; NANGIA AERO RESEARCH ASSOCIATES BRISTOL (UNITED KINGDOM)
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| One of the technologies emerging in recent years concerns variable aerofoil shaping (or morphing), using clever internal mechanisms. Previous studies have noted potential aerodynamic efficiency gains, gust loads alleviation, stagnation point control for laminar flow onset or Shock position / strength control. Previous work along some of these lines has also been in TACT & MAW programs. Although such mechanisms may provide a lower sectional Clmax, compared with a point ... |
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| Initial Assessment of the Operational Reusable Booster System (RBS) Rocketback |
Mar 2011 |
30 pages |
| Authors:
Barry Hellman; Jon Wallace; Brad St Germain; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE/STRUCTURES DIVISION
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| The U.S. Air Force is pursuing a reusable booster system (RBS) to meet future responsive launch needs. An RBS consists of a reusable booster with and expendable upper stage. To meet operability and life cycle cost (LCC) goals, the current approach is for the RBS to return to the launch site (RTLS) after releasing the upper stage to avoid the need of operating a downrange base and avoiding the cost ... |
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| Closed-Loop Control of Vortex Formation in Separated Flows with Application to Micro Air Vehicles |
25 Oct 2010 |
61 pages |
| Authors:
Tim Colonius; Morteza Gharib; Clarence W Rowley; Gilead Tadmor; David R Williams; CALIFORNIA INST OF TECH PASADENA
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| This research is concerned with developing theory, algorithms. and applications of model -based, closed loop flow control in order to enable robust and agile flight of micro air vehicles, the efforts are centered around the application to integrated closed-loop flow and fight control for stabilization and regulations of separated flows occurring on unmanned and micro air vehicles ( UAV/MAV). |
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| Alternative Methods to Standby Gain Scheduling Following Air Data System Failure |
Sep-2009 |
261 pages |
| Authors:
Matthew W Coldsnow; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
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| The United States Air Force has advanced fighter aircraft that lose the ability to operate in a large portion of their operating flight envelope when an air data system failure is experienced. These aircraft are reverted to a fixed set of standby-gains that limit their maneuverability, degrade handling qualities, and increase susceptibility to departure. The purpose of this research was to determine if three alternative methods of standby-gain-scheduling could provide ... |
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| Enabling Technologies for Nano Air Vehicles |
10-Feb-2009 |
86 pages |
| Authors:
Jamey D Jacob; OKLAHOMA STATE UNIV STILLWATER
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| This project investigated several areas with the aim of improving performance and operational use of nano air vehicles (NAVs) by understanding fundamental operating principles and developing key technologies. The project developed plasma actuators for thrust and maneuvering control and examined flapping flight through the development of a high speed videogrammetry system and a gust/shear tunnel to replicate flow fields seen as the NAY scale. In the first portion of the ... |
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| Aerodynamic Predictions, Comparisons, and Validations Using MissileLab and Missile Datcom (97) |
Dec-2008 |
51 pages |
| Authors:
Hoon H Teo; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Aerodynamic prediction software is often used in the early stages of missile systems designed to quickly and accurately estimate the aerodynamics of a wide variety of missile configuration designs operating over many different flight regimes. It is also possible to use these empirical packages to validate flight data collected from wind tunnel tests and other open sources. Analysis of such data provides users with insights to the performance of a ... |
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| Navier-Stokes Predictions of Dynamic Stability Derivatives: Evaluation of Steady-State Methods |
Sep-2008 |
44 pages |
| Authors:
James DeSpirito; Sidra I Silton; Paul Weinacht; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The prediction of the dynamic stability derivatives-roll-damping, Magnus, and pitch-damping moments-were evaluated for three spin-stabilized projectiles using steady-state computational fluid dynamic (CFD) calculations. Roll-damping CFD predictions were found to be very good across the Mach number range investigated. Magnus moment predictions were very good in the supersonic flight regime; however, the accuracy varied in the subsonic and transonic flight regime. The best Magnus moment prediction in the subsonic flight regime ... |
