Modern aerodynamic design practices have also been applied to reduce the drag and improve the handling characteristics of these gliders. Design tools such as Xfoil, created by Prof Mark Drela at MIT, have been applied to the design of these aircraft, creating much better understanding of low speed aerodynamics and inspiring new design practices, such as thin airfoils. In some cases, the minimum thickness of the wing is limited only by the thickness of the servos that must fit within that wing to control the flaps.