A vehicle with a reducing the resistance, the unusually ducks guide

摘要

1470718 Canard wing aircraft; reducing drag S E LARSON I H LARSON C I K LARSON B E H LARSON J E G LARSON L O A LARSON and G P G LARSON 30 April 1974 [4 May 1973] 18969/74 Headings B7W and B7M A vehicle for operation in air or water has a main wing 3 and a canard wing 4 located upstream of and below the level of the main wing, the canard wing having such camber and location relative to the main wing that during a main wing angle of attack increase in a vehicle pitching manoeuvre the canard wing flow effects, by interference with the flow round the main wing, a stabilization and linearization of the flow over at least the leading edge of the main wing, whereby flow separation at the main wing leading edge is suppressed and retarded and a flow of essentially potential flow character is maintained at the main wing up to high angles of attack whereby a flow drag reduction and smoothing of the vehicle pitching moment curve is achieved. Test results are described supported by CL/CD curves (Fig. 6, not shown), for a diagrammatically represented model provided with leading and trailing edge flaps (Figs. 7a, 7b, not shown), and an optimum region for positioning the canard wing forward and below the main wing is illustrated in Figs. 8 and 9, wherein the leading point 31 and trailing point 41 of the aerodynamic mean chord 30 and 40 of the main and canard wings respectively are projected on to the centre axis 32 at points 33 and 42, the point 33 being selected as origin for an orthogonal co-ordinate system (X, Z). The shaded area within which the canard or nose wing should be positioned to achieve optimum drag reduction is bounded by line a defined by the points 33 and 51 having the X-Z co-ordinates (0; 0) and (0; 0À25 # NW ) where # NW is the length of the symmetry chord of the nose wing; line b defined by the points 33 and 52 having the X-Z co-ordinates (0; 0) and (2 # NW ; 0À1 C NW ) respectively, and line c defined by points 51 and 53 having the X-Z co-ordinates (0; 0À25 C NW and 2 # NW ; # NW ) respectively. A wing placed in this area is stated to obviate the need for leading edge slats on the main wing.