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.

"The following surveys on the vibration response of the P-40 rudder and fin-rudder assembly were conducted during the fall of 1942 for the purpose of obtaining information on the flutter characteristics of high-speed airplanes of known performance. The tests on the rudder alone were made with the rudder suspended in a floating condition; the tests on the fin-rudder unit were made with the fin rigidly fastened to a concrete base" (p. 1). A variety of figures and diagrams for the assembly are provided.

Report presenting a study of the flutter characteristics of the P-47 tail assembly, which included replacing the original fabric-covered rudder with a metal-covered rudder and reinforcing the fin. Figures are provided for different configurations and the cycles per second under the same conditions are provided.

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 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 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.

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 presenting observations made of the air flow around a Martin PBM-3 flying boat. The observations are part of an analysis to aid in the determination of possible methods of reducing the air drag of the airplane. The behavior of the tufts on the hull and tip floats at various airplane speeds by still and moving pictures taken from an accompanying airplane.

"A machined mixed-flow centrifugal impeller of a relatively complex passage shape was used as a pattern to cast a number of aluminum-alloy impellers from two aluminum-base alloys (designated alloys 1 and 2) by the 'lost wax' process. An investigation was conducted to determine whether these cast impellers, could be considered satisfactory for use in compressors. The investigation included preliminary examination, physical tests, metallurgical examination, and performance tests" (p. 1).

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 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.

"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 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.

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 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 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 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."

From Summary: "Compression tests were made of two groups of panel specimens with hat-section stiffeners. The groups were identical except that the flat sheet of one group was Alclad 24S-T81 and of the other Alclad 24S-T86. Results of the tests are given in tables or charts which show the average stress at which the sheet buckles and the average stress at the maximum load."

"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 an investigation of the flying qualities of a Hawker Hurricane airplane. Thirteen flights and approximately 17 hours of flying time were required to complete the tests, which included extensive measurements of stability, controllability, and stalling characteristics. The results were similar to the flying qualities of other previously studied pursuit airplanes.

Report presenting wind tunnel tests of NACA 65(216)-420 and 66(218)-420 airfoils at speeds up to and slightly above the critical. Section coefficients of lift, drag, and pitching-moment and extensive pressure-distribution data are presented. The critical speed for these airfoils at their design life coefficient of 0.4 is shown to be about 460 miles per hour at seal level and about 415 miles per hour at 25,000 feet altitude.

Report presenting some statistical measurements of the accelerations encountered in gusty air over a period of years in order to determine the loads to which airplanes may be subjected. The statistical measurements have been evaluated to yield either effective or true gust velocities as applied to the wings of airplanes.

Report presenting a flight investigation of the flying qualities and stalling characteristics of a North American XP-51 airplane. The short-period longitudinal oscillation disappeared within one cycle in all conditions tested. Requirements for satisfactory stalling characteristics were met in all respects except for stall warning.

Report discussing the aerodynamic characteristics of a twin-fuselage pursuit airplane model, especially at high speeds. Information about the force data and critical Mach numbers for parts of the model is provided. Suggestions for increasing the Mach number of divergence by making modifications to the wing-fuselage fillets and external shape of the radiator are also included.