Many aircraft carry vane vortex generators from time of manufacture, but there are also aftermarket suppliers who sell VG kits to improve the STOL performance of some light aircraft [REF].
For twin-engined aircraft, manufacturers claim that VGs reduce single-engine control speed (Vmca), increase zero fuel and gross weight, improve the effectiveness of ailerons and rudder, provide a smoother ride in turbulence and make the aircraft a more stable instrument platform[REF] .