Report presenting estimates of downwash angles determined from an analysis of pressures measured on the horizontal tail of a supersonic aircraft configuration. The results are compared to an approximate application of linearized theory and force-test results for the same configuration.

Report presenting the design, construction, and investigation of an axial-flow compressor inlet stage with a maximum rotor relative inlet Mach number of 1.1. The rotor was designed for a high axial inlet velocity, no inlet guide vanes, and a tip speed of 1000 feet per second. Results regarding the overall performance, rotor inlet conditions, and stator exit conditions are provided.

Report presenting an investigation of the effect of separation vortex flow on the downwash, sidewash, and wake characteristics behind a 47.5 degree sweptback wing with symmetrical circular-arc airfoil sections. Three configurations were investigated: the basic wing, the wing with full-span drooped-nose flaps deflected 40 degrees, and the wing with semispan plain flaps and full-span drooped-nose flaps deflected 40 degrees. Results regarding the air-stream surveys, distribution of vorticity, average values of downwash and dynamic-pressure ratio, and correlation with theory are provided.

Report presenting some measurements of the dynamic lateral stability and lateral and longitudinal trim of a Douglas D-558-II in flights up to a Mach number of 1.87 and an altitude of about 67,000 feet. Testing indicated that the airplane flying in low density air at supersonic speeds had poor dynamic lateral stability, which worsened as the Mach number was increased to 1.85.

From Summary: "An analytical investigation was made to determine from component performance characteristics the effect of air bleed at the compressor outlet on the acceleration characteristics of a typical high-pressure-ratio single-spool turbojet engine. Consideration of several operating lines on the compressor performance map with two turbine-inlet temperatures showed that for a minimum acceleration time the turbine-inlet temperature should be the maximum allowable, and the operating line on the compressor map should be as close to the surge region as possible throughout the speed range. Operation along such a line would require a continuously varying bleed area."

Memorandum presenting an investigation of the effects of longitudinal location of the wing and varying body size on the interference characteristics of a 45 degree sweptback wing over a range of Mach numbers and angles of attack. The wing had an aspect ratio of 4, a taper ratio of 0.6, and NACA 65A006 airfoil sections. The results indicated that the zero-lift drag of the wing with interference in the forward position was lower throughout the Mach number range than for the wing with interference in the rearward position.

An investigation was conducted using static capsules fabricated from "L" nickel tubing to determine the effect of temperature level, temperature gradient, and test duration on corrosion and mass transfer by molten sodium hydroxide under free-convection conditions. A base temperature range from 1000 degrees to 1600 degrees F with temperature differences to 500 degrees was studied. The rate of mass transfer was found to be strongly dependent on both temperature level and gradient. The rate shows little tendency to decrease for test durations up to 200 hours, although the concentration of nickel in the melt approaches a limited value after 100 hours.

The report includes a description of the test facilities and methods, crash configuration, layout of crash site, instrumentation, data-recording systems, and the post-crash examination procedure of the fullscale crash-fire investigation, which is part of a comprehensive study of the airplane crash-fire problem.

"A preliminary evaluation was made of three types of combustor configurations in a 48-inch-diameter ram-jet engine to determine the one with the greatest promise of ultimately achieving efficient and stable combustion at low fuel-air rations and low combustor-inlet pressure. The combustor configurations evaluated include (1) a can-piloted configuration using a gutter-type flame holder with can-type pilot burners for stability, (2) an annular-piloted configuration using a gutter-type flame holder with an annular pilot burner to provide stability and to serve as a flow divider for confined fuel-air mixing, and (3) a can-type configuration using a flow divider for confined fuel-air mixing. No modifications were made to optimize the performance of any configuration" (p. 1).

Report presenting an investigation at Mach number 1.61. to determine the aerodynamic characteristics of a full-span trailing-edge control on a 60 degree delta wing with and without a partial-span spoiler mounted on the wing just ahead of the control. Pressure distribution and hinge-moment measurements were made over a range of angles of attack and control deflection. Results indicated that regions of increase pressure due to flow separation ahead of the control at the larger control deflections and ahead of the spoiler exist.

From Introduction: "Reported herein are results of the additional direct-stress fatigue tests on: (1) a plate-type specimen with cored centrally located hole and (2) 0.300-inch-diameter round polished specimens with various degrees of porosity."

"An analytical and experimental investigation was made with a J33-A-9 engine to determine the effectiveness of spray cooling as a means of increasing thrust by permitting engine operation at inlet-gas temperatures and speeds above rated. With the assumption of adequate spray cooling at a coolant-to-gas flow ratio of 3 percent, calculations for the sea-level static condition indicated a thrust may be achieved by engine operation at an inlet-gas temperature of 2000 degrees F and an overspeed of 10 percent. Of the water-injection configurations investigated experimentally, those located in the inner ring of the stator diaphragm provided the best cooling at rated engine speed" (p. 1).