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| Concepts and Methods of Helicopter Local Stability for Aggressive Maneuvers of Short Duration From Response Data Points |
31 MAY 2007 |
16 pages |
| Authors:
G. H. Gaonkar; FLORIDA ATLANTIC UNIV BOCA RATON
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| This STTR work presents an exploratory investigation of helicopter stability during unsteady maneuvers on the basis of the finite time Lyapunov exponents(FTLE), These maneuvers represent short duration dynamics that lasts long enough to stall the rotor but not long enough to reach a steady state, they also represent aggressive operations at the extremes of the flight envelope that often represent a design condition. The Floquet approach is not applicable because ... |
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| Variability and Model Adequacy in Simulations of Store-Induced Limit Cycle Oscillations |
03 MAY 2007 |
48 pages |
| Authors:
Ashley S. Myers; NAVAL ACADEMY ANNAPOLIS MD
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| A prominent phenomenon of the transonic flight regime is the potential for limit cycle oscillation (LCO) development. LCO is a stable oscillation produced by aeroelastic interactions within a component of the aircraft. Such oscillation shortens the fatigue life of the aircraft and increases the amount of maintenance necessary. These aspects are of great concern to the aerospace industry, particularly with high performance military aircraft that are required to operate beyond ... |
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| Output Feedback Control and Sensor Placement for a Hypersonic Vehicle Model (Preprint) |
DEC 2006 |
25 pages |
| Authors:
Pete Jankovsky; David O. Sigthorsson; Andrea Serrani; Stephan Yurkovich; Michael A. Bolender; David B. Doman; OHIO STATE UNIV COLUMBUS DEPT OF ELECTRICAL ENGINEERING
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| This paper addresses issues related to output feedback control, including sensor placement, for a model of an air-breathing hypersonic vehicle. The model presents a number of control challenges, in particular because of strong couplings between the propulsive and aerodynamic forces. Because of the vehicle's low weight, slenderness, and length, the vehicle's flexibility has a large impact on stability and control of the vehicle. Two output feedback control methods are developed. ... |
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| Current MBDA R&T Effort on Ram/Scramjet and Detonation Wave Engine |
May-2006 |
25 pages |
| Authors:
Francois Falempin; MBDA FRANCE CHATILLON
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| Since the fifties, MBDA France, in close cooperation with ONERA, has been leading a sustained effort to develop ramjet technology. This strong involvment led to the development of the Air Sol Moyenne Port?e (ASMP or Medium Range Air-to-Ground) missile which entered service in the French Air Force in 1986 and will be soon replaced by ASMP A. Beyond this development, a lot of advanced studies were performed during the nineties ... |
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| Development of Autonomous Unmanned Aerial Vehicle Platform: Modeling, Simulating, and Flight Testing |
MAR 2006 |
202 pages |
| Authors:
Nidal M. Jodeh; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
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| The Advanced Navigation Technology (ANT) Center at the Air Force Institute of Technology (AFIT) conducts extensive research in advanced guidance, navigation, and control to exploit the full potential of autonomous Unmanned Aerial Vehicles (UAV). The research in this thesis describes a UAV research platform developed to support the ANT Center?s goals. This platform is now the bedrock for UAV simulation and local flight test at AFIT. The research has three ... |
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| Methodologies for Predicting and Testing the Combat Damage on Flight Envelopes |
FEB 2006 |
7 pages |
| Authors:
Charbel Farhat; STANFORD UNIV CA
|
| Survivability of an aircraft in combat is achieved by not getting hit, or withstanding the effects of suffered hits. To assess the latter aspect of survivability of a given military aircraft, live-fire tests are performed on its wings. However, these tests may fail to provide accurate and complete vulnerability assessments, because the static and quasi-static ground loading techniques they currently rely on do not replicate the loads encountered during flight. ... |
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| Analytical Prediction of Trajectories for High-Velocity Direct-Fire Munitions |
AUG 2005 |
72 pages |
| Authors:
Paul Weinacht; Gene R. Cooper; James F. Newell; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| An analysis of the velocity-time-range equations for direct-fire munitions has been performed. The analysis characterizes these munitions in terms of three parameters: muzzle velocity, muzzle retardation (or velocity fall-off), and a single parameter defining the shape of the drag curve. Using firing tables drag data for a variety of munitions, the expected range of values of the single parameter defining the shape of the drag curve in the supersonic flight ... |
