Note presenting the basic equations of Timoshenko for the motion of vibrating non-uniform beams, which allow for effects of transverse shear deformation and rotary inertia, in several forms, including one in which the equations are written in the directions of the characteristics. Numerical traveling-wave solutions are obtained for some elementary problems of finite uniform beams for which the propagation velocities of bending and shear discontinuities are taken to be equal.

From Summary: "Axial-load fatigue tests at a stress ratio of zero were performed on notched and unnotched sheet specimens of 61S-T6 aluminum alloy and 347 and 403 stainless steels. Special emphasis was placed on tests at high stress levels which produce failures in small numbers of cycles."

"The principal planing characteristics have been obtained for two V-shaped prismatic surfaces having angles of dead rise of 20 degrees and 40 degrees. The load, wetted lengths, resistance, center-of-pressure location, and limited drag data are presented for speed coefficients up to 25.0, beam-loading coefficients from 0.85 to 87.33, keel-wetted-length-beam-ratios up to approximately 8.0, and trims up to 30 degrees. The data indicate that, for a given condition of load, speed, and trim, the wetted length, the distance of the center of pressure from the trailing edge, and the drag increase with an increase in the angle of dead rise" (p. 1).

Report presenting an investigation to develop simple, inexpensive electric analogs for determining temperatures of cooled turbine blades. Analogs were made for a 13-fin shell-supported air-cooled blade, a strut-supported air-cooled blade, and a liquid-cooled blade.

Note presenting testing under combined axial load and lateral pressure on 12 bonded sandwich panels with simply supported loaded edges and free unloaded edges. The maximum load and mode of failure were observed for all the panels. Lateral deflections and axial strains were also measured.

Note presenting a method for calculating the stresses produced by rectangular cutouts of any size in torsion boxes. The problem is divided into a "box problem" and a "cover problem". Three sets of tests are provided.

Report presenting an investigation of the observed discrepancy at supersonic speeds between theoretical and apparent experimental average flat plate friction-drag coefficients calculated from boundary layer total-pressure surveys. Some of the qualities investigated included the effects of the total-pressure probe, heat transfer through the leading-edge region, change in leading-edge radius and strength of the leading-edge wave, possible early transition to turbulent flow, and the slight streamwise pressure gradient in flat plate flow were investigated for plates with very sharp leading edges.

Report presenting a method for quickly estimating the separation point of a laminar boundary layer in a compressible flow. The method should be usable for any two-dimensional flow in which classical boundary-layer assumptions are satisfied. Results obtained from a variety of calculations indicate that for all velocity gradients, the amount of velocity recovery possible before laminar separation occurs decreases as Mach number increases.

Equations are presented for the attenuation characteristics of several types of mufflers. Experimental curves of attenuation plotted against frequency are presented for 77 different mufflers and the results are compared with theory. The experiments were made at room temperature without flow and the sound source was a loud-speaker. A method is given for including the tail pipe in the calculations. The application of the theory to the design of engine-exhaust mufflers is discussed, and charts have been included for the assistance of the designer.

"The main purpose of this paper is to present the results of measurements made on the Cal-Tech computer. The diagrams present only a small portion of the data which were obtained from the computer and which are given in complete form in the tables" (p. 1-2).

Report presenting a new shadowgraph technique for the observation of conical flow phenomena in supersonic flow. The particular advantage of this technique is that it permits observation of the conical flow phenomena in a plane normal or nearly normal to the axis of propagation. Results regarding cones and triangular wings are provided.

Report presenting a flight investigation on a four-engine bomber airplane to determine the effects of wing flexibility on wing strains developed in flight through clear-air turbulence. Amplification of the effects appeared to be a function of gust-gradient distance and was not significantly affected by airspeed or weight.

