Report presenting an analytical investigation to determine the effect of compressor interstage air bleed with the use of constant-area bleed ports on the acceleration characteristics of a typical high-pressure-ratio single-spool turbojet engine. Constant-area interstage bleed, properly located, gave smaller acceleration times than variable-area compressor exit bleed. Results regarding acceleration with interstage bleed, acceleration using constant-area interstage bleed in combination with compressor outlet bleed, variable-area interstage bleed, and comparison of acceleration modes are provided.

From Introduction: "The problem of thrust increase for jet engines by air mixture to the exhaust jet was introduced into aviation techniques by the suggestions of Melot (ref.1). Due to a too general interpretation of several theoretical investigations of A. Busemann (ref.2), so far no practical use has been made of these suggestions. The following considerations show that, in the case of low-pressure mixing according to Melot's suggestions, probably no thrust increase of technical significance will occur for the flight speeds of interest (however, the low-pressure mixture is highly promising for ground test setups and for special power plants of relatively slow sea and land vehicles."

From Summary: "The author first sets forth some observations about the theory of models. Then he established certain general criteria for the construction of dynamically similar models in water and in air, through reference to the perfect fluid equations and to the ones pertaining to viscous flow. It is, in addition, pointed out that there are more cases in which the analogy is possible than is commonly supposed."

"An investigation was conducted in the Lewis altitude wind tunnel to evaluate the performance and operational characteristics of the J40-WE-8 afterburner. A brief program of minor modifications to the flame holder, diffuser, and fuel system was undertaken to improve at a burner-inlet pressure level of 620 pounds per square foot. At this pressure level, modifications to the fuel system resulted in an increase in maximum net thrust from 1500 to 1600 pounds and a reduction in specific fuel consumption in the stoichiometric region from 3.70 to 3.15 pounds of fuel per hour per pound of net thrust" (p. 1).

Report presenting a review of available information on the behavior of brittle and ductile materials under conditions of thermal stress and thermal shock. A number of practical methods that have been used to minimize the negative effects of thermal stress and shock are provided.

Report presenting burning rates for single isooctane drops suspended in various quiescent oxygen-nitrogen atmospheres at room temperature and pressure. The burning rates were compared with those predicted by a previously developed theory based on a heat- and mass-transfer mechanism and with values predicted by a modification to the theory.

From Summary: "Various parts of aircraft propulsion engines that are in contact with hot gases often require cooling. Transpiration and film cooling, new methods that supposedly utilize cooling air more effectively than conventional convection cooling, have already been proposed. This report presents material necessary for a comparison of the cooling requirements of these three methods. Correlations that are regarded by the authors as the most reliable today are employed in evaluating each of the cooling processes."

Report presenting an investigation to determine if certain combinations of design nozzle-exit velocity distribution and wall contouring can alter the three-dimensional flow characteristics such that nozzle mass flow cannot be predicted by ordinary two-dimensional design techniques. Four nozzle configurations with different wall contours and velocity distributions were tested. Results regarding the comparison of analytical and experimental values of mass flow are provided.

"An investigation was conducted in the NACA Lewis altitude wind tunnel to improve the altitude performance and operational characteristics of an afterburner primarily by modifying the diffuser-exit velocity profile by changes in diffuser design and by changing the fuel distribution and the flame holder. Twenty configurations, consisting of combinations of six diffuser geometries, six flame-holder types, and twelve fuel systems, were investigated. Data were obtained over a range of afterburner fuel-air ratios at diffuser-inlet total pressures from 2750 to 620 pounds per square foot" (p. 1).

Report presenting a connected-pipe investigation to evaluate a can-type combustor configuration and to develop the configuration to give a wide operable fuel-air ratio range of high combustion efficiency. Results regarding the wind-tunnel tests and connected-pipe tests are provided.

Report presenting results of a systematic study in the 8- by 6-foot supersonic wind tunnel to determine the effect that area distribution in the subsonic diffuser might have on stability and overall performance of conical-type supersonic diffusers. Drag, pressure recovery, and mass flow are presented for five diffusers designed for maximum mass flow at Mach number 2.0.

