Wind-tunnel investigation of control-surface characteristics XXII : medium and large aerodynamic balances of two nose shapes and a plain overhang used with a 0.20-airfoil-chord flap on an NACA 0009 airfoil

Abstract : The NACA is conducting an extensive investigation determine the characteristics of various types of flap arrangement suitable for use as control surface and to provide data for design purpose. The investigation, which made in the Langley 4- by 6-foot vertical tunnel, had included test of modifications of flap profile, trailing edge angle, gap size, flap nose shape and balance chord, however most of those tests have been made in two dimensional flow with a flap having a chord 30 percent of the airfoil chord (0.30c). The present tests have extended the investigation of balance chord and flap nose shape, which was reported in reference 1 for a 0.40c flap, to a 0.20c flap. Data on the pressure across the flap nose seal and a method of applying these pressure across the flap nose seal and a method of applying these pressure data in the design of internal balances are presented. Tab data are presented for the plain flap and for a flap with aerodynamic balance.