Report presenting an investigation in the two-dimensional low-turbulence tunnels for the purpose of developing an optimum flap configuration for maximum lift on an airfoil section for the Republic XF-12 airplane equipped with a double slotted flap. Lift and flap loads were obtained at several flap deflections for two flap paths. Results regarding lift, drag, and flap loads are provided.

"Compression tests were made of 63 panels stiffened with corrugated sheet. The specimens were constructed from artificially aged alclad 24S-T aluminum alloy with minimum guaranteed yield strengths of 57 and 48 kips per square inch for the flat- and corrugated-sheet materials, respectively. Results of the tests are presented in charts which show the average stresses at the maximum load and at buckling of the sheet" (p. 1).

Report discusses a method of correlating engine-cooling data and its application to a representative engine-cooling test. Considerations for the correlation method are given, but the application to specific engine-cooling problems should be simple and direct. Information about experimental procedure and an example with specific values are included.

"A relatively simple equation has been found to express with fair accuracy, variation in manifold-charge temperature with charge in engine operating conditions. This equation and associated curves have been checked by multi cylinder-engine data, both test stand and flight, over a wide range of operating conditions. Average mixture temperatures, predicted by the equations of this report, agree reasonably well with results within the same range of carburetor-air temperatures from laboratories and test stands other than the NACA" (p. 1).

Behaviors of both model and full-scale airplanes were ascertained by making visual observations, by recording time histories of decelerations, and by taking motion picture records of ditchings. Results are presented in form of sequence photographs and time-history curves for attitudes, vertical and horizontal displacements, and longitudinal decelerations. Time-history curves for attitudes and horizontal and vertical displacements for model and full-scale tests were in agreement; maximum longitudinal decelerations for both ditchings did not occur at same part of run; full-scale maximum deceleration was 50 percent greater.

Report presenting an investigation of planing devices like hydroflaps and hydrofoils on several dynamically scaled models of military airplanes and their effectiveness in improving ditching characteristics. The ditching aids were generally found to be of value. Results regarding the hydroflap test in the impact basin, dynamic model tests at the outdoor catapult, and effect of ditching aids on ditching performance and rough water are provided.

Report presenting testing to determine the best way to land the SB2C-1 airplane in calm and rough water and to determine its probable ditching performance. The behavior of the model was determined by making visual observations and by recording the maximum longitudinal decelerations and by taking motion pictures of the ditchings. Results regarding the effect of flaps, attitude, weight, a wing-low landing, effect of simulated damage, effect of tail wheel, ditching aids, and seaway are provided.

Tests were made in 8-ft high-speed wind tunnel to determine the drag reduction possible by eliminating the barrel jacket of a protruding 50-caliber aircraft gun. It was found that the drag of a standard aircraft gun protruding into the air stream at right angles to the flow can be reduced by 23% by discarding the barrel jacket. At 300 mph and sea-level conditions, this amounts to a decrease in drag of from 83 to 64 pounds. A rough surface finish on the barrel was found to have no adverse effects on the drag of the barrel, the drag being actually less at high Mach Numbers.

Report presenting power-off wind tunnel tests of a scale model of a twin-engine cargo airplane equipped with amphibious floats. Longitudinal and lateral stability and control characteristics were investigated for three flap positions.

"The knock-limited performance of blends of 0,50; and 100 percent by volume of 2,2,3-trimethylpentane in 28-R fuel determined with a modified F-4 engine at three sets of conditions varying from severe to mild at each of three compression ratios (6.0, 8.0, and 10.0). A comparison of the knock-limited performance of 2,2,3-trimethylpentane with that of triptane (2,2,3-trimethylbutane) is included. The knock-Limited performance of 2,2,3-trimethylpontane was usually more sensitive to either compression ratio or inlet-air temperature than 28-R fuel, but the ratio of the knock-limited indicated mean effective pressure of a given blend containing 2,2,3-trimethypentane and 28-R to the indicated mean effective pressure of 28-R alone was not greatly affected by compression ratio if the engine operating conditions were mild" (p. 1).

