Closer Look at the Flight Dynamics of Wings with Non-Elliptic Lift Distributions

Prandtl’s alternative solution for wings with minimum induced drag opens another route for improving aircraft performance especially at the conceptual design phase. In this work, the lateral-directional characteristics of such wings are studied for a glider use case from a perspective that focuses on proverse yaw and handling qualities. The authors propose an aileron design methodology that ensures roll authority and proverse yaw characteristics. The results show that these conditions cannot be satisfied by a conventional Elliptic configuration, whereas wings with non-elliptic distributions provide several solutions. Non-linear flight dynamic models of the configurations that provided maximum proverse yaw were assessed in an engineering simulator and compared against the baseline Elliptic case. Proverse yaw was observed in the simulation data and pilot feedback indicated improved handling qualities in the non-elliptic cases. However, the inherent directional instability combined with other lateral-directional coupling effects masked the observations from the pilot’s perspective.