The horseshoe vortex system is a simple vortex model for an aircraft or lifting body which fits a box-shaped vortex system out from the wing. This is made up of the wing vortex, trailing vortices (see
trailing vortex) and starting vortex.
The latter is a vortex formed due to changes in the vorticity of the wing vortex, i.e due to changes in airspeed.