From Introduction: "The purpose of the present paper is to present results obtained recently relating to the characteristics of a full-span sharp-edge spoiler with an 0.02-chord projection above the wing surface at several chordwise positions and also to the relative effectiveness of the sharp-edge spoiler and a wedge-type spoiler located at the 80-percent-chord line."

From Introduction: "An analytical evaluation of the effects of inlet losses on the net thrust and the fuel economy of an axial-flow-compressor type turbojet engine with a two-stage turbine is presented herein. The analysis is based on engine performance characteristics that were determined from experiments in the NACA Cleveland altitude wind tunnel (references 1 and 2). The experimental investigation did not include tests in which inlet losses were systematically varied, but the effects of these losses can be accurately estimated from the experimentally determined performance characteristics of the engine."

Report presenting a flight investigation on a rectangular ram jet over a range of fuel air ratios, combustion chamber inlet velocities, and pressure altitudes. A comparative study to determine the effects of altitude, combustion-chamber-inlet velocity, and fuel-air ratio on starting characteristics, minimum blow-out limits, combustion efficiency, gas total-temperature ratio, and net-thrust coefficient for three flame holders was also conducted.

Report presenting the results of an investigation on a rectangular ram jet to determine the effect of variation in fuel pressure on the starting characteristics, minimum blow-out limits, combustion efficiencies, gas total-temperature ratio, and net-thrust coefficient. Testing occurred using three different fuel nozzles and over a range of pressure altitudes, airspeeds, and fuel-air ratios.

Report presenting a study of the effects of air velocity on the energy and power of the spark in a constant ignition source and the duration of the spark discharge in the spark gap for various conditions of electrode spacing, electrode diameter, air temperature, and pressure. Energy and average power increased with pressure, velocity, and electrode spacing and electrode diameter and air temperature had negligible effect.

Report presenting an investigation of icing and ice protection at the inlet of a turbojet engine in the altitude wind tunnel. A method of ice protection was studied that uses hot gas bled from a turbine inlet and injected into the air stream ahead of the compressor inlet. Ice was either prevented or accumulated slowly at various engine speed levels.

Report presenting a flight and wind-tunnel investigation to determine the aerodynamic vibration characteristics of ailerons for the Douglas D-558-2 airplane. Testing was conducted to investigate the possibilities of a single-degree-of-freedom flutter known as aileron "buzz" or aileron compressibility flutter. Results regarding the three types of aileron vibration observed and vibration amplitudes are provided.

From Summary: "A 19XB-1 combustor was operated under conditions simulating zero-ram operation of the 19XB-1 turbojet engine at various altitudes and engine speeds. The combustion efficiencies and the altitude operational limits were determined; data were also obtained on the character of the combustion, the pressure drop through the combustor, and the combustor-outlet temperature and velocity profiles. At altitudes about 10,000 feet below the operational limits, the flames were yellow and steady and the temperature rise through the combustor increased with fuel-air ratio throughout the range of fuel-air ratios investigated. At altitudes near the operational limits, the flames were blue and flickering and the combustor was sluggish in its response to changes in fuel flow."

"A method for calculating the flow fields of axially symmetric bodies from their pressure distributions is reported in NACA RM No. L8I17. In order to facilitate application of this method to the important case of the cowling-spinner combination, for use in the design of propellers, the present paper presents static-pressure distributions on the tops of 79 high-critical-speed NACA 1-series cowling-spinner combinations over wide ranges of inlet-velocity ratio at angles of attack of 0 degrees, 2 degrees, 4 degrees, and 6 degrees. Static-pressure distributions around the nose sections of several cowlings are given in greater detail to aid in estimating the pressures near the stagnation points and to show the effect of changes in the internal lip shape" (p. 1).

Report discussing a wing-alone and wing-fuselage configuration with particular characteristics as part of a series of tests of wings using the transonic-bump test technique. Lift, drag, pitching moment, and root bending moment were obtained for the configurations. The effective downwash angles and dynamic-pressure characteristics in the tail region are also described.

Report presenting a preliminary theoretical and experimental investigation of the supersonic characteristics of blunt-trailing-edge airfoils. Results regarding the drag measurements at zero lift, measurements at angle of attack, and a general discussion of the theoretical and experimental results is provided.