Report presenting testing of the vapor-oxidation of iscooctane at 550 degrees Celsius under conditions leading to rapid quenching of the reaction yielding hydrogen peroxide, diiosbutylene, and isobutylene as the major reaction products. Results regarding isooctane, n-Heptane, 2,2,5-Trimethylhexane, isobutane, and hydrogen-peroxide formation are provided.

Note presenting formulas derived by the use of linearized theory for the lift and drag due to lift, at supersonic speeds, of thin, flat wings with a discontinuity in the leading-edge sweep, the inboard portion of the leading-edge being very highly swept an the outboard portion less so. The lift-curve slope and drag have been calculated for several families of wings, all with straight trailing edges.

From Summary: "Pressure distributions around circular cylinders placed perpendicular to the stream for subsonic and supersonic flow conditions have been obtained. Drag coefficients calculated from these wind-tunnel tests and from transonic free-flight tests are presented. Drag data are presented for the Mach number range of 0.3 to 2.9."

Note presenting a method for solving the steady flow of a non-viscous compressible fluid along a relative stream surface between two adjacent blades in a turbomachine that is applied to investigate the low- and high-speed subsonic air flow through a single-stage and through a seven-stage axial compressor. Comparisons of the design, flow, and air compressibility are provided.

"A study is made of the effect of variation in rivet strength on the average panel stress at maximum load for 75S-T6 aluminum-alloy, flat, Z-stiffened compression panels that fail by local buckling. A curve is presented for the determination of the relationship between strength, diameter, and pitch of the rivets, and the strength of stiffened, flat compression panels of such proportions that failure is by local buckling" (p. 1).

"A revised gust-load formula with a new gust factor is derived to replace the gust-load formula and alleviation factor widely used in gust studies. The revised formula utilizes the same principles and retains the sample simple form of the original formula, but provides a more appropriate and acceptable basis for gust-load calculations. The gust factor is calculated on the basis of a one-minus-cosine gust shape and is presented as a function of a mass-ratio parameter in contrast to the ramp gust shape and wing loading, respectively, used in the alleviation factor" (p. 1).

Report presenting an analysis of 48,187 hours of normal-acceleration and airspeed data obtained on a four-engine type of transport airplane in commercial operation on an eastern United States route from November 1947 to February 1950 to determine gusts and gust loads for operations. Results regarding the presentation of data, effect of changes in operating conditions, effect of seasons, comparison with other results, reliability, acceleration, gusts, and airspeeds are provided.

The preliminary selection of a propeller on the basis of cruising and take-off performance for application to transport airplanes at flight Mach numbers up to 0.8 can be accomplished by the use of charts and methods presented. The charts are of sufficient scope to permit a fairly rapid evaluation of the propeller performance for engine power ratings of 1,000 to 10,000 horsepower. The method is presented primarily in the interest of propeller-noise abatement.

"The results of calculations are presented for the purpose of showing the effects of ionization and electronic excitation on the flow properties of one-dimensional shock waves in xenon gas. The calculations are based on statistical-mechanics theory with the assumption that thermal equilibrium exists at all points in the flow. The calculations are made by both including and neglecting the effects of electronic excitation, and the results of the calculations are qualitatively compared with experimental data" (p. 1).

Note presenting a damped sine-wave elevator motion used as a basis for computing the design maneuvering load on the horizontal tail. The results indicated that the maneuvering tail-load variation computed by operational methods with the assumed damped sine-wave elevator motion agreed closely with the loads computed by a method currently used by the US Air Force.

Note presenting an investigation which utilized the statistical methods developed in previous research to study the scatter found in aluminum alloys and the effect of the morphology of the carbide phase on the scatter in a eutectoid steel. The scatter in fatigue life for 24S and 75S aluminum was found to be comparable with that reported previously for steel.

Report presenting the hydrodynamic drag of three surface-piercing untapered struts at approximately 0 degrees angle of yaw at depths up to 6 chords for speeds up to 80 fps at various angles of rake. The section drag coefficient was determined from plots of drag against depth. Results regarding drag, spray, and cavitation and ventilation are provided.