Report discussing about 400 references pertaining to the hydrodynamic design of seaplanes have been compiled, and the information is presented in the form of abstracts classified under six main headings.

Report describing results of experiments that involved injecting radioactive yttrium into animals: "The excretion, retention, and distribution of the yttrium was measured, and its effect on survival and growth was observed. The average total excretion of Y91 to the time of death (from 76 hours to 24 days) was a little less than 30 per cent of the injected dose" (p. 2).

"The condensation of water vapor in an air has the following consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front" (p. 1).

Report issued by the U.S. Bureau of Mines discussing investigations of the research and technologic work done on coal during 1946. Mining methods, and properties of coal are presented. This report includes tables, illustrations, photographs, and maps.

From Summary: "A method for computing the effect of surface roughness on the drag coefficient of an airplane is presented. Calculated results using this method are compared with experimental results from both flight and wind-tunnel tests. In general, the agreement is believed satisfactory."

The following report covers investigations on the application of the beta counter as an analytical tool for use in experiments on the extraction and concentration of uranium from low-grade (.005-.02 % uranium) shale and phosphate rock ores.

Various biochemical effects of radiation have been studied in 10 patients given total body x-ray in total doses of 75 to 310 r (skin), in 5 patients given 20 to 36 mc. P{sup 32}, and in 5 project personnel accidentally exposed to excessive doses of external radiations. Similar studies have also been made of several hundred Plutonium Project personnel exposed in most instances to relatively small amounts of uranium, lead and other metals, and to chemicals and radioactive sources. These studies included the investigation of liver function, of white blood cell chemistry, and of various urinary constituents such as coproporphyrin, urorosein and other pigments, urobilinogen, ``corticosteroid-like`` substances, catalase, and uranium. Definitely excessive exposures resulted in various abnormalities in the above tests. With the exception of urinary uranium analysis none of them are specific in indicating overexposure to either radiation, metals, or chemicals. When interpreted in the light of the exposure and medical history, however, it is felt that they may aid in the clinical interpretation of relatively marked overexposure at least. In addition, they may afford further insight into the nature of radiation effects. The literature on the biochemical effects of radiation is reviewed briefly, and certain suggestions are offered …

"The present report concerns a method of computing the velocity and pressure distributions on bodies of revolution in axially symmetrical flow in the subsonic range. The differential equation for the velocity potential Phi of a compressible fluid motion is linearized tn the conventional manner, and then put in the form Delta(Phi) = 0 by affine transformation. The quantity Phi represents the velocity potential of a fictitious incompressible flow, for which a constant superposition of sources by sections is secured by a method patterned after von Karman which must comply with the boundary condition delta(phi)/delta(n) = 0 at the originally specified contour" (p. 1).

Report presenting a set of charts for the convenient determination of flow conditions behind a shock wave and at the surface of inclined planes and axially symmetric cones located in a uniform frictionless supersonic air stream. Shock angle, static-pressure coefficient, static-pressure ratio, total-pressure ratio, Mach number ratio, and velocity ratio for two-dimensional and conical flow fields are plotted for a range of free-stream Mach numbers.

Note presenting analytical comparisons of weights and volumes for flat-plate heat exchangers with the same calculated thermal output and friction pressure drop for three different fin configurations, including no fins, fins in both the air and exhaust gas passages, and fins in the air passages only. Two different heat exchangers were used and compared with predicted weights and volumes.

Report presenting an investigation in the stability tunnel on two semispan swept-wing models to determine experimentally the span-load distributions and to compare the experimental and theoretical results. Lift, drag, pitching moment, and stalling characteristics are provided.

Report presenting measurements of sound pressures for static conditions for two-blade, four-blade, and seven-blade propellers over a range of tip Mach numbers. Results regarding sound pressures and loudness are provided.

Note presenting comparisons of theoretical and experimental airfoil lift coefficients and pressure distributions made for two cascades of entrance vanes and three cascades of blower blades with NACA 6-series airfoils, and for one cascade of turbine blades. Results regarding the entrance vanes, blower blades, turbine blades, and possibilities of three-dimensional effects are provided.

The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.

