Wall corrections to longitudinal components measured on wind-tunnel models with tails

Abstract

Calculations have been made of the magnitude of the wall corrections to pitching moment for two models with tails using two methods of correction and two stages of approximation for each method. It is found that the first stage of approximation is accurate enough for values of lift coefficient up to four. For higher values of lift coefficient, it is suggested that it is not worth using the second approximations as the theory of wind tunnel wall-interference is not sufficiently accurate in its predictions for flows with the large values of downwash inherent in high-lift systems such as lifting jets or rotors. The correction to lift calculated for the two models is shown to be nonnegligible and it is recommended that it is applied in tests where differences are to be taken between tail-on and tail-off tests.