Airscrew Thrust and Take‐off Available to Purchase

IN the mathematical treatment of the take‐off problem it was formerly difficult to define any general relationships for the airscrew thrust. This difficulty was avoided usually by assuming certain mean values, such as, for example, 1 • 1 to 12 kg/h.p. for the static thrust and by using this value in the calculation. This procedure is incorrect in that the airscrew thrust is assumed to be constant for a given output and so ceases to be suitable as a governing factor. As we have shown in a previous article, it is now possible to estimate the static thrust more accurately and by appropriate engine design the static thrust can be made to satisfy the necessary demands within wide limits [11]‡ This makes it possible to adopt new viewpoints in the treatment of the take‐off problem, which it is proposed to examine.