Report discussing an investigation into the stalling characteristics, aileron effectiveness, and longitudinal stability of a scale model of the XB-36 airplane. The model was tested with the original configuration as well as with several modifications to the outboard panels and flap arrangement.

Report discussing testing of 2-percent additions of seven aromatic amines on the knock-limited performance of 28-R fuel in a CFR engine. The most effective antiknock additives are described.

"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 discussing the knock-limited performance of blends of 2,3-dimethylpentane and 23-R fuel in an F-4 engine at three sets of conditions and three compression ratios. The knock-limited performance of 2,3-dimethylpentane has about the same sensitivity to compression ratio and inlet-air temperature as 28-R fuel.

Report presenting a investigation covering the physical and chemical properties of various ethers as components of aviation fuels. Their antiknock effectiveness and methods of preparation and purification are included. Methyl tert-butyl ether gave the best knock-limited rich mixture response, but isopropyl tert-butyl ether and di-tert-butyl ether gave better results at lean mixtures.

Report presenting direct-reading tables and charts for determining the drag or thrust coefficients from wake-survey measurements in the subsonic speed range. Additionally, numerical examples are provided using information from the tables.

From Summary: "An analysis of the nose-inlet shapes developed in previous investigations to represent the optimum from the standpoint of critical speed has shown that marked similarity exists between the nondimensional profiles of inlets which have widely different proportions and critical speeds. With the nondimensional similarity of such profiles established, the large differences in the critical speeds of these nose inlets must be a function of their proportions. An investigation was undertaken in the Langley 8-foot high-speed tunnel to establish the effects of nose-inlet proportions on critical Mach number and to develop a rational method for the design of high-critical-speed nose inlets to meet desired requirements."

Report discussing the effects of supercharging on the take-off thrust and useful load for a typical helicopter. Performance of the engine with the supercharger and on the rotor thrust is detailed.

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.

"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 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 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 presenting a flight investigation made to determine the effectiveness of dive-recovery flaps installed on the XP-51 airplane as a safety device for recovery from contemplated terminal-velocity dives. The flap installation is described and results are presented of measurements obtained during stick-free pull-ups and pull-outs made by deflecting the dive-recovery flaps to two selected values of flap angle .

Report presenting an investigation to determine the knock-limited performance of AN-F-28, Amendment-2, fuel in a DCFR engine when water solutions of the following aliphatic amines were added as internal coolants: monomethylamine, dimethylamine, ethylendiamine, diethylamine, triethylamine, and butylamine. Results regarding the mean effective pressure, indicated specific fuel competition, indicated specific liquid consumption, and knock-limited inlet-air pressure plotted against fuel-air ratio are presented for each fuel and amine combination.

Report presenting testing to determine the influence of propeller rotation and vertical-tail design on the trim characteristics of a model of a twin-engine airplane with one engine inoperative. The tests showed that the effect of mode of propeller rotation on the directional trim characteristics of the model operating with asymmetric power was considerable. Results regarding the effect of mode of propeller rotation and effect of vertical-tail design are provided.

Report presenting an investigation to determine the nature and extent of the reversal of flow, which occurs at the inlet of centrifugal superchargers over a considerable portion of the operating range. Results regarding lampback patterns, tuft studies, backflow surveys, and effect of impeller tip speed on backflow are provided.

Report presenting a bibliography and review of information related to the hydrodynamics of seaplanes. Characteristics of conventional hulls and floats are discussed to show the effects upon performance of changes in design parameters like dead rise, depth of step, and angle of afterbody keel. Other topics include floats, lateral stabilizers, aerodynamic and propulsive considerations, unconventional configurations, hydrofoils, and piloting and handling.

"Tank tests were made of a flying-boat model having various types of fairing with and without ventilation ducts behind the main step to investigate the hydrodynamic characteristics of the model. All the types were designed to reduce significantly the air drag chargeable to the main step. The configuration that combined the best stability with a good aerodynamic form consisted of a shallow step and an adjoining ventilation aperture having an area about 7 percent of the square of the beam" (p. 1).

"As part of an investigation of the cooling characteristics of liquid-cooled engines, tests were conducted with an electrically heated single-tube heat exchanger to determine the heat-transfer characteristics of AN-E-2 ethylene glycol and other ethylene glycol-water mixtures. Similar tests were conducted with water and commercial butanol (n-butyl alcohol) for check purposes. The results of tests conducted at an approximately constant liquid-flow rate of 0.67 pound per second (Reynolds number, 14,500 to 112,500) indicate that at an average liquid temperature 200 degrees f, the heat-transfer coefficients obtained using water, nominal (by volume) 30 percent-70 percent and 70 percent-30 percent glycol-water mixtures are approximately 3.8, 2.8, and 1.4 times higher, respectively, than the heat-transfer coefficients obtained using an-e-2 ethylene glycol.

Report presenting testing of models of three flying-boat hulls with a length-beam ratio of 10.5. Testing occurred at two depths of step and two angles of dead rise. Results regarding resistance, trimming-moment, and wetted-length data for general fixed-trim and free-to-trim tests at load coefficients up to 4.0 are provided.

Report presenting tests to study the effectiveness of small pressure differences in removing the dust boundary layer through slots in the duct wall of airplane ducts and reducing separation losses. Two-dimensional diffusers of 15 and 30 degrees included angles and some 90 degree bends were tested. The 30 degree diffuser was tested with and without an intercooler.

Report presenting a generalized drag curve providing an estimate for the drag rise due to compressibility as obtained from an analysis of wind-tunnel data of several airfoils, fuselages, nacelles, and windshields at speeds up to and above the wing critical speed. Results regarding drag characteristics and terminal-velocity calculation are provided.

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 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.