Abstract:

ESDU 85017 sets up an accounting framework for the split between thrust and drag for propeller-driven aircraft. It is assumed that free-air thrust is known either from calculations or from tunnel measurements of minimum-body, or net, thrust. The corrections to free-air thrust, due to blockage and induced effects, and to propeller-off airframe drag, due to pressure gradients and increased velocities in the streamtube, are tabulated to form a check list of all interference contributions. The use of the interference corrections in deducing the excess thrust is explained, and differences between the current approach in the US and the UK are highlighted. Discussion of the various propeller-airframe interference effects will be found in ESDU 85015.