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Autonomous Flight Control Development on the Active Aeroelastic Wing Aircraft

Air Force Research Laboratory-Peter M. Flick
The Boeing Company-Ronald K. Hess
Published 2004-11-02 by SAE International in United States
A highly modified F/A-18 aircraft is being used to demonstrate that aeroelastic wing twist can be used to roll a high performance aircraft. A production F/A-18A/B/C/D aircraft uses a combination of aileron deflection, differential horizontal tail deflection and differential leading edge flap deflection to roll the aircraft at various Mach numbers and altitudes. The Active Aeroelastic Wing program is demonstrating that aeroelastic wing twist can be used in lieu of the horizontal tail to provide autonomous roll control at high dynamic pressures.Aerodynamic and loads data have been gathered from the Phase I AAW flight test program. Now control laws have been developed to exploit aeroelastic wing twist and provide autonomous flight control of the AAW aircraft during Phase II. Wing control surfaces are being deflected in non-standard ways to create aeroelastic wing twist and develop the required rolling moments without use of the horizontal tail. Wing control surfaces are also being deflected to provide maneuver load control during pitching maneuvers.Simulation of the AAW control laws shows acceptable flight performance using this new control surface scheme.…
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Technology Portfolio Assessments Using a Multi-Objective Genetic Algorithm

Aerospace System Design Laboratory (ASDL), School of Aerospace Engineering, Georgia Institute of Technology-Christopher M. Raczynski, Michelle R. Kirby, Dimitri N. Mavris
Published 2004-11-02 by SAE International in United States
This paper discusses the use of a Multi-Objective Genetic Algorithm to optimize a technology portfolio for a commercial transport. When incorporating technologies into a conceptual design, there are often multiple competing objectives that determine the benefits and costs of a certain portfolio. The set of designs that achieves the best values of these objectives will fall along a Pareto front that outlines the tradeoffs which will give the optimal design. Multi-Objective Genetic Algorithms determine the Pareto set by giving higher priority to dominant portfolios in the evolutionary optimization techniques of selection and reproduction. When determining the final Pareto optimal set it is important to ensure that only compatible portfolios of technologies are present. The technology compatibility represents a constraint on the optimization that can be handled internal to the genetic algorithms or through imposed logic that eliminates incompatibilities through a procedure known as gene correction. In order to properly benchmark the Multi-Objective Genetic Algorithm approach a comparison will be made with a traditional genetic algorithm utilizing a single fitness value incorporating the various objectives.
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Turbomachinery Blade Modal Analysis Using Contact Elements

Pratt & Whitney Canada-Lyne St-Georges
École de technologie supérieure (ÉTS)-Mario Guerra, Marc Thomas
Published 2004-11-02 by SAE International in United States
This paper presents a new methodology for analytically evaluating the natural frequencies and mode shape of a turbomachinery blade in an environment where friction phenomenon occurs. The blades analyzed in this study are unshrouded and located in the high-pressure turbine found in turbofan engines, and in the compressor turbine found in turboprop engines. The goal of this method is to correctly predict the modal parameters of the blade in order to determine whether there will be any resonance in the running range of the turbomachinery, and to more accurately predict the stresses at the blade-disc interface. This study was performed using ANSYS® contact elements. After comparison, the analytical results were found to agree with the experimental results. A convergence study was also performed, and it was found that only the friction coefficient and the surface contact stiffness had a considerable effect on the natural frequencies and mode shape convergence.
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Velocity Profile Measurements Under the Ramp of a Lockheed Martin C-130 Aicraft

CBR Defense Division, Naval Surface Weapons Center-Bruce J. Corso
Center for Industrial Research Applications, West Virginia University-Gerald M. Angle, F. Andy Pertl, James E. Smith
Published 2004-11-02 by SAE International in United States
Predicting the aerodynamic forces in the wake of an object can be difficult using theoretical and computational methods. This is particularly true for airframes that have multiple engines and whose flight envelope involves the use of large control surfaces. One such aircraft is the C-130 which adds the further complication of a rear cargo door and ramp. Modeling the wake near the rear of this aircraft can be difficult and inaccurate unless validated against actual flight data. For this study a simple test apparatus, developed by the authors, was used to measure the velocity profile in the wake area of the rear cargo door of such an aircraft.The test apparatus contained 32 pressure ports, one of these ports was assigned to a static pressure probe. All pressures were referenced to an additional static pressure measured at the edge of the cargo ramp. The remaining, 31 pressure probes were distributed regularly between three vertical rake assemblies. The area sampled by the probes was 60 inches wide by 24 inches tall. Temperature and absolute pressure were recorded…
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Flight Characterization of Micro Air Vehicles Using Morphing for Agility and Maneuvering

