Discusses different systems of forced-air ventilation as a means of harvesting and drying forage crops.

An annotated list of films about soil and water conservation. Includes information about the films' suitability for use in elementary and secondary schools.

From Summary: "The general characteristics of the flow field in a submerged air inlet are investigated by theoretical, wind-tunnel, and visual-flow studies. Equations are developed for calculating the laminar and turbulent boundary-layer growth along the ramp floor for parallel, divergent, and convergent ramp walls, and a general equation is derived relating the boundary-layer pressure losses to the boundary-layer thickness. It is demonstrated that the growth of the boundary layer on the floor of the divergent-ramp inlet is retarded and that a vortex pair is generated in such an inlet."

"By use of an approximate equation for the wave drag of slender bodies of revolution in a supersonic flow field, the optimum shapes of certain boattail bodies are determined for minimum wave drag. The properties of three specific families of bodies are determined, the first family consisting of bodies having a given length and base area and a contour passing through a prescribed point between the nose and base, the second family having fixed length, base area, and maximum area, and the third family having given length, volume, and base area. The method presented is easily generalized to determine minimum-wave-drag profile shapes which have contours that must pass through any prescribed number of points" (p. 1).

Note presenting the development of a generalized potential theory applicable to nonadiabatic and rotational flow in a two-dimensional field. Three partial differential equations are obtained determining the three variables. which are distribution of additional temperature, velocity perturbation, and an auxiliary function characterizing the rotationality of the flow. Application of the results to hot-wire anemometry are discussed.

Report presenting an investigation of the thermal and hydrodynamical behavior of air flowing along a passage with one flat side, which was steam-heated, and one wave-shaped side, which was unheated. Two series of tests were conducted, one with the plates in direct opposition and one with the plates slightly separated, which induced turbulence upstream of the thermal boundary layer. Results regarding heat transfer and static-pressure drop are provided.

Report presenting experimental results on the thermal performance of an aircraft combustion-type heater. The performance of the heater with a counterflow and a parallel-flow return passage on the gas side does not appear predictable by use of existing equations. The thermal conductance for the gases within the combustion chamber is predicted to be many times lower than the experimental data indicate.

Note presenting an investigation of the loss of strength of tensile specimens of polymethyl methacrylate as a result of stress-solvent crazing at 23 degrees Celsius and 50-percent relative humidity. the materials tested were commercial cast polymethyl-methacrylate sheets of both heat-resistant and ordinary grades from each of two manufacturers.

Note presenting an exploration of the Debye-Scherrer diagram of a stationary polycrystalline sample, which has an intensity distribution with an erratic line because of statistical irregularities of the crystal grain orientation. The fluctuations of intensity are discussed for the case that the only causes of line breadth are the natural spectral width of the primary radiation and the finite size of the grains.

Report describing the synthesis, purification, and several physical properties of five different types of hydrocarbons.

Report presenting an investigation of the sintering of chromium carbide under pressure in order to study the kinetics of grain growth and densification during this process. Densification of a sintered chromium carbide compact was accompanied by grain growth and density and grain size seem to be interdependent during this stage of the sintering process.

Note presenting experimental data for skin friction of turbulent boundary layers under adverse pressure gradients from several sources in graphical form. Data obtained by the momentum-balance method are shown to follow a trend opposite to that of data obtained by hot-wire and heat-transfer methods.

Note presenting a review of English and German literature on notch stress-rupture data, which included the effect of notching on rupture strength in general, the effect of chemical composition and heat treatment on notch stress-rupture characteristics, the mechanism of stress-rupture embrittlement and notch sensitivity in low-alloy steels, and a comparison of the influence of notch geometry on notch strength in stress-rupture tests and in conventional tensile tests.

Report presenting a numerical method for calculating thermal stresses in irregular cylinders cooled by one or more internal passages. The use of relaxation methods and elementary methods of finite differences was found to give approximations to correct values when compared with previously known solutions for concentric circular cylinders with symmetrical and asymmetrical temperature distributions.

Note presenting experiments made to measure the speed of sound in nitrogen at room temperatures in the pressure range of 0 to 2000 pounds per square inch, and the critical pressure ratio of air expanded isentropically from stagnation conditions in the same range. The experimental results were compared with values obtained by using the Van der Waals equation and the Beattie-Bridgeman equation.

Report presenting a wind-tunnel investigation to determine the effects of end plates of various areas and shapes on the aerodynamic characteristics of an unswept and untapered wing of aspect ratio 4. End plates were found to provide the basic wing with an increase in the lift-curve slope, a reduction in the induced drag, and an increase in the maximum lift coefficient.

Report presenting comparisons of theoretical and experimental lift coefficients and pressure distributions for five compressor-type cascades of highly cambered NACA 6-series airfoils. The experimental lift coefficients were generally less than the theoretical values for the same mean-flow direction. A justification of the experimental and analytical methods are also provided.

Note presenting some sets of solutions studied independently of the gas laws and some properties of the series obtained by means of these sets. The equations have been further transformed so as to have as independent variables the complex velocity and the complex mass velocity.

Report presenting measurements of the equilibrium temperature and heat-transfer coefficients for transverse cylinders in a high-speed stream of rarefied gas over a range of Knudsen and Mach numbers. Results regarding the temperature recovery for an insulated body and heat-transfer-test results are provided.

"Factors of stress concentration for deep, sharp, and symmetrically arranged grooves and fillets in tension members have been determined photoelastically and are given in this report. Curves are given showing the distribution of principal stresses on the section through the grooves. Complete isopachic patterns for several basic cases of grooved bars are included" (p. 1).

Report presenting the use of the similarity law to determine simple expressions for correlating the forces and moments acting on related shapes operating at hypersonic speeds. The shapes considered are wings, bodies, and wing-body combinations.

"Tabulated pressure coefficients and aerodynamic characteristics obtained in flight from pressure distributions over six chordwise rows of orifices on the right wing of the D-558-I research airplane (BuAero No. 37972) are presented. The data were obtained through a Mach number range of 0.80 to 0.89 and throughout the normal-force-coefficient range at Mach numbers of 0.61, 0.70, 0.855, and 0.88. This paper supplements similar tabulated data which have been presented in NACA RM L50J10 and NACA RM L50L12a" (p. 1).

Report presenting an investigation conducted at low speed of an air-induction system with twin scoop-type inlets on the sides of the fuselage of a model of an airplane designed for flight at supersonic Mach numbers. The leading edge of the lip of the scoop was rounded and there were provisions for control of the boundary layer ahead of the inlet. Results regarding the characteristics of the lips investigated, characteristics of the main duct with lip E, characteristics of the boundary layer control duct, and pressure coefficient distributions and boundary-layer characteristics are provided.

Report presenting results from a tank investigation of a powered dynamic model of the Grumman JRF-5 airplane fitted with a single hydro-ski and extended afterbody. Results indicated that the afterbody extension in place of a tail ski reduced the maximum resistance by 10 percent. Removal of the wing-tip skids gave a further reduction in maximum resistance of 3 percent.