"An investigation has been conducted in the NACA Cleveland altitude wind tunnel to evaluate the performance and windmilling drag characteristics of an original and a modified turbojet engine of the same type. Data have been obtained at simulated altitudes from 5000 to 45,000 feet, simulated flight Mach numbers from 0.09 to 1.08, and engine speeds from 4000 to 12,500 rpm. Engine performance data are presented for both engines to show the effects of altitude at a flight Mach number of 0.25 and of flight Mach number at an altitude of 25,000 feet" (p. 1).

Note presenting an approximate linearized solution for the wave drag and lift of an airfoil generated by rotating a thin supersonic profile about an axis parallel, or nearly parallel, to its chord. The aerodynamic coefficients are obtained from a surface distribution of sources, of strengths proportional to the local airfoil slopes, about a cylinder whose radius and chord equal those of the original ring airfoil.

Note presenting a method for determining the load distribution due to steady roll and pitch for thin flat-plate wings whose plan form is arbitrary except that a part of the leading edge must be supersonic. When the supersonic part of the leading edge is a straight line, these load distributions can be explicitly evaluated for all regions of the wing except those influenced by interacting flow fields off the plan form.

Report presenting bearing tests made of aluminum-alloy sand casings of 195-T4, 195-T6, and 356-T6 to evaluate the bearing strength and tensile properties of the alloys. Comparisons with individually cast bars and specimens machined from slabs indicate that size and form of casing may have a significant effect on mechanical properties. Results of the tensile, compressive, and shear tests are provided in charts and include specified minimum and typical properties for comparison.

From Summary: "Tests were made to determine bearing yield and ultimate strengths of bare and Alclad 15S-W(exp 1) and 14S-T(exp 1) sheet and plate in thicknesses of 0.064 inch, 0.250 inch, and 0.750 inch. From the results of these tests it was concluded that the ratios of bearing to tensile properties from the with-grain direction were essentially the same as proposed in NACA TN Nos. 901, 920, 974, and 981 for other high-strength aluminum-alloy sheet and plate."

This document details activities at the Hanford Works during the month of July 1948. (JL)

Shock-wave equations have been evaluated for a range of Mach number in front of the shock from 1.05 to 4.0. Mach number behind the shock, pressure ratio, derivation of flow, and angle of shock are presented on charts. Values are also included for density ratio and change in entropy.

A simulated altitude performance of a 25 1/2-inch-diameter annular-type turbojet combustor was performed to determine the effect of the distribution of basket-hole area on the altitude operational limits of the engine as imposed by the combustor.Total pressure drop was recorded, as well as the effect of fuel-nozzle flow capacity,and fuel-nozzle spray angle for one basket configuration. General observations were made for all configurations regarding flames, extent of afterburning, and durability of the baskets.

Note presenting a summary of some results of recent research that will aid the designers of an airplane in selecting or modifying a configuration to provide satisfactory stability and control characteristics. A discussion is given of the reasons for the requirements, of the factors involved in obtaining satisfactory flying qualities, and of the methods used in predicting the stability and control characteristics of the airplane.

"An analysis of the performance of the types A, B, and C combustion chambers of the 4000-pound-thrust axial-flow turbojet engine is presented. The data were obtained from investigations of the complete engine over a range of pressure altitudes from 5000 to 40,000 feet and ram pressure ratios from 1.00 to 1.86. The combustion-chamber pressure losses, the effect of the losses on cycle efficiency, and the combustion efficiency are discussed" (p. 1).

This memorandum is an outline of hydrologic investigations that seem desirable at the Hanford Directed Operations of the Atomic Energy Commission. In its present form, the outline is tentative and is intended as a basis for further considerations in the Commission, the Geological Survey, and other agencies concerned. In scope, it seeks to cover (1) advisory functions to the Atomic Energy Commission and its prime contractor with respect to an evaluation of the continuing hazards due to process wastes, also with respect to water-supply problems of the expanding operations at Hanford; also (2) civilian-protection aspects of possible emergencies, especially in the region adjacent to the Hanford reservation.