University of Florida-Mujahid Abdulrahim, Kenneth Boothe, Rick Lind, Peter Ifju
Published 2004-11-02 by SAE International in United States
No Abstract Available.
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Wind Tunnel Testing of Micro Air Vehicles at Low Reynolds Numbers

Mechanical and Aerospace Engineering Department, University of Florida-Roberto Albertani, Paul Hubner, Peter Ifju, Rick Lind, Jason Jackowski
Published 2004-11-02 by SAE International in United States
This paper documents the development of the capability to test MAVs (Micro Air Vehicles) in the University of Florida’s wind tunnel facility. The main goal of this work was to obtain, with a reliable procedure, good quality experimental data from wind tunnel tests of air vehicles at low Reynolds numbers, in the order of 100,000. An overview of the instrumentation and data analysis techniques will be presented, followed by some samples of results from tests on specific aircraft. A standard aerodynamic characterization test was developed to perform a “quick” System Identification (SID) characterization of an air vehicle. The requirements for those tests were established by the modeling and control portion of the project. The test procedure was aimed to find the main aerodynamic derivatives that will be used to model the aircraft and design the flight control system. Three distinctly different vehicles ranging in size from 60 cm to 15 cm wingspan are discussed.
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Agent Architecture for Aviation Data Integration System

NASA-Deepak Kulkarni, Yao Wang, Mei Wei
SAIC-May Windrem, Hemil Patel
Published 2004-11-02 by SAE International in United States
Aviation Data Integration System (ADIS) project explores methods and techniques for integrating heterogeneous aviation data to support aviation problem-solving activity. Aviation problem-solving activities include: engineering troubleshooting, incident and accident investigation, routine flight operations monitoring, flight plan deviation monitoring, safety assessment, maintenance procedure debugging, and training assessment. To provide optimal quality of service, ADIS utilizes distributed intelligent agents including data collection agents, coordinator agents and mediator agents. This paper describes the proposed agent-based architecture of the Aviation Data Integration System (ADIS).
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Performance Evaluation of an Integrated Retrofit Failure Detection, Identification and Reconfiguration (FDIR) System Using High-Fidelity and Piloted Simulations

Boeing Phantom Works-James M. Urnes, Mark Hood
NASA DFRC-Yohan Lin
Published 2004-11-02 by SAE International in United States
In this paper the results obtained under a NASA Dryden Phase II Small Business Innovative Research (SBIR) project are described. At Scientific Systems Company, Inc. (SSCI) we developed an efficient Integrated Failure Detection, Identification and Reconfiguration (FDIR) system referred to as the FLARE (Fast on-Line Actuator REconfiguration) system. The FLARE system achieves very fast detection and identification of failures in Electro-Mechanical Actuators (EMA), and effective control reconfiguration in the presence of single or multiple failures and recoveries even while rejecting external disturbances. The FLARE system combines different FDIR algorithms with a disturbance rejection mechanism within a retrofit control architecture. In collaboration with Boeing Phantom Works, the performance of the FLARE system has been extensively evaluated using high-fidelity and piloted simulators.
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Water Injection: Disruptive Technology1 to Reduce Airplane Emissions and Maintenance Costs

NASA Glenn Research Center-Chris Snyder, Jeff Berton
Rolls-Royce-David Eames
Published 2004-11-02 by SAE International in United States
Water injection is an old aviation technology that was previously used to generate increased engine power during takeoff. If water injection were now to be used without increasing thrust, it could result in large reductions in takeoff NOx emissions and would most likely enable longer engine life and reduced operator costs.Due to the cooling action of evaporating water, a large temperature reduction will be experienced at the point where the water is injected into the engine. This could improve combustion emissions, such as temperature-sensitive NOx, and help reduce temperatures throughout the turbine section of the engine.The two current preferred methods of water injection are: (1) direct injection into the combustor, and (2) misting of the conditioned water before the engine's compressor. Combustor injection could achieve up to 90% NOx reduction and offer few implementation challenges as it has been used in aero-derivative industrial engines for over 30 years. For compressor water misting, the rate of water flow is limited to about 3% of the core air flowiii, and so could only achieve slightly more than…
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Vibration Testing and Modal Analysis of Airplanes – Recent Advances

LMS International-Bart Peeters, Antonio Vecchio, Thierry Olbrechts, Herman Van der Auweraer
Lambert Aircraft Engineering-Filip Lambert
Published 2004-11-02 by SAE International in United States
The paper will introduce some recent advances in vibration testing and modal analysis of airplanes. Recently, a very promising parameter estimation method became available, that has the potential to become the new standard. The main advantage of this so-called PolyMAX method is that it yields extremely clear stabilization diagrams even for broadband and high-order analyses. The method will be applied to two aircraft cases: a Ground Vibration Test using broadband shaker excitation on a small composite aircraft and in-flight data using natural turbulences as excitation. These two data sets allow illustrating both the classical Frequency Response Function based as well as the operational output-only modal analysis process.
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