Abstract: The variation of horizontal tail position due to the angle of attack should be taken into account when wall-interference corrections on the longitudinal stability are performed. The interference factor at tail,τ,is determined by the actual position of the tail. In addition, in the ordinary wall correction method, the effectiveness of the tail panel (?)mz/(?)t which is contributed to the pitching moment coefficient is usually substituted by .It is corrected in this paper to account for the wall interference by using the improved method, and favourable results are obtained.

Key words: wall-interference, wind tunnel tests, experimental technique