An investigation has been conducted at low subsonic speeds to study the effects of canard planform and wing-leading-edge modification on the longitudinal aerodynamic characteristics of a general research canard airplane configuration. The basic wing of the model had a trapezoidal planform, an aspect ratio of 3.0, a taper ratio of 0.143, and an unswept 80-percent-chord line. Modifications to the wing included addition of full-span and partial-span leading-edge chord-extensions. Two canard planforms were employed in the study one was a 60° sweptback delta planform and the other was a trapezoidal planform similar to that of the basic wing. Modifications to these canards included addition of a full-span leading-edge chord-extension to the trapezoidal planform and a fence to the delta planform. For the basic-wing-trapezoidal-canard configuration, rather abrupt increases in stability occurred at about 12° angle of attack. A slight pitch-up tendency occurred for the delta-canard configuration at approximately 8° angle of attack. A comparison of the longitudinal control effectiveness for the basic-wing-trapezoidal-canard combination and for the basic-wing-delta-canard combination indicates higher values of control effectiveness at low angles of attack for the trapezoidal canard. The control effectiveness for the delta-canard configuration, however, is seen to hold up for higher canard deflections and to higher angles of attack. Use of a full-span chord-extension deflected approximately 30° on the trapezoidal canard greatly improved the control characteristics of this configuration and enabled a sizeable increase in trim lift to be realized.

An analysis of the effects of canard shape, position, and deflection on the aerodynamic characteristics of two general research models having leading edge sweep angles of 25 and 50 degrees is presented. The analysis summarizes findings of three experimental transonic wind-tunnel programs and one supersonic wind-tunnel program conducted at this Center between 1970 and 1974. The analysis is based on four canard geometries varying in planform from a 60-degree delta to a 25-degree swept wing, high aspect ratio canard. The canards were tested at several positions and deflected from -10 to +10 degrees. In addition, configurations consisting of a horizontal tail and a canard with horizontal tails are analyzed. Results of the analysis indicate that the canard is effective in increasing lift and decreasing drag at Mach numbers from subsonic to high transonic speeds by delaying wing separation. The effectiveness of the canard is, however, decreased with increasing Mach number. At supersonic speeds the canard has little or no favorable effects on lift or drag. It is further shown that the horizontal tail is a superior trimming device than the close- coupled canard at low-to-moderate angles of attack and that a configuration consisting of canard, wing, and horizontal tail is superior in performance, to either canard or horizontal tail at high angles of attack.

Experimental aerodynamic investigations were conducted at the CALSPAN Corporation's transonic wind tunnel to determine the aerodynamic characteristics of several nose-mounted canard wing configurations. Canard position, geometry, angular orientation, and model nose shape were varied systematically to determine their effects on model aerodynamics. Angle of attack was varied from -3 to 12 degrees and Mach number was varied from 0.6 to 1.25. Aerodynamic loads were measured separately for each of the four canards and tail surfaces, and the total model.