On the Evaluation of Negative Altitude Requirement for Flutter Speed Boundary of Transport Aircraft and UAV

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To maintain flight safety, all transport aircraft designs should satisfy airworthiness standard regulation. One fundamental issue of the aircraft design that relates directly to flight safety as well as commercial aspect of the aircraft is on the evaluation of the maximum speed within the designated flight envelope. In the present work, a study is performed to evaluate the negative altitude requirement related to aeroelastic instability analysis as one requirement that should be fulfilled to design the maximum speed. An analytical derivation to obtain the negative altitude is performed based on the airworthiness requirement that a transport airplane must be designed to be free from aeroelastic instability within the flight envelope encompassed by the dive speed or dive Mach number versus altitude envelope enlarged at all points by an increase of 15% in equivalent airspeed at both constant Mach number and constant altitude. To take into account variation in atmospheric condition as function of altitude, the international standard regulation is used as referenced. The analysis result shows that a single negative altitude can be obtained using these criteria regardless of the dive speed or dive Mach number. A further discussion on the application of the negative altitude concept to UAV (Unmanned Aerial Vehicle), in relation to UAV Standard Airworthiness Requirement STANAG 4671, is presented.

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Edited by:

R. Varatharajoo, E. J. Abdullah, D. L. Majid, F. I. Romli, A. S. Mohd Rafie and K. A. Ahmad

Pages:

397-402

Citation:

E. Sulaeman, "On the Evaluation of Negative Altitude Requirement for Flutter Speed Boundary of Transport Aircraft and UAV", Applied Mechanics and Materials, Vol. 225, pp. 397-402, 2012

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November 2012

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[1] Anon., Federal Aviation Regulation, Part 25- Airworthiness Standards: Transport Category Airplanes (FAR 25), U. S Department of Transportation, Amendment 117, January 25, (2006).

[2] Anon., Federal Aviation Regulation, Part 23- Airworthiness Standards: Normal, Utility, Acrobatic, and Commuter Category Airplanes (FAR 23), U. S Department of Transportation, October 27, (2003).

[3] Anon., Certification Specifications and Acceptable Means of Compliance for Large Aeroplanes CS-25, European Aviation Safety Agency, Amendment 11, 4 July (2011).

[4] Anon., Malaysia Civil Aviation Regulation, Part 25, (1996).

[5] Anon., UAV Systems Airworthiness Requirements (USAR) for North Atlantic Treaty Organization (NATO) Military UAV Systems – Standard Agreement STANAG 4671 (Edition 1), September 3, (2009).

[6] Anon., Federal Aviation Regulation, Advisory Circular 25. 629-1A Aeroelastic Stability Substantiation of Transport Category Airplanes, U. S Department of Transportation, 23 July (1998).

[7] Anon., U.S. Standard Atmosphere, 1976, NASA-TM-X-74335, October (1976).

[8] International Civil Aviation Organization, Manual of the ICAO Standard Atmosphere (extended to 80 kilometres (262 500 feet), Doc 7488-CD, Third Edition, 1993, ISBN 92-9194-004-6.

[9] Anon., Certification Specifications for Normal, Utility, Aerobatic, and Commuter Category Aeroplanes CS-23, European Aviation Safety Agency, Nov 14, (2003).

[10] Anon., Military Specification: Airplane Strength and Rigidity. Vibration, Flutter, and Divergence, MIL-A-8870C (AS), US Naval Air System Command, March 25, (1993).