Report presenting a brief series of airplane-wing aerodynamic-noise and boundary-layer-profile measurements made in flight as part of an extended investigation of boundary-layer noise. Results regarding the boundary layer data and ratio of root-mean-square sound pressure to the dynamic pressure are provided.

Memorandum presenting an investigation of an airplane model to determine the effect of area suction trailing-edge flaps and several leading-edge modifications on the aerodynamic characteristics of a 45 degree sweptback wing. The wing had an aspect ratio of 2.8 and a taper ratio of 0.17.

Report presenting an investigation in a 16-inch-diameter simulated afterburner using gaseous hydrogen fuel. Results regarding combustion efficiency, afterburner pressure losses, spontaneous ignition, and a heat-balance check are provided.

Memorandum presenting an investigation of a number of short turbojet combustor configurations for hydrogen fuel in a quarter-annulus duct. The best combustor liner consisted of an annular primary zone and a secondary zone composed of T-shaped channels sloping from the primary zone to the combustor wall.

Report presenting an investigation to determine the effect of motion periodicity on the aerodynamic derivatives due to yawing velocity and yawing acceleration for a 60 degree delta wing, a 45 degree sweptback wing, and an unswept wing. Results were obtained from steady-state yawing-flow tests and tests of model performing pure sinusoidal yawing oscillations. Results regarding the static longitudinal characteristics, derivatives due to yawing velocity, and derivatives due to yawing acceleration are provided.

Report presenting an investigation utilizing a blowdown-type tunnel to determine the effects of a propulsive jet on a zero angle-of-attack wing surface located in the vicinity of both a choked convergent nozzle and a convergent-divergent nozzle. Static-pressure surveys were made on a flat surface located in the vicinity of the propulsive jet. Results regaridng the jet-off and jet-on pressure coefficients, shock waves, and incremental normal force are provided.

From Summary: "Removal of compression-surface boundary layer from the throat of a supersonic aft inlet is shown to increase the critical total-pressure recovery to values comparable to the better axisymmetric nose inlets. Throat bleed on two-dimensional and three-dimensional-type inlets by discrete slots or by porous plates has provided gains in critical recovery of as much as 7 percent at Mach number 2.0. A proper combination of bleed ahead of the inlet and at the inlet throat to control both fuselage and compression-surface boundary layer is shown to produce maximum values of propulsive thrust."

The present paper re-examines the derivation of the integral equations for transonic flow around slender wings and bodies of revolution, giving special attention to conditions resulting from the presence of shock waves and to the reduction of the relations to the special forms necessary for the discussion of sonic flow, that is, flow at free-stream Mach number 1.

Report presenting basic principles affecting the performance of side-inlet air-induction systems as well as an examination of the performance of several fuselage side inlets and a comparison with nose inlets. Methods for improving the performance of both types of inlets are reviewed.

Report presenting a study of the survey results obtained from two transonic turbines in an effort to gain an insight into the physical aspect of the flow. The results indicate that the flow characteristics through a single-stage turbine can be deduced by rotor-exit surveys. Results regarding momentum variation and actual total-pressure loss are provided.

From Introduction: "This report also presents a method of optimizing the blade number and solidity for a given application if the blade loss variation with solidity can be estimated or experimentally determined. Also discussed are the penalties in performance that accompany deviations from optimum values of blade number and solidity."

From Summary: "An investigation was conducted in a 16-inch-diameter simulated afterburner using gaseous hydrogen fuel. No flameholder was used with a multipoint fuel injector. The burner length was varied from 9.5 to 38 inches. The afterburner-inlet conditions were: temperature of 1200 degrees or 1500 degrees F, pressure of 14 to 44 inches mercury absolute, and velocity of 300 to The measured combination efficiency ranged from 85 to 98 percent over an equivalence-ratio range of 0.2 to 1.0. The cold-flow pressure-drop coefficient was 1.0 for the system. Spontaneous ignition was always possible at temperatures above 1200 degrees F but was not possible at temperatures above 1200 degrees F but was not possible below 1100 degrees F for all pressures and velocities tested."

Data were calculated for equivalence ratios of 1 to 4, chamber pressures of 300 and 600 pounds per square inch absolute, and pressure ratios of 1 to 1500. Parameters included are specific impulse, combustion and exit temperatures, molecular weight, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, and thermal conductivity. A correlation is given which permits determination of performance for a wide range of chamber pressures. A method for obtaining specific impulse of JP-4 fuel with OF2 and O3-F2 mixtures is given.

Report presenting an investigation of an airplane model conducted to determine the effect of area-suction trailing-edge flaps and several leading-edge modifications on the aerodynamic characteristics of a 45 degree sweptback wing. Results regarding the effect of trailing-edge flaps on the aerodynamic characteristics of the model with horizontal tail off, effect of wing modifications on the high-lift characteristics of the model with the horizontal tail off, aerodynamic characteristics of the model with the horizontal tail installed, and area-suction requirements are provided.

Satisfactory combustion efficiencies and outlet radial-temperature distributions at low total-pressure loss were obtained in an experimental, quarter-annulus combustor with hydrogen fuel at total pressures as low as 5.7 inches of mercury absolute. The combustor was 25 percent shorter than previous models for liquid hydrocarbon fuels. Similar performance was obtained from this combustor design operated with hydrogen in a full-scale engine.

Report presenting an investigation of the effect of first-stator area changes on the overall component performance of the J71-97 experimental turbine. The performance of the turbine with the first-stator area reduced to 70 percent of design by reorienting the stagger angle of the design blade profiles is presented. Results regarding the overall performance, choking characteristics, and matching characteristics are provided.

The accuracy and durability of two means for measuring the metal temperature of gas-turbine blades were investigated experimentally in a turbojet engine. Cemented thermocouples that could be placed in walls as thin 0.010 inch and commercial temperature-indicating paints were evaluated at turbine-inlet temperatures up to about 1650 degrees F and for centrifugal forces equivalent to about 42,000 times gravity. The cemented thermocouples operated satisfactorily. The temperature-indicating paints were neither as accurate nor as durable as the cemented thermocouples.

This volume continues the NACA study of combustion principles for aircraft propulsion. The various aspects of combustion pertinent to jet engines are organized and interpreted with quite extensive information, particularly for basic or fundamental. subject matter. The report concerns only air-breathing engines and hydrocarbon fuels, and not rocket engines and high-energy fuels.