An investigation of the effect of extremely high altitude operation on the performance and operating characteristics of two turbojet engines using gaseous hydrogen and JP-4 fuels. At extremely high altitude conditions, engine performance was significantly poorer than at low altitudes. The majority of performance losses were due to the compressor because of low Reynolds number and the combustor because of low combustion efficiency.

A series of 11 fuels ranging in volatility and including various types of hydrocarbons were tested in a single tubular combustion chamber of a turbojet engine under inlet-air conditions simulating engine operation at two speeds at an altitude of 40,000 feet. Temperature-rise data at various fuel-air ratios were obtained for each set of air-flow conditions. Results regarding the effect of combustor inlet-air conditions on temperature rise, four different series of tests, and a review of some general considerations are provided.

Report presenting total-pressure recoveries obtained with four-cone inlet combinations at Mach number 1.85. The configurations tested included a cone designed to produce three oblique shocks ahead of the diffuser inlet combined with two other inlets, a cone generated by a parabolic arc in combination with two other inlets, a cone-inlet combination designed to produce an isentropic entrance flow at 0 degrees angle of attack, and a 30 degree single-shock cone combined with a perforated inlet section. Each of the configurations yielded total-pressure recoveries higher than what was reported in previous testing.

Report presenting measurements using the NACA wing-flow method of the lift, pitching-moment, and hinge-moment characteristics of a 35 degree sweptback NACA 65-009 airfoil of aspect ratio 3.04 with a full-span 1/4-chord unsealed plain flap. The tests were carried out at a range of Mach numbers, Reynolds numbers, angles of attack, and flap deflections. Variations of lift and pitching moment with angle of attack or flap deflection were approximately rectilinear at all Mach numbers for moderate angles of attack and flap deflections.

Investigation at transonic speeds in the high-speed 7- by 10-foot tunnel to determine the rolling-effectiveness characteristics of a spoiler on a double-wedge-type semispan wing with a sweepback angle of 42 degrees. Results regarding the variation of rolling-moment coefficient, spoiler effectiveness, and rolling effectiveness are provided.

"A study has been made of the variation of seaplane hull weight with length-beam ratio in a systematic series of hulls designed for constant gross weight and similar spray characteristics. It is found that increases in the length-beam ratio bring about small reductions in the hull weight if it is assumed that seaplanes having the same weight and bottom shape will be designed for the same load factor. A short discussion is also given to show the reduction in load factor that may occur with high length-beam ratios" (p. 1).

From Introduction: "Evaluation of tail-pipe burning in this engine with a larger tail-pipe combustion chamber is discussed in reference 1. Results of investigations on tail-pipe burning in this engine at static sea-level conditions are presented in reference 2. An investigation of thrust augmentation by means of injecting water at the inlet of an axial-flow compressor engine is discussed in reference 3."

From Introduction: "The present paper presents the scale effect on the longitudinal aerodynamic characteristics, the aerodynamic characteristics in yaw, and the tuft studies for 0^o and 3.7^o yaw. The results of the effect of leading-edge and trailing-edge flaps on the aerodynamic characteristics of the wing will be presented in later reports."

Report presenting a combustion-efficiency investigation of 10 special straight-run distillate fuels in an individual tubular-type combustor unit of a 14-unit assembly at two simulated engine operating conditions. These distillates were obtained from various crude oils and consisted of hydrocarbon mixtures with distillations temperature varying from 93 to 690 degrees Fahrenheit. Comparison of temperature measurements obtained from two locations in the exhaust duct showed that under certain operating conditions the flame extended beyond the turbine position.

Report presenting a high-speed wind-tunnel investigation of a pitot-static tube to provide information on the effects of compressibility upon the pressure indications of a representative airspeed head at high subsonic speeds. The calibration factor for the instrument has been evaluated for several small angles of pitch and yaw throughout a Mach number range from 0.30 to approximately 0.925. The results indicate that the calibration factor for each combination of pitch and yaw angles tested is almost constant with Mach number up to a Mach number of approximately 0.8.

Memorandum presenting low-speed wind-tunnel test conducted of a triangular wing of aspect ratio 2.0 with a symmetrical double-wedge section with a maximum thickness of 5 percent of the chord at 20 percent of the chord. The wing was also tested in the presence of a ground plane. Results regarding isolated wing and wing-body combinations, split-flap effectiveness, and ground effect are provided.

Report presenting an aerodynamic-control-effectiveness investigation using free-flight rocket-propelled RM-5 test vehicles at high subsonic, transonic, and supersonic speeds. Results regarding aileron control characteristics and drag measurements are provided.

