Instead of solving the nonlinear differential equation which governs the compressible flow, an approximate method of solution by means of the variational method is used. The general problem of steady irrotational flow past an arbitrary body is formulated. Two examples were carried out, namely, the flow past a circular cylinder and the flow past a thin curved surface. The variational method yields results of velocity and pressure distributions which compare excellently with those found by existing methods. These results indicate that the variational method will yield good approximate solution for flow past both thick and thin bodies at both high and low Mach numbers.

Note presenting a method by which the total temperature of the gases at the combustion-chamber outlet of a ramjet engine may be determined from the loss in total pressure measured across the combustion chamber. Values of total-temperature ratio across the combustion chamber of a 20-inch ram jet were obtained in the altitude wind tunnel over a range of pressure altitudes.

Note presenting an investigation of three ceramic coatings applied to four heat-resistant alloys that are tested for effectiveness in preventing carbon absorption under strongly carburizing conditions (box carburizing).

Report presenting an investigation to gain information concerning the durability of metallic coatings as affected by frit content, firing temperature, firing time, and number of coats. Four coatings of various frit content were prepared and applied to ceramals containing 80 percent chromium and 20 percent cobalt and heated at four different temperatures.

Report presenting a velocity-correction formula for the purpose of calculating, from the known Mach number distribution for a diamond-shaped airfoil at a stream Mach number of 1.0, Mach number distributions on the same airfoil at speeds from a Mach number of about 0.8 to shock-attachment Mach number. An expression for the rate of change of local Mach number with stream Mach number is derived and an explicit equation for the drag coefficient as a function of stream Mach number and thickness ratio is given.

Report presenting a partly linearized solution of plastic deformation of a rotating disk based on the deformation theory of plasticity and considering finite strains. The method can be used to investigate the general plastic behavior of a rotating disk.

"A theoretical discussion of the application of blade boundary-layer control to increase the efficiency and the stage pressure ratio and to improve off-design performance of turbomachines is presented. A method based on the potential flow of a compressible fluid is developed for designing suction, or ejection, slotted blades having a prescribed velocity distribution along the blade and in the slot. The effect of the boundary layer on the design of the slot and the effect of ejecting gas at stagnation pressures and temperatures different from free-stream values are discussed" (p. 1).

Results of tests conducted in the 6-foot-diameter rolling-flow test section of the Langley stability tunnel to determine the effects of varying taper ratio on the rolling and static stability characteristics of a swept wing are presented; results are also given for the effects of varying taper ratio on an unswept wing and for the effects of sweep on a tapered wing. All the models were of aspect ratio 2.61 and had NACA 0012 sections normal to the quarter-chord line. Taper ratios of 1.00, 0.50, and 0.25 and sweep angles of 0 degrees and 45 degrees were investigated.

Note presenting a wind-tunnel investigation to determine the effects of jet-outlet cut-off angle on the directional and spreading characteristics of an unheated, subsonic air jet, and on the pitching moment of the body from which the jet issued. Results regarding the jet operating with the wind tunnel off, jet off with the wind tunnel operating, jet operating with the wind tunnel operating, and flow studies with the jet operating and the wind tunnel off are provided.

"Wind-tunnel tests were performed at Mach numbers of 1.5 and 2.0 to investigate the influence of tail surfaces on the base drag of a body of revolution without boattailing and having a turbulent boundary layer. The tail surfaces were of rectangular plan form of aspect ratio 2.33 and has symmetrical, circular-arc airfoil section. The results of the investigation showed that the addition of these tail surfaces with the trailing edges at or near the body base incurred a large increase in the base-drag coefficient. For a cruciform tail having a 10-percent-thick airfoil section, this increase was about 70 percent at a Mach number of 1.5 and 35 percent at a Mach number of 2.0" (p. 1).

Report presenting practical methods for making the calculations required for the analysis of an autopilot and an autopilot-aircraft combination from frequency-response data. From Summary: "Equations are derived for determining the servo-system error voltage for both displacement input signal and displacement plus rate of displacement input signals, the autopilot frequency response for addition of rate of displacement input signal, the servo-system frequency response for a change of gain, and the relation between open-loop and closed-loop frequency responses for the servo system and the autopilot-aircraft combination."

