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.

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).

Report presenting a low-speed investigation to determine the effectiveness of a conventional aileron and various spanwise spoiler arrangements on a 42 degree sweptback wing. The rolling-moment characteristics of the aileron and the spoilers, as well as the aileron hinge-moment, normal-force, and balance-chamber pressure characteristics were determined for a plain wing and a wing equipped with several high-lift and stall-control devices.

Report presenting exploratory testing obtained with leading-edge wing chord-extensions on two 52 degree sweptback wings. The wings had the same aspect ratio but different airfoil sections. Results regarding force characteristics and flow characteristics are provided.

Report presenting an investigation using the transonic-bump method through a range of Mach numbers in the high speed 7- by 10-foot tunnel to determine the lateral-control characteristics of 30-percent-chord flap-type controls with various spans and spanwise locations. Rolling moments, pitching moments, and lift were obtained through a small range of control deflections.

Report presenting an investigation of a rectangular wing with a subsonic-type round-leading-edge airfoil section (NACA 65-009) at various Mach numbers. The results generally agreed with calculated values with the exception of the laminar-separated region on the low-pressure surface of the model. Results regarding the calculation of pressure distribution, experimental pressure distributions, aerodynamic characteristics, and shadowgraph studies are provided.

Report presenting an analysis of the flow conditions downstream of a cascade of turbine rotor blades at critical and supercritical pressure ratios. Five theoretical methods are compared with an experimental method using the conservation-of-momentum principle and static-pressure surveys as well as schileren photographs of the flow downstream of the blades. Results regarding static-pressure surveys and schileren photographs are provided.

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.

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.

Models of the Hermes A-3B missile were tested in the Ames supersonic free-flight wind tunnel to determine the static-longitudinal-stability characteristics at a Mach number of 5.0 and a Reynolds number based on body length of 10 million. The results indicated that the model center of pressure was 45.3 percent of the body length aft of the nose and the lift-curve slope based on body frontal area was 0.064 per degree. Estimates indicated that the effect on these characteristics of aeroelastic twisting of the model fins was small but important if a precise location of center of pressure is required. A comparison of the test results with predictions based on available theory showed that the theory was useful only for rough estimates, The drag coefficient at zero lift, based on body frontal area, was found to be 0.155.

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 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.

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."

"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).

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.

"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).

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.

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.

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."

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 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 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.