Aerodynamic Performance and Static Stability Characteristics of Aircraft with Tail-Mounted Propellers

Abstract

In this combined experimental and numerical study, the propeller–airframe aerodynamic interaction is characterized for an aircraft configuration with propellers mounted to the horizontal tailplane. The contributions of the propeller and airframe to the overall loading are distinguished in the experimental analyses by using a combination of external balance and internal load cell data. Validated computational fluid dynamics simulations are then employed to quantify the interaction at a component level. The results show that the propeller installation shifts the neutral point aft with increasing propeller thrust. For the configuration considered herein, the yawing moment due to sideslip is increased by approximately 10%, independent of the propeller thrust coefficient. The changes in propeller loading due to the airframe-induced flowfield are the dominant factor to change the airframe stability and performance. The prominent installation effects occur at high angle of attack, because in that condition the propeller experiences a significant nonuniform inflow that affects the propeller and tailplane. The relatively large propeller diameter compared with tailplane span leads to a change of the tailplane root vortex that causes the tailplane effectiveness to reduce with an inboard-up rotating propeller.