Report presenting an attempt to establish a correlation of the cooling characteristics of the Wright R-2600-8 engine with water as an internal coolant and to investigate methods of introducing the water. A cooling correlation, including the effect of water as an internal coolant, was established by use of the NACA cooling-correlation method. Results regarding the cooling-performance predictions and engine condition are provided.

Report presenting testing of a German superchrager from a Junkers Jumo 211F engine. The supercharger differed from conventional American superchargers in that it had a fully shrouded impeller, which discharged through a very short vaneless diffuser into a scroll-collector case. Tests were run at impeller tip speeds from 400 to 1200 feet per second at increments of 100 feet per second for a wide range of air flows.

Report presenting testing to determine the effect of special baffles on the temperatures and cooling-air requirements of the Wright 1820 G200 and R-2600-8 cylinders. Nine baffles were tested with the 18020 cylinder and two were tested with the R-2600-8 cylinder. Results indicated that the internal cylinder surfaces with good thermal connection with the external-cooling means respond to changes in external cooling.

Report presenting an investigation of the effect of progressive ring failure on piston life. Two endurance runs were conducted on an Allison single-cylinder engine at high power output until destruction of the pistons occurred at 33.1 and 84.25 hours.

Report presenting an examination of the surfaces of used cast-iron piston rings from various single-cylinder aircraft engine tests by electron diffraction. Generally, the oxide patterns were obtained to an appreciable extent from only the top compression ring of the piston-ring assembly; the other rings gave predominately a graphite pattern.

Report presenting the effect of internal cooling on the knock-limited performance of AN-F-28 fuel in a CFR engine with the following internal coolants: water, methyl alcohol-water mixture, ammonia-methyl alcohol-water mixture, monomethyllamine-water mixture, dimethylamine-water mixture, and trimethylamine-water mixture.

"An exhaust-port design was developed that provides a heat-flow path of increased area from the valve stem to the outside surface of a Wright C9GC cylinder. The effects of the new port design on exhaust-valve temperature and volumetric efficiency were determined from single-cylinder engine tests. A reduction of 70 degrees Fahrenheit in the exhaust-valve temperature was obtained with no decrease in volumetric efficiency or power output" (p. 1).

Report presenting strain-gage measurements made on the crankshaft of a Wright R-1820-73 test engine while under power. Bakelite-bonded wire strain gages were installed on the front half of the crankshaft and the connecting wires were brought out through the oil passages and connected to slip rings at the rear of the engine. The inertia-excited bending and tensile-compressive stresses increased almost directly with speed.

Report presenting an analysis of the pressure drop that is required to cool a typically baffled radial engine, which shows that a total pressure drop of 58 pounds per square foot is necessary at sea level and 112 pounds per square foot is required at an altitude of 40,000 feet.

Report presenting results of tests conducted with an air-cooled, radial aircraft engine to determine the reduction in the brake specific fuel consumption that would result from operating with a very low fuel-air ratio and an increased spark advance. Computed values of the brake specific fuel consumption corrected for cooling-air drag are also given.

Report presenting an investigation of a special single-cylinder test engine constructed with provision for operation with three different lengths of piston stroke. Results regarding the air capacity of the engine, extent to which the spark must be retarded in order to prevent detonation, and brake mean effective pressure are provided.

Report presenting an investigation of the effect of wing loading, power loading, and aspect ratio on the performance of pursuit airplanes. The study is based on data combined from specifications, wind-tunnel, and flight tests of various airplanes and presented in graphs.

Report presenting testing of the flutter characteristics of the SB2U-2 airplane. The secondary purpose of the test, which ended up being the primary purpose, was to study the behavior of the airplane just below the flutter speed. Results regarding flutter amplitude, frequencies, and energy-absorbing qualities are provided.

Report presenting an investigation of a P-513 airplane with the propeller removed in flight at Mach numbers up to 0.755 and a comparison of those results with those of a wind tunnel test with a scale model.

Report discussing flight measurements of the handling qualities of an F6F-3 obtained over the course of thirty flights and under a variety of conditions. The longitudinal stability and control of the plane were found to be satisfactory by the test pilots. Information about the elevator control, flaps, and the longitudinal trimming device is provided in greater detail.

Report discussing the lateral and directional stability and control of the F6F-3 airplane in a variety of flying conditions. Information about the control-free lateral oscillations, aileron control characteristics, maximum sideslip, dihedral effect, blow-up characteristics of the landing flaps, rudder, pitching moment, and power of the rudder trim tab and aileron trim tab is included.

Report discussing the stalling characteristics of the F6F-3 under a variety of flight conditions. Stall warnings, initial roll-off, and effects of stall are described.

Report presenting an investigation to determine the stability and control characteristics of a straight-wing, tailless fighter model with a pusher propeller in the free-flight tunnel. The investigation consisted principally of force and flight tests of a powered dynamic model. Results regarding longitudinal stability, longitudinal control, trim at high angles of attack, lateral stability, and lateral control are provided.

Report presenting the effects of large variations of lateral area on the lateral stability and control characteristics of a free-flying model when ailerons are used as the principal control as determined by flight tests. The effects of the lateral-force parameter were investigated for a wide range of values of the directional-stability parameter and the rotary-damping-in-yaw parameter.

"Two graphical methods are presented for determining the stick-free neutral point, and they are extensions of the methods commonly used to determine the stick-free neutral point. A mathematical formula for computing the stick-free neutral point is also given. These methods may be applied to determine approximately the increase in tail size necessary to shift the neutral point (stick fixed or free) to any desired location on an airplane having inadequate longitudinal stability" (p. 1).

Report presenting an investigation of the effectiveness of suction slots a a means of extending the laminar boundary layer in flight at high Reynolds numbers using an NACA 35-215 airfoil. Tests were made over a range of indicated airspeeds, lift coefficients, and Reynolds numbers. Results regarding boundary-layer control, air-intake distributions, character of the boundary layer, total-intake rate, and profile-drag coefficient are provided.

Report presenting tests conducted with two typical low-drag airfoils of 90-inch chord to determine the effects of surface projections, grooves, and sanding scratches on boundary-layer transition. Data were obtained for projections of various sizes and chordwise locations on both low-drag airfoils.

Report discusses a series of force tests of a NACA 0009 elliptical semispan wing equipped with a flap that is either 50 percent of the wing area or 30 percent of the wing area. Information about the lift, hinge moment, and drag and pitching moment is provided.

Report presenting a tabular method for determining the span load distribution at high Mach numbers by utilizing high-speed airfoil section data. This method, which is also called the generalized method, is an easily applied process of successive approximations by which a general application of the lifting-line theory may be used to determine the span load distribution for wings composed of sections with arbitrary lift curves. An example is provided to show how the method is used.