"The cooling characteristics of three R-1830-94 engines, two of which were mounted in a test stand and the other in a B-24D airplane, were investigated and the results were compared. The flight tests were made at a pressure altitude of 7000 feet; the test-stand runs were made at ground-level atmospheric conditions. Three cooling runs were made for each engine: variable cooling-air pressure drop, variable carburetor-air flow, and variable fuel-air ratio" (p. 1).

"Because previous work has indicated that jettisonable nose sections of airplanes may be inherently unstable, and thus may cause dangerous centripetal accelerations on a pilot after jettisoning during high-speed flight, an investigation has been conducted in the Langley 20-foot free-spinning tunnel to determine the behavior in descent of a model of the jettisonable nose section of the Douglas X-3 airplane. The effects of varying the center-of-gravity position, of attaching fins of various sizes, and of installing a stabilizing parachute were investigated. In the investigation the model descended with its front and trimmed 36 deg above the horizontal and rotated about a vertical wind axis while rolling about its longitudinal body axis" (p. 1).

From Summary: "Qualitative investigations have shown that use of the NACA injection impeller with the R-3350 engine increases the inertia of the fuel-injection system and, when the standard fuel-metering system is used, this increase in inertia results in poor engine acceleration characteristics. This investigation was therefore undertaken to determine whether satisfactory acceleration characteristics of the engine equipped with the injection impeller could be obtained by simple modifications to the fuel-monitoring system. The engine was operated with two types of carburetor; namely, a hydraulic-metering carburetor incorporating a vacuum-operated accelerating pump and a direct-metering carburetor having a throttle-actuated accelerating pump."

"The XF-12 airplane was designed by Republic Aviation Corporation to provide the Army Air Forces with a high performance, photo reconnaissance aircraft. A series of air-stream surveys were made n the vicinity of the empennage of a 1/8.33-scale powered model of the XF-12 airplane in the Langley 19-foot pressure tunnel. Surveys of the vortical-tail region were made through a range of yaw angles of plus or minus 20 degrees at a high and low angle of attack" (p. 1).

Report presenting comparative drag measurements at zero lift at transonic speeds for two sharp-leading-edge airfoils using the NACA wing-flow method. One airfoil had a symmetrical circular-arc section and one had a symmetrical double-wedge section. The primary difference in the drag characteristics of the two airfoils at zero lift is the earlier drag rise of the double-wedge section.

Report discussing the results of flight tests to determine the drag at zero lift of a swept-back wing of inverse taper using an NACA 65-009 airfoil. The data was compared to untapered wings with a similar degree of sweepback. The tapered wing was found to have a lower drag coefficient than the 34-degree swept-back untapered wing but a higher drag coefficient than the 45-degree swept-back untapered wing.

Memorandum presenting an analysis made of the probable range of the stability parameters of present and future missiles. Included is a short review of the dynamic theory and some of the factors and assumptions influencing the stability derivatives and equations of motion.

"Efficiency investigations were made on the two-stage turbine from a Mark 25 aerial torpedo to determine the performance of the unit with five different turbine nozzles. The output of the turbine blades was computed by analyzing the windage and mechanical-friction losses of the unit. A method was developed for measuring the change in turbine clearances with changed operating conditions. The turbine was found to be most efficient with a cast nozzle having a sharp-edged inlet to the nine nozzle ports" (p. 1).

Report presenting the drag of a series of wing-body combinations by the free-fall method in order to provide information on the drag characteristics of promising transonic and supersonic airplane arrangements. Time histories, Mach number variations, and drag coefficients for several areas of the body are provided.

The gust and draft velocities from records of NACA instruments installed in P-61c airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from July 12, to July 18, 1947 are presented.

Information concerning the parameters and design variables affecting an NACA submerged duct design is presented.

Investigation of a single-offset-duct system designed to prevent entrance of water into a turbojet engine was conducted on a half-scale nacelle model. An investigation was made to determine ram-pressure recovery and radial velocity profiles at the compressor section and icing characteristics of such a duct system. At a design inlet velocity of 0.77, the maximum ram-pressure recovery attained with effective water-separating inlet was 77 percent, which is considerably less than attainable with a direct-ram inlet. Continuous heating of the accessory-housing surface would be required for inlets that have a small ice storage space.

