Lifting Vortices on Kites

by Al
(USA)

Or, 'vortex generators'. Recently I have improved the flight characteristics of several different kinds of kites by modifying them with what I call FLOWTHRU SLOTS. Last year I conducted some simple wind tunnel tests and have determined that the enhanced performance of all the kites I tested was derived by inducing 'lifting vortices' and changing the lift-drag ratio.

Rectangular flaps or slots cut in the sail that are positioned close to the center of gravity and the center line of the kite have increased the flight angle and provided greater stability in high and turbulent wind conditions.

Whitold Kasper back in the 70's designed and patented an Airplane wing that incorporated variable wing configurations that produced 'lifting vortices' (a vortex generator) thus, allowing airplanes to generate lift at very slow airspeeds.

Many kites by their design features have the ability to direct a large amount of air flow thru slots in the sail that can produce 'lifting vortices'. I first encountered this phenomenon when I designed a flat kite called a TEECA back in 2002. I was pleasantly surprised by its high angle of flight and its stability in high and gusty wind conditions.