Wind-tunnel investigation of the spinning characteristics of a model of a twin-tail low-wing personal-owner-type airplane with linked and unlinked rudder and aileron controls

Walter J. Klinar, Lawrence J. Gale
naca-tn-1801
January 1949


A spin investigation has been conducted in the Langley 20-foot free spinning tunnel of a model a twin-tail low-wing personal-owner-type airplane with linked and unlinked rudder and aileron controls. The model was tested for two wing loadings and three mass distributions. The results obtained when the rudders and ailerons were linked for two-control operation indicated that the model generally would not spin. The spins that were obtained were steep, and the test results indicated that full reversal of the controls from any spining condition would result in satisfactory recovery. A study of the individual effects of rudders and ailerons at the various loadings showed that when a spin was obtained the inboard aileron (right aileron in a right spin) when deflected up was largely responsible for maintaining the spin. The results indicated that a reverse differential aileron system having the up aileron movement limited to a very small deflection would be effective in preventing the spin. The outboard rudder (left rudder in a right spin) was the more effective rudder in terminating or maintaining the spin, and differential rudder deflections which maintained the outboard rudder at or near neutral were particularly effective in preventing the attainment of spinning equilibrium.

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