The method used for the preparation of uranium metal in a fused state was reduction of uranium chloride with calcium in a refractory-lined bomb. The reaction was started by externally heating the bomb with a gas flame. The metal was obtained in a solid chunk which was covered with a layer of fused calcium chloride. The metal obtained by this process had a density of 17.6 which on remelting in a vacuum induction furnace rose to 18.8. The melting temperature of the metal was estimated to be no greater than 1400 C. The metal was malleable, and had a silvery surface when freshly cut which rapidly tarnished, becoming black in the course of a few days.

None

Validity of the colorimetric determination of nickel in solutions containing 1.5 N nitric acid and 0.3 c. postum (Polonium 210) per ml. was confirmed.

Memorandum presenting low-speed wind-tunnel test conducted of a triangular wing of aspect ratio 2.0 with a symmetrical double-wedge section with a maximum thickness of 5 percent of the chord at 20 percent of the chord. The wing was also tested in the presence of a ground plane. Results regarding isolated wing and wing-body combinations, split-flap effectiveness, and ground effect are provided.

Memorandum presenting low-speed wind-tunnel tests made of flat-plate wings with an aspect ratio of 2.0 and their leading edges swept back 63.4 degrees. Both plain and split flaps of several plan forms were investigated to provide qualitative information as to the relative merits of these flaps. The constant-chord flap was found to be the most effective and a skewed wing-tip flap the least effective.

"Low-speed wind-tunnel tests were made of a triangular wing with two arrangements of twin vertical fins. With these twin fins mounted either symmetrically or wholly above the wing chord plane, approximately constant effectiveness in proportion to the fin size was obtained throughout the angle-of-attack range. The addition of these fins, however, resulted in a decrease in maximum lift and a reduction in static longitudinal stability at lift coefficients above 0.4" (p. 1).

None

A preliminary investigation of an axial-flow gas turbine-propeller engine was conducted. Performance data were obtained for engine speeds from 8000 to 13,000 rpm and altitudes from 5000 to 35,000 feet and compressor inlet ram pressure ratios from 1.00 to 1.17.

Report presenting testing of several delta wing-aileron configurations as part of a general investigation of their rolling effectiveness characteristics at transonic and supersonic speeds. Results regarding wing-aileron rolling effectiveness and drag are provided.

"The effect of rotor-blade length, inlet angle, and shrouding was investigated with four different nozzles in a single-stage modification of the Mark 25 aerial-torpedo power plant. The results obtained with the five special rotor configurations are compared with those of the standard first-stage rotor with each nozzle. Each nozzle-rotor combination was operated at nominal pressure ratios of 8, 15 (design), and 20 over a range of speeds from 6000 rpm to the design speed of 18,000 rpm" (p. 1).

Report presenting flight measurements at low speeds to determine the static longitudinal stability, stalling, and lift characteristics of an airplane with a wing sweptback 35 degrees at the quarter-chord line. The airplane was tested without slots on the wing and with slots extending from 40 to 80 percent of the semispan of the sweptback-wing panels measured from the inboard end. Results regarding the static longitudinal stability, stalling characteristics, and lift characteristics are provided.

Note presenting experiments to study the characteristics of low-aspect-ratio wings at supercritical Mach numbers. The experiments consisted of tests of wings of aspect ratios ranging from infinity to 2. The results indicate that the detrimental effects of compressibility in the supercritical speed range on the stability and performance of aircraft are alleviated to a great degree by the use of low-aspect-ratio lifting surfaces.

Report presenting a method to calculate the surface temperatures of bodies in steady flight at any speed in a rarefied gas. Results regarding the incident translational energy, skin temperatures in the absence of solar radiation, internal cooling, the effect of solar radiation on skin temperature, the effect of emissivity on skin temperature, and the effect of accommodation coefficient on skin temperature are provided.