Research on the Effect of Aft-Mounted Propeller Slipstream on Aircraft Aerodynamic Characteristics

Propeller aircraft can generally be divided into tractor and pusher configurations. The difference in propeller installation leads to completely different effects of the propeller slipstream on the aircraft's overall aerodynamic properties. This work focuses on a twin-boom aircraft with a tractor propeller and numerically simulates the effect of the slipstream generated by its aft-mounted propeller on the aircraft's overall aerodynamics. The results show that the primary lifting component's lift performance is not significantly impacted by the aft-mounted propeller and wing, and the overall aircraft lift coefficient is basically unaffected by the slipstream. Because the aftmounted propeller is relatively close to the rear of the fuselage, its suction effect increases the airflow velocity and decreases the pressure ahead of the propeller, while also changing the pressure distribution on the fuselage tail. This causes the overall aircraft drag coefficient to increase by about 30%. When the horizontal tail is high-mounted and far from the propeller slipstream area, it is mainly influenced by a combination of factors, including wing downwash, aircraft angle of attack, and additional downwash generated by the propeller. The reduced nose-down pitching moment is a result of the additional downwash from the propeller, which lowers the effective angle of attack at the tail. When the horizontal tail is within the core influence area of the slipstream, the entering flow gains additional energy from the propeller's high-speed rotation, increasing the velocity of the airflow entering the slipstream region. This improves the horizontal tail's aerodynamic efficiency, contributing more to the nose-down pitching moment and a slight increase in its longitudinal static stability.