Accession Number : ADP006218

Title :   Wind Tunnel Investigation and Flight Tests of Tail Buffet on the CF-18 Aircraft,

Corporate Author : NATIONAL AERONAUTICAL ESTABLISHMENT OTTAWA (ONTARIO)

Personal Author(s) : Lee, B. H. ; Brown, D. ; Zgela, M. ; Poirel, D.

Report Date : SEP 1990

Pagination or Media Count : 26

Abstract : Investigations of tail buffet on the CF-18 have been conducted at the National Aeronautical Establishment (NAE) and the Aerospace Engineering Test Establishment (AETE). Flow visualization of the vortex burst phenomenon was carried out in a low speed water tunnel using a modified 1/72 scaled plastic model. In wind tunnel tests, a rigid 6% model was used for measurements in the NAE 5ft x 5ft Trisonic Tunnel. Unsteady pressure measurements on the vertical fin were made by means of 24 fast response transducers on each surface. Results of the acceleration experienced by the fin are presented Vortex flow structure was studied with the aid of a 49 pressure-sensor-rake mounted behind the fin. In addition to measuring steady pitot pressure values to deduce pressure contours, unsteady pressure fluctuations were obtained from 13 fast response transducers. The LEX was also instrumented with pressure orifices and fast response transducers. The investigation was carried out with LEX fences 'on' and 'off' to note their effect on tail buffet loads. Flight tests have been conducted at AETE on a test aircraft with accelerometers installed on the vertical fins and horizontal stabilators and strain gauges mounted on the aft fuselage structures and fin root attachment stubs. Flight test data are presented showing the effectiveness of the LEX fence in reducing aft fuselage structural to buffet loads.

Descriptors :   *BUFFETING, *TAILS(AIRCRAFT), *VORTICES, JET FIGHTERS, WIND TUNNEL TESTS, PRESSURE MEASUREMENT, AERODYNAMIC CONTROL SURFACES, FLIGHT TESTING, FINS, CANADIAN EQUIPMENT.

Subject Categories : Aerodynamics
      Attack and Fighter Aircraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE