"In the present report the theory of free turbulence propagation and the boundary layer theory are developed for a plane-parallel free stream of a compressible fluid. In constructing the theory use was made of the turbulence hypothesis by Taylor (transport of vorticity) which gives best agreement with test results for problems involving heat transfer in free jets" (p. 1).

Monthly report from the Public Relations Department to the National Board of Directors for the American Women's Voluntary Services discussing their news and activities including recreational leadership training and the code for junior auxiliary uniforms.

Report discusses the maximum lift coefficients for conventional and tailless airplanes in the gliding and landing conditions. Three areas are used to calculate the coefficients: wing area alone, wing area plus horizontal-tail area, and wing area plus horizontal- and vertical-tail areas.

Report presenting a consideration of the performance of sliding surfaces, such as piston rings, cylinders, journals, and bearings in aircraft engines with reference to the surface characteristics that they possess before and after running-in, prior to service operation. The phenomena accompanying the running-in process are analyzed.

Report presenting a study of nitrided-steel piston rings in nitrided-steel cylinder barrels, which showed material of high reflectivity on their running faces. The structure of the material could not be resolved at a magnification of 1500 diameters. Results regarding the occurrence of coating, thickness of coating, height of coating above the nominal surface, chemical characteristics, physical characteristics, metallurgical change, and additional tests are provided.

Report presenting a method of graphical analysis that allows for the prediction of the thermal and aerodynamic performance of a ram-operated heater and duct system, for cabin heating or wing de-icing, at any altitude and airplane speed. Performance can be predicted from the isothermal total pressure drop across the components of the duct system at several ventilating air rates and the thermal output of the heater at various air and exhaust gas rates.

Report presenting a study to determine the effect on the knock-limited permissible power output on the indicated specific fuel consumption and on the cylinder temperatures of exhaust-gas dilution of the inlet-air charge, inlet-air temperature without exhaust-gas dilation, and of compressible ratio.

Annual report submitted by the Boy Scouts of America to Congress describing highlights from 1943, activities, membership, cooperating agencies, organizational leadership, and other information about scouting programs.

Introduction: Measurements of polonium content in solids are usually performed by dissolving the material and preparing a thin sample which can be measured with one of the available instruments. A measurement of the radiation emerging from the thick sample should be sufficient to evaluate the polonium content. For this reason a calculation has been performed and the results have been compared with those obtained by the thin sample method. Obviously this proposed method using thick samples would be faster.

"An empirical equation has been developed that gives the approximate amount of ovalization for tubes under bending loads. Tests were made on tubes in the d/t range from 6 to 14, the latter d/t ratio being in the normal landing gear range. Within the range of the series of tests conducted, the increase in ovalization due to a compression load in combination with a bending load was very small" (p. 1).

Report presenting an investigation conducted with the propeller cuffs and spinner removed to determine their effect in flight on the pressure recovery of the cooling-air flow. Curves are presented to compare the pressure and temperature distribution over the front row of cylinders for flights with and without cuffs and spinner.

Report presenting the results of a study of the rupture-test characteristics of 13 wrought and 4 cast alloys which were considered to have promise for service in exhaust gas turbines. The results are given in the forms of a table of information and data, a page of curves, and a page of photomicrographs.

It was desired to determine a method of evaporating boron to form a rather pure uniform tenacious coat of specified thickness. These coats are needed as monitoring films for neutron intensities, particularly in steel ionization cylinders. The most satisfactory method of evaporating boron employed a graphite filament. A mixture of amorphous boron and Carbenoid A was painted onto the filament which was then heated by electrical resistance method to 2300 degree C at which temperature the boron evaporated. Opaque films with purities up to 98% boron or better could be deposited by this method. Much heat was liberated by the filament, and it was found necessary to cool the steel cylinders during evaporation to prevent alloying of boron with the steel. Cathodic deposition also proved satisfactory for producing high purity films; this method has the advantage that little or no heat is produced during the process, but requires much time. Other less efficacious methods of depositing lighter films of born were developed; these are included in the following discussion.

Report presenting elementary basic solutions of the equations of motion of a compressible fluid in the hodograph variables are developed and used to provide a basis for comparison in the form of velocity correction formulas, of corresponding compressible and incompressible flows.

Report presenting an investigation of thirteen exhaust-gas-to-air heat exchangers to determine the practicability of the use of such heat exchangers in the thermal ice-prevention systems on aircraft. The results show that the exchangers constitute an excellent source of heated air for aircraft ice prevention and can be constructed to resist thermal and vibrational stresses.

Results of subject tests indicate the difficulty of obtaining closely balanced rudder surfaces for most tail assemblies with shielded horns and maintaining a near zero rate-of-change of hinge-moment coefficient without an additional balancing device. A comparison is made between shielded and unshielded horn test results. Pressure distribution and tuft tests of flow over different shaped horns showed higher critical speed for medium-taper nosed horn. The trim tab nose shape had little effect on tab test results.

Report discusses the results of an investigation into the tightness, shear strength, tensile strength, and life under pulsating loads of hollow, hydraulically expanded rivets made of 17S-T aluminum alloy. The countersunk-head rivets with inserts had a much higher maximum load in shear than the modified-roundhead rivets, which did not have inserts.

A good determination of the resonance absorption of uranium when admixed with various substances is necessary so that calculations can be made on the efficiency of homogeneous piles. The original experiments along these lines were undertaken by Creutz, Jupnik, and Snyder (C-116) and consisted of experiments on the resonance capture in pure U, UO2, U3O8, and one experiment on capture in a mixture of U3O8 and graphite. These experiments were done at the cyclotron in Princeton and consisted of determining the ratio of the twenty-three minute activity of uranium to an iodine monitor placed in some position with respect to the sample. By using spheres of different radii both the volume and the surface absorptions were measured. It was considered very desirable to extend these measurements to mixtures containing large amounts of graphite to uranium and also to investigate other substances containing hydrogen and deuterium. In addition it was decided to use both iodine and gallium monitors in the experiments. While the experiments were in progress, an absorption curve for uranium metal was made by Marshall using iodine and gallium detectors, which showed that there was a certain amount of overlapping of resonance levels of uranium and iodine.

Report describes a balanced-diaphragm device for measuring dynamometer torque of single-cylinder or multicylinder engines that was developed for laboratory use. Design variables are described, included desired torque-measuring device characteristics, diaphragm design, pilot valve, the torque-indicating instrument, the capacity range, ability of reversed operation, and double-acting operation. The accuracy is described as satisfactory and effects of other variables are negligible.

Report presenting testing of fifty-eight lightened and five unlightened aluminum-alloy channels as simply supported beams in pure or simple bending produced by loads parallel to the plane of symmetry, and fifty-three lightened and four unlightened aluminum-alloy channels with loads parallel to the back. Four types of testing occurred with various types of support and loading.

Report issued by the U.S. Bureau of Mines on studies of the yields of primary tar and light oil. The combustion and carbonization of these yields are presented. This report includes tables, and graphs.

Report presenting an investigation of the flying qualities of a Curtiss SB2C-1 airplane. Tests were made to determine the effect of a bobweight in the elevator system and the effect of seals in the aileron gaps. Results regarding longitudinal stability and control, requirements for lateral stability and control, and stalling characteristics are provided.

Report presenting information regarding the development of a type GB-5 controllable glide bomb equipped with a target-seeking device. The model was tested on the six-component balance in order to measure the stability and control characteristics of the bomb in its original condition and with various modifications. Results regarding the effect of end plates on dihedral parameter, effect of vertical-tail arrangement on directional stability, aileron tests, and glide-path control are provided.

Report presenting an investigation to determine any injurious effects of knock on engine parts. Endurance tests were run on a single-cylinder engine to compare the conditions of cylinders operated with and without knock. Results regarding the history of the tests, conditions of pistons and cylinders, absence of surface ignition, and effect of knock on cylinder temperatures are provided.