Memorandum presenting an investigation of the performance of inlet configurations with a forebody designed for isentropic external compression at a nominal Mach number of 5.6. At zero angle of attack, all of the configurations yielded larger total-pressure recoveries than had previously been obtianed with a single-conical-shock inlet. Results regarding the flow about the forebody and performance comparisons are provided.

Report presenting an investigation of the Reynolds number for transition on the outside of a hollow cylinder with heat transfer from the boundary layer to the wall at Mach number 6.9. At a given Mach number, it appears that the Reynolds number based on leading-edge thickness is an important parameter in comparisons of flat-plate transition data from various installations.

Tests on a high-speed single-cylinder engine are described. The regularity of the spark timing was varied by driving the timer from different engine shafts. A simple and reasonably accurate method of determining the spark timing is described. The results show that irregular spark timing may cause large errors in tests of the knocking properties of fuels. For the engine tested, it was found that a change of one crankshaft degree in spark restart was equivalent to an 0.85 inch Hg change in allowable inlet pressure.

The heat-transfer coefficients have been determined for five steel cylinders having fins 1.22 inches wide and the spacing between the fins ranging from 0.022 to 0.131 inch. The cylinders were tested with and without baffles in a wind tunnel; they were also tested enclosed in jackets with the cooling air supplied by a blower. A maximum heat transfer was reached at a fin space of about 0.45 inch for the cylinders tested with each of the three methods of cooling investigated. The rise in temperature of the air passing between the fins and the change in flow pattern were found to be important factors limiting the heat transfer that may be obtained by decreasing the fin space. The use of baffles for directing the air around the cylinders with closely spaced fins proved very effective in increasing the over-all heat-transfer coefficient, provided that the spacing was not appreciably less than that for maximum heat transfer.

Report presenting testing at two engine speeds on six representative fuels rated at 100-octane number by the C.F.R. aviation method. Blends of the fuels with benzene, toluene, xylene, and isopropyl comprise nine other fuels, leading to testing on 15 fuels. Results regarding the tests at 2000 rpm and 250 degrees Fahrenheit inlet-air temperature, at 3100 rpm and 250 degrees Fahrenheit inlet-air temperature, 2000 rpm and 150 degrees Fahrenheit inlet-air temperature, and 3100 rpm and 150 degrees Fahrenheit inlet-air temperature, effect of speed on knock rating, effect of inlet-air temperature on knock rating, and effect of spark advance on knock rating are provided.

"Tests were made of eight full-scale propellers of different shape at various tip speeds up to about 1,000 feet per second. The range of blade-angle settings investigated was from 10 degrees to 30 degrees at the 0.75 radius. The results indicate that a loss in propulsive efficiency occurred at tip speeds from 0.5 to 0.7 the velocity of sound for the take-off and climbing conditions" (p. 517).

Report presenting an investigation to determine the floating characteristics of full-length plain and horn-balanced rudders during rotary tests at spinning attitudes on a scale model of a typical low-wing personal-owner airplane. The investigation included the determination of the effects of the horizontal tail and the wing on the rudder floating characteristics.

Report presenting an investigation in the transonic blowdown tunnel to determine the effects of variations in inlet lip swagger from 0 to 60 degrees on the internal-flow characteristics of an unswept semielliptical scoop-type air-inlet model without boundary-layer control. Tests were made for a range of Mach numbers and mass-flow ratios. Results regarding the flow over the fuselage nose, total-pressure recovery at inlet, flow distortions at inlet, and inlet-design considerations are presented.

Report presenting calculations of the lateral response to representative time histories of atmospheric turbulence for two airplanes with widely different dynamic properties and explanations for their differences in behavior. The results indicate that atmospheric turbulence can cause and maintain a lateral hunting oscillation of a plane, which can be fairly regular and more pronounced for lightly damped airplanes. This may explain some of the cases of airplane snaking that have not been explained by other causes.

Report presenting a technique for obtaining a physical picture of the flow behind a wing, combination of wings, or other aircraft components is described. The technique involves photographing from far downstream the action of a large number of tufts of uniform length mounted on a screen. Results regarding the angle of attack variations at zero yaw, effect of sideslip, deflecting tip controls, and yawing oscillation tests are provided.

Report presenting a test-stand investigation conducted on a rectangular ramjet engine design for installation in an aircraft wing. The engine operated without excessive engine noise or vibration over the entire range of operating conditions. Results regarding inlet velocity, exhaust flame characteristics, fuel-air ratio, and total-temperature rise are provided.

