Report presenting testing of the effects of the following variables on combustion performance are determined: inlet-air temperature, combustion-chamber-inlet Mach number and pressure, and fuel density and volatility.

"Flight icing-rate data obtained in a dense and abnormally deep supercooled stratiform cloud system indicated the existence of liquid-water contents generally exceeding values in amount and extent previously reported over the midwestern sections of the United States. Additional information obtained during descent through a part of the cloud system indicated liquid-water contents that significantly exceeded theoretical values, especially near the middle of the cloud layer. The growth of cloud droplets to sizes that resulted in sedimentation from the upper portions of the cloud is considered to be a possible cause of the high water contents near the center of the cloud layer" (p. 1).

"In the analytical investigation reported herein, which was conducted in the NACA Lewis laboratory, both velocity and temperature distribution are obtained for fully developed laminar flow in tubes of gases and of liquid metals with variable fluid properties" (p. 1).

From Introduction: "The auxiliary apparatus described in this paper was constructed to meet this need and has been developed to a point where satisfactory measurements of relative drag can be obtained. In this paper, the apparatus is described and some comparisons are made between the results obtained with this apparatus and the measurements of free-fall, rocket, and supersonic-tunnel techniques."

Report presenting an analysis of two x-ray absorption methods for determining small air-density gradients. One method uses a Geiger-Mueller counter for detection and the other uses photographic film for detection. Both of the methods are found to have some advantages and disadvantages.

Note presenting an approximate blade-element design method for compressible or incompressible nonviscous flow in high-solidity stators or rotors of axial-, radial-, or mixed-flow compressors, turbines, or two-dimensional cascades. The method is based upon channel-type flow between blade elements on a specified surface of revolution that lies between the hub and shroud and is concentric with the axis of the compressor turbine.

Note presenting the development of the axial-momentum theory for compressible flow as a step in the formulation of a rational propeller theory for compressible flow. The simple theory neglects some properties but predicts flow conditions through a propeller that are significantly different from the conditions predicted by the incompressible-flow theory.

Note presenting testing of an autopilot sensitive to yawing acceleration, which was used to control four simulated airplane (mass-spring) configurations, and a series of bench tests to determine the response characteristics of the combinations.

Report presenting a wind-tunnel investigation of two semispan wing models with 45 degrees of sweepback, an aspect ratio of 5, and a taper ratio of 0.565. One wing had no camber or twist while the other was cambered for a design lift coefficient of 0.4 and twisted to relieve loading at the tip. Results regarding the plane wing, cambered and twisted wing, wing-body combinations, effect of camber and twist, effect of fences, effect of surface roughness, and lift-drag ratio are provided.

"Charts giving the compressive-buckling stress coefficients for sheet panels of a shape occurring in swept-wing plan forms are presented. The panels are assumed to be a part of a continuous flat sheet divided by nondeflecting supports into parallelogram-shaped areas. The stability analysis was performed by the energy method and the results show that, over a wide range of panel aspect ratio, such panels are decidedly more stable than equivalent rectangular panels of the same area" (p. 1).

From Summary: "This paper supplements a previously published one on the effect of design parameters on ditching characteristics. The supplementary information is based on additional data available from both model tests and full-scale experience. In addition, summary tables compiled from the NACA model ditching investigations are presented."

"A method is presented for the computation and graphic representation of a series of possible turbine designs for any specific application. The use of a preliminary design chart is suggested for determining the number of stages and the effects of exit whirl and annular-area divergence on possible configurations. A specific design chart can then be made to aid in the study of the relations between turbine radius ratio, diameter, and significant design parameters such as Mach numbers, turning angles, and blade root stresses" (p. 1).

Report presenting an investigation using the NACA wing-flow method at transonic speeds to determine the contributions of wing, tail, and fuselage to the aerodynamic characteristics of a semispan airplane model with a long slender fuselage and straight wing and tail of low aspect ratio with faired symmetrical double-wedge airfoil sections 4.6 percent of the chord in thickness. Results regarding the drag, pitching moment, downwash, and lift are provided.