Given three presumably identical lots of commercial, sintered, wrought molybdenum, the 1-hour recrystallization temperature of one lot remained above 2900 F by limiting the amount of effective restraining to 35 percent or less. Different recrystallization temperatures were obtained in various atmospheres, the highest in argon and the lowest in hydrogen. Metal thus fabricated and then stress-relieved possessed an ultimate tensile strength at room temperature within 10 percent of metal swaged 99 percent and also possessed equivalent ductility. At 1800 F, equivalent strength and ductility was obtained irrespective of the amount of swaging over the range of 10 to 99 percent.

Note presenting the velocity potentials, span loadings, and corresponding force and moment derivatives for a number of slender-tail arrangements performing a steady rolling motion at supersonic speeds. The method of analysis is based on an application of conformal-transformation techniques.

Memorandum presenting a summary of the methods for estimation of water landing loads on hydro-ski-equipped aircraft in order to provide a unified picture and bibliography of NACA work on the subject. Two approaches to the problem of calculating hydro-ski landing loads are covered. Results regarding the impact load theory for rigidly mounted hydro-skis, effect of chine immersion on landing loads, impact load theory for shock-mounted hydro-skis, and estimation of the water pressure distribution on impacting hydro-skis are provided.

Report presenting the results of a wind-tunnel investigation of the torsional damping characteristics of a constant-chord control surface. The results indicated that the damping coefficient at supersonic speeds was near zero with a tendency toward instability at low supersonic Mach numbers. Results regarding theory, damping moments, and restoring moments are provided.

Memorandum presenting an investigation of the durabilities of several protective coatings applied to air-cooled gas turbine rotor blades of nonstrategic steels in modified turbojet engines. Four types of coatings (ceramic, nickel, Nicrobraz, and aluminized) were applied to a total of 20 blades.

Memorandum presenting an investigation of variable-area auxiliary inlets intended to provide for the variation of engine air requirements with speed and altitude. Three auxiliary scoop inlets were tested in combination with a nose inlet at a range of Mach numbers tested at zero angle of attack.

Report presenting experiments conducted to obtain information on heat transfer in turbulent, mixed-free- and -forced-convection flow. The investigation revealed that the total flow regime as characterized by its Reynolds and Grashof numbers can be subdivided into a forced-flow regime, a free-flow regime, and a mixed-free- and -force-convection regime.

Report presenting free-flight and free-jet testing of a twin side-inlet configuration, including a pilot's canopy and a wheel-well fairing, between a range of Mach numbers from 0.8 to 1.55. Using side inlets provides two important advantages: the inlet can be located closer to the engine and it frees up the nose for other uses. Results regarding the effects of oscillating flow, external-drag coefficient, and total-pressure recovery are provided.

Report presenting an investigation of the flow properties of a constant-outer-wall annual diffuser in combination with a tailpipe in order to come up with a configuration suitable for turbojet afterburners. Information about axial inlet flow and whirling inlet flow is provided. During testing, a vena contrata region formed downstream from the center body terminal and rendered the first 1/2 diameter of the tailpipe ineffective.

Note presenting an investigation of the principal high-speed planing characteristics for a prismatic surface with an angle of dead rise of 0 degrees determined over a wide range of planing variables. Wetted length, resistance, center-of-pressure location, and draft were determined at speed coefficients ranging up to 25.0, beam loadings up to 87.3, and trims up to 30 degrees.

"An analytical solution has been obtained for the equations of motion of water droplets impinging on a wedge in a two-dimensional supersonic flow field with a shock wave attached to the wedge. The closed-form solution yields analytical expressions for the equation of the droplet trajectory, the local rate of impingement and the impingement velocity at any point on the wedge surface, and the total rate of impingement. The analytical expressions are utilized to determine the impingement on the forward surfaces of diamond airfoils in supersonic flow fields with attached shock waves" (p. 1).

Report presenting an experimental investigation using a 16-inch impulse-type supersonic-compressor rotor as a separate component, which obtained a maximum total-pressure ratio of 5.42 and an adiabatic efficiency of 0.76 at 101-percent design speed. The rotor could operate over a wide range of back pressures, but it did not obtain the design impulse condition. Results regarding the rotor-component investigation and stage investigation are provided.

"An investigation has been made in the NACA Lewis icing research tunnel to determine the aerodynamic and icing characteristics of a full-scale induction-system air-scoop assembly incorporating a flush alternate inlet. The flush inlet was located immediately downstream of the offset ram inlet and included a 180 deg reversal and a 90 deg elbow in the ducting between inlet and carburetor top deck. The model also had a preheat-air inlet" (p. 1).