2 edition of Flight flutter testing - advanced methodologies. found in the catalog.
Flight flutter testing - advanced methodologies.
Matthew Jonathan Desforges
Thesis (Ph.D.), University of Manchester, School of Engineering.
|Contributions||University of Manchester. School of Engineering.|
|The Physical Object|
|Number of Pages||277|
In essence, flight flutter testing is a systematic method of progressing towards an instability boundary while ensuring that the instability is never attained. 2 FLIGHT FLUTTER TEST METHODOLOGY Whilst on the ground, the aircraft has a fixed set of normal modes of vibration, each with a constant shape, natural frequency and damping. Copper J. E. Parameter Estimation Methods for Flight Flutter Testing. Advanced Aeroservoelastic Testing and Data Analysis, AGARD-CP, Vol. 10, , p. Koenig K. Problems of System Identification in Flight Vibration Testing. AGARD-R, Koenig K. Pretension and Reality of Flutter-Relevant Tests. Advanced Aeroservoelastic Testing.
Analysis Spectral Flutter Margin Fast Fourier Advanced ýt Method Methods Plotting Transform System time/frequency Identification methods Algorithms Processing of By Hand Automated Interactive Data Processing Processing s s s s s Figure 3. Major Advances in Flight Flutter Testing Methodology. 3. Future Developments in. Purchase Flight Test Instrumentation - 1st Edition. Print Book & E-Book. ISBN ,
Wing flutter was encountered during flight testing of the F2H-2 airplane with full wing tip tanks. As a result, more refined theoretical analysis as well as flight flutter tests were initated to establish corrective measures and to experimentally verify the stability of the improved system. Flight flutter testing is done early in the flight test program. It involves expanding the flight test envelope thru dive testing. You don't induce resonances by pulling G's, but by control inputs like Tom describes. Sometimes shakers are used in the wing tips to induce structural resonances.
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Flight flutter testing is an essential part of the certification process for all new and significantly modified aircraft. As flutter is a potentially catastrophic phenomenon, it is vital that accurate modal parameter estimates are obtained at each flight condition, in order that the aircraft can be shown to be flutter-free throughout the flight : Matthew J.
Desforges. A number of relevant technologies are considered in relation to flight flutter testing. Suggestions are made as how these aspects could be improved in order to speed up and reduce the cost of flight flutter testing, while maintaining the levels of safety. About the methods for Aeroelastic solution, see [1–12].Cited by: 1.
Flight envelope expansion based on active mitigation of flutter via a V-stack piezoelectric actuator 5 November | Journal of Physics: Conference Series, Vol. Assessment of Advanced Flutter Flight-Test Techniques and Flutter Boundary Prediction MethodsCited by: been made in flight flutter test technique, instrumentation, Maximum response amplltude m i i Ii 0 Vflutte r Airspeed _c_7_ Figure 1.
Von Schlippe's flight flutter test method. and response data analysis. Flutter testing, however, is still a hazardous test for several reasons. First, one still must fly close to actual flutter speeds before. Most common flight flutter prediction methods are reviewed.
Finally, key considerations for successful flight flutter testing are noted by referencing the related literature., – Online, real time monitoring of flutter stability during flight testing is very crucial, if the flutter character is Cited by: 5. Publication Date (online): Febru The paper presents an experimental study, conducted by the Israel Air Force, aimed at the assessment of several advanced flutter flight-test Flight flutter testing - advanced methodologies.
book that are designed to improve the efficiency and accuracy of flutter tests. The application of the vector plotting technique to flight flutter testing of the Hawker Siddeley Trident is then considered. Subsequent chapters focus on the use of high-accuracy instrumentation techniques for non-steady flight measurements; strain gauging for transient heating cases; and free-flight model techniques for aerodynamic research.
being developed in the United Kilngdon for flight vibration testing and flight flutter testing aircraft. This includes a description of the instnznentation used for recotiing the Vibratioml response, and a comparative assessment of the vaious methods used for exciting the aircraft in i'lipht flutter tests.
