Report presenting an investigation of the effects of simulated surface conditions, which involved exposure to various combinations of moisture, heat, and ultraviolet light, on the weight, dimensional stability, and flexural properties of reinforced plastics.

"The purpose of this report is to provide designers of airplanes with information that will be helpful in obtaining good ditching characteristics in new designs. The results from a number of model tests and report of actual ditchings are used as a basis for which to draw conclusions as to the effect on ditching performance of general arrangement, interior arrangement, fuselage shape, and other design parameters. The characteristics of several types of ditching aids that could be incorporated in a design are also discussed" (p. 1).

Report presenting an investigation to determine the influence of strength and ductility on the room-temperature burst characteristics of solid disks, disks with large-diameter central holes, and disks with small-diameter central holes. Results regarding the stress concentrations causing fracture, ratio of disk strength to tensile strength, effect of small holes, and evaluation of most ductile materials are provided.

Note presenting an analysis of the available data on the longitudinal stability characteristics of sweptback wings at low speeds. The analysis indicated that the shape of the pitching-moment curve near the stall for sweptback wings is greatly dependent on the aspect ratio. The addition of a horizontal tail behind the wings may be destabilizing and requires further investigation.

Report presenting a low-speed wind-tunnel investigation to determine the effect of taper ratio on the static and yawing stability derivatives of three tapered wings with a constant sweepback of 45 degrees at the quarter-chord line and with an aspect ratio of 2.61 but different taper ratios. Results regarding the characteristics in straight flow and yawing flow are provided.

Report presenting flutter of propellers at high angles of attack and flutter data obtained in connection with tests of models of large wind-tunnel propellers. The stall flutter speed was found to be much lower than the calculated classical flutter speed. That flutter speed is only obtainable if the propeller operates at the ideal angle of zero twist.

Report presenting determination of air-flow quantity in front of and behind three orifice plates to determine the errors introduced in the quantity measurements by the turbulence behind the orifice plates. For the orifice plates tested, the results showed that the measurements must be taken 40 to 60 hole diameters downstream from the plates to ensure accuracy.

Report presenting testing of arc-welded butt joints in a 1/8-inch SAE 4130 steel sheet of aircraft quality under various conditions of welding and heat treatment in order to evaluate the effects of specific welding-technique factors on the strength of the joints. Results regarding static tension tests and fatigue tests are provided.

"An investigation was made in the NACA 19-foot pressure wind tunnel to determine the effect of various win-gun installation on the aerodynamic characteristics of a model with an NACA low-drag wing. Measurements were made of lift and drag over an angle-of-attack range and for several values of dynamic pressure on a four-tenths scale model of a high-speed airplane equipped with the low-drag wing and with various wing-gun installations. Two installations were tested: one in which the blast tube and part of the gun barrel protrude ahead of the wing and another in which the guns is mounted wholly within the wing" (p. 1).

Report presenting testing to determine the effect of xylidines of the corrosiveness of aircraft-engine oil toward engine bearings as part of an investigation on the suitability of xylidines as an antiknock component in aviation gasoline. Results regarding the loss in bearing weight, corrosion losses, temperature characteristics, and types of corrosion are provided.

Note presenting an approximate method for determining the convective cooling requirement in the laminar boundary layer region of a body of revolution in high-speed flight that was developed and applied to a sample body. The convective cooling requirements were found to be small for the range of Mach numbers considered, but increased rapidly with increasing Mach number.

Report presenting testing of six, 3-inch-chord symmetrical airfoil sections with systemic variations in thickness and maximum-thickness location at Mach numbers near flight values for propeller-shank sections. The tests were performed to illustrate the effects of compressibility on the flow past thick symmetrical airfoil sections. Results regarding flow characteristics and airfoil force characteristics are provided.

