Report presenting an investigation of the stalling characteristics of the Supermarine Spitfire, which was made as part of the flying-qualities measurement of the airplane. The results are presented in the form of time histories of the motions and controls during stalls in various conditions of flight. Generally, the Spitfire possessed good stall warning in the form of buffeting and stall motions were not violent.

Report presenting a theoretical study of the effects of aileron adverse yawing moment on lateral maneuverability at a high lift coefficient. The study included the effects of changes in effective dihedral angle, vertical-tail area, and tail length.

Bulletin presenting the results of bending tests on a monocoque box with the door on the compression side. The results indicate that the effectiveness of a stress-carrying door depends on the intended function of the door.

Report presenting force-test measurements in two-dimensional flow in the 4- by 6-foot vertical tunnel to determine the characteristics of an NACA 0015 airfoil equipped with a straight-contour plain flap with a chord 30 percent of the airfoil chord. Results regarding the lift, hinge moment of flap, pitching moment, and drag are provided.

Report presenting tests of 10-foot diameter, single- and dual-rotating tractor propellers with two to eight blades conducted in the 20-foot propeller-research tunnel. The blades were 50 percent wider than those used in previous investigations. Results regarding the effect of dual rotation and effect of solidity are provided.

Report presenting the section critical speeds and profile drags of the shank and hub sections of a propeller used on a current liquid-cooled-engine pursuit type of airplane. Results indicated that serious adverse compressibility effects can be expected at speeds of about 400 miles per hour. Suitable fairings for shank and hub sections were found to be necessary for maximum propulsive efficiency.

Report presenting a series of calculations made to determine the probable dynamic wing stress of two large airplanes in atmospheric gusts. The results indicate that in both isolated and repeated gusts of probable occurrence, the dynamic overstress is about 10 percent when referred to the present static design standard.

Report presenting tests on the Bell XP-63 wing root section fitted with an 0.18c split flap hinged at approximately 0.805c on the lower surface. The tests were conducted to determine the effect of a 10 degree deflection of the split flap on the drag characteristics of the model at low lift coefficients.

Report presenting tests made in the 4- by 6-foot vertical wind tunnel of an NACA 0009 airfoil with a 30-percent-chord flap with a medium amount of aerodynamic overhanging balance. In this investigation, the effects of the shape of the flap-nose overhang and the gap at the nose of the flap have been determined. The results indicate that, generally, the lift effectiveness of the aerodynamically balanced flap was increased slightly over that of a plain flap when a blunt or medium flap nose was used on the balanced flap.

A preliminary investigation made to study the hydrodynamic properties and general behavior of simple hydrofoils. Six plain, rectangular hydrofoils were tested in a tank at various speeds, angles of attack, and depths below the water surface. The results are presented as curves of the lift and drag coefficients plotted against speed for various angles of attack and depths for which the hydrofoils were tested.

Report presenting an investigation in the 20-foot wind tunnel to determine the drag, propulsive and net efficiencies, and cooling characteristics of several scale-model arrangements of air-cooled radial-engine nacelles and present-day propellers in front of an 18-percent-thick, 5-by-15-foot airfoil. Two 3-blade propellers with differing diameters were tested in conjunction with a 12-inch-diameter nacelle in three positions in front of the wing and with a 16-inch-diameter nacelle in six positions in front of the wing. Lift, drag, cooling-air flow, and propeller characteristics were determined for each arrangement.