From Summary: "The effects of ice formations on the section lift, drag, and pitching-moment coefficients of an unswept NACA 65A004 airfoil section of 6-foot chord were studied.. The magnitude of the aerodynamic penalties was primarily a function of the shape and size of the ice formation near the leading edge of the airfoil. The exact size and shape of the ice formations were determined photographically and found to be complex functions of the operating and icing conditions."

Note presenting an experimental study of the wet-surface temperature and stream conditions that result in ice-free surfaces for bodies in flight through icing clouds, and the results obtained are compared with values calculated using an analytical method. Two symmetrical airfoil models, one of diamond shape and the other of double-circular-arc contour, were used in the investigation. Results regarding the chordwise variation of pressure distribution, chordwise variation of recovery factor, the diamond airfoil, and circular-arc airfoil are provided.

From Summary: "A flight investigation has been made of the practical problems associated with the use of porous-leading-edge suction. The wing leading edge of the test airplane was porous over approximately 83 percent of the span and the first 8 percent of the chord on the upper surface. Various other extents of suction area within these limits were also tested."

"An empirical relation has been obtained by which the change in drag coefficient caused by ice formations on an unswept NACA 65A004 airfoil section can be determined from the following icing and operating conditions: icing time, airspeed, air total temperature, liquid-water content, cloud droplet impingement efficiencies, airfoil chord length, and angles of attack. The correlation was obtained by use of measured ice heights and ice angles. These measurements were obtained from a variety of ice formations, which were carefully photographed, cross-sectioned, and weighed" (p. 1).

From Summary: "An experimental investigation was conducted to determine the penetration of air jets directed perpendicularly to an air stream. Jets issuing from circular, square, and elliptical orifices were investigated and the jet penetration at a position downstream of the orifice was determined- as a function of jet density, jet velocity, air-stream density, air-stream velocity, effective jet diameter, and orifice flow coeffIcient. The jet penetrations were determined for nearly constant values of air-stream density at three tunnel-air velocities arid for a large range of jet velocities and densities."

"Trajectories of water droplets moving in the ideal two-dimensional flow field ahead of a body of rectangular cross section and infinite extent in the downstream direction have been calculated by means of a differential analyzer. Data on collection efficiency and distribution of water impingement are presented" (p. 1).

Report presenting tables for determining the total-absorption coefficients as well was the intensities and spectral distribution of gamma rays at any scattering angle. Both experimental and computed data on gamma rays of quantum energies up to 20 million electron volts for all elements which have significant data available are provided. The accuracy of results is obtained by the use of tables.

Report presenting an investigation to determine the feasibility of bearing lubrication by a process involving the transfer of molybdenum disulfide from within the structure of a composite bearing material to the interface between the contacting surfaces. The experiments were performed with a kinetic-friction apparatus employing a rotating steel disk and a bearing-specimen assembly suspended and restrained by metal springs.

"The slip theory of plasticity is applied to the problem of calculating the strains associated with biaxial tension for the case of constant stress ratios and is found to be in better agreement with experiment than the octahedral-shear and maximum-shear theories usually employed to analyze such data" (p. 1).

Note presenting surface-tension measurements from room temperature to 180 degrees Celsius of a series of aeronautical lubricating oils and a few liquids of associated interest. The critical temperatures of the liquids are calculated and a general classification of existing oils into three groups is provided.

Note presenting comparative data on the volume of foam and stability of foams of aeronautical lubricating oils produced at 100 degrees Celsius by the air-bubbling method. All of the data were obtained with the same foam meter, by a standard technique, and at various rates of air flow. Results regarding the reproducibility of foam tests and treatment of data are provided.

Note presenting an investigation of nine hydrocarbons mixed in pairs, sealed in glass tubes, and foamed by shaking in order to examine the foaming properties of the hydrocarbons. Results for benzene, toluene, xylene, cumene, butyl benzene, isopentane, octene, octane, and decane are provided.

Note presenting measurements of the rates of rise of small air bubbles, up to 2 millimeters in diameter, at room temperature in an undoped oil, in the same oil containing foam inhibitors, and in an oil containing lubricating additives. The apparent diameter of the air bubbles was measured visually through an ocular micrometer on a traveling telescope. A method is derived to calculate the thickness of the liquid shell which would have to move with the bubbles in the doped oils to account for the abnormally slow velocity.

Report presenting an approximate method for determining the pressure distribution due to unsteady motion for thin wings of fairly general plan form. The method is valid for arbitrary motions when the second derivative of the perturbation velocities with respect to time is not large.

Report presenting the equations of motion of a conventional airplane penetrating a gust in order to determine the effects due to stability on the gust load factor. A numerical method is derived in matrix notation which affords a systematic procedure of solving the equations for a unit jump or arbitrary forcing function. Sample calculations were performed to illustrate the application of the equations.

"An investigation to determine the structural damping characteristics of a full-scale airplane wing was conducted by the shock-excitation method wherein the wing was loaded to a predetermined deflection and the load suddenly released. The test specimen vibrated at its fundamental bending frequency of 1.69 cycles per second. Only the first 2 or 3 cycles showed any indication of a higher frequency being superimposed upon the fundamental bending frequency. The damping was found to increase from about 0.002 to critical at an amplitude of vibration of plus and minus 0.05 inch to approximately 0.006 of critical at an amplitude of + or - 5 inches" (p. 1).

Note presenting comparisons of the low-speed experimental lift and hinge-moment parameters of flapped lifting surfaces with and without sweepback with values computed by several theoretical procedures. Based on these limited results, one theoretical method appears to be more satisfactory than the other methods investigated and is therefore recommended fore preliminary design estimates. Sample calculations are included.

"The sandwich plate consisting of corrugated sheet fastened between two face sheets is considered. Application of existing theories to the analysis of such a sandwich plate requires the knowledge of certain elastic constants. Formulas and charts are presented for the evaluation of these constants" (p. 1).

Note presenting the lift-due-to-pitching derivative and the damping-in-pitch derivative, which were derived for a series of thin sweptback tapered wings with streamwise tips and subsonic leading edges. The effects of camber and thickness were not considered.

Note presenting static and fatigue tests made on several types of joints in 75S-T6, 24S-T4, and 14S-T6 high-strength aluminum-alloy extruded bar. In the static tensile tests, the 75S-T6 double-shear joint withstood the highest ultimate load, 115,250 pounds, and the 75S-T6 clamped-keyed joint the lowest, 55,000 pounds, a ratio of 2.08 to 1.

Report presenting an investigation in Langley tank no. 1 to determine the effects of increasing the angle of dead rise on various hydrodynamic qualities of a flying-boat hull with a length-beam ratio of 15. Results regarding the longitudinal stability, spray characteristics, take-off performance, rough-water landing characteristics, and a summary chart are provided.

Note presenting an investigation using microscopic observation of the action to determine the cause of fretting corrosion. Glass and other noncorrosive materials, as well as metals, were used as specimens. Results regarding metal against metal, metal against nonmetal, and nonmetals against nonmetals are provided.

Report presenting an investigation to determine the influence of aspect ratio, boundary-layer control by means of slots and porous surfaces, Reynolds number, and tunnel end-wall condition on the performance of airfoils in cascade. A representative compressor-blade section of three aspect ratios has been tested at low speeds in cascades with solid and porous side walls.

From Summary: "A small-deflection theory that takes into account deformations due to transverse shear is presented for the elastic-behavior analysis of orthotropic plates of constant cylindrical curvature, with considerations of buckling included. The theory is applicable primarily to sandwich construction."