Accession Number : ADA262482


Title :   Modal Survey of a Full-Scale F-18 Wind Tunnel Model


Descriptive Note : Interim rept. Mar 91-Jul 92


Corporate Author : WRIGHT LAB WRIGHT-PATTERSON AFB OH


Personal Author(s) : Levraea, Vincent J ; Henderson, Douglas A ; Pacia, Arnel P ; Banford, Michael P


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a262482.pdf


Report Date : Sep 1992


Pagination or Media Count : 64


Abstract : The purpose of this investigation was to perform a ground vibration test (GVT) to determine the resonant frequencies, damping, and mode shapes for the F-18 vertical tail structure. This effort represents a subtask of the twin tail buffet work currently studying the buffet response of the F-18 vertical tails to forebody vortices generated at high angles of attack. The GVT was conducted on a full-scale F-18 airframe which had been significantly modified to enable it for use as a full-scale wind tunnel model in the NASA Ames 80 ft x 120 ft wind tunnel facility. Because the major emphasis of the test was to obtain the dynamic characteristics of the vertical tails under tunnel mounting conditions, the GVT was performed with the full-scale model mounted on the tunnel pedestals in the same configuration as would be used for the wind tunnel tests. The primary excitation frequencies of the vortical wake were expected to be below 100 hertz, thus the GVT only measured tail response frequencies below this value. The results give dynamic response information for the first bending, second bending, and first torsional modes of the vertical tails.... Aircraft vibration, Buffet, Tail buffet, Fatigue, Resonant, Vibration, Vibration testing.


Descriptors :   *VIBRATION , *WIND TUNNEL TESTS , TEST AND EVALUATION , AIRCRAFT , SCALE MODELS , MODELS , EXCITATION , DYNAMIC RESPONSE , FACILITIES , SHAPE , STRUCTURES , DAMPING , VORTICES , BENDING , RESONANT FREQUENCY , CONFIGURATIONS , AIRFRAMES , WAKE , FATIGUE , WORK , VALUE , WIND TUNNEL MODELS , HIGH ANGLES , TAILS(AIRCRAFT)


Subject Categories : Aerodynamics
      Attack and Fighter Aircraft


Distribution Statement : APPROVED FOR PUBLIC RELEASE