A turbine designed to power a supersonic compressor was investigated with four nozzle settings and one nozzle modification to determine the effect on turbine performance. With the correct ratio of nozzle throat area to rotor effective throat area, the design specific work was obtained near the peak efficiency. From the results of the investigation it was concluded that the convex in sweep of the rotor inner wall and high degree of blade taper caused the turbine configuration to have two aerodynamic disadvantages in comparison with a turbine configuration with an axial inner wall at the rotor outlet and little axial taper.

"A mixed-flow impeller was designed to give a prescribed blade-surface velocity distribution at mean blade height for a given hub-shroud profile. The blade shape at mean blade height, which was produced by the prescribed velocity distribution, was extended by means of radial lines to form the composite blade shape from hub to shroud. The resulting blade was relatively thick; therefore, it was necessary to retain the inverse blade taper which resulted from extension of the radial lines in order to prevent merging or near merging of the separate blades near the hub. For the first test version of the impeller, designated the MFI-2A, the blade height was arbitrarily made greater than that for the basic impeller (the MFI-2) to allow for viscous effects" (p. 1).

Report presenting an investigation on a full-scale turbojet engine to obtain the altitude-ignition characteristics of three fuels with different ASTM distillation curves. Two of the fuels had a Reid vapor pressure of 2.7 pounds per square inch and the third had a vapor pressure of 1.7 pounds per square inch. Results regarding the effect of fuel volatility and fuel-air ratio on altitude-ignition and propagation characteristics and effect of altitude variation on altitude ignition and propagation characteristics of fuel 53-39 are provided.

Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel of large-chord NACA and 23021, and 23030 airfoils with split flaps 10, 20, 30, and 40 percent of the wing chord to determine the section aerodynamic characteristics of the airfoils as affected by airfoil thickness, flap chord, and flap deflection. The complete section aerodynamic characteristics of all the combinations tested are given in the form of graphs of lift, drag, and pitching-moment coefficients, and certain applications to aerodynamic design are discussed.

Memorandum presenting experimental force and moment characteristics, including lift-drag ratios, which have been measured and briefly studied for two families of wing-body combinations. One family consisted of essentially arrow wings with half conical bodies. The other consisted of a fineness-ratio-12 body of revolution alone and with flat-plate triangular wings of aspect ratios ranging from 0.375 to 1.8.

Report presenting an investigation to determine the effect of a distributed granular-type roughness on boundary-layer transition at several temperatures. The roughness was not found to introduce any disturbances of significant magnitude to influence transition. Surface cooling did not increase the value of the critical roughness Reynolds number for a distributed granular-type roughness either.

Memorandum presenting an investigation in the 4- by 4-foot supersonic pressure tunnel at Mach number 2.01 to determine the longitudinal and lateral stability and control characteristics of a 60 degree delta-wing airplane configuration equipped with a trapezoidal canard control and with wing trailing-edge flap controls. The investigation included studies of the flap control with and without canard surface and studies of the canard control alone and with the flap control.

Report presenting an experimental investigation to evaluate the internal performance of two types of auxiliary air inlets, a submerged and a scoop inlet, operating within the turbulent boundary layer existing on the bottom of a typical supersonic fighter aircraft afterbody. Results regarding boundary-layer flow and inlet performance are provided.

From Summary: Test results are presented which indicate that the pickup is aerodynamically stable and has accuracy, obtained from a bench calibration, of better than 0.3^o under conditions including acceleration up to 20g in any direction, Mach numbers from 0.5 to 2.8, and dynamic pressures up to at least 65 psi. Equations and curves which can be used to obtain flow direction at the center of gravity of a maneuvering model are presented."

Report discussing an investigation of wing-inlet oil-cooler ducts on a twin-engine airplane to determine internal and external-flow characteristics of the ducting installation. Testing was also performed on revised inlets to attempt to develop a ducting system with low overall losses throughout the operating range.

From Summary: "Tests with a dynamically similar model of the Navy XP4M-1 airplane were made to determine the best way to land the airplane in calm and rough water, to determine its probable ditching performance, and to determine practicable modifications which could be incorporated in the design of the airplane that would improve its ditching characteristics. The results were obtained by making visual observations, by recording longitudinal decelerations ,and by taking motion pictures of the landings. A list of conclusions from the test results is included."

"The results obtained from measurements of gust and draft velocities within thunderstorms for the period July 22, 1946 to July 23, 1946 at Orlando, Florida, are presented herein. These data are summarized in tables I and II, respectively, and are of the type presented in reference 1 for previous flights. Inspection of photo-observer records for the flights indicated that no data on ambient air temperature variations within thunderstorms were obtained" (p. 1).