Report presenting an investigation of the maximum hovering time, or the time that a helicopter can sustain itself without motion, for helicopters using a reciprocating engine, by ramjet engines at the tips of rotor blades, and by pulse-jet engines at the tips of rotor blades. Testing showed that the reciprocating engine permitted much longer hovering time than the jet-propulsion engines, but the jet-propulsion engines were much lighter and could lift greater disposable loads.

Report presenting measurements of the local flow angles near the fuselages of a triangular-wing wind-tunnel model and an F-86A-5 airplane in flight using airflow detectors on the fuselages. A comparison of the measured and predicted flow angles is provided. Results indicated that the accuracy of the predicted indicated angles of attack was not sufficient to eliminate the necessity of a flight calibration of a detector mounted on a fuselage.

Report presenting an investigation to determine the effect on performance of two methods of throat-area modulation of two convergent plug nozzles. Data were obtained over a range of pressure ratios. Results regarding the performance of the translatable outer-shell-type plug nozzle, performance of the iris-outer-shell-type plug nozzles, sensitivity to throat-area variation, and air-flow parameter are provided.

Report presenting a comparison of the vertical-tail loads determined from pressure-distribution measurements in flight in various maneuvers with the corresponding vertical-tail loads. Some of the maneuvers investigated included slow rolls, steady sideslips, fishtails, and rolling pull-outs.

Report presenting experimental data from calm- and rough-water landing impacts with a dynamic model of a seaplane incorporating a flat-bottom hydro-ski mounted on a rigid strut and on a shock-absorber strut. Results regarding the fixed-ski case and translating-ski case are provided.

From Summary: "The over-all component performance characteristics of a J71 experimental three-stage turbine with 97 percent design stator areas were determined over a range of speed and pressure ratio at inlet-air conditions of approximately 35 inches of mercury absolute and 700 degrees R. The turbine break internal efficiency at design operating conditions was 0.877; the maximum efficiency of 0.886 occurred at a pressure ratio of 4.0 at 120 percent of design equivalent rotor speed. In general, the turbine yielded a wide range of efficient operation, permitting flexibility in the choice of different modes of engine operation."

"An experimental investigation of the internal-flow conditions of a J71 experimental turbine equipped with 97-percent-design stator areas was conducted at equivalent design speed and near equivalent design work. The results of the investigation indicate that the stage work distribution closely approximates design, the actual distribution being 44.1, 33.4, and 22.5 percent for the first, second, and third stages, respectively. The first-, second-, and third-stage efficiencies were 0.894, 0.858, and 0.792, respectively" (p. 1).

"Computations were made to determine the temperature distribution and cooling of solid gas-turbine blades.A range of temperatures was used from 1500 degrees to 2500 degrees F, blade-root temperatures from 100 degrees to 1000 degrees F, blade thermal conductivity from 8 to 220 BTU/(hr)(sq ft)(degrees F/ft), and net gas to metal heat transfer coefficients from 75 to 250 BTU/(hr)(sq ft)(degrees F)" (p. 1).

Report presenting an investigation using the NACA wing-flow method at transonic speeds to determine the contributions of wing, tail, and fuselage to the aerodynamic characteristics of a semispan airplane model with a long slender fuselage and straight wing and tail of low aspect ratio with faired symmetrical double-wedge airfoil sections 4.6 percent of the chord in thickness. Results regarding the drag, pitching moment, downwash, and lift are provided.

Report presenting an investigation at transonic speeds to determine the control characteristics of a linked flap and spoiler. The control consisted of a linked combination of a quarter-span inboard plug-type spoiler and a full-span flap. Results regarding the hinge-moment, pitching-moment, lift, and rolling-moment are provided.

"An analysis was developed for calculating the radial temperature distribution in a gas turbine with only the temperatures of the gas and the cooling air and the surface heat-transfer coefficient known. This analysis was applied to determine the temperatures of a complete wheel of a conventional single-stage impulse exhaust-gas turbine. The temperatures were first calculated for the case of the turbine operating at design conditions of speed, gas flow, etc. and with only the customary cooling arising from exposure of the outer blade flange and one face of the rotor to the air" (p. 1).

A theoretical analysis of the radial temperature distribution through the rotor and constant cross sectional area blades near the coolant passages of liquid cooled gas turbines was made. The analysis was applied to obtain the rotor and blade temperatures of a specific turbine using a gas flow of 55 pounds per second, a coolant flow of 6.42 pounds per second, and an average coolant temperature of 200 degrees F. The effect of using kerosene, water, and ethylene glycol was determined. The effect of varying blade length and coolant passage lengths with water as the coolant was also determined. The effective gas temperature was varied from 2000 degrees to 5000 degrees F in each investigation.

Report presenting an investigation of an axial-flow compressor rotor with an inlet hub-tip radius ratio of basically zero. Results regarding the radial distribution of total-pressure ratio and efficiency, measured pressure ratio at design speed, weight flow, and low-speed cascade data are provided.