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| Time-Optimization of High Performance Combat Maneuvers |
JUN 2005 |
243 pages |
| Authors:
Benjamin R. Carter; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| Recent developments in post-stall maneuverability and thrust vectoring have opened up new possibilities in the field of air combat maneuvering. High angle of attack maneuvers like the Cobra, Herbst Reversal, and Chakra demonstrate that today's cutting edge fighters are capable of exploiting the post-stall flight regime for very dynamic and unconventional maneuvers. With the development and testing of Unmanned Combat Aerial Vehicles, even greater maneuvering ability is expected. However, little ... |
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| Methodologies for Predicting and Testing the Effects of Combat Damage on Flight Envelopes |
31 DEC 2004 |
16 pages |
| Authors:
Charbel Farhat; COLORADO UNIV AT BOULDER DEPT OF AEROSPACE ENGINEERING SCIENCES
|
| Survivability of an aircraft in combat is achieved by not getting hit, or withstanding the effects of any suffered hits. To assess the latter aspect of survivability of a given military aircraft, live-fire tests are performed on its wings. However, these tests may fail to provide accurate and complete vulnerability assessments, because the static and quasi-static ground loading techniques they currently rely on do not replicate the loads encountered during ... |
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| Fluidic-Based Virtual Aerosurface Shaping |
01 OCT 2004 |
20 pages |
| Authors:
Ari Glezer; GEORGIA INST OF TECH ATLANTA SCHOOL OF MECHANICAL ENGINEERING
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| Recent work on a novel approach to the control of the aerodynamic performance of lifting surfaces by fluidic modification of their apparent aerodynamic shape, or virtual aerosurface shaping is reviewed. This flow control approach emphasizes fluidic modification of the "apparent" aerodynamic shape of the surface with the objective of altering or prescribing the streamwise pressure gradient. Control is effected by the interactions of arrays of synthetic jet actuators with the ... |
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| NATO AGARD Night Vision Systems Testing |
APR 2004 |
14 pages |
| Authors:
Bruce P. Hunn; TEST WING ( 412TH) EDWARDS AFB CA
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| Night vision systems (NVSs) have revolutionized the combat operations of war fighters by denying the enemy the cover of darkness, and by providing greatly enhanced night flight capabilities. Navigation, safety, loadmaster coordination of air drop, target detection and target acquisition have all been dramatically improved due to the use and advances NVSs. Once limited to weapon aiming and surveillance, modern NVSs provide aircrew's with enhanced situation awareness of the night ... |
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| A Study on the Bionomics of Anopheles darlingi Root (Diptera: Culicidae) in Belize, Central America |
MAR 2004 |
321 pages |
| Authors:
Nicole Achee; UNIFORMED SERVICES UNIV OF THE HEALTH SCIENCES BETHESDA MD F EDWARD HEBERT SCHOOL OF MEDICINE
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| Interdisciplinary studies were conducted to describe the bionomics of the malaria vector Anopheles darlingi Root in Belize, Central America. Studies investigated the following: nightly adult biting patterns; seasonal population densities; flight behavior patterns; the role of overhanging bamboo in larval habitat preference; the association between deforestation and bamboo growth; and the associations between land cover and river characteristics to the distribution of positive larval habitats. Results from all-night biting studies ... |
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| Configuration Studies Supporting Design/Assessment of Sensor Craft |
21 NOV 2003 |
70 pages |
| Authors:
Rajendar K. Nangia; NANGIA AERO RESEARCH ASSOCIATES BRISTOL(UNITED KINGDOM)
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| This report results from a contract tasking Nangia Aero Research Associates as follows: The objective of the proposed work is to support on-going research at the Configuration Aerodynamics Branch (AFRL/VA) for design/ assessment of a Sensor Craft configuration. The sensor aircraft is subject to challenging flight envelope (mission profile). The design at present is relatively "fluid". Box wings of different layouts arise. It has to cruise and loiter (very high ... |
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| Internal Energy Mode Relaxation in High Speed Continuum and Rarefied Flows |
07 MAY 2003 |
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| Authors:
Eswar Josyula; Dean C. Wadsworth; ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
|
