"The NACA has conducted a flight investigation to improve the cooling characteristics of the installation of a double-row radial engine. The tests reported herein concern the use of the NACA injection impeller and ducted head baffles in various combinations on both the port inboard and the port outboard engines. The performance of the modified installation was evaluated by comparing it with that of the standard engines" (p. 1).

Report discussing tests to determine the effect of 2-percent additions of six aromatic amines on the knock-limited performance of 28-R fuel. All of the aromatic amine blends increased the performance and power of the base fuel. Different blends performed better at different fuel-air ratios.

Report discusses the results of bench testing on a German BMW 301D2 to determine the relation between the control parameters and any special methods by which the control principles are adapted to the control of the engine. Characteristics are presented for a variety of simulated manifold pressures, charge-air temperatures, engine speeds, and altitudes. Special attention is paid to the pressure characteristics of the servo-oil system and the potential effects of its failure on the operation of the automatic engine-control system.

Report presents a comparison of predicted qualities of the A-26B airplane with actual flying qualities determined in testing. From Summary: "The results indicate that the control-fixed, power-off stability and control characteristics of a conventional airplane can be predicted from the dimensions of the airplane and from general wind-tunnel data now available with sufficient accuracy for design purposes. No estimate of control forces, of effects of power on stability, or of adverse aileron yaw has been made."

Report discussing a cooling-correlation equation based on the average temperature of exhaust-valve seats of a large double-row radial engine. From the equation, predicts can be made about the cooling-air pressure drop required to cool the critical region of engine cylinders. Using a modified carburetor to improve the fuel-air-ratio distribution to the cylinders increased the accuracy of the equation's predictions.

"The longitudinal-stability and -control characteristics of a twin-engine patrol airplane as predicted from the results of wind-tunnel tests of a powered model and as measured in flight are compared in this report. The accuracy of the wind-tunnel predictions and the reasons for discrepancies are analyzed and discussed" (p. 1).

Report presenting tests with dynamically similar models made to study the behavior of the Army B-17F and B-17G when ditched and to determine the best way to land them in calm and rough water. Various landing attitudes, speeds, and conditions of damage were simulated. The ideal landing condition was found to be in a three-point landing attitude and with the flaps 45 degrees at the slowest possible speed.

Testing conducted to determine the best way to ditch the Army B-24 airplane in calm and rough water and to determine its probable ditching performance. A dynamically similar model was ditched in calm water in tank no. 2 and calm and rough water from an outdoor catapult. Results regarding the effect of attitude and speed, effect of flap setting, effect of vertical velocity, effect of location of center of gravity, effect of simulated damage, effect of ditching aids, effect of fuselage length, effect of landing gear, effect of load, and effect of seaway are provided.

Report discussing an investigation to determine the effect of fuel volatility on the relation between mixture temperature and knock-limited performance on a liquid-cooled single-cylinder test engine. The mixture temperature at which the curve of indicated mean effective pressure plotted against mixture temperature becomes nonlinear was found to be independent of fuel volatility. The effects of vaporization on the knock-limited power output are also described.

Report discussing the effect of valve clearance on valve-lift diagrams, knock-limited performance, and engine cooling. The performance of single-cylinder and multicylinder engines was also compared across these variables.

Report discussing tests on three sets of elevators with various combinations of section contour, balancing tabs, bobweights, and control-system mechanical advantage on an SB2C-1C airplane. Effects on maneuvering stability, a comparison of production elevators and recommended arrangement, and internal elevator pressures are described.

Report discussing testing of an HNS-1 (Army YR-4B) helicopter to determine the hovering data in the ground-effect region and at altitude with an original set of rotor blades and an alternate set with different aerodynamic design and surface condition.

Report discussing basic performance data obtained on the PV-2 helicopter rotor. Blade motion, rotor forces, and power were measured for static-thrust condition and a limited range of forward-flight conditions. Recommendations are provided for further testing to obtain blade-motion data and force-test data in order to develop a more detailed analysis.

Report discussing tests on the PBN-1 airplane to determine the effects of modifications on spray characteristics and take-off and landing stability. Spray strips were found to reduce the spray over the bow at low speeds. The effects of changing the main step location and altering the elevator position are described.

Report discussing the aerodynamic characteristics of the wing and isolated tail of the Bell XP-83 airplane in attitudes simulating spin conditions. Information about the the aileron hinge moment, angle of attack, and elevator hinge-moment is provided.

Report discussing testing on a retractable spoiler aileron on the NACA 66(215)-216 airfoil with a 25-percent-chord slotted flap. The effects of spoiler thickness, spoiler gap, spoiler bevel angle, spoiler roughness, and flap deflection on aerodynamic characteristics are described.