Report presenting performance testing of a supersonic compressor designed for a tip speed of 1400 feet per second, a pressure ratio of 2.0, and a corrected weight flow of 30.5 pounds per second. The overall performance results of the rotor alone at design speed gave a pressure ratio of 2.17, an adiabatic efficiency of 89 percent, and a weight flow of 28 pounds per second. A comparison with the predicted design results is provided.

From Summary: "Modifications A and B of impeller model MFI-1 and A, B, and C of impeller model MFI-2 were investigated experimentally in an attempt to determine what allowance in blade height should be made for boundary layer and viscous losses in an impeller designed for isentropic compressible flow. A gradual increase in blade height was arbitrarily made from inlet to outlet in anticipation of a gradual build-up of boundary layer. Apparently there was a rapid build-up of boundary layer near the inlet in the experimental case rather than a gradual one. Therefore, the proper allowance for boundary layer cannot be described from the data obtained."

Report presenting an investigation of a series of flame holders designed with the objective of providing a high combustion efficiency in a ramjet combustor at an inlet air velocity of 200 feet per second, inlet-air pressure of 60 inches of mercury absolute, inlet air temperature of 200 degrees Fahrenheit, and near stoichiometric fuel-air ratio. Results regarding the preliminary experiments, two parallel rows of gutters, three rows of gutters, staggered gutters, simultaneous use of three rows and staggered gutters, use of molybdenum, and magnitude of pressure fluctuations are provided.

"Two theoretical procedures are developed for designing asymmetric supersonic nozzles for which the calculated exit flow is nearly uniform over a range of Mach numbers. One procedure is applicable at Mach numbers less than approximately 3. This approach yields, without iteration, a nozzle for which the calculated exit flow is uniform at two Mach numbers and, with proper design, is nearly uniform at Mach numbers between, slightly above, and slightly below these two" (p. 1).

From Summary: "A series of investigations of several 1/14-scale models of an inboard nacelle for the XB-36 airplane was made in the Langley two-dimensional low-turbulence tunnels. The purpose of these investigations was to develop a low-drag wing-nacelle pusher combination which incorporated an internal air-flow system. As a result of these investigations, a nacelle was developed which had external drag coefficients considerably lower than the original basic form with the external nacelle drag approximately one-half to two-thirds of those of conventional tractor designs. The largest reductions in drag resulted from sealing the gaps between the wing flaps and nacelle, reducing the thickness of the nacelle training-edge lip, and bringing the under-wing air inlet to the wing leading edge."

Report presenting flight testing on models of the proposed Consolidated Vultee Aircraft Corporation MX-1626 airplane with nacelles and without nacelles. Results regarding drag level, design modifications, dampening, trimming, and the use of ventral boosters are provided.

Memorandum presenting net jet thrusts for stoichiometric hydrocarbon-air, hydrogen-air and pentaborane-air mixtures for equilibrium and frozen expansion in the exhaust nozzle at flight Mach numbers up to 10. Net jet thrusts for equilibrium flow were three to five times that for frozen flow at Mach 10 for the three fuels cited, a hydrocarbon, hydrogen, and pentaborane. Results regarding dissociation energies, reaction rate, residence time, and estimated minimum performance are provided.

Memorandum presenting net jet thrusts for stoichiometric hydrocarbon-air, hydrogen-air and pentaborane-air mixtures for equilibrium and frozen expansion in the exhaust nozzle at flight Mach numbers up to 10. Examinations of the dissociation products involved and the energies associated with them, for the hydrocarbon- and hydrogen-air mixtures indicated that a major portion of the dissociation energy for the hydrocarbon mixture is involved in the carbon monoxide molecule.

Report presenting an investigation of transient operation of a turboprop engine in an altitude wind tunnel at 35,000 feet over a range of Mach numbers to determine the effect of flight speed upon the dynamic response of the engine. The generalized time constant of the engine-propeller combination varied with flight speed and power level.

The effect of fuel volatility on altitude starting limits of an axial-flow-compressor-type turbojet engine was investigated using fuels with Reid vapor pressures of 1.1 and 5.4 pounds per square inch. At flight Mach numbers from 0.40 to 0.85, the AN-F-58 fuel allowed consistent windmilling at altitudes 2000 to 8000 feet higher than was obtained with the 1.1-pound Reid vapor pressure fuel. At a flight Mach number of 0.25, ignition could not be established at any altitude with the lower-volatility fuel.

Report presenting an investigation of an experimental 15-stage axial-flow compressor to determine the effect of inlet-annulus area blockage on disrupting the rotating stall and altering the overall performance and stall characteristics of the compressor. It is part of a general investigation to determine how to alleviate the general problems of blade vibration and poor off-design performance associated with compressor rotating stall.