"General relationships for the lead susceptibilities of paraffins, cycloparaffins, and olefins are presented. Methods are described by which the lead response may be estimated for these hydrocarbon classes, whether the lead response is indicated by octane number, critical compression ratio, or indicated mean effective pressure as limited by knock" (p. 1).

Report presenting an investigation made on a supercharged CFR engine to determine a method for estimating lead susceptibilities of pure or blended paraffinic fuels. As a result of these studies, a chart consisting of a series of straight lines passing through the origin was developed to represent the lead susceptibilities of pure and blended paraffinic fuels in terms of knock-limited indicated mean effective pressures and octane numbers.

Report discussing the results of testing to discover the effects of fuel-vapor loss on F-3 and F-4 knock-limited performance ratings and inspection properties of two aviation fuels, 28-R and 33-R. The percentage of loss at several temperatures, ability to meet Army-Navy fuel specifications, and antiknock rating change is described.

Report presenting data that show the knock-limited performance of methyl tert-butyl ether obtained from tests made in a 17.6-cubic-inch-displacement engine under supercharged conditions. Tests for temperature sensitivity, speed sensitivity, and lead susceptibility were made on a blend of 20 percent methyl tert-butyl ether and 80 percent S-2 reference fuel.

Report presenting an investigation of the suitability of methyl tert-butyl ether as a component of aviation fuel from considerations of knock-limited performance tests and laboratory inspection tests. Data were obtained from testing on the 17.6 engine under supercharged conditions with fuel blends containing 10 and 20 percent methyl tert-butyl ether. Results regarding small-scale-engine data, full-scale-engine data, and inspection data are provided.

"The effect on the propulsive efficiency of locking or windmilling one propeller of a six-blade dual-rotating propeller installation was determined in the Langley propeller-research tunnel. Tests were made of both pusher and tractor configurations, with the unpowered propeller both leading and following the powered propeller, which was set at a blade angle of 40 degrees. The maximum propulsive efficiency of the powered propeller in combination with the locked or windmilling propeller was, in all cases, lower than that of the powered propeller operating alone" (p. 1).

Report discussing the mutual interference effects of tail surfaces and a stern propeller on a model of the XB-42.The main focus was to determine the effect of tail surface-propeller spacing upon the periodic tail surface loading coincident with propeller blade passage.

An investigation was conducted to determine and compare the tensile strength of NACA and conventional machine-countersunk flush rivets of several rivet-head angles and varying countersunk depth. The results of the investigation are presented in the form of curves that show the variation of the tensile strength of the rivet with the ratio of the sheet thickness to the rivet diameter. For the same rivet-head angle and for a given angle of c/d, the NACA rivets developed higher tensile strength than the conventional rivets.

Report presenting an exact solution and a closely concurring approximate energy solution for the buckling of an infinitely long flat plate under combined shear and transverse direct stress with edges elastically restrained against rotation. An appreciable fraction of the critical stress in pure shear may be applied to the plate without any reduction in the transverse compressive stress necessary to produce buckling.

Report presenting a theoretical investigation of the buckling of an infinitely long flat plate with edges elastically restrained against rotation under combinations of longitudinal and transverse direct stress. Interaction curves are presented that give the critical combinations of stress for several different degrees of elastic edge restraint, including simple support and complete fixity.

Report presenting data obtained when a float with both horizontal and vertical velocity contact on a water surface. The report is confined to a presentation of the relationship between resultant velocity and impact normal acceleration for various float weights when all other parameters are constant.

Report discusses the results of testing "to determine the relationship between impact normal acceleration and flight-path angle for seaplanes landing on smooth water" (from Summary). The testing was done with a model at high and low forward speeds at 3 degrees trim, a dead-angle rise of 22.5 degrees, and consistent weight.