 | The presence of shock waves in high speed flow of a polyatomic gas presents considerable difficulties for accurate numerical simulation of the flowfield. The shock wave redistributes the high kinetic energy of the oncoming flow into various internal energy modes, which relax relatively slowly, leading to significant chemical and thermal nonequilibrium the stagnation region. In the gas kinetic description, intermolecular collisions change the translational, rotational, vibrational, and electronic energies of ... |
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| Dynamic Aeroelastic Instabilities of an Aircraft Wing with Underwing Store in Transonic Regime |
MAY 2003 |
31 pages |
| Authors:
Chakradhar Byreddy; Ramana V. Grandhi; Philip Beran; ADVANCED STRATEGIC AND TACTICAL INFRARED EXPENDABLES OFFICE WRIGHT-PATTERSONAFB OH
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| The research used the Transonic Small Disturbance (TSD) theory to better understand the dynamic aeroelastic phenomena and factors that affect the onset of flutter and store induced Limit-Cycle Oscillations (LCO) in the transonic regime. Several parametric studies of the flutter and LCO of an aircraft wing with underwing store in the transonic regime were conducted, as well as an investigation of the effect of inclusion of store aerodynamics on the ... |
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| Distributed Modeling and Control of Adaptive Wings |
10 MAR 2003 |
7 pages |
| Authors:
Daniel J. Inman; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG CENTER FOR INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES
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| New generations of highly-maneuverable aircraft, such as Uninhabited Combat Air Vehicles (UCAV) or Micro Air Vehicles (MAV), are likely to feature very flexible lifting surfaces. In order to enhance their stealth properties and maneuverability, the possibility of using smart wings and morphing airfoils instead of conventional, hinged control surfaces is investigated. This task requires a fundamental understanding of the interaction between fluid, structure and control system, in a coded form ... |
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| Hybrid Verification of an Interface for an Automatic Landing |
DEC 2002 |
8 pages |
| Authors:
Meeko Oishi; Ian Mitchell; Alexandre Bayen; Claire Tomlin; Asaf Degani; STANFORD UNIV CA DEPT OF AERONAUTICS AND ASTRONAUTICS
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| Modern commercial aircraft have extensive automation which helps the pilot by performing computations, obtaining data, and completing procedural tasks. The pilot display must contain enough information so that the pilot can correctly predict the aircraft's behavior, while not overloading the pilot with unnecessary information. Human-automation interaction is currently evaluated through extensive simulation. In this paper, using both hybrid and discrete-event system techniques, we show how one could mathematically verify that ... |
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| F/A-18A/B/C/D F404-GE-400/402 Engine Slotted Spraybar Inlet Flameholder Follow-On Flight Test Evaluation |
23 SEP 2002 |
70 pages |
| Authors:
Mary Pleard; Scott Whitley; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
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| The current production F404-GE-400/402 flameholder (P/N 6056T68G07) experiences a high rate of replacement in the F/A-18A-D fleet, The replacement of the F404-GE400 (-400) and F404-GE-402 (-402) flameholder requires the removal of the spraybars and support links, which can only be accomplished with the removal of the engine from the aircraft, For the -402 engine, flameholder replacement is the number one reason for unscheduled engine removals. The flameholder is exchangeable between ... |
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| Navier-Stokes Computations for a Spinning Projectile From Subsonic to Supersonic Speeds |
SEP 2002 |
38 pages |
| Authors:
Sidra I. Silton; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| A computational study has been undertaken to predict the aerodynamic coefficients of a standard spinning projectile using a modem unstructured Navier-Stokes flow solver. Numerical and semi-empirical results have been obtained for a wide range of Mach numbers to include subsonic, transonic, and supersonic flight regimes. Effects of 00, 20, and 50 angles of attack have been investigated. Comparison of computational fluid dynamics results to both experimental range data and semi-empirical ... |
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| Multi-Agent Algorithms for Chemical Cloud Detection and Mapping Using Unmanned Air Vehicles |
SEP 2002 |
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| Authors:
Michael A. Kovacina; Daniel Palmer; Guang Yang; Ravi Vaidyanathan; ORBITAL RESEARCH INC CLEVELAND OH
|
| Traditional control approaches fall well short of the necessary flexibility and efficiency needed to meet the commercial and military demands placed upon UAV swarms. Effective coordination of these swarms requires development of control strategies based on emergent behavior. We have developed a rule-based, decentralized control algorithm that relies on constrained randomized behavior and respects UAV restrictions on sensors, computation, and flight envelope. |
