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 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.

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.

From Summary: "An investigation has been conducted in the NACA Cleveland altitude wind tunnel to evaluate the operational characteristics of a 3000-pound-thrust axial-flow turbojet engine over a range of simulated altitudes from 2000 to 50,000 feet and simulated flight Mach numbers from 0 to 1.04 throughout the operable range of engine speeds. Operational characteristics investigated include engine operating range, acceleration, deceleration, starting, altitude and flight-Mach-number compensation of the fuel-control system, and operation of the lubrication system at high and low ambient-air temperatures."

"Tests were made of a 1/18-scale dynamically similar model of the Lockheed Constellation airplane to investigate its ditching characteristics and proper ditching technique. Scale-strength bottoms were used to reproduce probable damage to the fuselage. The model was landed in calm water at the Langley tank no. 2 monorail. Various landing attitudes, speeds, and fuselage configuration were simulated" (p. 1).

Two low-acceleration transonic-flutter vehicles were launched and flown. The first carried two test wings, one of which fluttered at M = 0.92 at a frequency of 61.4 cycles per second. The reference flutter speed determined from two-dimensional theory for an unswept wing in incompressible flow is conservative when compared to the experimental flutter speed. The second vehicle carried two test wings, one of which failed at M = 0.71 because of low-frequency divergent oscillation. Since this failure was not caused by conventional flexure-torsion flutter, no comparison with a reference flutter speed can be made.

From Summary: "An investigation was conducted in the NACA Cleveland altitude wind tunnel to determine the operational characteristics of the Westinghouse 19B-2, 19B-8, and 19XB-l jet-propulsion engines. The 19B engine is one of the earliest experimental Westinghouse axial flow engines. The 19XB-1 engine is an experimental prototype of the Westinghouse 15 series, having a rated thrust of 1400 pounds. Improvements in performance and operational characteristics have resulted in the 19XB-2B engine with a rated thrust of 1600 pounds. The operational characteristics were determined over a range of simulated altitudes from 5000 to 30,000 feet for the 19B engines and from 5000 to 35000 feet for the 19XB-l engine at airspeed from 20 to 380 miles per hour."

"Gust-velocity measurements and air-borne-radar observations obtained during a transcontinental flight in July 1947 have been analyzed as part of a general investigation of the uses of air-borne radar. The analysis indicates that some reduction in turbulence and a consequent reduction in the risk of encountering the larger gust velocities may be obtained by avoiding portions of clouds giving a radar echo" (p. 1).

Memorandum describing a way in which the data of three previous reports can be used to compute the incompressible flow fields for cowling-spinner combinations and open-nose inlets for use in the design of propeller shanks and cuffs. The method consists of regarding the cowling surface as replaced by a ring vortex sheet whose strength at any point is equal to the local tangential velocity.

From Summary: "This report presents the results of a wind-tunnel investigation conducted to determine the effects of Mach number on the aerodynamic characteristics of a wing of triangular plan form."

Report presenting drag measurements made on a 10-percent-thick wing and 8-percent-thick tail and a 8-percent-thick wing, 6-percent-thick tail version of the X-1 airplane at a variety of Mach numbers. The drag of the thicker wing was found to be much higher than that of the thinner wing. The fuselage was found to cause interference with the wing of both models, making the separation of wing and fuselage drag difficult to determine.

Report presenting a wind-tunnel investigation at a range of Mach numbers with a constant Reynolds number of a semispan model of a thin, unswept wing of aspect ratio 4 and taper ratio 0.5 with a constant-chord aileron and a modified diamond profile. Results regarding lift and rolling-moment characteristics and aileron effectiveness are provided.

"An investigation has been conducted in the Langley 300 MPH 7- by 10-foot tunnel to determine the static stability characteristics at low speeds of complete models with various swept wings so that comparisons might be made with available theoretical and empirical methods of predicting the stability characteristics. Longitudinal and lateral stability characteristics, flaps up and down, were obtained for models having 0 degree, 15 degrees, 30 degrees, and 45 degrees sweptforward and sweptback wings. The results of the investigation indicate that static stability characteristics can be estimated with reasonable accuracy in the low-lift range by means of existing theories" (p. 1).

The results of tests at a Mach number of 1.94 of an ogives-nose cylindrical pitot-static tube and similar tests at Mach numbers of 1.93 and 1.62 of a service pitot-static tube to determine body static pressures and indicated Mach numbers are presented and discussed. The radial pressure distribution on the cylindrical bodies is compared with that calculated by an approximate theory.

"A Westinghouse 24C-2 combustor was investigated at conditions simulating operation of the 24C Jet engine at zero ram over ranges of altitude and engine speed. The investigation was conducted to determine the altitude operational limits, that is, the maximum altitude for various engine speeds at which an average combustor-outlet gas temperature sufficient for operation of the jet engine could be obtained. Information was also obtained regarding the character of the flames, the combustion efficiency, the combustor-outlet gas temperature and velocity distributions, the extent of afterburning, the flow characteristics of the fuel manifolds, the combustor inlet-to-outlet total-pressure drop, and the durability of the combustor basket" (p. 1).

Report presenting control requirements and parameters for a ram jet with a variable-area exhaust nozzle, which have been analyzed from calculated performance charts covering flight Mach numbers from 0.6 to 3.0 and altitudes from sea level to 30,000 feet. Requirements for maximum efficiency, safe and stable operation, maximum range of thrust at a given flight Mach number, and control of fuel flow are discussed and control parameters are selected.

Memorandum presenting the modifications to the J35 engine that are necessitated with the use of non-strategic materials. Two proposals for cooling the rotor disk and blades are: finned hollow blades that are air cooled and blades with circular passages for liquid cooling in which the fuel could be used as the coolant.

From Summary: "Results are presented of an experimental investigation of the characteristics of NACA submerged inlets on a model of a fighter airplane for Mach numbers from 0.30 to 0.875. The effects on the ram-recovery ratio at the inlets of Mach number, angle of attack, boundary-layer thickness on the fuselage, inlet location, and boundary-layer deflectors are shown. The data indicate only a slight decrease in ram-recovery ratio for the inlets ahead of or just behind the wing leading edge as Mach number increased, but showed large decreases at high Mach numbers for the inlets aft of the point of maximum thickness of the wing."