Report presenting an investigation to determine the effects of several design changes on the performance of large-capacity, double-entry, centrifugal compressors. Four modifications of a turbojet engine compressor were operated over a range of equivalent impeller tip speeds an the compressor overall and component performances were determined. Results regarding the impeller performance, diffuser performance, and compressor performance are provided.

"An investigation to determine the structural damping characteristics of a full-scale airplane wing was conducted by the shock-excitation method wherein the wing was loaded to a predetermined deflection and the load suddenly released. The test specimen vibrated at its fundamental bending frequency of 1.69 cycles per second. Only the first 2 or 3 cycles showed any indication of a higher frequency being superimposed upon the fundamental bending frequency" (p. 1).

Report summarizing several experimental tail-pipe-burner investigations to indicate the effects of tail-pipe-burner design variables on the performance and operating characteristics. Most of the configurations were investigated over a wide range of altitudes and flight Mach numbers. The results indicate the desirable design features of a tail-pipe burner that will operate with high combustion efficiency and exhaust-gas temperature up to an altitude of approximately 50,000 feet.

Report presenting a description and results of an investigation of a model of the XH-17 two-blade, jet-powered helicopter. Tests were made with a standard configuration and with several modifications, including varying the size of blade counterweights, changing the control stiffness and chordwise bending stiffness of the blades, and varying the pylon and undercarriage damping and spring constants. Results regarding flutter testing, ground-vibration tests, and three-per-revolution rotor-blade unsymmetric bending oscillations are provided.

Report presenting an investigation of a rectangular wing with a subsonic-type round-leading-edge airfoil section (NACA 65-009) at various Mach numbers. The results generally agreed with calculated values with the exception of the laminar-separated region on the low-pressure surface of the model. Results regarding the calculation of pressure distribution, experimental pressure distributions, aerodynamic characteristics, and shadowgraph studies are provided.

From Summary: "By application of a hyperbolic approximation to the form of the bow waves caused by blunt leading edges on an infinite cascade of supersonic blades, the approximate losses in relative total pressure due to the external bow-wave system arising from blunt edges and subsonic axial entrance velocities were computed. The losses increase linearly with leading-edge radius for any given relative Mach number. For a relative Mach number of 1.60, leading-edge radii may be approximately 1.5 percent of the normal blade gap with a 1-percent loss of relative total pressure."

Report presenting flight tests at Mach numbers from 0.8 to 1.4 on three rocket-propelled general research models of airplane configurations. Two models had thin unswept tapered wings of aspect ratio 3 and hexagonal airfoil sections, two wings had different structural stiffness characteristics, and the third model had no wing. Results regarding the static and dynamic longitudinal stability, control, trim, and drag characteristics are provided.

From Summary: "Experimental force, moment, and center-of-pressure variations for a large number of bodies of revolution have been compared with the calculated characteristics based on the approximate theory developed in NACA-RM-A9I26. The bodies varied in fineness ratio from 4.5 to 21.1, from blunt unboattailed bodies to airship hulls, and the experimental results are given for widely varying Mach number ranges of angle of attack. It is shown that the lift and drag characteristics are fairly accurately predicted by the theory but that the actual center of pressure is more rearward than the theory indicates."

Memorandum presenting wind tunnel tests to determine the aerodynamic characteristics of a semispan wing with a modified NACA 0012-64 section and a 26.6-percent-chord, plain, trailing-edge aileron. Results are shown for the wing with the 0.229-chord line unswept and swept back 45 degrees and for a Mach number range from 0.40 to 0.925.

Memorandum presenting lift, drag, and pitching-moment data and some static rolling-moment data are presented for missile configurations having wing-tail-span ratios equal to and less than 1. The configurations include variations in wing and tail plan forms, wing-tail-span ratios, body length, and nose shape.

Report presenting a compilation of free-spinning model results of investigations of the spin and recovery characteristics of 12 flying-wing and unconventional-type designs. Dimensional data, mass data, and three-view drawings of the models that correspond to each of the 12 airplane designs are provided. Results regarding erect spins, inverted spins, and spin-recovery parachutes are also provided.