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| Flight Control Failure Detection and Control Redistribution Using Multiple Model Adaptive Estimation with Filter Spawning |
MAR 2002 |
259 pages |
| Authors:
Michael L. Torres Jr; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| In the current research, the MMAE with Filter Spawning and Control Redistribution (MMAE/FS/CR) are used together to identify failures and apply appropriate corrections. This effort explores the performance of the MMAE/FS/CR in different regions of the flight envelope using model and gain scheduling. The MMAE/FS/CR is able to detect complete and partial actuator/surface failures, as well as complete sensor failures. Once the actuator/surface failure is identified and the effectiveness is ... |
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| Mathematical Modelling of Helicopter Slung-Load Systems |
DEC 2001 |
|
| Authors:
R. A. Stuckey; DEFENCE SCIENCE AND TECHNOLOGY ORGANISATION VICTORIA (AUSTRALIA) AERONAUTICAL AND MARITIME RESEARCH LAB
|
| The primary goal of this work is to use mathematical modelling to assist in defining the operational limits of the Australian Army CH-47D Chinook when carrying mixed density slung loads. This report presents the first phase in the program: the development of a simple helicopter slung-load model for simulation and analysis of the system dynamics. General system equations of motion are obtained from the Newton-Euler equations in terms of generalized ... |
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| Alleviation of Buffet on the Twin-Tail Assemblies of High-Performance Aircraft (aasert) |
31 OCT 2001 |
19 pages |
| Authors:
Ali H. Nayfeh; Dean T. Mook; VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIENCE AND MECHANICS
|
| We carried out experiments on a structural dynamic model of the twin- tail assembly of the F-15 fighter built by Professor Sathya Hanagud of Georgia Tech. The model was placed on a 250 lb shaker and subjected to a principal parametric excitation. We fixed the excitation amplitude and varied the excitation frequency around 18 Hz. For the same excitation amplitude and frequency, we found five possible responses depending on the ... |
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| Blending Methodology of Linear Parameter Varying Control Synthesis of F- 16 Aircraft System |
OCT 2001 |
24 pages |
| Authors:
Jong-Yeob Shin; Gary J. Balas; Alpay M. Kaya; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CENTER
|
| This paper presents the design of a linear parameter varying (LPV) controller for the F-16 longitudinal axes over the entire flight envelope using a blending methodology which lets an LPV controller preserve performance level over each parameter subspace and reduces computational costs for synthesizing an LPV controller. Three blending LPV controller synthesis methodologies are applied to control F-16 longitudinal axes. Using a function substitution method, a quasi-LPV model of the ... |
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| Helicopter Noise Reduction by Individual Blade Control (IBC) -Selected Flight Test and Simulation Results- |
JUN 2001 |
16 pages |
| Authors:
W. R. Splettstoesser; K. J. Schultz; B. van der Wall; H. Buchholz; W. Gembler; DEUTSCHES ZENTRUM FUR LUFT-UND RAUMFAHRT (DRL) BRAUNACHWEIG (GERMANY)
|
| A collaborative flight test programme was conducted to study among other objectives the potential of open- loop Individual Blade Pitch Control (IBC) to reduce the external noise of a helicopter in partial power descent, a flight regime known to generate the highly annoying Blade-Vortex Interaction (BVI) impulsive noise. The blade root control system employing actuators in the rotating frame, was installed on a BO 105 helicopter, which was flown over ... |
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| Adaptive Rotor Blade Concepts -Direct Twist and Camber Variation- |
JUN 2001 |
12 pages |
| Authors:
A. Bueter; U. C. Ehlert; D. Sachau; E. Breltbach; GERMAN AEROSPACE CENTER BRAUNSCHWEIG (GERMANY) INST OF STRUCTURAL MECHANICS
|
| Applying adaptronics to helicopters has a high potential to significantly suppress noise, reduce vibration and increase the overall aerodynamic efficiency. Since the interaction of nonstationary helicopter aerodynamics elastomechanical structural characteristics of the helicopter blades causes flight envelope limitations, vibration and noise, a good comprehension of the aerodynamics is essential for the development of structural solutions to effectively influence the local airflow conditions and finally develop a structural concept. With respect ... |
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| Operational Lessons Learned from the F/A-18E/F Total Flight Control Systems Integration Process |
JUN 2001 |
12 pages |
| Authors:
Robert J. Hanley; David A. Dunaway; Kenneth P. Lawson; NAVAL AIR SYSTEMS COMMAND PATUXENT RIVER MD
|