Six 100-octane and two 87-octane aviation engine fuels were tested in a modified C.F.R. variable-compression engine at 1,500, 2,000 and 2,500 rpm. The mixture temperature was raised from 50 to 300 F in approximately 50 degree steps and, at each temperature, the compression ratio was adjusted to give incipient knock as shown by a cathode ray indicator. The results are presented in tabular form. The results are analyzed on the assumption that the conditions which determine whether a given fuel will knock are the maximum values of density and temperature reached by the burning gases. A maximum permissible density factor, proportional to the maximum density of the burning gases just prior to incipient knock, and the temperature of the burning gases at that time were computed for each of the test conditions. Values of the density factors were plotted against the corresponding end-gas temperatures for the three engine speeds and also against engine speed for several and end-gas temperatures. The maximum permissible density factor varied only slightly with engine speed but decreased rapidly with an increase in the end-gas temperature. The effect of changing the mixture temperature was different for fuels of different types. The results emphasize the desirability of …

Report presenting an investigation in free flight of the rolling effectiveness of plain ailerons in conjunction with wings having 0 and 45 degrees sweepback with several airfoil sections. Results regarding the rolling characteristics of rectangular and sweptback-wing configurations and drag measurements are provided.

"Following the law of stress adopted in the Navier-Stokes equations, the configuration of the viscous flow in planes at right angles to the axis of an infinite cylinder is found to be independent of the axial motion of the cylinder. In the limiting case of a yawed or swept wing of very high aspect ratio, certain boundary-layer and separation phenomena are thus determined independently by the crosswise component of velocity" (p. 1).

"Following a law of stress adopted in the Navier-Stokes equations, the configuration of the viscous flow in planes at right angles to the axis of an infinite cylinder is found to be independent of the axial motion of the cylinder. In the limiting case of a yawed or swept wing of very high aspect ratio, certain boundary-layer and separation phenomena are thus determined independently by the crosswise component of velocity. It follows that the effect of sweepback is to increase the area of stable laminar flow and to decrease the lift coefficient at which flow separation occurs" (p. 487).

Note presenting an investigation of the effects of tip dihedral on lateral stability and control characteristics by flight tests of models in the free-flight tunnel. The results indicate that at high lift coefficients, tip dihedral may cause a lightly damped lateral oscillation, which does not occur with full-span dihedral at similar values of effective dihedral and directional stability.

Report discussing the effects of various inlet pressures, inlet temperatures, wheel speeds, pressure ratios, and cooling-air flows on the performance of a radial-flow exhaust-gas turbosupercharger turbine with a 12.75-inch tip diameter. Information about efficiency is provided for a given blade-to-jet speed ratio.

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All of the available evidence leads to the view that the 5f electron shell is being filled in the heaviest elements giving rise to a transition series which begins with actinium in the same sense that the rare earth or 'lanthanide' series begins with lanthanum. Such an 'actinide' series is suggested on the basis of evidence in the following lines: (1) chemical properties, (2) absorption spectra in aqueous solution and crystals, (3) crystallographic structure data, (4) magnetic susceptibility data and (5) spectroscopic data. The salient point is that the characteristic oxidation state (i.e., the oxidation state exhibited by the member containing seven 5f and presumably also by the member containing fourteen 5f electrons, curium and element 103) is the III state, and the group is placed in the periodic table on this basis. The data also make it possible to give a suggested table of electronic configurations of the ground state of the gaseous atom for each of the elements from actinium to curium inclusive.

The following items of equipment have been completed: Two Scaler Multipliers, EO-18 and EO-338, undergoing test and adjustment. One Thyratron Heater Control for Scioto Laboratory. One Pilot model switch box for Group 16 hoods at Scioto Laboratory. One Pilot model patch box used as auxiliary to the present switch boxes. Installation of electronic equipment and sorting and cataloguing of stock at Scioto Laboratory has been started. The Y Section induction heaters have been installed electrically. With the present setup in the WD Building, it has been necessary to recycle all the solution which passes through the pH chamber on the clariflocculators. Sufficient tests have been run on the Berkeley Decimal scaler to indicate that, by using a pre-emplifier, it will be a satisfactory replacement for the scaler multiplier. Reworking of B-wall tubes has been held up pending the delivery of neon gas. Further investigations have been made on the frequency compensated constant voltage Sola transformers. Three automatic potential controllers have been modified in accordance with investigations of Group 10. The program of preventative maintenance on automatic potential controllers has resulted in a marked reduction of service calls and down-time for the operating group.

The emf of galvanic cells at high temperatures was measured using uranium metal in equilibrium with its chloride as one half of the cell, the other half of the cell being some reference electrode such as silver - silver chloride. Several designs of cells tried are described. A value of 2.83 volts/eq. at 1170[degree]K and also at 990[degree]K is considered as the most probably value for the potential of the uranium halide couple.

Describes the necessary steps for logging farm woodlands and transporting and preparing the wood to be sold.

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