Effect of Microlift Force on the Performance of Ultralight Aircraft

Microlift force, which is the aerodynamic force developed in the presence of a wind gradient, can be responsible for a sizeable improvement of gliding performance of ultralight aircraft. A mathematical formulation based on Lagrange's equation method for the analysis of microlift is presented, where the effects of vertical velocity gradients on aircraft motion are taken into account. After giving some details on the modeled vehicle, the behavior of an ultralight sailplane during flight in a wind gradient is investigated. Optimal maneuvers are computed to interpret and discuss the performance of ultralight sailplanes soaring in a wind gradient. The proposed approach provides an effective means for understanding and improving the piloting techniques for sailplane and ultralight aircraft in nonuniform wind