Note presenting an investigation of the effects on porous-material permeability characteristics of the absolute pressure level, choking of the flow, bending the material, and other factors. Experiments showed permeability characteristics to be appreciably affected by absolute pressure level, flow choking, and thickness of the material. Results regarding testing with wire cloth and sintered metal are provided.

Note presenting measurements made of the resistance to air flow of a series of perforated metal sheets with open areas ranging from less than 1 percent up to 41 percent. The results showed that the permeability of a perforated sheet is governed principally by its open-area ratio. The number of holes per square inch, the sheet thickness, and the shape of the individual holes had little or no effect on permeability.

From Summary: "The convective heat transfer from the surface of an ellipsoidal forebody of fineness ratio 3 and 20-inch maximum diameter was investigated in clear air for both stationary and rotating operation over a range of conditions including air speeds up to 240 knots, rotational speeds up to 1200 rpm, and angles of attack of 0 deg, 3 deg, and 6 deg. The results are presented in the form of heat-transfer coefficients and the correlation of Nusselt and Reynolds numbers. Both a uniform surface temperature and a uniform input heater density distribution were used."

"An airborne cloud aeroscope by which droplet size, size distribution, and liquid-water content of clouds can be determined has been developed and tested in flight and in wind tunnels with water sprays. In this aeroscope the cloud droplets are continuously captured in a stream of oil, which Is then photographed by a photomicrographic camera. The droplet size and size distribution can be determined directly from the photographs" (p. 1).

From Summary: "Tests of two wing-body combinations have been conducted in the Langley 19-foot pressure tunnel at a Reynolds number of 4 x 10(exp 6) and a Mach number of 0.19 to determine the effects of the bodies on the wing span load distributions. The wings had 45 degrees sweepback of the quarter-chord line, aspect ratio 8.02, taper ratio 0.45, and incorporated 12-percent-thick airfoil sections streamwise. One wing was untwisted and uncambered whereas the second wing incorporated both twist and camber. Identical bodies of revolution, of 10:1 fineness ratio, having diameter-to-span ratios of 0.10, were mounted in mid-high-wing arrangements."

"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).

"The rate and area of cloud droplet impingement on several two-dimensional swept and unswept airfoils were obtained experimentally in the NACA Lewis icing tunnel with a dye-tracer technique. Airfoil thickness ratios of 6 to 16 percent; angles of attack from 0 deg to 12 deg, and chord sizes from 13 to 96 inches were included in the study. The data were obtained at 152 knots and are extended to other conditions by dimensionless impingement parameters" (p. 1).

Trajectories were determined for water droplets or other aerosol particles in air flowing through 600 elbows especially designed for two-dimensional potential motion. The elbows were established by selecting as walls of each elbow two streamlines of a flow field produced by a complex potential function that establishes a two-dimensional flow around. a 600 bend. An unlimited number of elbows with slightly different shapes can be established by selecting different pairs of streamlines as walls. Some of these have a pocket on the outside wall. The elbows produced by the complex potential function are suitable for use in aircraft air-inlet ducts and have the following characteristics: (1) The resultant velocity at any point inside the elbow is always greater than zero but never exceeds the velocity at the entrance. (2) The air flow field at the entrance and exit is almost uniform and rectilinear. (3) The elbows are symmetrical with respect to the bisector of the angle of bend. These elbows should have lower pressure losses than bends of constant cross-sectional area.

Note presenting tables of thermal properties of molecular nitrogen that have been prepared in an NBS-NACA series and grouped together for convenient use. Some of the properties include the thermodynamic functions for the gas, both real and ideal, the transport properties for the gas, and the vapor pressure of the liquid and the solid.

Note presenting tables based on the Lennard-Jones 6-12 potential for nonpolar molecules to be used in the representation of second and third virial coefficients and equation-of-state corrections for enthalpy, entropy, specific heats at constant volume and at constant pressure, the ratio of specific heats, the isentropic expansion coefficient, and the velocity of sound.

Note presenting tables of thermal properties of stream that have been prepared in an NBS-NACA series. They include, for real gas, the compressibility factor, the density, the specific heat at constant pressure, the enthalpy, the entropy, the free-energy function, the viscosity, and the thermal conductivity.