Memorandum presenting a group of alkylsilanes consisting of monoethylsilane, diethylsilane, and trimethylsilane prepared in 65- and 90-percent yield by reduction of the respective alkylchlorosilanes with either lithium hydride or lithium aluminum hydride. The boiling points, densities, refractive indices, and freezing points were determined and presented with a survey of literature values.

Report presenting the rates of flame propagation of four alkylsilanes as determined by the tube method. Results regarding alkylsilane flame velocities, blends of diethylsilane and n-pentane, and flame propagation theories are provided.

Report presenting time histories of the aerodynamic loads on the vertical and horizontal tail surfaces of a jet-powered bomber airplane (B-45A) in sideslip maneuvers. Information about maximum measured rudder and fin loads, maximum total vertical-tail load, horizontal-tail-load dissymmetry, maximum elevator loads, and elevator-load dissymmetry is provided.

Memorandum presenting a discussion of the strategic-material problems of airplane engines as a whole, especially as related to parts of the engine that are not the disk or blades. Several possible approaches to the material-conservation problem are presented, including the advantages and disadvantages, and the relative gains that might result from one, or combination of a number, of these approaches.

Report presenting the effects of a low-speed wind-tunnel investigation to determine the effects of vertical-fin location and area on the static and rotary lateral stability characteristics of semitailless airplane models. Results regarding straight flow, yawing flow, and rolling flow are provided.

"Flutter tests of sweptback cantilever wing models have been made in a small intermittent two-dimensional supersonic tunnel where the testing technique involved changing the structural parameters so that the models would flutter at the tunnel design Mach number of 1.3. Data for 21 models covering sweep angles from 30 degrees to 60 degrees and with varying parameters are included" (p. 1).

Report presenting a free-flight investigation of two rocket-powered model configurations to determine the damping in roll. The model had rectangular wings of 4.5 aspect ratio and were the same except for the airfoil sections. Results regarding rolling velocity and total-drag coefficient are provided.

Memorandum presenting a wind-tunnel investigation of the low-speed, static, lateral and directional characteristics of a model of an early design of the X-3 airplane with the wing flaps neutral and deflected. The model utilized a wing with an aspect ratio of 3.01, a 4.5-percent-thick hexagonal section, and a taper ratio of 0.4. Results regarding lateral stability and control with the flaps neutral, with the flaps fully deflected, with miscellaneous additions to the complete model, directional stability and control with the flaps neutral, with the flap fully deflected, with miscellaneous additions to the complete model, and oscillating rolling moments are provided.

Report presenting the use of Theodorsen's propeller theory to calculate the performance of a dual-rotating propeller with nonideal load distributions. Results regarding the propeller characteristics were made for several blade-angle settings and flight Mach numbers.

Report presenting local coefficients of convective heat transfer as measured from skin temperature along the body of an RM-10 NACA research missile, which consisted of a parabolic body of revolution. Results regarding recovery factors, adiabatic wall temperatures, Nusselts, Prandtl, and Reynolds numbers, and boundary-layer transition are provided.

Report presenting an investigation conducted to determine the minimum spark energy required for ignition in a single tubular combustor. Inlet-air pressure and flow rates limiting ignition are compared with those limiting steady-state burning in the combustor. Results regarding ignition at sea-level conditions, altitude steady-state burning limits, altitude ignition, and reproducibility are provided.

Memorandum presenting an investigation of the effects of stator cone angle and tip leakage on turbine performance. A single-stage turbine with 40-percent reaction was operated with two stators and two stationary shrouds. The turbine was operated at an entrance temperature of 660 degrees R with total-pressure ratios from 1.25 to 3.70 and equivalent mean blade speeds from 166 to 655 feet per second.

From Summary: "NACA research on afterburners for turbojet engines during the past 5 years is summarized. Although most of this work has been directed toward the development of specific afterburners for various engines rather than toward the accumulation of systematic data, it has, nevertheless, provided a large fund of experimental data and experience in the field. The references cited present over 1000 afterburner configurations and some 3500 hours of operation. In the treatment of the material of this summary, the principal effort has been to convey to the reader the "know-how" acquired by research engineers in the course of the work rather than to formulate a set of design rules."