Report discussing the creation of a thermal ice-prevention system of a bomber-type airplane to provide protection against ice and fog formations on the transparent fairing over the landing light in the wing leading edge. A comparison between the design performance and actual performance showed that the outer-surface heat-transfer coefficient was correctly predicted, but the inner-surface heat-transfer coefficient was four times as large, leading to failure of the plastic fairing.

From Summary: "Tests on the B-34 fin-rudder-tab assembly were performed in the NACA 8-foot high-speed tunnel. Two cases of tab flutter were studied. It was shown conclusively that the frequency of the original or heavy tab was too low and caused coupling with one of the lower bending frequencies. A general conclusion was made that the tab frequency should be considerably higher than the lower modes of the fin-rudder assembly because there is generally a weaker coupling between the tab and the higher mode responses."

Report presenting a series of tests on the Brewster XSBA-1 airplane to determine the effects of various tail modifications. Some of the modifications include variations of the chord of the elevator and rudder while the span and total area of the surfaces are kept constant and variations of the total area of the vertical tail surface. Results regarding the longitudinal stability and control and lateral stability and control are provided.

Report presenting 10 practical-construction models of sections of helicopter rotor blades tested in the NACA two-dimensional low-turbulence pressure tunnel at atmospheric pressure. Lift, drag, and pitching-moment characteristics of blades representing the present method of construction of the YR-4A helicopter were determined.

Tests were conducted at dynamic pressure of 50 lb per square foot with lift drag and pitch moment measurements throughout useful angle of attack range for constant flap deflection and position of a low-drag airfoil. Two slots were investigated and practical flap paths were selected for each Slot shape had a negligible effect on the maximum lift coefficient flap deflected, the rounded-entry slot had lower profile drag.

Report presenting drag measurements in the two-dimensional low-turbulence tunnel of an available 100-inch-chord model of the NACA 23016 wing section. Results regarding the curves of section drag coefficient plotted against Reynolds number for various surface conditions and lift coefficients, variation of drag coefficient with lift coefficient, and effects of skin friction are provided.

Report presenting flight measurements of the pressures on the horizontal tail surfaces of a typical propeller-driven pursuit airplane during stalled pull-outs at high Mach number. Unit loads measured on the stabilizer at safe maneuvering limits were not only considerably in excess of the design unit loads, but also occurred in a direction opposite to the design loads. Revision of the tail-load design requirements and manner of specifying safe maneuverability limits to pilots appears necessary.

Report discussing the results of using an enlarged vertical tail on a P-63A-1 on directional stability. The tests included measurements of the amount of sideslip at various speeds and normal accelerations. Potential required modifications for increased performance using the larger tail are also described.

Report presenting a wind tunnel investigation of a beveled aileron shape designed to increase the useful deflection range. The purpose of the investigation was to determine the general aerodynamic characteristics of this aileron and, in particular, to determine its useful angular range. Results regarding the effect of the hinge-gap seal, the surface condition and Reynolds number, and effect of aileron profile are provided.

Report discussing the mutual interference effects of tail surfaces and a stern propeller on a model of the XB-42.The main focus was to determine the effect of tail surface-propeller spacing upon the periodic tail surface loading coincident with propeller blade passage.

"This report contains the results of tests of a full-scale semispan horizontal tail plane of a bomber airplane. The effects of fabric distortion on the aerodynamic characteristics of the elevator are determined by comparing the aerodynamic characteristics of a fabric-covered elevator with those of a metal-covered elevator. In addition, the results of cutting holes in the balance seal, the effect of fixing transition, the tab effectiveness both sealed and unsealed, and the section drag of this tail plane are presented" (p. 1).

Report presenting testing in the two-dimensional low-turbulence tunnels on a 24-inch-chord model of the NACA 66(215)-116 a = 0.6 airfoil with a 0.25-chord slotted flap. The optimum flap pivot positions were found for three different conditions. The conditions were determined from a consideration of the landing, take-off, and strafing requirements of the airplane.

Report presenting results of compression tests of six paper-base plastic panels with outward-acting normal pressure. All panels failed by separation of the skin, either from the rib or from the stiffeners. Results regarding the introduction of air pressure and types of failures encountered are provided.

Report presenting testing to determine which of three spinner-diffuser designs on an NACA cowling was the most effective in cooling a Pratt & Whitney R-2800 engine installation. The results of pressure-distribution studies in front of and behind each bank of cylinders are presented for a wide range of propeller-operating conditions.

Report presenting an investigation of carburetor-air scoops designed for the XTB2D-1 airplane in the NACA propeller-research tunnel. The purpose of the investigation was to determine the performance of several scoops and to make modifications necessary to improve the pressure recovery without adversely affecting the drag of the airplane. The investigation included tests of nine carburetor-air scoops with numerous boundary-layer-bypass and ducting modifications, the original engine cowl, and two canopies.

Report presenting a combination oil sump and scavenge pump constructed to eliminate some of the oil-system difficulties in an aircraft engine that result from the aeration of the scavenged engine oil and air-lock of the scavenge pump. Information regarding test results and design recommendations are provided.

Report discussing tests on the N9M-2 airplane to evaluate the airplane efficiency factor and to investigate the characteristics of the aeroboost in the elevon control system. The efficiency factor compared reasonably well to conventional airplanes and the aeroboost system and valve-chatter tests were satisfactory.

Report discussing testing to check the improvement of 3 or 4 miles per hour in the maximum speed of the P-51B airplane as a result of sealing the wing-gun access doors and flap-spar lightening holes. Large variations in speed were observed during testing, so additional testing and analysis was carried out to determine the effects of various factors that were suspected of contributing to the inconsistency of the plane's performance.

Report presenting a study of the effect of aftercooling on the brake horsepower, weight, and weight-power ratio of a power plant consisting of a 2000-horsepower air-cooled engine, an intercooler, and two stages of supercharging. Three cases are considered: inadequate supercharging, supercharging to constant manifold pressure, and supercharging to detonation-limited manifold pressure.

Report presenting an investigation of the cooling of a Franklin 6-AC-29S horizontally opposed cylinder air-cooled engine installed in a Fleetwings model 33 trainer. The cowling on the airplane did not provide satisfactory cooling, but several alterations were tested, including with cylinder baffles. Results regarding engine cooling, aerodynamics of the cowling installation, and predicted versus actual cowling performance are provided.

Report presenting an investigation conducted with the propeller cuffs and spinner removed to determine their effect in flight on the pressure recovery of the cooling-air flow. Curves are presented to compare the pressure and temperature distribution over the front row of cylinders for flights with and without cuffs and spinner.

Report presenting an investigation of the flying qualities of a Curtiss SB2C-1 airplane. Tests were made to determine the effect of a bobweight in the elevator system and the effect of seals in the aileron gaps. Results regarding longitudinal stability and control, requirements for lateral stability and control, and stalling characteristics are provided.

Report discussing testing of the Douglas A-26B to determine the longitudinal stability and control characteristics. Information about the elevator, stick-fixed and stick-free stability, center of gravity, and flap effects are described.

Report discussing the flying qualities of a high-speed bomber with a dual pusher propeller aft of the empennage. The airplane was found to have satisfactory flying qualities except for stability issues with aft center of gravity, high elevator control forces in landing, insufficient elevator control in take-off, and low rudder-free directional stability.