"Results are reported of current studies at the Forest Products Laboratory to develop a metal-bonding adhesive with greater resistance to temperatures up to 600 degrees Fahrenheit that is easier to use than present ones. Most promising is a formulation of phenol and epoxy resins modified with hexamethylenetetramine and supplied for use as a dry tape supported on a glass-mat base" (p. 1).

Note presenting wind-tunnel tests to ascertain the total-pressure recovery of a circular nose inlet utilizing various shapes of inlet lips. The tests were conducted at a free-stream Mach number of 0.237 with inlet flows ranging from low values to choking and at angles of attack from 0 to 25 degrees.

Drag and longitudinal trim at low lift of the North American YF-100A airplane at Mach numbers from 0.76 to 1.77 as determined from the flight test of a 0.11-scale rocket model are presented herein. Also included are some longitudinal stability and some qualitative pitch-damping data.

Report presenting a flight investigation to determine the effectiveness of three fuselage indentations for reducing the pressure drag of a 45 degree sweptback-wing-body configuration at a range of Mach numbers. The results indicate that the supersonic area rule can be used to determine indentations with low pressure drag over a Mach number range in which the blunt leading edge is subsonic. Information about total drag and pressure drag is provided.

Report presenting a free-flight test technique that can be used to obtain damping in roll of sting-mounted wings and wing-fuselage combinations over high subsonic, transonic, and supersonic speeds with rocket-propelled test vehicles. Results regarding delta wings and unswept tapered wings are provided.

Report presenting an investigation in an altitude test chamber using a turbojet engine equipped with an afterburner and ejector to compare directly two techniques of determining thrust that are both applicable to flight installations. One method uses a swinging uncooled rake at the ejector outlet while the other requires extensive instrumentation to measure the momentum forces of systems and the force on the internal surface of the ejector nozzle. Results regarding the swinging-rake technique and internal-pressure technique are provided.

From Introduction: "As a part of the comprehensive investigation of the XJ34-WE-32 engine conducted in the NACA Lewis altitude wind tunnel, the over-all-performance was determined over a range of altitudes and flight Mach numbers. Other phases of the investigation are reported in reference 1. The results are given in tables and also in graphical form to show the trends of engine performance associated with changes of altitude, flight Mach number, and exhaust-nozzle area."

Report presenting performance data on a Trane exhaust gas and air heat exchanger. Heat transfer rates were measured using specified exhaust gas rates and ventilating-air rates. The measured thermal outputs and static pressure drops are compared with predicted magnitudes.

Report presenting the available sources of data on the mechanical properties of aluminum alloys at low temperatures and a summary of the material to be found in each source. General conclusions regarding commercially available aluminum alloys are also provided.

"An investigation has been completed in the Langley 20-foot free-spinning tunnel on a l/18-scale model of the Ryan X-13 airplane to determine its spin, recovery, and tumbling characteristics, and to determine the minimum altitude from which a belly landing could be made in case of power failure in hovering flight. Model spin tests were conducted with and without simulated engine rotation. Tests without simulated engine rotation indicated two types of spins: one, a slightly oscillatory flat spin; and the other, a violently oscillatory spin" (p. 1).

The results of an experimental investigation of the load distribution over two triangular wings in sideslip at Mach numbers from 1.20 to 1.79 are presented and compared with theory. The two wings tested have identical plan form, 45 degrees sweepback of the leading edge, and an aspect ratio of 4.0. One model was composed of round-nose airfoil sections and the other of sharp-nose, biconvex sections. For both wings the maximum thickness of streamwise sections was 6 percent and was located at the 30-percent chord.

Report presenting an investigation in the transonic tunnel on a submerged inlet with a divergent-walled approach ramp to determine flow phenomena, pressure recovery, and external forces to provide correlation with available data obtained on similar inlets. Results regarding the pressure characteristics, aerodynamic forces, and performance comparisons are provided.

Note presenting an investigation of several laminated glass windshields to determine their suitability for use in airplanes with pressurized cabins. The various constructions of the extended portions of the windshields which serve for mounting purposes included plastic alone, plastic and one sheet of glass extended, plastic extension reinforced with an aluminum strip, and plastic extension reinforced with a steel strip. The results indicated that the laminated windshields with plastic-mounting extensions reinforced by aluminum or steel were resistant to creep and bursting at pressures of the order that will be encountered in service.