From Introduction: "Water injection at the compressor inlet has been successfully used to increase the thrust of turbojet engines. References 1 and 2 indicate that the sea-level static thrust of a centrifugal-flow-type turbojet engine may be increased about 25 percent by use of liquid injection. Reference 3 indicates that greater thrust augmentation is possible at a compressor pressure ratio of 11 than of 4."

"Studies have been made by the NACA wing-flow method of the use of fuselage static orifices between the wing and tail of a swept-wing airplane for possible application to service airspeed installations. The tests were made at zero angle of attack. The results indicate that, although the maximum errors are large, these locations are usable from the consideration that the local Mach numbers at the locations studied are sensitive to variation of the true Mach number within the test Mach number range of 0.7 to 1.2" (p. 1).

Report presenting an experimental investigation to determine the vibration characteristics of loosely mounted turbine blades during service operation of a turbojet engine. High-temperature strain gages were used to measure turbine-blade vibrations. Results regarding oscillograph records, critical speeds and frequencies, vibratory-stress levels, and effect of tightening the blade mount are provided.

From Introduction: "Some experimental data on flame-holder pressure losses have been presented (reference 1 to 4). A theoretical analysis that assume a sudden enlargement of flow area was made at the NACA Lewis laboratory to determine the effect of flame-holder open area and combustion-chamber-inlet Mach number on the pressure losses across flame holders. The results of this analysis were then compared with experimental data obtained with several different flame-holder designs."

Report presenting the results of an investigation in the full-scale tunnel of the static longitudinal stability and control of a convertible-type airplane as affected by articulated- and rigid-propeller operation. The investigation included force measurements for a large angle-of-attack range with the all-movable horizontal tail installed and removed.

From Summary: "An investigation of turbojet-engine thrust augmentation by means of tail-pipe burning has been conducted in the NACA Lewis altitude wind tunnel. Several fuel systems and flame holders were investigated in a 29-inch-diameter tail-pipe burner to determine the effect of fuel distribution and flame-holder design on tail-pipe-burner performance and operational characteristics over a range of simulated flight conditions. At an altitude of 5000 feet, the type of flame holder used had only a slight effect on the combustion efficiency."

Report presenting an investigation of the characteristics of a low-aspect-ratio wing at high subsonic Mach numbers in the high-speed tunnel. The wing model had an NACA 65-108 airfoil section, an aspect ratio of 4.01, a taper ratio of 0.498, and no twist or dihedral. Results regarding normal-force characteristics, pitching-moment characteristics, and drag characteristics are provided.

Report presenting the ditching characteristics of the Douglas DC-4 and DC-6 in a water tank. Dynamically similar models of 1/16 scale were used for the investigation, which was conducted in calm and rough water. The ditching characteristics and safest ditching procedures were determined by testing at various landing attitudes, speeds, and simulated conditions of damage.

Report presenting turbulent-boundary-layer profiles at large Reynolds numbers and with Mach numbers up to 1.2. In this investigation, velocity profile shapes were substantially unaffected by compressibility. Results regarding the temperature considerations, velocity profiles, and turbulent boundary layer under normal shock are provided.

Report presenting an investigation of the low-speed, power-off static longitudinal stability and control characteristics of a canard model with a triangular wing and horizontal tail in the free-flight tunnel. Results regarding the horizontal tail used to overcome change in stability and horizontal tail used for longitudinal control are provided.

Memorandum presenting a bibliography of unclassified aircraft fire literature consisting of reports from a 20-year period ending January 1, 1949. The reports are separated into the following categories: aircraft fire accidents and statistics, combustibles, ignition sources, fire protection, fire prevention, fire resistance of materials, fire detecting, fire extinguishing, and passenger protection or rescue.

Report presenting the results of an experimental investigation to determine the downwash in the region of the trailing vortex behind a trapezoidal-wing tip in a supersonic stream. Results regarding the downwash at spanwise stations, downwash at chordwise stations, and wake survey are provided.

Report presenting a discussion of the aerodynamic forces and moments on inclined bodies of revolution. An approximate theory to allow for the effects of viscosity is developed and applied. Results regarding the variation of lift and pitching moment, and center of gravity are provided.