Abstract
Positional stability analysis based on aerodynamic forces and induced moments of formation flight using two small aircraft models is presented. The aerodynamic force and moments of the trailing aircraft are analyzed in the aspect of flight stability. The induced moments with the change of local flow direction by wing-tip vortex from the leading aircraft can affect the flight positional stability of aircraft in closed formation flight. Aerodynamic forces and moments of trailing aircraft model are measured by 6-component internal balance at the 49 locations with vertical and lateral space between two aircraft models. Results are shown that the positional stability of trailing aircraft in formation flight can be analyzed by positional stability derivatives with vertical and lateral space. It is concluded that flying positions can be important factors for aircraft position stability due to induced aerodynamic force and moments with vertical and lateral spacing by the variation of flow pattern from the leading aircraft in formation flight.