Report presenting a correlation of the experimental and calculated effects of the product of inertia on the stability of lateral oscillations of airplanes. The experimental and calculated boundaries were in good agreement with one another, but neglecting the product of inertia led to wide discrepancies. Results regarding stability and its influence on general flight behavior are provided.

Note presenting theories of bending and torsion as applied to the problem of calculating the deflections in aircraft shell structures, particularly of wings. Bending as well as torsional deflections are discussed for wings without or with cut-outs.

From Summary: "The point-source-distribution method of calculating the aerodynamic coefficients of thin wings at supersonic speeds was extended to include the effect of the region between the wing boundary and the foremost Mach wave from the wing leading edge. The effect of this region on the surface velocity potential has been determined by an equivalent function, which is evaluated over a portion of the wing surface. In this manner, the effect of angles of attack and yaw as well as the asymmetry of top and bottom wing surfaces may be calculated."

In the vicinity of a body in a wind tunnel the displacement effect of the wake, due to the finite dimensions of the stream, produces a pressure gradient which evokes a change of drag. In incompressible flow this change of drag is so small, in general, that one does not have to take it into account in wind-tunnel measurements; however, in compressible flow it beoomes considerably larger, so that a correction factor is necessary for measured values. Correction factors for a closed tunnel and an open jet with circular cross sections are calculated and compared with the drag - corrections already bown for high-speed tunnnels.

"With an approach of the velocity of flight of a ship to the velocity of sound, there occurs a considerable increase of the drag. The reason for this must be found in the boundary layer separation caused by formation of shock waves. It will be endeavored to reduce the drag increase by suction of the boundary layer. Experimental results showed that drag increase may be considerably reduced by this method" (p. 1).

Note presenting the results of pressure-distribution measurements made during high-speed wind-tunnel tests of a tapered wing of NACA 230-series airfoil sections for a range of angles of attack and free-stream Mach numbers. The peak values of minimum pressure coefficient attained were found to correspond to local Mach numbers of 1.2 to 1.4 except at angles of attack near the low-speed stall. Results regarding the wing lift characteristics, pressure coefficients and section normal-force coefficients, and a comparison of theoretical and experimental chordwise pressure distributions are provided.

Report presenting a consideration of the development of the laminar boundary layer in a compressible fluid. Formulas are given for determining the boundary-layer thickness and the boundary-layer Reynolds number, which is a measure of the boundary-layer stability, for airfoils and bodies of revolution.

Report presenting a dynamometer-stand investigation to determine the effect of exhaust pressure on the performance of a 12-cylinder liquid-cooled aircraft engine equipped with a conventional exhaust collector. The results are presented in the form of curves that show the effect of exhaust pressure on engine power, charge-air flow, volumetric efficiency, inlet-manifold mixture temperature, exhaust-gas temperature, cylinder-head temperature, and heat rejected to the coolant.

As part of a study of the effects of fuel composition on the combustor performance of a turbojet engine, an investigation was made in a single I-16 combustor with the standard I-16 injection nozzle, supplied by the engine manufacturer, at simulated altitude conditions. The 10 fuels investigated included hydrocarbons of the paraffin olefin, naphthene, and aromatic classes having a boiling range from 113 degrees to 655 degrees F. They were hot-acid octane, diisobutylene, methylcyclohexane, benzene, xylene, 62-octane gasoline, kerosene, solvent 2, and Diesel fuel oil. The fuels were tested at combustor conditions simulating I-16 turbojet operation at an altitude of 45,000 feet and at a rotor speed of 12,200 rpm. At these conditions the combustor-inlet air temperature, static pressure, and velocity were 60 degrees F., 12.3 inches of mercury absolute, and 112 feet per second respectively, and were held approximately constant for the investigation. The reproducibility of the data is shown by check runs taken each day during the investigation. The combustion in the exhaust elbow was visually observed for each fuel investigated.

Note presenting force tests of two isolated vee-tail surfaces with various amounts of dihedral made to provide an experimental verification of a simplified vee-tail theory and the results are presented which were found to be in good agreement with calculations of previous reports. Plots of the basic test data and summaries of the data in the form of plots of the variation of static-stability derivatives and control-effectiveness parameters with dihedral angle are included.