Aerodynamic and icing studies were conducted on a one-half-scale model of an annular submerged inlet for use with axial-flow turbojet engines. Pressure recoveries, screen radial-velocity profiles, circumferential mass-flow variations, and icing characteristics were determined at the compressor inlet. In order to be effective in maintaining water-free induction air, the inlet gap must be extremely small and ram-pressure recoveries consequently are low, the highest achieved being 65 percent at inlet-velocity ratio of 0.86. All inlets exhibited considerable screen icing. Severe mass-flow shifts occurred at angles of attack.

Experiments were conducted with 1000-pound-thrust rocket engine to determine feasibility of cooling convergent-divergent nozzle by internal film of water introduced at nozzle entrance. Water flow of 3 percent of propellant flow reduced heat flow into nozzle to 55 percent of uncooled heat flow. Introduction of water by porous ring before nozzle resulted in more uniform coverage of nozzle than water introduced by single arrangement of 36 jets directed along nozzle wall. Water flow through porous ring of 3.5 percent of propellant flow stabilized wall temperature in convergent section but did not adequately cool throat or divergent sections.

Report presenting the results of an investigation to determine the effects of several methods of fuel injection on the operational performance of a 20-inch ram jet. Four fuel-injection arrangements using the same flame holder were presented. Results regarding the variation of combustion efficiency, ram-pressure ratio, location of the point of fuel injection, and range of fuel-air ratios over which combustion can be maintained are provided.

Report presenting an experimental investigation of thrust augmentation of an axial-flow-type turbojet engine with a 4000-pound-thrust rating using a water-alcohol injection at the compressor inlet at sea-level conditions and zero ram. Three injection systems were investigated in order to obtain satisfactory atomization and distribution of the injected liquids. Results regarding engine performance and engine operation are provided.

Report presenting the results of pitching-moment and lift measurements on a model of the D-558-1 airplane with no nose-inlet flow at several tail and elevator settings at a range of Mach numbers. Information about the stability, control, and downwash results is provided.

Memorandum presenting an analysis of the two-dimensional, geared, trailing-edge flap-tab combination at supersonic speeds to determine if the combination could be used to reduce the hinge moments to extremely small values while retaining a large part of the lift effectiveness of a plain flap with the same ratio of flap chord to wing chord.

"The compression plane is intended for operation on or close to the surface of the water, and has a hull with a concave bottom which forms the upper surface of a tunnel into which air is forced under pressure to support part of the load. The results of the tests made in Langley tank no. 1 include values of the horizontal forces, trimming moment, and static pressure in the tunnel for a wide range of loads and speeds and two power conditions, and are presented in the form of curves against speed with load as a parameter. The results are scaled up to 10 times the model size for three conditions at which the model is self-propelled at a steady speed" (p. 1).

Report presenting the use of a flush-type electrical pressure cell for measuring rapidly changing aerodynamic forces on a fluttering control surface. The use of the cell is valuable for the measurement of the aerodynamic forces. Results regarding the individual cells, integrated results, resolution of aerodynamic moments, comparison of aerodynamic with inertia moments, and comparison of static and dynamic hinge moments are provided.

Report presenting an investigation using the NACA wing-flow method to determine the longitudinal stability and control characteristics at transonic speeds of a semispan airplane model with a long slender fuselage, straight wing, and tail of low aspect ratio with faired symmetrical double-wedge airfoil sections. Measurements of the normal force and pitching moments at various angles of attack with five different stabilizer angles of incidence were recorded. The tests were carried out a range of Mach numbers.

Report presenting low-speed testing in the pressure tunnel to determine the aerodynamic characteristics in yaw of a 52 degree sweptback wing with aspect ratio 2.88 and taper ratio 0.625 with NACA 64(sub 1)-112 airfoil sections. Testing included an investigation of the effects on the lateral stability of a fuselage and leading-edge and split flaps. Results regarding the lateral stability parameters of a plain wing, effect of flaps on the lateral stability parameters, effect of scale, and airflow characteristics in the region of a vertical tail are provided.

Report discussing three fuels conforming to AN-F-58 specification were investigated in order to determine the influence of boiling temperatures and aromatic content on altitude performance in single combustor of a 4600-pound-thrust turbojet engine.

Report presenting an analysis of the estimated flying qualities of a tailless airplane with the wing quarter-chord line swept back 35 degrees in a range of Mach numbers based on tests of a model of the airplane in the 7- by 10-foot tunnel. Results regarding performance, longitudinal stability and control, and lateral stability and control are provided.