A typical inlet axial-flow compressor inlet stage, which was designed on the basis of constant total enthalpy with symmetrical velocity diagram at all radii, was investigated. At a tip speed of 1126 feet per second, a peak pressure ratio of 1.28 was obtained at an efficiency of 0.76. At a tip speed, the highest practical flow was 28 pounds per second per square foot frontal area with an efficiency of 0.78. Data for a rotor relative inlet Mach number range of from 0.5 to 0.875 indicates that the critical value for any stage radial element is approximately 0.80 for the stage investigated.

Report presenting the results of a series of qualitative studies with tufts on three wings with sweepback angles of 30 degrees, 45 degrees, and 60 degrees, which show that under certain conditions, a leading-edge vortex can exist in the unsteady flow associated with a gust. The results indicated that if a wing in steady flight prior to entering a gust is at an angle of attack several degrees less than that at which vortex flow first begins in steady flow, it may penetrate the gust without having the vortex develop, even if its angle of attack is increased by the gust into the vortex-flow regime.

Report presenting an analysis of a series of wing-body combinations in the 8-foot high-speed tunnel. The paper presents the results of an investigation of a wing-fuselage combination with a wing of unswept quarter-chord line, aspect ratio 4, taper ratio 0.6, and an NACA 65A006 airfoil section. Results regarding force and moment characteristics and wake and downwash characteristics are provided.

Turbine centrifugal stress is a limiting factor for all flight conditions studied. This stress is more severe for sea-level operations than for subsonic flight at the tropopause. Turbines designed for a stress of 30,000 psi are capable of driving a light, compact, high-spedd compressor but only at high values of specific fuel consumption. An increase in turbine-inlet temperature is accompanied by an increase in turbine centrifugal stress.

Report presenting an investigation of the effect of combustion on diffusion in the fuel preparation zone of a ram-jet engine. The information was applied in the design of combustor to operate at lean fuel-air ratios.

Report presenting testing of six flutter wings, two swept 45 degrees and four unswept, attached to three freely falling bodies. Flutter frequency and phasing were recorded.

Report presenting an investigation of a model of the Kingfisher XAUM-2 flying torpedo to determine the pressure recoveries within the jet engine nacelle and to determine the effects of several changes in model configuration on the aerodynamic characteristics of the model. The effectiveness of elevons and tabs as control devices was also investigated.

Report presenting an investigation of the hydrodynamic characteristics of a powered dynamic model of the Martin PBM-5 seaplane equipped with a single Edo hydro-ski. Various hydro-ski positions were investigated. Results regarding aerodynamic and hydrodynamic characteristics, including excess thrust, smooth-water landings, smooth-water take-offs, rough-water take-offs, and spray are provided.

Report presenting a determination of the combustion efficiency of gaseous hydrogen fuel in a ramjet engine in a connected-pipe test facility. Operating conditions simulated a range of Mach numbers and altitudes. Results regarding the effect of inlet parameters and design variables on combustion efficiencies, comparison between methods of determining efficiency, and ignition characteristics are provided.

Report presenting an investigation of the NACA 4-(4)(06)-057-45A and NACA 4-(4)(06)-057-45B two-blade swept propellers in the high-speed tunnel at blade angles of 25 degrees, 55 degrees, 60 degrees, 65 degrees, and 70 degrees. The swept propellers were compared with straight propellers and were found to be 10 percent more efficient at a forward Mach number of 0.85 for the design blade angle of 60 degrees. Results regarding the effect of forward Mach number, blade sweep, advance ratio, and constant power coefficient on efficiency are also provided.

Report presenting an investigation of two sharp-edge annular inlets with conical central bodies at low airspeeds in the propeller research tunnel to obtain information concerning the surface-pressure, drag, and pressure-recovery characteristics of the inlets at subsonic flight. Results regarding the nose and inner surface of the diffuser, inlet lips, minimum surface pressures and critical Mach numbers, pressure surveys in inlets, and pressure surveys in diffusers are provided.

"At the request of the Air Material Command, Army Air Forces, an investigation was conducted by the NACA Cleveland laboratory to determine the performance characteristics of the compressor of the XJ-41-V turbojet engine. This report is the second in a series presenting the compressor performance and analysis of flow conditions in the compressor. The static-pressure variation in the direction of flow through the compressor and the location and the cause of the maximum flow restriction at an equivalent speed of 8000 rpm are presented" (p. 1).

