Summary: Tests of a single-engine scout-bomber airplane showed that the rudder deflection required for trim at low speed in the critical wave-off condition may be reduced approximately 10° by a lateral shift of the center of gravity equal to 1.8 percent of the wing span. The reduction in rudder deflection required for trim consists of the rudder deflection required to offset yawing moments from the ailerons and from the component of the weight in the direction of the longitudinal axis and the rudder deflection required to hold the sideslip angle necessary to maintain straight flight. The effect of the lateral loading must be taken into account in tests to determine the adequacy of the rudder for trim. The lateral center-of-gravity location is also important in the service operation of airplanes because, by suitable distribution of the useful load in the wings, the ability of the rudder to trim the airplane in critical power-on conditions may be markedly improved.

The modified airplane possessed the following inherent safety characteristics: (1) motions accompanying the stall were greatly reduced, (2) no motions that did not result from the pilot's action occurred in turns with the elevator held full up, and (3) the airplane was spinproof. The general flying characteristics of the airplane were not materially altered in normal flight . The maximum speed in level flight and the rate of climb were slightly reduced.