From Summary: "Values of the downwash of a horseshoe vortex in compressible flow are presented in the form of charts and tables. The use of the charts and tables in the calculations of the downwash of wings of arbitrary plan form is discussed. The results of a few calculations are compared with experimental results."

Report presenting two closely related methods which employ operations tables that have been developed and used in the calculation of buckling load of a monocoque cylinder subjected to pure bending. The buckling loads of three cylinders with very different characteristics were calculated using the methods.

Report presenting a method utilizing precalculated solutions graphically presented for calculating subsonic or supersonic ramjet performance parameters with the associated equations and graphs. By assuming constant values of specific-heat ratio and gas constant equal to those of standard air, the thrust-coefficient calculation has been reduced to a few simple operations.

Report presenting an investigation to determine the floating characteristics of full-length plain and horn-balanced rudders during rotary tests at spinning attitudes on a scale model of a typical low-wing personal-owner airplane. The investigation included the determination of the effects of the horizontal tail and the wing on the rudder floating characteristics.

Report presenting data for turbulent-velocity-fluctuation components and mean-velocity distributions measured in the subsonic jet issuing from a pipe in which a fully developed turbulent flow was established. Axial and radial components of the fluctuation velocities were examined as functions of Reynolds number and position in the jet.

"The present report covers a series of torsional tests on stiffened D-tubes of alclad 24S-T3 aluminum alloy having a cross section similar to the NACA 0012 airfoil section and a closing web at 30 percent of the chord. The stiffeners consisted of ribs and stringers. An average-strength chart has been developed for this type of structure that takes into account the skin thickness, rib spacing, and stringer spacing. This chart may also be used for unstiffened D-tubes" (p. 1).

Note presenting an account of explicit solutions in terms of Mathieu functions of the problem of two-dimensional subsonic compressible flow past oscillating airfoils. The results are applied to the calculation of three-dimensional corrections for the two-dimensional theory and the effect of the incorporation of the three-dimensional effects on the Mathieu function solution of the two-dimensional problem is shown.

Note presenting an analysis of the problem of two-dimensional flow behind a curved stationary shock wave. The method assumes a given shock-wave shape, which automatically determines certain initial conditions on flow variables, and flow-pattern, including any body shape, follows from initial conditions.

"Three-dimensional interaction surfaces are presented for the computation of elastic buckling stresses for an infinitely long flat plate subjected to combinations of bending, shear, and transverse compression in its plane - a loading approximating that occurring in a shear web. Surfaces are presented for two sets of edge conditions: both edges simply supported and lower edge simply supported, upper edge clamped. Present results are in good agreement with data for one-load and two-load limiting cases previously published" (p. 1).

Note presenting the results of an investigation consisting of a series of one-engine climb tests with a twin-engine transport airplane, which indicate that light turbulence of the type generally present in clear air over flat terrain has no significant effect on the average rate of climb for a series of runs. Turbulence does, however, increase the variation in the rate of climb from run to run. Results regarding mean rate of climb, standard deviation of the rate of climb, effects of climb duration, and implications of these results are provided.

Note presenting a review of the literature on the sonic studies of the problem of the excitation of molecular vibrations by collision. The theory on which the interpretation of almost all the sonic work has been based is discussed rather qualitatively in some detail. Results concerning techniques, principal experimental programs, and an interpretation of the results are provided.

Report presenting four necessary conditions for steady irrotational compressible flow through a straight cascade of blades as derived from the irrotationality condition and conservation of mass and momentum. The expressions used can only give an approximate solution to the conditions, as there are an infinite number of them.

Report presenting force, moment, pressure-distribution, and boundary-layer measurements for a series of five airfoil sections. The stalling characteristics of the three airfoil sections at low speeds can be separated into three types. A deeper discussion of the role of boundary-layer flow and separation processes in relation to stalling and the sensitivity of stall to factors that influence boundary-layer growth is provided.