Study of the bending stress in smooth skin, aluminum alloy, true monocoque fuselage sections of varying ratio of diameter to thickness.

Note presenting a description of a large number of corrugated diaphragms of beryllium copper, phosphor bronze, and Z-nickel with geometrically similar outlines but various diameters and thicknesses were formed by hydraulic pressing. The apparatus and technique used in the manufacture, testing, and heat treatment are described. Results regarding pressure-deflection curves, load limit, effect of center reinforcing, snap-action diaphragms, deflection traverse, thickness variations, and concentrated central loads are provided.

The following paper is based on the results of tests, upon duralumin columns, contained in two theses presented to the Department of Civil and Sanitary Engineering of the Massachusetts Institute of Technology.

From Summary: "Solutions of mainstream flow patterns for three-dimensional, laminar, incompressible thin-boundary-layer flows (over flat or slightly curved surfaces) having similarity with respect to stationary polar coordinates in the plane of the surface are derived. The solutions are summarized in a table."

Note presenting laminar burning velocity measured at pressures of 1 atmosphere and below and critical boundary velocity gradient for flashback at pressures below 1 atmosphere over a range of compositions for hydrogen-air burner flames. Pressure exponents of 0.23 for burning velocity and 1.35 for flashback velocity gradient was found. Results regarding blowoff and general stability loop, burning velocity, relations among various combustion properties, and reaction order from pressure exponents are provided.

Note presenting an investigation to determine the effects of wing position on the low-speed static longitudinal and static lateral stability of airplane models with fuselages of square and rectangular cross sections and unswept and 45 degree sweptback surfaces. The results of the investigation indicated that at low angles of attack, the complete unswept models with the wing in the high position were more stable or least longitudinally unstable. The results also showed that wing-fuselage interference causes an increase in effective dihedral angle when the wing is moved to the high position.

Report discussing a flight investigation of rocket-powered models of a tailless triangular-wing airplane configuration was made through the transonic and low supersonic speed range at the Langley Pilotless Aircraft Research Station at Wallops Island, Va. An analysis of the aerodynamic coefficients, stability derivatives, and flying qualities based on the results obtained from the successful flight tests of three models is presented.

Report presenting an investigation in the high-speed 7- by 10-foot tunnel to determine the effectiveness of a given deflector arrangement as a gust alleviator on a model of the Bell X-5 airplane with various wing sweep angles, Mach numbers, and angles of attack. Results regarding lift, drag, and pitching moment are provided.

From Summary: "Elevated-temperature compressive-strength test results form room temperature to 600 degrees Fahrenheit and creep test results from 350 degrees Fahrenheit to 500 degrees Fahrenheit are presented for V-groove edge-supported plates of 7075-T6 aluminum alloy. The test data are compared with calculations obtained from procedures for estimating maximum strength from material stress-strain curves and creep-failure stresses from isochronous stress-strain curves. The strength and creep results from this investigation are also compared with similar results from 2024-T3 aluminum-alloy plates."

A criterion is developed for the stiffness required of elastic lateral supports at the ends of a compression member to provide stability. A method based on this criterion is then developed for checking the stability of a continuous beam-column. A related method is also developed for checking the stability of a member of a pin-jointed truss against rotation in the plane of the truss.

From Introduction: "The data for operations both with and without radar installed have been analyzed and the results are presented in this paper. Although these results are of limited extent, they provide a basis for early examination of any trends in the gust loads and associated operating practices which might be attributed to the use of radar."

A thermal quenching equation and the Semenov burning velocity equation were combined to give expressions for the product and quotient of burning velocity and quenching distance. Experimental results for hydrocarbon-oxygen-inert gas, hydrocarbon-nitrous oxide, hydrogen-air, hydrogen-bromine, and the ethylene oxide decomposition flames were fairly well correlated by the product equation.

Note presenting measurements of turbulent flame speeds and space-heating rates, which were made in a 1/2- by 2-inch glass-walled burner in which area blockage was introduced. Results regarding the effects of fuel-air ratio and velocity variation, effect of restriction shapes, effect of flameholder size without downstream restriction, heat-release rates, flame blowout and interruption by restrictions, flow tracer study, and shadow and direct photographs of the flame are provided.

Report presenting testing of missiles in which temperatures are approximated and aerodynamic heating of the model is representative of that experienced by the missile in high-velocity flight. The paper describes a piston compressor type of light-gas gun, which shows good agreement between predictions of performance charts and experimental data.

Note presenting a study of the effect on the boundary layer of blowing air through a porous flat plate into a main airstream flowing parallel to the plate. Measurements were made of velocity profiles and wall friction coefficients. The observed friction coefficients are predicted by mixture-length theory if the Reynolds number at the outer edge of the laminar sublayer is permitted to vary with the dimensionless ratio.

A monocoque box beam consisting of a 24S-T aluminum-alloy sheet reinforced by four bulkheads and by longitudinal stringers and corner posts was subjected to bending loads as follows: pure bending about the lift axis, cantilever bending about the lift axis, and pure bending about both lift and drag axis. Longitudinal strains were measured for loads up to a load at which permanent set became measurable. The loads were sufficient to produce buckling of the sheet between stringers on the compression side of the box. The only noticeable effect of this buckling was a small increase in extreme-fiber strain on the compression side. The measured strains and measured deflections differed less than 10 percent from those computed from the simple beam theory after taking account of the effective width of the buckled sheet. The effect of the bulkheads on the distribution of stringer strain was negligible.

Report discussing an experimental investigation was carried out on air- and vacuum-melted M-252 and S-816 alloys to find conditions of heating and hot-working which resulted in abnormal grain growth. The experiments were mainly limited to normal conditions of heating for hot-working and heat treatment and normal temperatures of solution treatment were used to allow grain growth after susceptibility to abnormal grain growth was developed by various experimental conditions. Results indicated that small reductions of essentially strain-free metal were the basic cause of such grain growth.

Note presenting existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is inclined to the flow.

Report presenting ground testing to determine pilots' force capabilities on a proposed side-loaded aircraft controller on one side of the cockpit and situated so the pilot's arm is supported. Data were obtained from 11 pilots, including five research pilots and six research engineers. Results regarding the force levels and operating range of the controller, deviations in data, effect of arm position, and need for additional testing are provided.

Report presenting radiosonde measurements of upper-air temperatures taken over a 5-year period at nine stations in the northern hemisphere are summarized in order to provide information on the temperatures likely to be encountered during airplane and missile operations up to 100,000 feet.

Report presenting an analysis of the heat-absorption characteristics of several materials for the use of ballistic missile heat sinks. The four materials considered were copper, Inconel-X, graphite, and beryllium.

"Data from full-scale experimental airplane crashes were studied to determine how impact injuries occur and how the chance of such injuries may be reduced. The following hazards were considered: (1) being crushed, (2) being struck by missiles, (3) striking objects by tearing loose or flailing about, and (4) being injured by the crash decelerations. Transport, cargo, fighter, and light airplane crashes were studied" (p. 1).

From Introduction: "The object of the present paper is to present an approximate method for calculating accurately the thermal stresses in a thin plate with both chordwise and spanwise variations in temperature and chordwise but restricted spanwise variations in thickness."

The theoretical lift of a cylindrical afterbody at zero angle of attack due to incidence of the wing is calculated by means of slender-body theory. It is assumed that the vortex sheet becomes fully rolled up ahead of the tail, and the vortex paths in the presence of the body are determined analytically. The total lift of a variety of slender wing-body-tail combinations due to wing incidence is also calculated.