Report presenting a comparison of three hypervelocity vehicles: a ballistic rocket, a skip rocket, and a rocket glider. Range efficiency, automatic heating, and problems of glide rockets are explored.

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 flight tests conducted on two straight-wing jet airplanes of generally similar configuration, one exhibiting a diving tendency and the other a climbing tendency, in order to investigate the cause for the particular type of behavior of each airplane at high Mach numbers. The results showed that the diving tendency experienced by the one airplane was due to the predominant effect of an increased angle of attack of the horizontal tail.

Report presenting an investigation of an NACA submerged inlet operating over a range of mass-flow ratios and oncoming flow angles through a range of Mach numbers by use of a transonic bump. Results regarding the ram-recovery ratio, pressure distributions, and tuft studies are provided.

Report presenting the results of testing in the transonic range of four flutter airfoils attached to a freely falling body. Failures of the airfoils were metered and recorded in order to determine the Mach numbers and altitudes of failure.

"The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of the Douglas XSB2D-1 airplane. Comparisons are made between the root bending moment and section torsional moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending moment coefficients but considerable disagreement for the torsional moment coefficients, the measured moments being greater than the analytical moments. The effects of Mach number on both the bending moment and torsional moment coefficients were small" (p. 1).

From Introduction: "The engine evaluation of blends reported herein was conducted at the NACA Lewis laboratory. The data contained in references 2 to 14 are therefore summarized and the effect of the molecular structure of fuels on antiknock performance is shown in herein."

Report presenting an experimental investigation performed to determine the effect on base and forebody pressures of using a sting modified with varying length splitter plates and fins instead of a conventional sting to support a cone-cylinder body of revolution.

Memorandum presenting the results of a wind-tunnel investigation of the damping in pitch of a model triangular wing with an aspect ratio of 4 combined with a slender pointed body. The investigation was conducted at Mach numbers from 0.10 to 0.95 for Reynolds numbers of 550,000 and 1,250,000 with additional data obtained at Reynolds numbers of 3,000,000 and 6,000,000 at Mach number 0.23. Results regarding the effects of oscillation amplitude, Mach number, Reynolds number, angle of attack, frequency, and pitching axis position are provided.

An investigation was made of the variation of the pressure limits of flame propagation with tube diameter for quiescent propane with tube diameter for quiescent propane-air mixtures. Pressure limits were measured in glass tubes of six different inside diameters, with a precise apparatus. Critical diameters for flame propagation were calculated and the effect of pressure was determined. The critical diameters depended on the pressure to the -0.97 power for stoichiometric mixtures. The pressure dependence decreased with decreasing propane concentration. Critical diameters were related to quenching distance, flame speeds, and minimum ignition energy.

From Introduction: "In the present investigation, lift, drag, and pitching moment were determined over a Mach number range 0.6 to 1.42. Smooth-water takeoff and landing stability and resistance were investigated. A brief check of the rough-water spray and behavior was also made."

This report presents the results of wind tunnel tests made to determine the interference drag arising from various arrangements of streamline struts and round struts, or cylinders. Determinations were made of the interference drag of struts spaced side by side, struts in tandem, tandem struts encased in a single fairing, a strut intersecting a plane, and struts intersecting to form a v. Three sizes of struts were used for most of the tests. These tests show that the interference drag arising from struts in close proximity may be of considerable magnitude, in some instances amounting to more than the drag of the struts themselves.

"A supplementary investigation has been conducted in the Langley 20-foot free-spinning tunnel on a l/24-scale model of the Grumman F11F-1 airplane to determine the spin and recovery characteristics with alternate nose configurations, the production version and the elongated APS-67 version, with and without empty and full wing tanks. When spins were obtained with either alternate nose configuration, they were oscillatory and recovery characteristics were considered unsatisfactory on the basis of the fact that very slow recoveries were indicated to be possible. The simultaneous extension of canards near the nose of the model with rudder reversal was effective in rapidly terminating the spin" (p. 1).

Report presenting an investigation of the performance of slurry fuels consisting of 50 percent magnesium powder in a hydrocarbon carrier in a flight-type, 6.5-inch-diameter ramjet engine mounted in a connected-pipe facility. Results regarding the slurry performance and a comparison of slurry and ethylene performance are provided.

