From Introduction: "The purpose of this report is to gather together in one place information on the skipping characteristics of number of flying boats. A graph showing the influence of the hull form on the skipping characteristics is given which should be useful in laying out the proportions of the hull in preliminary design to insure good landing behavior."

Report of a study to develop a method of obtaining gas temperatures from the frequency of knock-induced gas vibrations in an internal-combustion engine cylinder. Temperatures calculated from frequency data were in agreement with temperatures measured by the spectral line-reversal method in previous investigations and were about 700 degrees Fahrenheit lower than temperatures obtained from thermodynamic charts.

Report presenting the effects of negative dihedral on lateral stability and control characteristics at high lift coefficients determined by flight tests with a model. As the effective dihedral was decreased, the model became increasingly difficult to fly. Results regarding the effect of directional stability and lift coefficient on flight behavior are also provided.

Report discussing a series of single-cylinder engine tests to determine the effect of special surface coatings in porous chrome-plated cylinder barrels on oil consumption and ring wear. The coating materials were selected for their bearing and lubrication properties and on their applicability to processing. The surface coatings tested were lead overplates, silver overplates, and colloidal graphite base paint.

Report presenting a series of single-cylinder engine tests run to determine a satisfactory method of reducing oil consumption in radial air-cooled engines with flat-face compression rings as standard parts and equipped with cylinder barrels salvaged by porous chrome plating. Testing was conducted using porous chrome-plated cylinders with straight and choke bores with standard flat-face compression rings.

Report discusses an investigation into the spray characteristics of a twin-engine flying boat model similar to the Boeing XPBB-1 but with a modified length-beam ratio of the hull. The spray characteristics of the modified model compared favorably with the standard XPBB-1 flying boat and no adverse effects on spray characteristics were introduced by modifying the length-beam ratio and hull.

"Equations have been derived for the change in the quantities that define the thermodynamic state of air - pressure, density, and temperature - at an abrupt increase in cross-sectional area of flow of compressible air. Results calculated from these equations are given in a table and are plotted as curves showing the variation of the calculated qualities with the area expansion ratio in terms of the initial Mach number as parameter. Only the subsonic region of flow is considered" (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 presenting an analysis of the effect of wing loading of the landing flare, which indicated that it had an important effect on landing technique and distance. Results regarding the approach and flare path and ground run are provided.

Report presenting tests to determine the critical shear stress of curved sheets. The empirical formula derived from the tests is applicable to panels with a ratio of radius to thickness of 300 or greater, a central angle of 1 radian or less, and a ratio of arc length to axial length not greater than 1.

Report presenting knock-limited small-scale-engine tests of isopropyl-benzene, benzene, and o-xylene blended individually in various concentrations with selected base fuels. Data were obtained to determine the blending sensitivity, lead susceptibility, and sensitivity of the blends to inlet-air temperatures. Isopropylbenzene was found to be the most effective overall.

"A method is developed for calculating the tunnel-wall corrections to rolling and yawing moments due to aileron deflection on models in closed rectangular wing tunnels. Graphs are presented which permit a rapid determination of these corrections for models mounted in 7- by 10-foot or 8- by 12-foot wind tunnels. The method is so developed that the corrections may be calculated for the deflection of either aileron alone or both ailerons simultaneously" (p. 1).

"The two-dimensional incompressible potential flow over corrugations and bumps of arbitrary shape is derived by conformal transformation. The results are compared with those obtained by the methods of thin-airfoil theory. Some discussion is included of the flow over bumps that protrude both inward and outward from a wall" (p. 1).

"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).

From Introduction: "A typical ice formation on a wing leading-edge-type light installation is shown in figure 1. Although the primary purpose of this analytic investigation was to determine the practicability of providing a landing-light thermal ice-prevention system which could be incorporated with the wing leading-edge thermal ice-prevention system of the B-17 F airplane, the analysis has been developed in a general form for future application to similar deigns. "

Report presenting comparisons between the approximate substitute single-stringer method of shear-lag analysis and the exact solutions, which indicate that for beams of practical proportions the approximate method yields a value for the maximum root stress that exceeds the value obtained by use of the exact solution by less than 10 percent.

Report presenting the potential function for flow, with circulation, of a compressible fluid about a circular cylinder, which is obtained in series form including terms of the order of M(exp 4) where M is the Mach number of the free stream. The equations are used to obtain pressure coefficient as a function of Mach number at a point on the surface of the cylinder for different values of circulation.

Report presenting an analysis which shows that, when account is taken of sideslip and wing flexibility, the calculated rolling maneuverability of an airplane is in good agreement with the results obtained from flight tests. The method used avoids the complications of successive approximations but is nevertheless believed to be more nearly accurate than other methods based on semirigid-wing assumptions. The method is applied to a wing of tubular shell construction and the procedure is illustrated for a modern pursuit airplane.

Report presenting an investigation of the existence of energy dissipations in gas dynamics, which must be attributed to a lag in the vibrational heat capacity of the gas, and most specifically the flow about a very small impact tube. A new method of measuring the relaxation time of gases is introduced in which the total-head defects observed with a specially shaped impact tube are compared with theoretical considerations.

Report presenting a determination of the mean effective emissivity as a function of temperature for the surfaces of several metals and insulating materials. A description and discussion of the measuring technique is presented. The results are plotted on a variety of graphs.

Report presenting an investigation of a large variety of different metals used as an intermediate metal between aluminum and steel for the purpose of securing a good bond both from the viewpoint of strength and thermal conductivity. The principal result was that it was found possible to secure a satisfactory bond between aluminum and steel by electroplating the steel with a layer of silver of proper thickness.

Report presenting a theoretical investigation of the two-dimensional, incompressible potential flow past a symmetrical lattice of airfoils of arbitrary shape. Expressions are given for evaluation of the velocity and pressure distribution at the airfoil boundary.

"Strain measurements were made on the compression side of two box beams with corrugated aluminum-alloy covers loaded to failure. Angles formed from sheet were used for corner flanges in beam 1; whereas extruded angles were used in beam 2. Failure in each beam occurred in the corner angle at a stress that was above the compressive yield stress for the material" (p. 1).

"Flights were made in natural icing conditions at the NACA Ice Research Project, Minneapolis, Minn. to test several designs of thermal-electric propeller de-icing blade shoes and a hub-generator design. It was found that a minimum average unit power of 2.5 watts per square inch of blade-shoe area would protect the propeller blades at the test conditions. The most satisfactory blade shoe of the three designs tested extended to the 20-percent-chord point and to 90 percent of the blade radius" (p. 1).