Report presenting an investigation of spontaneous ignition temperatures from 1 to 9 atmospheres in the air for n-heptane, isooctane, benzene, JP-4, and JP-5 fuels. Time lags before ignition were measured at each pressure for all fuels. Results regarding the effect of pressure, general comparisons of all fuels, and ignition-lag experiments are provided.

"The results of an experimental investigation of the strength of multiweb beams with corrugated webs are reported. Included in the investigation were two types of connection between the web and the skin. A comparison between the structural efficiency of corrugated-web and channel-web multiweb beams is presented, and it is shown that, for a considerable range of the structural index, corrugated-web beams can be built which are structurally more efficient than channel-web beams" (p. 1).

Report presenting mass-flow tables for ratios of specific heats for the entire range of critical velocity ratio. The tables enable a quick and accurate determination of the integrated average specific mass flow across a region where the end-point velocities are known. A numerical example using the tables is also provided.

Report presenting an application of airfoil design methods to a series of related turbine-blade profiles to satisfy the conditions of inlet flow angle and turning angle encountered in the usual range of turbine operation. Satisfactory flow conditions were obtained in all of the blade passages tested. Results regarding the turning angles, wake losses, surface pressure distributions, critical Mach numbers, application of compressibility corrections to low-speed tests, and selection of design camber are provided.

Note presenting a description of a new class of frequency-selective shock absorbers called band-pass shock absorbers, which were conceived as a means of overcoming some of the limitations of conventional shock absorbers. The shock absorbers may be designed to isolate two bodies from each other over certain ranges of exciting frequencies or rates of load application while coupling them over the remainder of the frequency spectrum.

The interaction of bearing and tensile loads on the creep behavior of joints was studied. A specimen was designed for this study which possessed some of the general features of pin and rivet joint connections and an apparatus was constructed to apply both bearing and tensile loads to the joint model. Deformation measurements were made by use of a photogrid printed on the joint model.

Report presenting an investigation in the low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition. Transition was observed by means of a hot-wire anemometer at various chordwise stations for each position of roughness.

A simple method for calculating the characteristics of the Dutch roll motion of an airplane is obtained by arranging the lateral equations of motion in such form and order that an iterative process is quickly convergent. Primary effects of variation of the important stability derivatives on the period and damping can be seen more clearly from the iterative method than from the fourth-order characteristic equation.

Report presenting an experimental determination of radiation and recovery corrections and time constraints for several designs of shielded and unshielded thermocouple probes using chromel-alumel wire. Radiation and time constant data were obtained for Mach numbers from 0.3 to 0.9 and a range of static pressures and temperatures. Tables and graphs are presented which show the correction factors of the various designs to aid in selecting a probe for a particular application.

From Summary: "Solutions of mainstream flow patterns for all possible incompressible laminar-boundary-layer flows having classical similarity with respect to rectangular coordinate systems are derived. These solutions, which apply to a wide range of flows, are summarized in table form."

Report presenting an investigation of a method of casting full-size cermet turbine blades from titanium carbide. An extremely thick piece of titanium carbide was prepared with a small amount of binder, cast into a mold by vibration, centrifuged, and frozen to retain the shape of the mold. Densities and radiographs of the blade prior to infiltration were used as criteria for soundness.

Note presenting an analysis of the low-speed wake characteristics of two-dimensional cascade and isolated airfoil sections based on available experimental data and supplementary theory. Empirical and theoretical variations with downstream distance of such wake properties as minimum velocity, form factor, momentum thickness, full thickness, and total-pressure loss are presented. The analysis indicates a general similarity between turbulent cascade and isolated airfoil wake characteristics.

Report presenting three experimental investigation conducted with 75-millimeter-bore cylindrical roller bearings to determine the effects of roller axial clearance ratio, cage diametral clearance ratio, and cage land width-diameter ratio on bearing operating temperatures, wear, cage slip, and high-speed operating characteristics.

Report presenting a treatment of several problems on the large deflections of curved plates with compound curvature. Testing demonstrated that the effective width of the curved plates in longitudinal compression is reduced by the presence of an initial deflection function.

Report presenting local rates of heat transfer obtained from a parabolic-nosed cylinder at Mach number 3.12. The laminar-heat-transfer coefficients obtained from the conical portion of the cone cylinder were found to agree closely with theory at all temperature levels when corrected for the axial temperature distribution.

Technical note presenting a simplified model of a crash deceleration pulse that incorporates the essential properties of the pulse. The model pulse is considered to be made up of a base pulse on which are superimposed one or more secondary pulses of shorter duration. Data are presented from full-scale laboratory and crash studies on the deceleration loads measured on dummy passengers in seats of standard and novel design.

Report presenting information about the acoustical near field produced by the exhaust of a stationary turbojet engine with a high pressure ratio measured for a single operating condition without afterburning. Additional testing was made at a few points to determine the difference in value between sound-pressure levels at rigid surfaces and corresponding free-field values. Results regarding overall sound pressure, sound-pressure level in frequency bands, sound-pressure-level spectra along jet boundary, and second-source noise are provided.

Report presenting a change in flow pattern that was observed as the free-stream Mach number was increased in the vicinity of 0.8. The paper presents an investigation of the consequences of shock-wave-boundary-layer interaction, which are proposed as a factor that may be important in determining the conditions under which the change in flow pattern occurs.

A theory is presented for calculating the variation with frequency of the lateral-force and yawing-moment coefficients due to sinusoidal side gusts passing over the profile of a simple fuselage-vertical-fin combination. The analysis is based on slender-body theory. The method considers the penetration effect of both fuselage and vertical tail in calculating side force and yawing moment due to side gusts, as opposed to a simple lag concept which considers the flow angle to be uniform over the configuration.

A correlation factor applicable for converting inviscid aerodynamic normal-force coefficients of simple shapes in helium to equivalent coefficients in air is found by using calculations based on the shock-expansion method at Mach numbers of 12, 16, and 20.

The effects of compressibility arising from high-tip-speed operation on the flapping, thrust, and power of a helicopter rotor in forward speed are investigated for a particular set of airfoil characteristics. Tip-speed ratios ranging from 0.2 to 0.5 were covered at several tip-speed values.

"Vertical-tail loads were measured in turbulent air on a four-engine jet bomber. Results showed large load oscillations which were lightly damped. Comparison of experimental results with discrete-load calculations indicated that discrete-gust calculations underestimated the loads by 30 to 40 percent and gave no indication of the low damping. Power spectral analysis, on the other hand, indicated the general frequency characteristics and gave a somewhat better estimate of the peak-load distributions" (p. 1).

Note presenting a description of an adiabatic specific-heat calorimeter bridging the interval between 4 and 15 degrees Kelvin temperatures. The instrument uses a constant-volume helium gas thermometer as the working thermometer. The instrument is tested on an alloy and a sample of pure titanium and the results are described.

From Summary: "A free-swiveling vane-type pickup for measuring air flow direction in both the angle-of-attack and angle-of-sideslip directions is described. Test results are presented which indicate that the pickup is aerodynamically stable and has an accuracy, obtained from a bench calibration, of better than 0.3^o under conditions including acceleration up to 20g in any direction, Mach numbers from 0.5 to 2.8, dynamic pressures up to at least 65 psi. Equations and curves which can be used to obtain flow direction at the center of gravity of a maneuvering model are presented."