The present paper deals with the effect of ground upon the aerodynamic characteristics of a monoplane wing. In the first part of the paper theoretieal calculations are worked out, taking into account of the finite dimensions of the chord and thickness of the wing. Results of calculations are then reduced to a simple form, which is readily applicable to practical uses. In the second part of the paper, results of wing model experiments are reported, which were carried out in the 2m wind tunnel of the Aeronautical Research Institute, Tokyô Imperial University. For moderate values of the lift coefficient, the calculated effects of ground agree very well with the experimental results.
The changes of the drag coefficient c_x, the coefficient of pitching moment about the leading edge c_m and the angle of attack α due to the ground effect at a certain value of lift coefficient c_z may be summarized as follows: c_x is reduced for all values of c_z, c_m is reduced and α is increased for small values of c_z, and c_m is increased and α is reduced for moderately large values of c_z. The maximum lift is somewhat reduced when the distance of the wing above the ground is of moderate value, while it is increased when the distance becomes extraordinarily small.
A detailed account will be published soon, in the Report of the Aeronautical Research Institute, Tokyô Imperial University.