| The F/A-18E/F Super Hornet is a growth version of the F/A-18 A through D model 'heritage' Hornet, first fielded in 1983. Sone of the primary design goals for the Super Hornet, included increasing the range, providing greater weapon loading flexibility increasing carrier landing bring back weight and improving survivability. Improving the survivability was addressed in various ways including reductions in radar cross section expanded self-protection systems, and enhanced maneuverability. The ... |
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| Offset Piezoceramic Stack Actuators and Acceleration Feedback Control for Tail Buffet Alleviation of a High Performance Twin Tail Aircraft: Robustness Issues |
JUN 2001 |
12 pages |
| Authors:
S. Hanagud; M. B. de Noyer; GEORGIA INST OF TECH ATLANTA SCHOOL OFAEROSPACE ENGINEERING
|
| In high performance twin-tail aircraft tail buffet occurs when unsteady pressures associated with separated flow excite the modes of the vertical fin structural assemblies At high angles of attack flow separates and is convected by the geometry of the wing-fuselage interface toward the vertical tails. This phenomenon. along with the aeroelastic coupling of the tail structural assembly results in vibrations that can shorten the fatigue life of the empennage assembly ... |
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| Human Factors Considerations in the X-31 Aircraft |
MAY 2001 |
11 pages |
| Authors:
Joseph Antonio; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
|
| The purpose of this report is to provide an insight to human factors issues that are relevant to the X-31 BSTOL maneuver. |
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| Minimizing Load Effects on NA4 Gear Vibration Diagnostic Parameter |
05 APR 2001 |
12 pages |
| Authors:
Paula J. Dempsey; James J. Zakrajsek; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| NA4 is a vibration diagnostic parameter, developed by researchers at NASA Glenn Research Center, for health monitoring of gears in helicopter transmissions. NA4 reacts to the onset of gear pitting damage and continues to react to the damage as it spreads. This research also indicates NA4 reacts similarly to load variations. The sensitivity of NA4 to load changes will substantially affect its performance on a helicopter gearbox that experiences continuously ... |
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| Testing and Development of a Shrouded Gas Turbine Engine in a Freejet Facility |
DEC 2000 |
87 pages |
| Authors:
Hector Garcia; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Testing and analysis of a shrouded turbojet engine with possible application for high speed propulsion on low cost Unmanned Combat Aerial Vehicles (UCAV), Unmanned Aerial Vehicles (UAV) and missiles. The possibility of a turbojet providing thrust at subsonic conditions and the ramjet section providing the thrust in the supersonic regime exists. The combined cycle engine (CCE) could be incorporated into a variety of applications. The building of a new freejet ... |
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| Nonlinear Flight Control Using Forebody Tangential Blowing |
29 NOV 2000 |
128 pages |
| Authors:
Yuji Takahara; Stephen R. Rock; STANFORD UNIV CA DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| Forebody Tangential Blowing (FTB) is a pneumatic device that modifies the vortical flow over the forebody of an aircraft operating at high angles of attack. Modified vortical flow in turn creates roll and yaw moments for control. Consequently, it provides a mechanism that could greatly expand the flight envelope of future aircraft systems. One major factor that currently limits the use of FTB as a control effector is that it ... |
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| Transonic Simple Straked Delta Wing |
01 OCT 2000 |
20 pages |
| Authors:
Evert G. Geurts; NATIONAL AEROSPACE LAB AMSTERDAM (NETHERLANDS)
|
| The unsteady transonic flow during manoeuvres of fighters is not very well understood. For instance, large time delays and severe dynamic overshoots in normal force may occur, which cannot be predicted accurately by numerical methods. As a consequence to be conservative structures must be over-designed or flight envelopes must be unnecessarily restricted There fore, a better understanding of the unsteady transonic flows, which occur during maneuvers, is of interest for ... |
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| Development of Shrouded Turbojet to Form a Turboramjet for Future Missile Applications |
JUN 2000 |
101 pages |
| Authors:
Suleiman M. AL-Namani; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Development of shroud to form part of an afterburner for a turbo- ramjet engine which has a possible application for high speed long range missile applications. Research has been conducted on scram-jet engines with little or no emphasis on a turbojet/ramjet combined cycle engines. With the possibility of the turbojet providing the thrust at subsonic conditions and the ramjet providing the thrust at supersonic conditions. A small ... |
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| Toward Validating a Generic Rotorcraft Model Structure for the Emerging Concepts Technology Applications Categories. Abstract only |
