edges. Wings with vortex lift over the inboard section are the moderate-sweep wings with an easily identified LERX used on high-manoeuvrability combat aircraft, such as the Northrop F-5 and McDonnell Douglas F/A-18 Hornet. Vortex lift sharp forebody strakes are used on the General Dynamics F-16 Fighting Falcon. Benefits and shortcomings Vortex lift provides high lift with increasing AoA at landing speeds and in manoeuvring flight. A high AoA needed to meet landing requirements has, in the past, restricted pilot visibility and led to design complications to accommodate a drooping nose, as in the case of the Fairey Delta 2 and Concorde. For moderate swept wings the addition of a LERX reduces wave drag and improves turning performance and enables a far wider range of flying attitudes. The use of vortex lift is restricted by vortex breakdown or bursting and an inherent instability in yaw . There is considerable drag due to increased lift production and loss of leading edge suction that is part of normal attached flow round a leading edge. Among animals Animals such as hummingbirds, and bats that eat pollen and nectar, are able to hover. They produce vortex lift with the sharp leading edges of their wings and change their wing shapes and curvatures to create stability in the lift. See also Kármán vortex street Aerodynamics Crab claw sail References Aerodynamics Vortices