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.

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 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.

Note presenting an investigation of three theories: the momentum transfer theory of Prandtl, the vorticity transfer theory of Taylor, and the similarity theory of Von Kármán. The primary focus is to examine Von Kármán's theory using modern concepts.

Note presenting a treatment of the problem of turbulent boundary layer over a flat plate in compressible flow. The dissipation term in the energy equation, often neglected, is first carefully studied and found to be of importance. The four main approximations include the turbulence pattern, the boundary-layer growth, the two choices of the length scale, and the effect of pressure gradient.

Note presenting an investigation of the turbulent-boundary-layer flow over a flat plate in compressible flow. The report shows how the influence of the Mach number can be predicted from the theory after the constant coefficients in the theory are determined by one set of experimental measurements. By averaging the Navier-Stokes equations, differential equations for the mean flow are obtained.

Note presenting a modification of certain variational methods for the approximate solution of subsonic and transonic flows to compensate for the fact that those methods fail as soon as shock waves occur. By applying a variational principle to the regions of flow behind shock waves and Bateman's original principle to the other regions in the fluid, shock equations can be directly obtained.

Note presenting the results of an investigation to obtain hydrodynamic information on a series of hull models suitable for small flying boats or amphibians of from 2000 to 5000 pounds gross weight. The series of hulls consisted of a basic hull with simple lines, and of plus and minus variations to the design in which the beam, stern-post angle, and afterbody length were altered. The results show that it is possible to design a hull with simple lines that will be suitable for small flying boats or amphibians.

Note presenting concepts involved in the harmonic-response-function method, such as the direct or conjugate characteristic modes, by application of the method to the calculation of the change in flutter characteristics of a wing due to adding concentrated masses.

Note presenting a new technique for studying corrosion phenomena. The method permits the detection of the presence of currents produced by local cells on the surface of a corroding metal specimen. The method can be applied to the study of stress corrosion; in this case a hollow specimen if subjected to sufficient hydraulic pressure to produce the desired stress level.

Report presenting the results of an experimental determination of the thermal and hydrodynamic behavior of air in the downstream portion of two types of double-skin passages used in heated-air leading-edge anti-icing systems. Results regarding heat transfer and pressure drop are provided.

Report presenting a study of the effect of inclination of the air stream on the measured pressures of six shielded total-pressure tubes for a range of angles of attack. The tests were conducted over a range of Mach numbers. Results indicated that the shape of the venturi entry has a pronounced effect on the range of angles of attack over which the tubes remain insensitive to inclination of the air stream.

Note presenting an investigation of the hydrodynamic lubrication of cyclically loaded bearings in order to check the validity of the analytical studies of loading and lubrication studies.

Note presenting flexural fatigue tests made on riveted box beams of 14S-T6, 75S-T6, and various tempers of 24S alclad aluminum-alloy sheet in order to gain new knowledge of the fatigue strength of built-up structures. Of the five alloy-temper combinations studied in riveted box-beam sections, the flexural fatigue strengths were found to lie in a rather narrow band and no one combination was found to have higher strength values than all others for the entire range of fatigue life covered in these tests.

Note presenting an analysis of discrepancies between theory and the experimental behavior of a cyclically loaded shaft rotating in a sleeve bearing. For constant loads rotating at one-half the frequency of shaft rotation, eccentricity ratios were found to be unity when kerosene was used to lubricate the test bearing.

Note presenting information from the results of an investigation to measure the true viscosities of nitrogen and air at a range of pressures and temperatures. Results regarding the region of slip and region of free-molecule viscosity are provided.

Note presenting a study of the flow of a compressible fluid through a channel with locally supersonic regions by using the Tricomi equation in the hodograph variables as an approximation in the sonic region to the equation of flow of an irrotational, inviscid gas. It is shown that this is equivalent to studying the flow of a gas with a pressure-density relation matching the isentropic relation to the third derivative at the sonic point. As specific examples, flows are computed with Mach number equal to unity and to 0.86 at the center of the throat section.

"A method is presented for obtaining amplitude and single plots for rational algebraic functions of an imaginary variable. Application of the method is illustrated by an example in which the frequency response of an automatically controlled aircraft is plotted. The method involves the use of templets but does not require the factoring of polynomials" (p. 1).

The aerodynamic characteristics of an airplane configuration composed of a swept-back, nearly constant chord wing and a triangular tail mounted on a cylindrical body are presented. The analysis is based on the assumption that the free-stream Mach number is near unity or that the configuration is slender. The calculations for the tail are made on the assumption that the vortex system trailing back from the wing is either a sheet lying entirely in the plane of the flat tail surface or has completely "rolled up" into two point vortices that lie either in, above, or below the plane of the tail surface.

"The infrared spectra are presented for 59 dicyclic hydrocarbons consisting of some diphenylalkanes, dicyclohexyalkanes, alkylbiphenyls and alkylbicyclohexyls ranging from C(sub 12) through C(sub 18). The physical properties of these compounds, which were available in a high state of purity, are tabulated for reference purposes" (p. 1).

Note presenting a theoretical and experimental investigation of the condensation of air in hypersonic wind tunnels. The condensation was detected and measured by condensation-fog light scattering, static-pressure measurements, and changes in wedge shock angles at degrees of supersaturation lower than those predicted by existing condensation theory.

"This report summarizes numerous theories relating to creep phenomena and the extent of current knowledge on the subject. Various possible mechanisms by which creep occurs both in single crystals and in polycrystals are described. An extensive bibliography of published works in this field is also included" (p. 1).

Note presenting measurements of the spectrum and correlation functions at large Reynolds number as well as a series of accurate spectrum measurements at lower Reynolds number. Results regarding decay, spectrum and correlation measurements in the GALCIT 10-foot tunnel, spectrum measurements in the 20-inch tunnel, moments of the spectrum, behavior of the spectrum at high frequencies, the spectrum at very large distances from the grid, and the spectrum of derivative are provided.

Note presenting two approaches to the problem of stall flutter. First, the aerodynamic reactions on wings oscillating harmonically in pitch and translation in the stall range have been measured, evaluated, and correlated where possible with available published data, with the purpose of providing empirical information where no aerodynamic theory exists. Second, the results of numerous experimental observations of stall flutter have been reviewed and the various known attempts at its prediction have been examined, compared, and extended.