This report describes and develops methods by which the aerodynamic characteristics of an airfoil may be calculated with sufficient accuracy for use in airplane design. These methods for prediction are based on the present aerodynamic theory and on empirical formulas derived from data obtained in the N. A. C. A. variable density wind tunnel at a Reynolds number corresponding approximately to full scale. (author).

A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for construction of the chart are given.

From Introduction: "The difficulties experienced in cooling the exhaust-valve seats of the rear-row cylinders have been overcome to a considerable extent by improving the mixture distribution through application of the injection impeller (reference 1) and by augmenting the flow of cooling air to the critical baffles (reference 2). Flight tests of this airplane (reference 3) indicated that the temperatures of exhaust-valve seats on rear-row cylinders were markedly lowered by these modifications and that airplane range, altitude, and gross weight previously limited by these temperatures could be greatly increased."

Abstract: "A method of recovering the tuballoy from the trap washes of the high temperature salvage chlorinator is described."

"Tests were made with a 1/16 size dynamically similar model of the Navy XP2V-1 airplane to study its performance when ditched. The model was ditched in calm water at the Langley tank no. 2 monorail. Various landing attitudes, speeds, and conditions of damage were simulated" (p. 1).

The results obtained from measurements of gust velocities, draft velocities, and ambient-air temperature within thunderstorms for the period September 17, 1946 to September 18, 1946 at Orlando, Fla. are presented herein. These data are summarized in tables I, II, and III, respectively, and are of the type presented in reference 1 for previous flights.

Report presenting an investigation of the low-speed longitudinal stability and control characteristics of a scale model of a Bell X-5 airplane design with various leading-edge slat and trailing-edge flap arrangements. A marked increase in stability with increasing sweep angle at low lift coefficients was noted. Results regarding the basic longitudinal characteristics, leading-edge slats, trailing-edge flaps, and longitudinal control are provided.

"At the request of the Air Materiel Command an investigation was made in the Langley free-flight tunnel to determine the static longitudinal stability and control characteristics of models coupled together in a tandem configuration proposed by All American Airways, Inc. Force tests were made using 1/20-scale models of B-29 end F-80 airplanes to determine the effects of coupling the fighter to the tail of the bomber. The results of the investigation showed that for the bomber alone the aerodynamic center was 0.21 mean aerodynamic chord behind the center of gravity (stable) but that for the tandem configuration the aerodynamic center was 0.09 mean aerodynamic chord forward of the center of gravity, of the combination (unstable)" (p. 1).

Report presenting a description and results of an investigation of a model of the XH-17 two-blade, jet-powered helicopter. Tests were made with a standard configuration and with several modifications, including varying the size of blade counterweights, changing the control stiffness and chordwise bending stiffness of the blades, and varying the pylon and undercarriage damping and spring constants. Results regarding flutter testing, ground-vibration tests, and three-per-revolution rotor-blade unsymmetric bending oscillations are provided.

Report presenting time histories of the aerodynamic loads on the vertical and horizontal tail surfaces of a jet-powered bomber airplane (B-45A) in sideslip maneuvers. Information about maximum measured rudder and fin loads, maximum total vertical-tail load, horizontal-tail-load dissymmetry, maximum elevator loads, and elevator-load dissymmetry is provided.

Report presenting flight tests at Mach numbers from 0.8 to 1.4 on three rocket-propelled general research models of airplane configurations. Two models had thin unswept tapered wings of aspect ratio 3 and hexagonal airfoil sections, two wings had different structural stiffness characteristics, and the third model had no wing. Results regarding the static and dynamic longitudinal stability, control, trim, and drag characteristics are provided.

The outstanding oxidation resistance of molybdenum disilicide at 2400 F and above was found to depend on the formation of a protective siliceous coating which a-cristobalie has been identified. Molybdenum disilicide is not inherently resistant to oxidation and in powdered form burns at low temperatures.Melting and casting experiments have demonstrated the decomposition of the material at the melting point. The room-temperature modulus of elasticity has been determined and electric-resistivity data are given to 2000 F.

Report presents the results of studies made in an attempt to provide information on the control operations of the human pilot. These studies included an investigation of the ability of pilots to control simulated unstable yawing oscillations, a study of the basic characteristics of human-pilot control response, and a study to determine whether and to what extent pilot control response can be represented in an analytical form.

Equations for the quantity of thorium daughters on an air sampler after various times of collection and decay are derived and evaluated. The most limiting assumption is the constant concentration over the sampling period. Applications of these equations to measurement of decay curves, alpha energy analysis and the simultaneous solution involving measurements at the three decay times are discussed.

A method is presented for calculating the loading on a finite wing oscillating in subsonic or sonic flow. The method is applicable to any plan form and may be used for determining the loading on deformed wings. The procedure is approximate and requires numerical integration over the wing surface.

A centerless-ground, 0.25-in.-diam. by 0.75-in.-long sapphire single crystal exposed to an integrated thermal neutron flux of 2 x 10 19 nvt at a temperature of 350 deg C (660 deg F) did not change its dimensions appreciably simple beam, with slightly less force than was required to break a similar unirradiated rod. In a darkened room the irradiated sapphire begins to thermoluminesce noticeably at 280 deg C (535 deg F) and most of the amber or brown coloration produced by the pile exposure is retained after annealing for 24 hr at the pile exposure temperature of 350 deg C (660 deg F). (auth)

The design of the Purex Off-Gas Treatment Facility requires the use of new dissolver off-gas jets which will be installed in series with present jets in the Purex in-canyon "donut" jumpers. When the new jets are placed in operation, the motive air and steam supply services to the in-canyon jets will no longer be required and the in-canyon jets will become flow restrictions in the dissolver off-gas train. Calculated values of pressure drop across these "dead" jets at maximum off-gas rate varied from about 18 to 7 inches of water depending on whether the dead jets were considered as sharp-edged orefices or venturi meters without downstream pressure recovery. In the preparation of process specifications for hets for the new facility, accurate values for the pressure drcp introduced by the dead jets were required to avoid oversizing the new jets with resultant waster of motive jet fluid.

The following report describes a thermonuclear reactor based on the use of a long layer of rotating relativistic electrons to confine and heat the plasma.

The essential physical and mechanical properties of materials which enter into the design considerations of high-temperature systems have been outlined, and the relationship of these factors to the detailed design of structural members noted. Particular attention is given to the phenomenon of strain-cycling and relaxation, and several engineering devices wherein these effects can markedly influence design are mentioned. Techniques and apparatus for the measurement of strain-cycling and relaxation properties are described and some recent data for Inconel at 1500 F is reported. A brief discussion is presented on design-criterial for high-temperature applications, and it is pointed out that in some high performance devices the considerations of the strain-cycling phenomenon may impose the design philosophy of "steady-state" operation. Some elementary applications of strain cycling data to design are described, and test experience indicates that analytical techniques can be developed for predicting with reasonable reliability of the fatigue life of structures.

Abstract: Mine mapping of the tyuyamunite-type deposits In the Salt Wash member of the Jurassic Morrison formation of the Lukachukai Mountains, Apache County, Arizona revealed recognizable spatial relationships between ore mineralization and: fractured areas, sedimentary features, and interstitial carbonate.

From abstract: "This report describes a functional mercury vapor detector which is a portable, self-contained, survey instrument, and had a minimum range from zero to two-tenths milligram of mercury per cubic meter of air."

Report regarding experiments made to determine the fallout-radiation protection offered by a "single-story stucco and frame house with a heavy shake roof and no basement," (p. 5) which is noted as being popular in the southwestern United States.