Report presenting a blade-vibration and rotating-stall survey on a modified version of a production turbojet engine with a 13-stage axial-flow compressor with a design pressure ratio of 7 and an air flow of 120 pounds per second. This testing was carried out due to the problems rotating stall can cause with both experimental and production axial-flow compressors. Results regarding the rotating-stall patterns, rotor-blade vibrations, radial and axial strength of rotating stall, and maximum rotating-stall speed are provided.

Report presenting a flight test of pentaborane fuel in an air-launched ramjet engine with a design free-stream Mach number of 1.8. The ramjet used in the investigation had a revised spray bar-flameholder configuration. Results regarding propulsive thrust and propulsive-thrust specific fuel consumption are provided.

"An approximate method for the development of flow and thermal boundary layers in the laminar region on cylinders with arbitrary cross section and transpiration-cooled walls is obtained by the use of Karman's integrated momentum equation and an analogous heat-flow equation. Incompressible flow with constant property values throughout the boundary layer is assumed. The velocity and temperature profiles within the boundary layer are approximated by expressions composed of trigonometric functions" (p. 339).

"The external wave drag of bodies of revolution moving at supersonic speeds can be expressed either in terms of the geometry of the body, or in terms of the body-simulating axial source distribution. For purposes of deriving optimum bodies under various given conditions, it is found that the second of the methods mentioned is the more tractable. By use of a quasi-cylindrical theory, that is, the boundary conditions are applied on the surface of a cylinder rather than on the body itself, the variational problems of the optimum bodies having prescribed volume or caliber are solved" (p. 131).

Report presenting testing of gaseous hydrogen fuel burned in a connected-pipe combustor with a cross section equal to 35 degrees sector of a 28-inch diameter. Eleven shrouded fuel-injector configurations were used to obtain combustion data at specified high-altitude ramjet combustor conditions. Results regarding shroud air blockage, mixing tabs, higher equivalence-ratio burning, injector size, flameholder durability, burner length, combustion efficiency, and temperature profile are provided.

"Several methods of cyclic de-icing of a gas-heated airfoil were investigated to determine ice-removal characteristics and heating requirements. The cyclic de-icing system with a spanwise ice-free parting strip in the stagnation region and a constant-temperature gas-supply duct gave the quickest and most reliable ice removal. Heating requirements for the several methods of cyclic de-icing are compared, and the savings over continuous ice prevention are shown. Data are presented to show the relation of surface temperature, rate of surface heating, and heating time to the removal of ice" (p. 1).

Memorandum presenting performance calculations for hypothetical hydrogen expansion engines in which only a small part of the engine airflow passes through the heat exchanger. The flight path was representative of those for long-range, high-speed aircraft. Results regarding the off-design operation and engine performance are provided.

Report described five short multielement turbojet combustors for use with hydrogen fuel and their performance. Information about the combustion efficiency, temperature profiles, pressure loss, durability, and comparison with previous short combustors is included.

Flight investigation of pentaborane fuel in 9.75- inch-diameter ramjet engine with downstream fuel injection.

Double-ramp side inlet with combinations of fuselage, ramp, and throat boundary layer removal.

"A turbojet engine incorporating a conventional-type afterburner was operated over a range of afterburner pressure levels from 1000 to 2000 pounds per square foot absolute and a range of engine-inlet water-air ratios from 0 to 0.08. At each pressure level and water-air ratio, the afterburner fuel flow was varied from lean blowout to maximum burner-outlet temperature" (p. 1).

The effects of power on the stability and the control characteristics of an airplane are discussed and methods of analysis are given for evaluating certain dynamic characteristics of the airplane that are not directly discernible from wind tunnel tests alone. Data are presented to show how the characteristics of a model tested in a wind tunnel are affected by power. The response of an airplane to a rolling and a yawing disturbance is discussed, particularly in regard to changes in wing dihedral and fin area. Solutions of the lateral equations of motion are given in a form suitable for direct computations. An approximate formula is developed that permits the rapid estimation of the accelerations produced during pull-up maneuvers involving abrupt elevator deflections.

