EFFECT OF CANARD LOCATION AND SIZE ON CANARD-WING INTERFERENCE AND AERODYNAMIC-CENTER SHIFT RELATED TO MANEUVERING AIRCRAFT AT TRANSONIC SPEEDS

摘要

A generalized wind-tunnel model, typical of highly maneuverable aircraft, was tested in the Langley 8-foot transonic pressure tunnel at Mach numbers from 0.70 to 1.20 to determine the effects of canard location and size on canard-wing interference effects and aerodynamic center shift at transonic speeds. The canards had exposed areas of 16.0 and 28.0 percent of the wing reference area and were located in the chord plane of the wing or in a position 18.5 percent of the wing mean geometric chord above or below the wing chord plane. Two different wing planforms were tested, one with leading-edge sweep of 60° and the other 44 both wings had the same reference area and span. The results indicated that the largest benefits in lift and drag were obtained with the canard above the wing chord plane for both wings tested. The low canard configuration for the 60° swept wing proved to be more stable and produced a more linear pitching-moment curve than the high and coplanar canard configurations for the subsonic test Mach numbers. In general, the canard downwash reduced the lift on the wing and was found to be essentially independent of Mach number for the 60 swept wing. There was a favorable effect of the up wash from the wing on the canard lift for the subsonic Mach numbers except for the canard below the wing chord plane (60° swept wing) where the wing up wash had no effect on the canard lift at a Mach number of 0.70 and adversely affected the canard lift at Mach numbers of 0.90 and 0.95. In the transonic Mach number range, the aerodynamic-center shift with Mach number for the 60° swept-wing configuration with canard on was considerably less than that for the 44° swept-wing configuration with canard on.