Report providing charts to assist with estimating F-3 and F-4 knock-limited performance ratings for several ternary and quaternary fuel blends. Several unusual behaviors were noted in the F-3 engines using the aromatic-paraffinic blends, so the charts for them may not be as accurate. General trends observed in different types of fuel are also described.

Report presenting stability, maximum lift, and high-speed tests of an observation airplane fitted with Maxwell leading-edge slots. The static and dynamic longitudinal and lateral stability was generally satisfactory and not affected much by the slots.

Report discussing testing on the spin and recovery characteristics, longitudinal-trimming characteristics at extreme angles of attack, and tumbling characteristics of a model of the Cornelius XFG-1 glider. The effects of loading, mass distribution, and center-of-gravity position were determined. They also explored the inverted spin characteristics and spin-recovery parachute requirements.

Report presenting testing in the full-scale tunnel to provide data for estimating the longitudinal stability and control characteristics of the Curtis XP-55 airplane. Testing included lift, drag, pitching-moment, hinge-moment, and elevator pressure measurements for various combinations of angle of attack, elevator deflection, and elevator tab settings. The results of the force tests and some correlation of the results of the force tests and the pressure measurements are presented in the report.

Report presenting tests of representative models of flying boat hulls to determine the resistance at low speeds. Results regarding the effect of load coefficients, resistance coefficients, and towing and drifting calculations are provided.

Supplement using data from a previous report to show the cargo that can be carried at various ranges, pounds of cargo that can be carried per pound of fuel, and other graphs to simplify the problem of determining which cargo can be carried at any range. The assumptions, parameters, and equations from the original report are carried over in the supplement.

Report discussing an investigation of the cooling characteristics of an R-2600-22 engine installed in a PBM-3D nacelle. The investigation explored the general cooling characteristics by the NACA cooling-correlation method and an investigation of specific points on the engine cylinder where cooling was critical, including the exhaust-valve-crown and number 3 cylinder.

Report presenting tests of airplane models that included investigations to determine the longitudinal stability and control, effects of various constituent parts or their modification on longitudinal stability and control, critical speed, and distribution of wing load. Some of the changes made in attempts to improve longitudinal control and to increase critical speed included auxiliary control flaps on the lower surface of the wing, revision of the windshield, increase in dimensions of outboard nacelles, and alteration in profile of wing leading edge.

Report presenting tests made in order to determine the differences in high-speed aerodynamic characteristics between models of a four-engine transport airplane and a similar bomber airplane. The main conclusion found is that the critical Mach number of the transport model is about 0.05 less than that of the bomber model.

Report discussing an investigation into several types and sizes of flaps and spoilers located forward of the elevators on the upper surface of the horizontal stabilizer of a model of a radial-engine pursuit airplane. Information about the elevator characteristics, elevator-fixed and elevator-free balance lift coefficient, and trim drag coefficient for a range of Mach numbers is provided.

Report discussing testing on two types of single cylinders to determine the effect of the relation of exhaust pressure to inlet-air pressure on knock-limited performance. Variables explored included exhaust pressure, fuel-air ratio, and engine speed. Three types of fuels were also used to explore the effect of exhaust pressure on fuel ratings.

Report discussing an investigation into cowl-flap and cowl-outlet designs for the B-29 in order to determine the effects of cowling performance of different types of flaps and elements of flaps. Details of the available pressure drop and cooling-air pressure-drop distribution are also provided.

Report investigating five cowl-inlet configurations for the B-29 to obtain design information for improving the cowl performance. The effects of propeller spinners and increased inlet diameters on the cooling-air pressures at the cowl inlet and face of the engine and on the drag and critical speed of the cowl are described.

Report presenting an investigation of the effect of spray strips on the low-speed spray characteristics on a model of the Consolidated PB2Y-3 flying boat. The main purpose of the investigation was to determine what form the strips should be fitted to give the most practicable answer to the problem of controlling the spray at heavy loads.