"A formula, based on a semirational analysis, is presented for estimating the torsional stiffness necessary to prevent flutter of a sweptback or unswept uniform wing that attains supersonic speeds. Results of missile flights at speeds up to Mach number 1.4 demonstrate the usefulness of the formula" (p. 1).

Report presenting testing of a rocket-powered model of a fin-stabilized parabolic body of revolution with fineness ratio 8.91 and maximum diameter at 80 percent of body station at a range of Mach numbers to determine the static pressures at two orifices on the rearward side of the stabilizing fins. Results regarding measured pressures, comparison of theory and experiment, and drag are provided.

Report presenting an investigation to determine the effects of flap size and location on an unswept semispan wing in combination with a half-fuselage. The wing had an aspect ratio of 2.5, a taper ratio of 0.625, and 6-percent-thick modified double-wedge airfoil sections. Results regarding wing characteristics and flap characteristics are provided.

Memorandum presenting an investigation conducted using a single combustor from a 4600-pound-thrust turbojet engine to determine if ignition-plug fouling by carbon deposits could be prevented by retracting the plug from the combustion zone during operation after ignition had taken place. The fuels used were normally conducive to forming carbon. The results indicated that retracting the ignition plug from the combustion zone after ignition prevented plug fouling by carbon.

Report presenting wing-flow-method measurements for 0.47 to 1.15 Mach number of the longitudinal-stability and -control characteristics of a triangular wing of aspect ratio 2 equipped with a constant-chord flap. Changes in the lift-curve slope and aerodynamic-center position through the transonic speed range were moderate and gradual. Results regarding triangular-wing characteristics, flap characteristics, and a comparison of the wind-tunnel and free-flight-test results at higher Reynolds numbers are provided.

An altitude-test-chamber investigation of a 28-inch-diameter ram-jet engine at a simulated flight Mach number of approximately 2.0 for altitudes of 40,000 to 50,000 feet was conducted at the NACA Lewis laboratory. Three different flame holders, varying in the number and size of the annular gutters, in conjunction with several fuel-injection systems were investigated. The combustion efficiency for the flame-holder fuel-injection system that provided the best over-all operational fuel-air-ratio range (0.03 to 0.075) was over 0.9 at a fuel-air ratio of about 0.065 for the altitude range investigated.

An investigation was conducted in the NACA Lewis altitude wind tunnel to determine the effect of compressor-outlet bleedoff on the performance of an axial-flow turbojet engine equipped with a variable-area exhaust nozzle. Results presented indicate the effect of compressor-outlet bleedoff on performance at altitudes of 25,000 and 40,000 feet and a flight Mach number of 0.53. Variation of performance with bleedoff flow is indicated for operation with fixed- and variable-area exhaust nozzles. Temperature and pressure losses through the bleedoff ducting system are also discussed.

Suggested formula are given for determining air-cooled turbine-performance characteristics, such as power and efficiency, as functions of certain parameters. These functions, generally being unknown, are determined from experimental data obtained from specific investigations. Special plotting methods for isolating the effect of each parameter are outlined.

Report discussing the stability and control characteristics and drag of a canard or tail-first configuration explored using the free-fall method. Information about the basic flight characteristics, experimental coefficients, zero-lift drag configurations, and longitudinal stability and trim characteristics is provided.

The effects of turbine-blade cooling on engine performance were analytically investigated for a turbojet engine in which cooling air is bled from the engine compressor. The analysis was made for a constant turbine-inlet temperature and a range of altitudes to determine the minimum cooling requirements to permit substitution of nonstrategic materials in turbine blading. The results indicate that, for a constant inlet temperature, air cooling of the turbine blades increases the specific fuel consumption and decreases the thrust of the engine. The highest possible cooling effectiveness is desirable to minimize coolant weight flow and its effects on engine performance.

A heat-transfer investigation was conducted with air flowing through an electrically heated Inconel tube having either a long-approach or a right-angle-edge entrance, an inside diameter of 0.402 inch, and a length of 24 inches over a range of Reynolds numbers up to 375,000 and average inside-tube-wall temperatures up to 2000 degrees R. Good correlation of heat-transfer data was obtained for both entrances, which substantiates work previously reported. A fair correlation of friction data was obtained for both entrances. The entrance configuration had little effect on the average heat-transfer and friction coefficients.

Report of an investigation into the effect of leading-edge radius on the high-speed aerodynamic characteristics of a symmetrical, 9-percent-thick airfoil using three different airfoils at several Mach and Reynolds numbers. Information about the normal-force coefficients, drag coefficients, moment coefficients about the quarter chord, pressure-distribution diagrams, Schileren photographs, and a comparison with data obtained in other tunnels is included.