"In the present paper attention is directed to the aerodynamic parameters, the so-called stability derivatives, that affect the lateral behavior of airplanes and missiles. The discussion is centered on three important quantities, the effective-dihedral derivative, the directional-stability derivative, and the damping-in-roll derivative. These quantities are considered for a large angle-of-attack range at subsonic speeds" (p. 1).

Report presenting measurements downwash angles behind a model of a high-aspect-ratio wing at points near the probable tail location at Mach numbers up to 0.89 in the high-speed tunnel. The model has an NACA 65-210 section, an aspect ratio of 9.0, a taper ratio of 2.5:1, no twist, dihedral, or sweepback. Results regarding experimental data and comparison of experimental and calculated results are provided.

Report presenting testing of a semispan model of a wing of triangular plan form and aspect ratio 2 in the 12-foot pressure tunnel to determine the aerodynamic characteristics of the wing as influenced by the independent effects of Reynolds number and Mach number up to Mach numbers approaching unity. Results regarding the effect of body and effect of wing-profile modification are also provided.

The third report in a series of five that present unanalyzed pressure data obtained in tests of five full-scale propellers with NACA 16-series blade sections. Pressure distributions on the blade sections were measured under operating conditions to determine the aerodynamic characteristics of each blade section. This particular report presents information for nine radial stations of the NACA 10-(3)(090)-03 propeller.

The stage performance of the X24C-2 axial-flow compressor, as determined from radial distributions of total pressure and temperature measured in each stator-blade row, was investigated at design speed at weight flows corresponding to those of the maximum weight-flow, peak-efficiency, and surge points. The stage performance is presented as the measured stage pressure ratios and the calculated velocity diagrams. The average stage total-pressure ratio at the surge operating condition in the first stage was approximately 1.10; in the second stage, approximately 1.13; and in all remaining stages, approximately constant at a value of 1.15. Regions of inefficient flow are discussed so as to point out the reasons for the poor flow conditions.

Memorandum presenting the results of a wind-tunnel investigation of the low-speed characteristics of horizontal tails of aspect ratio 3 with unswept and swept-back plan forms. Two models were tested which had identical areas, aspect ratio, taper ratio, and airfoil section, differing only in the angle of sweepback and elevator area ratios. The major effect of sweepback was to increase the rate of change of hinge-moment coefficient with angle of attack, to reduce the rate of change with elevator deflection, and to reduce the elevator effectiveness.

Report presenting an investigation of the hydrodynamic take-off and landing characteristics of a model of a hypothetical jet- and rocket-propelled high-speed airplane fitted with various designs of a single monoplane hydrofoil mounted near the center of gravity. This testing is performed to determine the feasibility of the water-based operation of high-speed airplanes. Results regarding the general hydrodynamic characteristics, development of hydrofoils, and effects of some hydrofoil parameters are provided.

Report presenting an investigation in free flight of the rolling effectiveness of plain ailerons in conjunction with wings having 0 and 45 degrees sweepback with several airfoil sections. Results regarding the rolling characteristics of rectangular and sweptback-wing configurations and drag measurements are provided.

Report presenting an investigation of turbine operating temperatures as affected by liquid cooling, especially if materials of high conductivity are used, at gas temperatures up to 1925 degrees Fahrenheit. Results regarding the statio heat-transfer rig and turbine rig are provided. The investigation showed that nonstrategic material such as aluminum alloy can be used in liquid-cooled turbine wheels at high gas temperatures.

From Introduction: "The effects of variations in altitude, flight Mach number, and exhaust-nozzle-outlet area on the compressor performance characteristics are graphically presented. A complete tabulation of the compressor performance data is also presented."

Report presenting tests to determine the effect of sweepback angle and aspect ratio on the drag at supersonic speeds of wings of NACA 65-009 airfoil section. The current report is part of a bigger investigation and includes results for aspect ratios of 3.8 and 5.0. Results regarding the drag coefficient and general effect of aspect ratio are provided.

"Gust-velocity measurements and air-borne-radar observations obtained during a transcontinental flight in July 1947 have been analyzed as part of a general investigation of the uses of air-borne radar. The analysis indicates that some reduction in turbulence and a consequent reduction in the risk of encountering the larger gust velocities may be obtained by avoiding portions of clouds giving a radar echo" (p. 1).