Report presenting a low-speed wind tunnel investigation of an exploratory nature in order to determine a satisfactory location for a spoiler lateral-control device for a sweptback wing. The semispan wing used for the tests had 42 degrees sweepback referred to the wing leading edge and an aspect ratio of 4.01. The best location appeared to be near the trailing edge of the wing, slightly inboard from the wing tip, and skewed with reference to the wing so as to be perpendicular to the free-stream air flow.

Note presenting pressure measurements on a triangular wing with an aspect ratio of 2 and an NACA 0012 airfoil section parallel to the center line. The wing angle of attack was varied from 4.3 to 48.1 degrees with the airspeed held constant at approximately 100 miles per hour. Results regarding chordwise pressure distribution, section lift characteristics, span load distribution, centers of pressure, and comparison of pressure data with force-test data are provided.

"The theory of supersonic flow in nozzles is discussed, emphasis being placed on the physical rather than the mathematical point of view. Methods, both graphic and analytic, for designed nozzles are described together with a discussion of design factors. In addition, the analysis of given nozzle shapes to determine velocity distribution and possible existence of shock waves is considered" (p. 1).

Report presenting an investigation of the interference effects between an airfoil of high critical speed with no sweepback and a nacelle of high critical speed mounted in various positions with respect to the wing. The main objective was to obtain a wing-nacelle combination which has the force break occurring at a Mach number as high as for the wing alone. Results regarding the wings alone, pressure contours on wing and nacelle, influence of wing on nacelle, influence of nacelle on wing, and leading-edge modifications are provided.

Report presenting results to show the effects on the flutter characteristics of mounting concentrated weights at various positions on an untapered wing model. The moment of inertia, chordwise position of the weight, and spanwise position of the weight were varied. Results regarding the flutter parameters, flutter-speed ratio, flutter-velocity coefficients, and curves of ratio of first-bending frequency to torsion frequency and second-bending frequency to torsion frequency and provided.

Note presenting a study to gain information as to the fundamental mechanism of fretting corrosion. The specific questions to be answered were whether chemical action played an important role in fretting of metal surfaces and whether any such action would improve the corrosion resistance of the metal investigated. The results indicated that the chemical action is of primary importance in fretting-corrosion effects and oxide formation does not give any protection to the metals but rather increases the rate of wear.

Report presenting an investigation to determine the effect of leading-edge flaps on the maximum lift coefficient of an NACA 64-009 airfoil and to compare the results with data obtained from previous testing of a similar flap. Two types of flaps, one intended to slide forward on the upper surface and one hinged at the center of the airfoil leading-edge radius, were tested. Results regarding lift characteristics, pitching-moment characteristics, and effect of leading-edge roughness are provided.

Report presenting a theoretical investigation of the effects of steady rolling on the longitudinal and directional stability of aircraft. Simplifying assumptions have been made with regard to the longitudinal and lateral motions of the airplane in order to obtain a solution which shows the principal effects of rolling motion.

The properties of five discs of Timken alloy at room temperature and 1200 degrees Fahrenheit. Testing occurred short-time tensile, stress-rupture, creep, and hardness along with a metallographic examination of the materials before and after testing. The Timken alloy discs appear to have similar properties to other types of discs.

Note presenting an experimental investigation conducted to determine the penetration of a circular air jet directly perpendicularly to an air stream as a function of jet density, jet velocity, air-stream density, air-stream velocity, jet diameter, and distance downstream from the jet. The penetration was determined for nearly constant values of air-stream density at two tunnel velocities, four jet diameters, four positions downstream of the jet, and for a large range of jet velocities and densities.

Report presenting the knock-limited performance of four paraffins blended in several base fuels and tested in three different types of engines. Report presenting a method of comparing the fuels, a classification of engine conditions, a comparison of the fuels at various levels of engine severity, compression temperature-density curves, inlet-air-temperature sensitivity, and lead susceptibility are provided.

Report presenting an investigation to determine the effect of exhaust pressure on the knock-limited performance of an air-cooled aircraft-engine cylinder. Results are presented in the form of curves showing the relation between the ratio of exhaust pressure to inlet-manifold pressure, the inlet-manifold pressure, and the inlet mixture temperature at incipient knock.

Note presenting a list of commonly used and standardized symbols for combustion research in order to facilitate the exchange of technical information and to provide a basis for comparison of results obtained by various investigators.

From Introduction: "In the present paper, the variation of effective gust velocity in convective-type clouds with altitude is investigated. Data obtained during 1941 and 1942 at altitudes up to 34,000 feet and data obtained more recently from the Thunderstorm Project (reference 5) at altitudes up to 26,000 feet are utilized for this purpose. Consideration is given in analyzing the results both to data for the range

"A simplified compound-pendulum method for the experimental determination of the moments of inertia of airplanes about the x and y axes is described. The method is developed as a modification of the standard pendulum method reported previously in NACA report, NACA-467. A brief review of the older method is included to form a basis for discussion of the simplified method" (p. 1).

Report presenting an investigation at a range of Reynolds numbers in the two-dimensional low-turbulence tunnels to determine the effectiveness of boundary-layer control by suction and of suction-slot location in increasing the maximum lift and decreasing the drag of a NACA 65(sub 5)-424 airfoil equipped with a double slotted flap. Results regarding the determination of slot configurations, lift, and drag and lift-drag ratio are provided.

Report presenting an investigation to determine the efficiency at low tip speeds of two 10-foot-diameter six-blade dual-rotating propellers differing only in pitch distribution. Propeller forces were determined from wind tunnel testing and by using an analytical method using two-dimensional airfoil section data. Results regarding propeller characteristics, analysis of energy losses, and design considerations are provided.

"Results are presented of strength tests of curved and plane shear webs and plane beam webs of 24S-T aluminum alloy stiffened transversely (in the direction of curvature) by uprights that are not connected to the flanges. A method of predicting ultimate strengths based on a modified theory of incomplete diagonal tension in plane webs is given" (p. 1).

Report presenting an extension of a finite-difference method to include the computation of disk stresses when plastic flow and creep are considered. The results of numerical examples indicate qualitatively that plastic flow markedly alters the elastic-stress distribution and that, if the amount of creep is small, the effect on stress distribution is also small.

Report presenting an investigation using a cylinder of a V-type liquid-cooled engine to observe the behavior of the cylinder when operated under preignition conditions. The effects of fuel-air ratio, power output, aromatic content of fuel, engine speed, mixture temperature, and preignition source are provided.

"The average low-speed jet-boundary constriction correction is presented for a large model spanning a closed circular tunnel. The experimentally determined variation of the local constriction correction with spanwise and chordwise location is also shown. A brief comparison with existing theory is given for the constriction correction and the induced-curvature correction resulting from lifting section" (p. 1).

Report presenting a full-scale-tunnel investigation to study the effects of time rate of change of angle of attack, idling propeller operation, and Reynolds number on the maximum lift coefficient of a single-engine fighter-type airplane. Flight test measurements of maximum lift coefficient were also made and compared to wind-tunnel data.

Report presenting an experimental investigation of a 62 degree valve overlap, 18-cylinder, air-cooled, radial engine modified with 40 degree-valve-overlap cams to determine the effect of a change in valve overlap on engine performance. Computations were made to show the effect of change in valve overlap on compound-engine performance.

Report presenting a method consistent with the assumptions of small perturbation theory, which provides a means of determining the downwash behind a wing in supersonic flow for a known load distribution. The analysis is based on the use of supersonic doublets, which are distributed over the plan form and wake of the wing in a manner determined from wing loading.