Report discusses the results of testing "to determine the relationship between impact normal acceleration and flight-path angle for seaplanes landing on smooth water" (from Summary). The tests were performed at 12 degrees trim, 22.5 degree angle of dead rise, and a total weight of 1100 pounds. The effect on the maximum impact normal acceleration and the effects of immersion on acceleration are described.

Report discusses the results of testing "to determine the relationship between impact normal acceleration and flight-path angle for seaplanes landing in smooth water" (from Summary). The tests were done at high and low forward speeds and trims at 6 degrees and 9 degrees, a 22.5 degree angle of dead rise, and a gross weight of 1100 pounds. Information about the forces acting on the aircraft and maximum depth of immersion and trim is provided.

Report presenting determinations of boundary-layer transition on the NACA 0012 and 23012 airfoils in the high-speed wind tunnel over a range of Reynolds numbers. For all of the lift coefficients that testing occurred at, transition occurred in the region of estimated laminar separation at low Reynolds numbers and approached the point of minimum static pressure as a forward limit at high Reynolds numbers.

Report presenting testing in the high-speed wind tunnel to determine the drag characteristics of several types of radial-engine nacelle on a low-drag airfoil. The drag coefficients of nacelles incorporating cowling-nose shapes shown by previous tests to be efficient and afterbodies of adequate length were about the same magnitude as commonly obtained for comparable installations on conventional wings. Results regarding the reduction of data, effect of nacelles on lift, and pressures at wing-nacelle juncture are provided.

Report presenting force tests of the NACA 23012 and 23012-64 airfoils of 24-inch chord in the high-speed wind tunnel at a range of Mach numbers. The results show the variation with mach number of lift, drag, and pitching-moment coefficients at a range of angles of attack.

Report presenting testing in the 8-foot high-speed wind tunnel to determine the effect on external drag and pressure distribution of air inlet openings on the stagnation point of a streamline body. The results showed that external drag of the body with suitably designed nose-inlet and tail-outlet openings over a wide range of rates of internal air flow was no higher than the drag of the streamline body. Specific results for the streamline body, nose-inlet openings, outlet openings, and inlet-outlet combinations are provided.

Report presenting an analysis of the effects of heat and compressibility in the flow through the internal systems of aircraft. Equations and charts are developed whereby the flow characteristics at key stations in a typical internal system may be readily obtained.

Test of a ducted body with Internal flow were made in the 8-foot high-speed wind tunnel for the purpose of studying the effects on external drag and an critical speed of the addition of efficient inlet and outlet openings to a basic streamline shape. Drag tests of a 13.6- inch-diameter streamline body of fineness ratio 6.14 were made at Mach numbers ranging from 0.20 to 0.75. The model was centrally mounted on a 9-percent-thick airfoil and was designed to have an efficient airfoil-body juncture and a high critical speed.

Report presenting simple curves by which the basic pressure-drop characteristics of unheated tubular radiators can be corrected to operating conditions in which the radiator is heated and in which the Mach number of the tube flow is of appreciable magnitude. The only data required for the use of the curves are the radiator dimensions, the rate of heat input, the pressure and temperature ahead of the radiator, and the rate of mass flow of air through the radiator.

Report presenting tests conducted in the 8-foot high-speed wind tunnel of a scale model pursuit-type fuselage with practicable internal duct arrangement designed to meet all of the air requirements of a 1000-horsepower radial engine submerged at the maximum section. The results showed that the required internal flow can be obtained with negligible ducting losses provided that basic principles are observed in designing the air passages.

"This report describes tests in the Langley 16-foot high-speed tunnel to determine whether these failures could be attributed to changes in the aerodynamic characteristics of the ailerons at high speeds" (p. 1).

"Tests of a 1/3-scale model of an NACA E-type cowling were made in the 8-foot high-speed tunnel for the purpose of determining the effect of the gap between the skirt of the hollow spinner and the cowling proper on the pressures available for cooling. It was found that even a large gap (0.096 in. on the model) had no appreciable effect on the available cooling pressures" (p. 1).