The Effect of Dive Recovery Flaps on the Lift of a Two Dimensional Symmetrical Airfoil with Changes in Chordwise Location of the Flaps

Citation

Weitzenfeld, Daniel Kehr and Trauger, Robert James and Kronmiller, George Hannibal (1946) The Effect of Dive Recovery Flaps on the Lift of a Two Dimensional Symmetrical Airfoil with Changes in Chordwise Location of the Flaps. Engineer's thesis, California Institute of Technology. doi:10.7907/CV3E-KC83. https://resolver.caltech.edu/CaltechETD:etd-11262008-112929

Abstract

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It was desired in this investigation to determine the effect of the chordwise position of dive recovery flaps on the lift of a laminar flow, low drag, two-dimensional airfoil at high subsonic Mach numbers. Schlieren pictures were taken to relate the formation, extension and strength of shock waves to the measured lift. Tests were made on a four inch chord airfoil of section 65,1-012 at Mach numbers from .50 to .83, a Reynolds number of 1,600,000 at M[subscript o] = 0.7, angles of attack from 1 to 3 degrees, and flap locations at 15%, 30%, and 45% chord; the flap is 10% of the chord.

The investigation was carried out by the authors at the Guggenheim Aeronautical Laboratory of the California Institute of Technology during the school year 1945-1946.

It was concluded that dive recovery flaps materially increase the lift of an airfoil, and there is an optimum flap location for maximum lift and one for maximum […]. Moreover, it was concluded that the formation and development of shock waves is directly related to the lift, but that the successive development of the shock wave pattern as a function of Mach number is independent of angle of attack or flap location; the Mach number for initial shock formation varies. Finally, in this tunnel where the thickness of the boundary layer is a large percent of the tunnel width the correction for non-uniform spanwise lift distribution must be investigated more carefully before absolute lift values can be computed.

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