Flight flutter testing continues to be a challenging research area because of the concerns with cost, time, and safety in expanding the envelope of new or modified aircraft. Testing is often done at stabilized test points to generate numerous data sets while attempting to estimate aeroelastic stability in an accurate and efficient manner.
Design/methodology/approach – Flight flutter test requirements are first reviewed by referencing the relevant civil and military specifications. Excitation systems utilized in flight flutter. DEVELOPMENT OF FLIGHT FLUTTER TEST TECHNIQUES Von Schlippe conducted the ﬁrst formal ﬂight ﬂutter test in Germany in The objective of his test method was to lessen the risk associated with ﬂutter testing.
The usual practice at this time was to ﬂy the airplane to the maximum speed and then to observe the stability of the structure. Divided into three sections, the book begins by reviewing the underlying disciplines of vibrations, aerodynamics, loads and control.
It goes on to describe simplified models to illustrate aeroelastic behaviour and aircraft response before introducing more advanced methodologies. Parameter Estimation Methods for Flight Flutter Testing,” Structures and Materials Panel Specialists Meeting on Advanced Aeroservoelastic Testing and Data Analysis, AGARD CP E Cooperj.
Tests explore and validate the flight envelope, structural flutter, aircraft stability, natural stalls, handling qualities, and others.
Data is typically stored by on-board data acquisition systems and backed up on the ground via telemetry stations. Flight tests are very costly, as testing time allotment and number of prototypes are limited. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): This paper reviews the test techniques developed over the last several decades for flight flutter testing of aircraft.
Structural excitation systems, instrumentation systems, digital data preprocessing, and parameter identification algorithms (for frequency and damping estimates from the response data) are described.
In flight flutter testing of modern aircraft, it is very important to be able to lean on results of preflight flutter calculations or wind tunnel flutter tests, to reduce the danger inherent in this type of testing. From this point of view, it is desirable that methods for flutter calculations be improved.
All aircraft must be free from flutter for flight safety and per airworthiness requirements. TLG performs certification aircraft flutter analyses for all required aircraft configurations and conditions. We also plan and participate in the required ground and flight testing and subsequent analysis.
Aircraft Flutter. Flight flutter testing is the process of envelope expansion that determines a range of flight conditions within which an aircraft is safe from aeroelastic instabilities.
This testing, which must be done for new and reconfigured aircraft, incurs dramatic time and costs because of the danger associated with encountering unpredicted instabilities. advanced ﬂight ﬂutter test and analysis methods. This paper presents F/A SRA ﬂight test results and analyses using the wingtip exciter.
Preliminary results from the F/A HARV aircraft using an on-board excitation system (OBES) for control surface excitation are also presented.
Flight ﬂutter test. Flutter is an oscillation caused by interaction of aerodynamic forces, structural elasticity and inertial effects. Perhaps the best known example of flutter is the bridge over the Tacoma Narrows ('Gallopin' Gertie') that collapsed due to flutter in gale force winds.
Flutter in aircraft causes the wings and / or stabilizers to oscillate. Traditional methods of flight flutter testing analyze system parameters such as damping levels that vary with flight conditions to monitor aircraft stability.
In the past, the actual flight envelope developed for aircraft operation was essentially determined only by flight testing. The edges of the envelope are points where either the aircraft cannot fly any faster because of engine.Our Flutter Exciter is built using commercial/industrial grade electronic components, the system has undergone a wide range of DO tests and is ruggedized for use in flight test applications.
Each in² Exciter produces a maximum dynamic load of ± lbs (± N) at KEAS for frequencies Hz.The typical approach to flight flutter testing is to fly the aircraft at several stabilized test points arranged in increasing order of dynamic pressure and Mach number.
The data obtained are used to establish a damping trend as a function of airspeed. Information is then extrapolated to predict the stability of the next test point.