Modeling the Propeller Slipstream Effect on Lift and Pitching Moment

Thijs Bouquet, Roelof Vos
2017 55th AIAA Aerospace Sciences Meeting   unpublished
A semi-analytical prediction method is presented to predict the effect of the propeller slipstream on the lift and pitching moment of a propeller-powered aircraft. The method assesses three effects caused by the propeller slipstream: an increase in lift over the wing due to the slipstream, a change in the tail-off pitching moment, and a change in the horizontal tail contribution to the pitching moment due to increased downwash and (possibly) dynamic pressure. This prediction method is validated
more » ... using wind tunnel data for the Fokker 50 and a special version of the Saab 340 with T-tail. The prediction method shows good correlation with the experimental results for various combinations of flap deflection, angle-of-attack, and thrust coefficient. Further analysis of the results demonstrates that the propeller slipstream effect reduces the tail effectiveness due to an increase in downwash gradient at the horizontal tail. Furthermore, it is shown that the effectiveness of the tail is influenced by the vertical position of the tail with respect to the slipstream due to slipstream inflow and a (possible) change dynamic pressure ratio.
doi:10.2514/6.2017-0236 fatcat:5h6kuof6dfepze7ogbnj7gnq3e