"A general method of design is developed for two-dimensional unbranched channels with prescribed velocities as a function of arc length along the channel walls. The method is developed for both compressible and incompressible, irrotational, nonviscous flow and applies to the design of elbows, diffusers, nozzles, and so forth. In part I solutions are obtained by relaxation methods; in part II solutions are obtained by a Green's function. Five numerical examples are given in part I including three elbow designs with the same prescribed velocity as a function of arc length along the channel walls but with incompressible, linearized compressible, and compressible flow" (p. 153).

Note presenting static and fatigue tests made on 355-T6 sand-cast plate-type aluminum-alloy specimens incorporating holes, bosses, and ribs. In the static tests, the tensile strength of the plain plate-type specimen agreed within 3 percent with the strength of separately cast test bars. Of the design details studied, the unreinforced hole was the most effective stress-raiser for fatigue lives from 10,000 to 25,000,000 cycles.

Report presenting an investigation of two large-scale, semispan, wing-fuselage models with the 0.25-chord line swept back 45 degrees to determine and compare the effects of partial-span, double-slotted flaps on the characteristics of a 45 degree sweptback wing with and without camber and twist. A secondary investigation was also conducted to determine the effects of various full-span, leading-edge modifications on the characteristics of the models with and without the flaps.

Effects of humidity during fabric conditioning and during fabrication upon some physical properties of laminates prepared with glass fabric and an unsaturated polyester resin were investigated. Tests on these laminates included the measurement of flexural strength on the diagonal, both dry and after 7 days' immersion in water, specific gravity, resin content, percentage of voids, and total light transmission. Some data were also taken on lengthwise flexural strength.

Report presenting an aerodynamic investigation in the high-speed 7- by 10-foot tunnel to determine the effects of taper-in-thickness on the aerodynamic characteristics of wings with 35 and 45 degrees of sweepback, aspect ratio 6, and taper ratio 0.60. The wings were tested over a range of Mach numbers.

The effects of water injection on a compressor are presented. To determine the effects of varying water-air ratio, the compressor was operated at a constant equivalent impeller speed over a range of water-air ratios and weight flows. Operation over a range of weight flows at one water-air ratio and two inlet air temperatures was carried out to obtain an indication of the effects of varying inlet air temperature. Beyond a water-air ratio of 0.03 there was no increase in maximum air-weight flow, a negligible rise in peak total-pressure ratio, and a decrease in peak adiabatic efficiency. An increase in inlet air temperature resulted in an increase in the magnitude of evaporation. An analysis of data indicated that the magnitude of evaporation within the compressor impeller was small.

Report presenting an investigation of the validity of the reduced-mass method of representing wing-lift effects in free-fall drop tests of landing gears by means of tests of a small landing gear in the impact basin. The free-fall drop tests with full weight produced excessive values of load factor, impact period, strut stroke, mass travel, and impact energy.

"An experimental determination of the critical bending moment of a box beam stiffened by posts is described and discussed. The experimental buckling load is in good agreement with that given by theory. Since appreciable distortion of the beam cross section occurred before the buckling load was reached, modification of post construction by the use of several ribs may be necessary for maintenance of the rectangular shape of the cross section" (p. 1).

Report presenting an investigation at subsonic speeds of a scoop-type air-induction system designed for use at subsonic and supersonic speeds. Measurements of the ram-recovery ratio and static pressures in a scoop-type intake on the upper surface of the fuselage were taken for a large range of mass-flow ratios, angles of attack, and angles of sideslip.

Report presenting testing of several turbojet engines with both constant- and variable-area nozzles to extend full-scale nozzle performance to higher exhaust-nozzle pressure ratios and to investigate the effects of constant- and variable-area nozzles on turbojet-engine operation. Results regarding the different types of nozzles are provided.

Report presenting an investigation to determine the ability of a vane mounted ahead of the nose of an airplane to give an indication of the average angle of attack over the entire wing span during flight through rough air. The main purpose was to determine the suitability of such a vane as a sensing device for an acceleration alleviator. The vane gives a sufficiently accurate measure of average angle of attack over the wing span to be used that way, but rapid fluctuations in angle of attack caused by turbulence would have to be filtered from the output.