Note presenting general equations for the linear responses of inner- and outer-spool speed to change in turbine-inlet temperature and exhaust-nozzle area are derived and evaluated from hypothetical two-spool-engine characteristics at design speed. Experimental corroboration of analysis is also provided in the form of response to fuel flow, response to exhaust-nozzle area, and response to turbine-inlet temperature are provided.

"A method is presented for obtaining the attenuation of a shock wave in a shock tube due to the unsteady boundary layer along the shock-tube walls. It is assumed that the boundary layer is thin relative to the tube diameter and induces one-dimensional longitudinal pressure waves whose strength is proportional to the vertical velocity at the edge of the boundary layer. The contributions of the various regions in a shock tube to shock attenuation are indicated" (p. 1).

Note presenting an investigation of the effect of phosphate coatings on the temperature of metal specimens placed in a flame. Small cylindrical specimens of mild steel and S-816 alloy were placed in a natural-gas-air flame at specific temperatures. Special attention is given to the fact that temperature drop was noted in certain specimens and the potential reasons for this reaction are explored.

Note presenting measurements of space heating rate, which can yield information that is useful in characterizing turbulent combustion. For Bunsen burner flames stabilized over a field of pipe-induced turbulence, the space heating rate decreased with increasing linear flow and burner diameter and was independent of pilot conditions. Results regarding residual heat values, space conversion rate, turbulent burning velocities, and a comparison of concepts are provided.

Report presenting an investigation to determine the effect of type and location of impact damage on the fatigue strength of jet-engine compressor blades. The most serious damage was found in the nicks at the leading and trailing edges in the vicinity of the maximum-vibratory-stress section of the airfoil. Results regarding stress distribution in the blades, fatigue of the damaged blades, the fatigue test results, the correlation of reduction in strength, an analysis of the results, and testing using reworked blades are provided.

Report presenting a combination of two previously published reports with an extension of the data to cover properties of fuels up to temperatures as high as 400 degrees Fahrenheit.

Report presenting an investigation of a method for producing hypersonic flow in a wind tunnel by using the hot gaseous products obtained from the thermal decomposition of nitrous oxide. Testing was conducted at a variety of temperatures and pressures.

Report presenting a determination of the nonwhirling propulsive characteristics of a helicopter-type pulse-jet engine mounted on a simulated helicopter rotor blade in the 16-foot transonic tunnel. Propulsive characteristics as a function of fuel-flow rate at a variety of Mach numbers and angles of yaw. Results regarding engine propulsive characteristics, comparison of whirling and nonwhirling data, and effect of engine operation on airfoil surface pressures are provided.

Report presenting an extension to another report, which used hot-wire-anemometer measurements of the intensity, scale, and spectra of turbulence in a 3.5-inch-diameter free subsonic jet for downstream distances from 8 to 20 jet diameters.

Report presenting measurements made of the flow around a 10-percent-thick, double symmetrical, two-dimensional wedge at Mach number 1.30 and a 14.2-percent-thick wedge at two Mach numbers for various angles of attack. Pressure and Mach number distributions, lift and drag coefficients, center of lift, and pitching moment are presented.

Report presenting measurements of unsteady-flow turbulent boundary-layer characteristics for artificially thickened boundary layers using a new optical technique involving the bow-wave shape of bullets fired in a shock tube. Measurements using several different methods are compared in the study. Results regarding boundary-layer measurements, velocity-profile measurements, attenuation measurements, pipe-flow effect, and qualification of results are provided.

Report discussing the use of radioisotope tracer techniques to study the following phenomena: the effect of nickel dip on the deposition of cobalt metal during firing of a cobalt-bearing ground coat, the effect of surface pretreatment on the amount and distribution of nickel deposited from nickel dip on enameling iron, and the effect of application and firing of cobalt-free and cobalt-bearing enamels on the chemical form and physical distribution of nickel previously deposited on enameling iron by the nickel dip.

From Introduction: "The purpose of the present paper is to present summary of the information gleaned from various transonic-bump investigations of wing and wing-fuselage configurations at two representative tail heights and to compare these results with theoretical estimations made in subsonic and supersonic Mach number range."