Abstract:
This report describes measurements of profile drag made on the wing of the King Cobra aircraft, which has a low-drag profile of X.A.C.A. design. The profile drag was high with the original surface finish and although it was improved when the surface was polished the profile drag was still much too high for a low-drag aerofoil. By reduction of the surface waviness to ± one thousandth of an inch low drag coefficients of the order of 0.0028 were obtained. The report describes the technique used to reduce the waviness and also the effect of flies, dust, water, high Mach number and normal acceleration upon the low drag characteristics of the wing.
