From Introduction: "Certain alternations of a qualitative nature may be performed in spite of the fact that a pressure change cannot be prescribed. It is the purpose of this paper to indicate a method by which qualitative alternation may be performed. It will be noted that the present method of contour modification will serve the intended purpose of the inverse method."

"Increments in structural loads due to atmospheric turbulence can be accurately expressed in terms of flight speed and effective gust velocities (reference 4). Data from which the effective gust velocities could be computed were also obtained during the flights of the XC-35 airplane. These data have been used to determine the significance of the fluctuations in the pilot's indicated-airspeed readings in relation to structural loads to due to atmospheric turbulence" (p. 3).

From Introduction: "This paper contains data on the mechanical properties of sand-cast test bars having a considerable range in zinc, magnesium, and copper content and more detailed data on the properties and foundry characteristics of an aluminum-zinc-magnesium-copper alloy having a preferred composition for high strength and ductility."

From Summary: "The independent variables considered in the analysis included stress-concentration factor, stress-load relation, wing loading, design and cruising speeds, design gust velocity, and airplane size. Several methods for estimating fatigue life from gust frequencies are discussed."

Report presenting an analytical study of the influence of full-span slotted and Fowler flaps on the requirements for horizontal tail surfaces. The elevator deflection required to land at three-point attitude, elevator deflection required to stall the airplane at altitude, and permissible center-of-gravity range have been calculated for a fighter-type airplane.

Report presenting column and plate compressive strengths of extruded 24S-T aluminum alloy determined both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-, and channel-section columns. The tests are part of a research investigation to provide data on the structural strength of various aircraft materials. Results regarding compressive stress-strain curves and column and plate compressive strengths are provided.

Column and plate compressive strengths of extruded 24S-T aluminum alloy were determined both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-,and channel-section columns. These tests are part of an extensive research investigation to provide data on the' structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.

Report presenting column and plate compressive strengths of extruded 75S-T aluminum alloy both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-, and channel-section columns. The tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. Results regarding compressive stress-strain curves and column and plate compressive strengths are provided.

Report presenting a comparison of two flight-test procedures for the determination of the aileron control capabilities of an airplane. The procedures consist of performing rudder-fixed aileron rolls from straight unbanked flight and from steady turning flight. Results regarding rate of roll comparison and sideslip-angle comparison are provided.

Report presenting testing to obtain experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. Testing occurred over a wide range of air flows and density altitudes.

Report presenting a survey of aircraft heat exchangers in three parts: design, selection, and installation. Appendices give the physical properties of air, properties of standard atmosphere as defined by the Navy, Army, and NACA, and an impact-pressure chart.

Report presenting a technique of testing wind tunnel powered models developed as a result of experience gained in the investigation of the static longitudinal and lateral staiblity and control characteristics of several powered models in the 7- by 10-foot wind tunnel. A discussion of the conditions to be investigated, methods of presenting and interpreting the data, and a suggested operating technique are given.

Report presenting an analysis of the effect of cooling-air blowers on thrust power using an assumed airplane. Results indicated that when aviation-engine heat exchangers are used above their design altitude, blowers may be used to give additional available pressure and to increase jet thrust. Results regarding airplane speed, altitude, fin width, physical significance of the heat cycle, and thermodynamic efficiency are provided.

Report presenting a method of constructing fins of nearly optimum proportions to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences. Results regarding cooling equations, cylinder-temperature relationships, and a comparison of three cylinder cooling performances are provided.

To determine the effect of piston-head temperature on knock-limited power, tests were made in a supercharged CFR engine over a range of fuel-air ratios from 0.055 to 0.120, using S-3 reference fuel, AN-F-28, Amendment-2, aviation gasoline, and AN-F-28 plus 2 percent xylidines by weight. Tests were run at a compression ratio of 7.0 with inlet-air temperatures of 150 F and 250 F and at a compression ratio of 8.0 with an inlet-air temperature of 250 F. All other engine conditions were held constant.

Report presenting determination of air-flow quantity in front of and behind three orifice plates to determine the errors introduced in the quantity measurements by the turbulence behind the orifice plates. For the orifice plates tested, the results showed that the measurements must be taken 40 to 60 hole diameters downstream from the plates to ensure accuracy.

"Tests were made of a model representative of a single-engine tractor-type airplane for the purpose of determining the stability and control effects of a propeller used as an aerodynamic brake. The tests were made with single-and dual-rotation propellers to show the effect of type of propeller rotation, and with positive thrust to provide basic data with which to compare the effects of negative thrust. Four configurations of the model were used to give the effects of tilting the propeller thrust axis down 5 deg., raising the horizontal tail, and combining both tilt and raised tail" (p. 1).

An investigation to determine the feasibility of measuring surface contours with an aerial-mapping contour finder on stereoscopic electronic micrographs of replicas of metal surfaces. Results regarding the measurement of stereoscopic electron micrographs, measurement of surface contours, possible sources of low stereographic values, and limitations on stereoscopic-contour measurements are provided.

Report presenting tests conducted with an air-cooled aircraft-engine cylinder to determine the effect on the knocking tendency of cutting out one spark plug when the engine is operating at or near the knock point with two spark plugs firing. The results indicate that cutting out one spark plug will not lead to knock but will actually stop or decrease knock that is occurring with both spark plugs firing.

Report presenting tests of the flow of air through brass tubes with the friction coefficient and incompressible flow relation as the main focus. The analytical relation between friction coefficient, tube length, and Mach number is shown for flow without shock and the conditions for flow with and without shock are delimited.

Report presenting the results of recent spin-tunnel tests on models of seven multiengine airplanes and compared with corresponding results for representative single-engine airplanes loaded along the fuselage. Multiengine airplanes were found to give steep spins with high rates of descent and high load factors.

Report presenting a method for obtaining exact potential-flow patterns in a compressible fluid. The method is based on a complex-function theory developed for the solutions of the simultaneous first-order partial differential equations in the hodograph variables.

Report presenting a direct comparison between the observed and the calculated longitudinal dynamic stability of a particular dynamic model of a flying boat moving on the water. Good agreement was obtained between experiment and theory for trim angles in the vicinity of lower limit, at one speed a little above the hump.

"The results are given of an investigation of some of the limitations that now prevent increases in the temperature level of engine cylinder heads, and a review of previous work in the field is included to supplement these results. Attention was given, in particular, to the effects of fuel knock and surface ignition on cylinder temperatures and the effects of cylinder temperatures on performance. Data were obtained from a Wright C9GC air-cooled cylinder and from a Lycoming O-1230 liquid-cooled cylinder" (p. 1).