Report discussing the effects of circular-arc spoilers on the section characteristics of an NACA 66,2-216 airfoil with a 0.25-chord slotted flap. Spoilers were tested on the upper surface of the airfoil, on the lower surface, and on both simultaneously. Only the simultaneous placement of spoilers was found to provide satisfactory results as a lateral control device.

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 a study of oil coolers, especially in regards to three factors: the congealing tendency of the cooler, the power cost chargeable to the installation, and the performance characteristics of the oil cooler in operation at altitude.

Report presenting an investigation of the performance of a mixed-flow impeller and vaned diffuser unit with several modifications in a variable-component supercharger test rig. The investigation covered impeller tip speeds from 800 to 1200 feet per second over the range of air flows from wide-open throttle to incipient surge. The results showed the supercharger to have a peak efficiency of 0.77 and a peak pressure coefficient of 0.61 with the impeller frontal clearance at 0.035 inch.

Propellers with trailing-edge extensions were studied to determine aerodynamic characteristics. Trailing-edge extension increased power absorbed by propeller with little loss in efficiency. Power coefficient for maximum efficiency was greater for 20% camber type extension than for 20% straight type extension over range of advance ratio of 1.0 to 2.5 although camber type was less efficient. Efficiency was about the same for cruising and high-speed at a high power coefficient for propeller with extension.

"A preliminary analysis has been made of the conditions of stability of free oscillations of a hinged rotor in hovering flight. The case analyzed is a rotor with hinges allowing freedom in flapping and lagging and having a completely reversible cyclic pitch-control system, so that a twisting moment on a blade moves the control stick without hindrance from spring or friction constraint. The principal results of this study are presented in the form of a stability chart" (p. 1).

Report presenting testing of a steel cylinder barrel with aluminum fins in order to evaluate the effect of using preformed aluminum fins on a steel barrel or aluminum barrel. Results regarding the heat-transfer tests and physical tests are provided.

Report discussing the effects of various inlet pressures, inlet temperatures, wheel speeds, pressure ratios, and cooling-air flows on the performance of a radial-flow exhaust-gas turbosupercharger turbine with a 12.75-inch tip diameter. Information about efficiency is provided for a given blade-to-jet speed ratio.

Report presenting testing to determine methods for reducing the temperatures of the hot cylinders on air-cooled aircraft engines. A Pratt & Whitney R-1830-43, 14-cylinder engine used for the tests. Results regarding the cooling-air ducts, mixture-enriching tests, additional cooling area, baffle modifications, and an application of the information are provided.

Report discussing testing to determine the longitudinal stability and control and stalling characteristics of a DeHavilland Mosquito F-8. Special focus is given to the control forces, elevator control, trim changes, and stick fixed and stick free characteristics of the aircraft.

Report presenting a study of the performance of bombers powered by one, two, four, and six 2000-horsepower engines supercharged to 25,000 feet. The performances are computed and are based on drag coefficients equal to the best obtained on modern airplanes and on weight estimates obtained from modern Army Air Forces airplanes. A chart is provided with the coordinates of power loading and wing loading noted so that all performances can be compared.

Report presenting an investigation of means to increase the range of several airplanes to 6000 miles, including the B-17E, B-24D, B-26C, and B-25A. Tank-wing trailers and tank gliders were found to be the most practical ways of increasing range and calculations are provided for determining the proper loading and dimensions.

"The purpose of this report is to provide designers of airplanes with information that will be helpful in obtaining good ditching characteristics in new designs. The results from a number of model tests and report of actual ditchings are used as a basis for which to draw conclusions as to the effect on ditching performance of general arrangement, interior arrangement, fuselage shape, and other design parameters. The characteristics of several types of ditching aids that could be incorporated in a design are also discussed" (p. 1).

Results of flight tests of a control-feel aid presented. This device consisted of a spring and dashpot connected in series between the control stick and airplane structure. The device was tested in combination with an experimental elevator and bobweight which had given unsatisfactory dynamic stability and control-feel characteristics in previous tests. The control-feel aid effected marked improvement in both the control-feel characteristics and the control-feel dynamic longitudinal stability of the airplane.

Report discussing flight tests on a low-drag wing pursuit airplane to determine the effects of Mach and Reynolds numbers on the maximum lift coefficient obtainable in gradual and abrupt stalls. The obtainable maximum lift coefficient was found to be greatly affected by the Mach and Reynolds numbers in gradual stall. In abrupt stalls, the maximum lift coefficient was affected by the Mach number, but not the Reynolds number.

Report presenting an investigation to obtain data on the vertical and horizontal gusts in the atmosphere by reworking accelerometers and airspeed records from past investigations of vertical gusts. The results indicate that the vertical and horizontal gusts are of about equal intensity in the atmosphere.

The effects of jet-motor operation on the stability and control characteristics of two fighter-type airplanes as determined by wind-tunnel tests of 1/5-scale models are presented. It is shown that the action of the jets is to cause a small loss in stick-fixed stability which is predictable from known theories.

Report discussing the icing characteristics of a rectangular-throat pressure-type carburetor. Serious ice was not found to form under the conditions of this particular test, although visible ice and frost formed in certain areas.

Report presenting investigations to determine the effect of xylidines on the saturation concentration of water in aviation gasoline. The saturation concentration of water in gasoline containing 0, 1, and 3 percent xylidines was determined using fresh water at two temperatures and sea water at one temperature.

Report presenting testing to determine the effect of xylidines of the corrosiveness of aircraft-engine oil toward engine bearings as part of an investigation on the suitability of xylidines as an antiknock component in aviation gasoline. Results regarding the loss in bearing weight, corrosion losses, temperature characteristics, and types of corrosion are provided.

Report presenting an analysis of cylinder-to-cylinder temperature and mixture distributions of four different aircraft engines to determine the possible economy of automatically supply water or additional fuel to only those cylinders having excessive temperatures. The cooling problem as distinguished from the fuel-knock problem was studied and an analysis limited to those cases in which additional cooling is ordinarily obtained by carburetor enrichment was made.

Report discusses the results of testing conducted to determine the performance of automatic, internal-coolant valves actuated by cylinder temperatures.The performance of the valves with respect to temperature sensitivity, rapidity of response, and hunting characteristics is described. The relative effects on cylinder performance obtained by internally supplying water and additional fuel were also examined.

"In the course of an investigation to find a satisfactory vertical tail for the XP-62 airplane, a 0.45-scale vertical tail model on a stub fuselage was tested in the Langley 7- by 10-foot tunnel. This model was fitted with a flat plate to represent the horizontal tail surface. The data are presented herein for their general interest value rather than their application to this particular airplane" (p. 1).

"Flight tests of an A-26B airplane have been conducted to determine the changes in maximum speed, as affected by changes in carburetor ram and aerodynamic refinement of the nacelles, resulting from the addition of sealed spinners and modification of the charge air system, cowling, and nacelle afterbodies. The changes in nacelle drag resulting from these modifications were measured independently by means of a revolving wake survey rake behind the nacelle and boundary layer rakes on the cowling, and provide a quantitative check of the speed measurements as well as a means of analyzing the components of nacelle drag" (p. 1).