found: Work cat.: Wenzinger, C.J. Wind-tunnel investigation of the aerodynamic balancing of upper-surface ailerons and split flaps, 1937.
found: Academic Press dictionary of science and technology, 1992(split flap; aviation; a flap set into the underside of a wing; depressed downward to increase drag)
found: Chambers dictionary of science and technology, 1999(split flap [aeronautics]; trailing edge flap in which only the lower surface of the aerofoil is lowered)
found: McGraw-Hill dictionary of scientific and technical terms, 2003(split flap [aerospace engineering]; hinged plate forming the rear upper or lower portion of an airfoil; the lower portion may be deflected downward to give increased lift and drag; the upper portion may be raised over a portion of the wing for the purpose of lateral control)
found: Wikipedia, May 22, 2007(Flap (aircraft); Split flap; upper and lower surfaces are separate, the lower surface operates like a plain flap, but the upper surface stays immobile or moves only slightly)