"An altitude-test-chamber investigation was conducted to determine the operational characteristics and altitude blow-out limits of a Solar afterburner in a 24C engine. At rated engine speed and maximum permissible turbine-discharge temperature, the altitude limit as determined by combustion blow-out occurred as a band of unstable operation of about 8000 feet altitude in width with maximum altitude limits from 32,000 feet at a Mach number of 0.3 to about 42,000 feet at a Mach number of 1.0. The maximum fuel-air ratio of the afterburner, as limited by maximum permissible turbine-discharge gas temperatures at rated engine speed, varied between 0.0295 and 0.0380 over a range of flight Mach numbers from 0.25 to 1.0 and at altitudes of 20,000 and 30,000 feet" (p. 1).

"Three modifications of the auxiliary-stage supercharger for the V-1710-93 engine were designed and tested as part of an investigation to improve the power output and the altitude performance of the engine. A 12-vane diffuser was substituted for the standard 11-vane diffuser, and a vaneless discharge passage and a modified scroll were designed to increase the flow capacity of the supercharger and thereby to increase the performance at the high volume flows required by the engine. With the 12-vane diffuser installed and the carburetor replaced by an adapter, the equivalent volume flow at the peak efficiency point was increased 25 percent at the lowest speed investigated and 9.5 percent at the highest speed" (p. 1).

Memorandum presenting an investigation of the low-speed static stability characteristics of a canard model with a 45 degree sweptback wing and a 60 degree triangular horizontal control surface. Results regarding longitudinal stability and control and lateral stability and control are provided.

Component data on the J35-A-23 compressor and two-stage turbine were used to determine the problems in matching the two units for operation in a turbojet engine. Possible operating regions were determined and an equilibrium operating line was also determined for the assumed conditions of zero flight speed and a jet nozzle area approximately 5.5 percent greater than the wide-open nozzle area.

From Introduction: "A 12-percent-chord-thick wedge section and a reversed NACA 0012 section were chosen for these tests as they are representative of sections having no boat tailing and appreciable boat tailing (i.e., blunt and rounded trailing edges, respectively), and the results of this investigation are compared with those obtained from a previous investigation of the NACA 0012 section. Conclusions are drawn regarding the relative merits of the two unconventional sections and the conventional section in transonic speed range."

Report presenting an investigation of two types of jet controls in the 8- by 6-foot supersonic wind tunnel. One used a converging swiveled nozzle and the other was a biconvex circular-arc vane mounted in a shroud and placed downstream of a convergent nozzle. Results regarding the jet vane, swiveled nozzle, and a preliminary evaluation are provided.

Report presenting testing of a wing with 0 degree sweepback of the 0.25-chord line in combination with a body of revolution at Mach numbers from 0.60 to 1.11 for angles of attack up to 24 degrees. Results regarding lift characteristics, pitching moment, drag characteristics, and lift-drag ratio are provided.

Report presenting a determination of the relative reactivities of six fuels with red fuming nitric acid in a 40-pound-thrust rocket engine with rapid liquid-phase mixing. Hydrazine, trimethyl-trithiophosphite, furfuryl alcohol, unsymmetrical dimethylhydrazine, allylamine, and o-toluidine were studied. Results regarding the combustion characteristics of the fuels, fuel ratings, pressure in the mixing cup, effect of chamber diameter, and overall combustion efficiency are provided.

Report discussing testing on a high-thrust turbojet engine capable of operation at high flight speeds. The report presents the overall performance and blade-element performance of the engine at a specified hub-tip radius ratio and specific weight flow of air.

From Summary: "An investigation was conducted in the Cleveland altitude wind tunnel to determine the operational characteristics of an axial flow-type turbojet engine with a 4000-pound-thrust rating over a range of pressure altitudes from 5,000 to 50,000 feet, ram pressure ratios from 1.00 to 1.86, and temperatures from 60 deg to -50 deg F. The low-flow (standard) compressor with which the engine was originally equipped was replaced by a high-flow compressor for part of the investigation. The effects of altitude and airspeed on such operating characteristics as operating range, stability of combustion, acceleration, starting, operation of fuel-control systems, and bearing cooling were investigated."

Report presenting an investigation in the supersonic pressure tunnel to determine the effects of various vertical positions of a wing and horizontal tail on the static longitudinal aerodynamic characteristics of a trapezoidal wing model. Results regarding effect of wing vertical position and tail-on characteristics are provided.

The effect of spark repitition rate on the altitude ignition limits of a single tubular (turbojet engine) combustor was investigated. An increase in sparking rate from 3 to 140 sparks per second reduced the ignition limiting combustor-inlet pressure about 2 to 4 inches of mercury for air-flow rates of 1.87 and 2.80 pounds per second per square foot.520::At 3.75 pounds pe At 3.75 pounds per second per square foot, the corresponding reduction was 4 to 12 inches of mercury. The trend was similar for both low-and high-volatility fuels and for two spark-energy levels.