Effect of sideslip angle on the aerodynamic characteristics of a following aircraft in close formation flight

Abstract

The effect of sideslip angle on the aerodynamic characteristics of a following aircraft in formation flight is investigated by experiment. Measured data from subsonic wind-tunnel testing are obtained by changing the magnitude of the sideslip angle and the relative distances between the two-5% scaled small sized jet aircraft models. The variations of aerodynamic forces and moments of a following aircraft model are measured at 49 locations on the cross-section area behind a leading aircraft. Results show the considerable changes of the aerodynamic forces and moments of the following aircraft compared to those of a single aircraft alone. The effect of the sideslip on the aircraft in formation flight is a very complex function of relative distances between two aircraft, and has a significant effect on the lateral/ directional stability of the following aircraft. Among the changes of the aerodynamic coefficients, the changes of the rolling moment coefficients are the largest. It is believed that the formation flight itself can be a very dangerous to the safety flight of the aircraft.