Abstract:
An expression has been derived for the factor to he applied to ideal induced drag to allow for Wing-tail interference. This factor is primarily dependant on the wing-taillift and span ratios. It is of the order of 1.1 for a normal aircraft when the tailplane carries 10 per cent of the weight of the aircraft, and can reach unexpectedly large values at high speed. Charts, generalised curves, and sufficient information are included to permit rapid evaluation of the factor for any particular case.