2000 |
3 pages |
| Authors:
Dean Carico; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
|
| The high projected cost associated with rotorcraft flight testing and training in the New Millennium needs to be minimized using emerging technology applications. In the past, each service has employed the tendency to develop individual models to support training applications for specific aircraft. Reductions in recent DoD procurement budget imply that multi-service partnerships will be very important in the New Millennium. Testing and training cost ... |
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| Computational Analysis of the Off-Design Performance of a Mach 6 (L/D) ispmax Optimized Waverider |
SEP 1999 |
145 pages |
| Authors:
Ellen Coyne; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| In a continuation of ongoing Naval Postgraduate School efforts to study the performance characteristics of waverider configured vehicles, a computational fluid dynamic (CFD) analysis of the Mach 6 L/DI(sp)(max) optimized Price waverider was conducted. This analysis was performed to determine the theoretical force and moment data over a broad Mach number spectrum, and to compare theoretical and experimental results in the subsonic flight regime. The ... |
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| Modular Control Law Design for the Innovative Control Effectors (ICE) tailless Fighter Aircraft Configuration 101-3 |
JUN 1999 |
154 pages |
| Authors:
James F. Buffington; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
|
| A modular flight control system is developed for a tailless fighter aircraft with innovative control effectors. Dynamic inversion control synthesis is used to develop a full envelope flight control law. Minor dynamic inversion command variable revisions are required due to the tailless nature of the configuration studied to achieve nominal stability and performance. Structured singular value and simulation analysis shows that robust stability is achieved ... |
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| Simulation Validation and Flight Prediction of UH-60A Black Hawk Helicopter/Slung Load Characteristics |
MAR 1999 |
303 pages |
| Authors:
Peter H. Tyson; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| Helicopter/slung load systems are two body systems in which the slung load adds its rigid body dynamics, aerodynamics, and sling stretching dynamics to the helicopter. The slung load can degrade helicopter handling qualities and reduce the flight envelope of the helicopter. Confirmation of system stability parameters and envelope is desired, but flight test evaluation is time consuming and costly. A simulation model validated for handling quality assessments would significantly reduce ... |
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| The Effect of Sabot Grooves on Lift Force for Kinetic Energy Projectiles |
FEB 1999 |
52 pages |
| Authors:
Ameer G. Mikhail; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| The effect of grooves on the normal force of an anti-armor long rod kinetic energy (KE) projectile was analyzed and numerically quantified. The effect was studied for body alone and body with fins in which clear and distinct effects were experimentally observed for each. Wind tunnel data sets were analyzed, and algebraic, semi-empirical correlations were constructed using the main physical parameters of the projectile body and ... |
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| An Experimental Study of Passive Control of Hypersonic Cavity Flow Oscillations |
01 MAR 98 |
140 pages |
| Authors:
D. S. Dolling; S. W. Perng; Y. L. Leu; TEXAS UNIV AT AUSTIN DEPT OF AEROSPACE ENGINEERING AND ENGINEERING MECHANICS
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| An experimental study of open cavity flow has been made in a high Reynolds number, Mach 5 turbulent boundary layer. The majority of measurements made were of fluctuating wall pressures. The objectives were: (1) examine how effective changes in front and rear wall geometry were at attenuating the pressure oscillations, (2) explore how impingement of a shock wave (variable strength and position) the cavity flow, and (3) how stores (different ... |
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| Guidance and Control Development of the Multimode Airframe Technology (MAT) Missile |
1998 |
10 pages |
| Authors:
Justin L. S. Walls; NICHOLS RESEARCH CORP HUNTSVILLE AL
|
| This paper overviews development of the guidance and control system design of the Multimode Airframe Technology (MAT) missile being developed at the Missile Research, Development, and Engineering Center, U.S. Army AMCOM. The teleoperated missile accomplishes high speed flyout, slowdown for target search using a variable wing/flap configuration, and provides high speed precision targeting at terminal attack. The control system's objective is to achieve these flight regimes and overall mission objectives. ... |
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Reports by Keyword(s)
FLIGHT ENVELOPE
