Memorandum presenting a study of an acceleration-limiting control on a turbojet engine in order to determine its feasibility as an acceleration control. A proportional-plus-integral type of controller was used in the investigation. Results regarding the one-loop control and two-loop control are provided.

Memorandum presenting an acceleration-limiting control used on a turbojet engine to study the feasibility of its use as an acceleration control. A proportional-plus-integral type of controller was used in this investigation. Results regarding one-loop control and two-loop control are provided.

Low cowl drag, external compression inlet with subsonic dump diffuser for high Mach number application.

Report presenting an investigation of a zero-cowl-drag, all-external-compression inlet with an abrupt area discontinuity or subsonic dump diffuser for high Mach number application. Results regarding the diffuser performance characteristics, effect of spike retraction, a comparison with other inlets, and some theoretical calculations related to the results are provided.

Report presenting an investigation conducted to determine the relative advantages and limitations of a number of fluids for use as either heat sinks or coolants for hypersonic aircraft. The feasibility of the fluids tested as heat sinks and cooling in the high-level and low-level regions is described.

Memorandum presenting theoretical rocket performance for both equilibrium and frozen composition during expansion, which was calculated for the propellant combination of liquid ammonia with liquid oxygen at two chamber pressures and a wide range of pressure ratios and oxidant-fuel ratios. Some of the performance parameters explored include specific impulse, specific impulse in vacuum, combustion-chamber temperature, nozzle-exit temperature, molecular weight, molecular-weight derivatives, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, thermal conductivity, Mach number, and equilibrium gas compositions.

"A general matrix method is developed for the solution of characteristic-value problems of the type arising in many physical applications. The scheme employed is essentially that of Gauss and Seidel with appropriate modifications needed to make it applicable to characteristic-value problems. An iterative procedure produces a sequence of estimates to the answer; and extrapolation techniques, based upon previous behavior of iterants, are utilized in speeding convergence. Theoretically sound limits are placed on the magnitude of the extrapolation that may be tolerated" (p. 747).

"An experimental investigation has been conducted to determine the dynamic stability and control characteristics in hovering and transition flight of a 0.13-scale flying model of the Convair XFY-1 vertically rising airplane with the lower vertical tail removed. The purpose of the tests was to obtain a general indication of the behavior of a vertically rising airplane of the same general type as the XFY-1 but without a lower vertical tail in order to simplify power-off belly landings in an emergency. The model was flown satisfactorily in hovering flight and in the transition from hovering to normal unstalled forward flight (angle of attack approximately 30deg)" (p. 1).

From Summary: "Tests and calibrations of an AWS instrument shelter were made in the Langley 300 MPH 7- by 10-foot tunnel for the Signal Corps, U.S. Army. The behavior of the wind vane, the 3-cup anemometer, and the shelter cover was determined in wind speeds up to 150 miles per hour. It was discovered that the rotational speed of the anenometer was greatly influenced by the location, with respect to the wind direction, of three spacer posts that held two upper bays of instruments above the anenometer."

Report presenting the flying qualities of a C-54D airplane measured as a preliminary to an investigation to determine the necessity of additions or revisions to flying-quality requirements in view of the problems associated with making instrument approaches to low altitudes. Results regarding control friction, dynamic longitudinal stability, static longitudinal stability, maneuvering stability, take-off and landing characteristics, effectiveness of the trim tabs, trim changes, and stalling characteristics are provided.

Report presenting the results of testing on a model of the D-558-1 in order to determine its pitching-moment, lift, and drag characteristics with no nose-inlet flow, and with the tail removed and at a constant setting. Only a limited analysis is provided.

Report presenting an investigation of two 10-foot-diameter three-blade propellers to determine the effect of swept-back blade tips on propeller aerodynamic characteristics. Results regarding the effect of swept-back tips on maximum efficiency and constant-power propeller operation are provided.

Memorandum presenting high-speed wind-tunnel testing to investigate the aerodynamic characteristics at subsonic speeds of two symmetrical double-wedge airfoil sections of 4- and 6-percent-chord thickness suitable for application to supersonic aircraft. Section coefficients of lift, drag, and quarter-chord pitching moment are presented for a moderate range of angles of attack at Mach numbers up to approximately 0.93. The double-wedge airfoil exhibits no characteristics other than those common to the usual subsonic profile which would contribute to unsteady or uncontrollable flight at subsonic speeds of aircraft employing such a section for lifting surfaces.

Report discussing the results of testing on the suitability of six aromatic amines as fuel additives. Antiknock effectiveness, availability, physical properties, and chemical properties for knock tests were explored. The six aromatic amines were xylidines, cumidines, N-methylxylidines, N-methylcumidines, N-methylaniline, and N-methyltoluidine in 28-R aviation fuel.

"Various transparent organic plastics, including both commercially available and experimental materials, have been examined to determine their suitability for use as flexible windshields on aircraft, The properties which have been studied include light transmission, haziness, distortion, resistance to weathering, scratch and indentation hardness, impact strength, dimensional stability, resistance to water and various cleaning fluids, bursting strength at normal and low temperatures, and flammability" (p. 1).

This report is the second of a series giving the results obtained in the 20-foot wind tunnel of the National Advisory Committee for Aeronautics on the interference drag and propulsive efficiency of nacelle-propeller-wing combinations. The first report gave the results of the test of a N.A.C.A. cowled air-cooled engine nacelle located in 21 positions with reference to a thick wing. The present report gives results of tests of a normal engine nacelle with several types of cowling and fairings in four of the positions with reference to the same wing. (author).

The National Bureau of Standards tested a 300-horsepower Hispano-Suiza engine to determine the characteristic performance of the engine at various altitudes. The engine was operated at the ground, at 25,000 feet, and at intermediate altitudes, both at full loads similar to those that would be imposed upon the engine at various speeds by a propeller whose normal full-load speed was 1,800 r.p.m. Friction horsepower also was determined in order that the mechanical efficiency of the engine might be calculated.