Measurements were made of the cooling on the fronts of model cylinders in a conventional cowling for cooling in both the ground and the cruising conditions. The mechanisms of front and rear cooling are essentially different. Cooling on the rear baffled part of the cylinders continually increases with increasing fin width. For the front of the cylinder, an optimum fin width was found to exist beyond which an increase in width reduced the heat transfer. The heat transfer coefficient on the front of the cylinders was larger on the side of the cylinder facing the propeller swirl than on the opposite side. This effect became more pronounced as the fin width was increased. These results are introductory to the study of front cooling and show the general effect of several test parameters.

"Evaluation of the rotating multicylinder method for the measurement of droplet-size distribution, volume-median droplet size, and liquid-water content in clouds showed that small uncertainties in the basic data eliminate the distinction between different cloud droplet-size distributions and are a source of large errors in the determination of the droplet size. Calculations of the trajectories of cloud droplets in incompressible and compressible flow fields around a cylinder were performed on a mechanical analog constructed for the study of the trajectories of droplets around aerodynamic bodies" (p. 1).

Report presenting measurements in a wind tunnel of the static and dynamic-rotary stability derivatives of a model with an unswept wing of low aspect ratio and a high horizontal tail. Tests were conducted at a range of Mach numbers and angles of attack. Results regarding a variety of aerodynamic characteristics are provided.

Memorandum presenting the effects on combustor performance of operation at the high inlet-air pressures, temperatures, and velocities representative of conditions that may be encountered in high-pressure-ratio turbojet engines or at high flight speeds studied in a single tubular combustor. Some of the performance characteristics investigated were combustor-liner temperatures, carbon deposition, smoke formation, and combustion efficiency.

From Summary: "A theoretical investigation of the velocity profiles for laminar mixing of a high-velocity stream with a region of fluid at rest has been made assuming that the Prandtl number is unity. A method which involves only quadratures is presented for calculating the velocity profile in the mixing layer for an arbitrary value of the free-stream Mach number. Detailed velocity profiles have been calculated for free-stream Mach numbers of 0, 1, 2, 3, and 5."

Report presenting an analysis of the causes of compressor stall and flame-out when armament is fired during flight at high altitudes. Experimental data are also presented. The increase in compressor-inlet temperature during armament firing was found to be the most important single factor affecting engine performance.

Theoretical studies of the turbojet and ramjet combustion process are summarized and the resulting equations are applied to experimental data obtained from various combustor tests. The theoretical treatment assumes that one step in the over-all chain of processes which constitute jet-engine combustion is sufficiently slow to be the rate-controlling step that determines combustion efficiency.

From Summary: "As part of an overall program for the experimental investigation of large-scale jet nozzles, a preliminary evaluation of the internal performance characteristics of several variable-throat extended-plug-type nozzles was obtained over a range of nozzle pressure rations from 2 to 15 with nozzle throat variations as great as 2:1. The extended-plug nozzle attained peak thrust coefficients as high as those which have been attained with fixed-geometry convergent-divergent nozzles. The thrust coefficients of the extended-plug nozzles were relatively insensitive to both nozzle pressure ratio and throat area over the range investigated."

From experience gained by NACA test pilots in flying at high subsonic Mach numbers and from interpretation of the data obtained, some general precautionary rules for test flying near sonic Mach numbers have been formulated. The reasons for these rules are discussed and observations are made with respect to the hazards arising from undesirable stability and control characteristics which have been noted in test flights of various airplanes. This paper, although written primarily for the attention of test pilots, contains general information of interest to those who are concerned with various phases of flight testing near sonic Mach numbers.

Tests of a 1/5 scale model of a proposed 153-foot high-speed submarine have been conducted in the Langley full-scale tunnel at the request of the Bureau of Ships, Department of the Navy. The test program included: (1) force tests to determine the drag, control effectiveness, and static stability characteristics for a number of model configurations, both in pitch and in yaw, (2) pressure measurements to determine the boundary-layer conditions and flow characteristics in the region of the propeller, and (3) an investigation of the effects of propeller operation on the model aerodynamic characteristics. In response to oral requests from the Bureau of Ships representatives t hat the basic data obtained in these tests be made available to them as rapidly as possible, this data report has been prepared to present some of the more pertinent results. All test results given in the present paper are for the propeller-removed condition and were obtained at a Reynolds number of approximately 22,300,000 based on model length.