Report presenting an application of the principle of aileron-stick forces and mechanical advantage to an aileron installation in which the stick forces are small over the low-deflection range and excessively large at full deflection.

Report presenting a method of comparing the performance, weight, and general dimensional characteristics of intercoolers. The performance and dimensional characteristics covered in the comparisons include cooling effectiveness, pressure drops and weight flows of the charge and cooling air, power losses, volume, frontal area, and width.

Report presenting a control-motion study in flight that is part of series covering a range of types and sizes of modern airplanes. This particular one involves the PBM-3 flying boat, which is equipped with a control mechanism typical of the cable-type systems in large transport, cargo, or bomber airplanes as well as those employed in flying boats. The elasticity of the elevator control system of the PBM-3 was such to limit the obtainable acceleration to about 3g for center-of-gravity positions in the usual operating range; that is, 26 to 30 percent mean aerodynamic chord, and for the range of airspeeds covered by the tests.

Report presenting an investigation conducted in the full-scale tunnel to determine methods of improving the cooling of the B-24D engine installation. The B-24D is a four-engine high-wing monoplane having a span of 110 feet, a wing area of 1048 square feet, and a gross weight of 56,000 pounds.

Report presenting tests on a single-cylinder, air-cooled engine to determine the effect of several different exhaust-stack shapes on the design and performance of the individual cylinder exhaust-gas jet-propulsion systems. Results regarding the effect of nozzle area and stack shape on exhaust-gas jet thrust, effect of nozzle area and stack shape on overall performance for the S-shape, the 90 degree bend, and the 180 degree bend, the effect on the shape on engine power and volumetric efficiency, and the effect of a branched stack on engine power are provided.

Report presenting an ice detector that can serve as a basis for a rate-of-icing indicator. The instrument consists of a wire screen and a pitot tube mounted behind the screen with both enclosed in a cylindrical shell. Observed data and some possibilities for future development are provided.

Report presenting results of high-speed and climb tests of an NACA C cowling on the XP-42 airplane. Results regarding maximum speed, pressures and temperatures, ground cooling, and effects of cuffs are provided.

Report presenting an investigation of propellers designed specifically for pusher operation behind fixed contravanes on a large-scale model of a four-engine airplane. In the test, the wing trailing edge was twisted to serve as a contravane and to produce the rotating inflow required for optimum propulsive efficiency. Results indicated that gains in efficiency of about 3.5 percent at a blade angle of 40 degrees can be obtained by the use of contravanes with specifically designed pusher propellers.

Report presenting extensive force tests covering a wide range of propeller thrust coefficients on a typical twin-engine tractor monoplane model with the horizontal tail surface removed and attached. Measurements were made with flaps retracted and deflected at various angles of attack with different stabilizer and elevator settings. Results regarding the effect of propeller operation on wing-fuselage combination and forces and air flow at tail are provided.

From Summary: "Interdependence of intercooler parameters and performance for a pursuit-type airplane using a 1675-horsepower engine is shown at altitudes of 25,000, 36,000, 47,000, and 60,000 feet by means of perspective drawings. Qualitatively, the drawings have general application. Intercooling between stages of supercharging at high altitudes results in no saving in the power to supercharge and cool the engine air."

Three airfoils were tested with an intersecting flat plate normal to the span as a preliminary study of interference effects on airfoils. Small interference effects were noted on the first two airfoils, while larger effects were noted on the NACA 66,2-422 section, which had previously been shown to be unconservative with respect to separation. Airfoils known to be conservative should be used for inboard sections subject to nacelle and fuselage interference.

Bulletin presenting an investigation of the boundary layer about the NACA 66,2-216, a = 0.6 airfoil section in the two-dimensional low-turbulence tunnel. The primary purpose was to find an explanation for the decreased slope of the lift curve observed for some of the low-drag sections outside the low-drag range at low Reynolds numbers.

Report presenting the flight tests of beveled trailing-edge ailerons on the North American XP-51 airplane which were extended to determine the aileron characteristics in high-speed dives. Standard recording instruments were used to determine airspeed, aileron position, stick force, and rate of roll. The results show that the beveled trailing-edge form of aerodynamic balance had no abnormal or unusual characteristics in high-speed flight.

Report presenting testing of dynamic models that has been helpful in the determination of the longitudinal stability characteristics on the water of a number of specific flying boats. Results regarding the constant-speed tests, accelerated runs, effect of variations in moment of inertia, effect of variations in mass moving vertically, effect of variations of depth of step, and effect of variations of gross load coefficient are provided.

Data taken from tests at constant speed to establish trim limits of stability, tests at accelerated speeds to determine stable limits of center of gravity shift, and tests at decelerated speeds to obtain landing characteristics of several model hull forms were used to establish hull design effect on longitudinal stability of porpoising. Results show a reduction of dead rise angle as being the only investigated factor reducing low trim limit. Various methods of reducing afterbody interference increased upper trim limit.

Report presenting a consideration of some problems related to longitudinal stability in power-on flight. The results indicated that the destabilizing effects of power are more pronounced when the horizontal tail is required to carry a down load to maintain flight equilibrium.