Memorandum presenting an investigation of the flow characteristics over a 6-percent-thick symmetrical circular-arc airfoil section with a 30-percent-chord trailing-edge flap at a Mach number of 6.90 and a Reynolds number of 1.65 x 10(sub 6). The model was tested over an angle-of-attack range of 0 to 16 degrees and a flap-deflection range of -16 degrees to 16 degrees. Results regarding pressure results and aerodynamic characteristics are provided.

"An analysis shows that the scattering of unpolarized plane light waves which penetrate turbulent, transparent gases provides a measure of the average integral scale and intensity of the turbulent density fluctuations. The analysis is based upon the scattering coefficient deduced by Booker and Gordon and, thus, assumes isotropic fluctuations having an exponentially decaying (Markoffian) correlation function. Photometric data taken through turbulent boundary layers in air are found to conform functionally with the analytical prediction" (p. 1).

Attenuation of tangent-pressure oscillation in liquid-oxygen-heptane rocket engine combustion chamber using longitudinal fin. Results regarding the engine performance with injector A, effect of fins with injector A, and destructiveness of screaming are provided.

An investigation of the use of fins to prevent high-frequency combustion-pressure oscillations (screaming) in the combustion chamber of a 1000-pound-thrust rocket engine with a chamber pressure of 300 pounds per square inch and using liquid oxygen and n-heptane as propellants. Tangential combustion-pressure oscillations were found to be eliminated with longitudinal fins located in the combustion zone. Results regarding engine performance, effect of fins, and destructiveness of screaming are provided.

Memorandum presenting an annotated bibliography of NACA reports containing information of interest to designers and manufacturers of controls for turbojet engines. The eleven major topics include starting, acceleration, flame-out, temperature control, stability and dynamics of small disturbances, combustion dynamics, engine inlet diffuser control, steady-state engine performance, fuel systems, sensors, and general control system theory.

Report presenting pressure-drag coefficients and the changes in these coefficients with mass-flow ratio, which have been measured in tests of six open-nose conical cowls at an angle of attack of 0 degrees. Testing occurred in the Ames 8 by 8-inch supersonic wind tunnel at a range of Mach numbers. Results regarding pressure distributions, change in cowl pressure drag with mass-flow ratio, cowl pressure drag at a given mass-flow ratio, and changes in cowl pressure drag with mass-flow ratio as a function of Mach number are provided.

Note presenting an evaluation of the existing theories of linearized tire motion and wheel shimmy. A series of systematic approximations to the summary theory is developed for the treatment of problems too simple to merit the use of the complete summary theory. Procedures are discussed for applying the summary theory and its systematic approximations to the shimmy of more complex landing-gear structures than have previously been considered.

"A ditching investigation was made of a l/l2-scale dynamically similar model of the Douglas F4D-1 airplane to study its behavior when ditched. The model was landed in calm water at the Langley tank no. 2 monorail. Various landing attitudes, speeds, and configurations were investigated. The behavior of the model was determined from visual observations, acceleration records, and motion-picture records of the ditchings. Data are presented in tables, sequence photographs, time-history acceleration curves, and attitude curves" (p. 1).

"An investigation has been conducted in the 27- by 27-inch preflight jet of the Langley Pilotless Aircraft Research Station at Wallops Island, Va., of the release characteristics of a dynamically scaled streamlined-type internally carried store from a simulated bomb bay at Mach numbers M(sub o) of 0.8, 1.4, and 1.98. A 1/17-scale model of the Republic F-105 half-fuselage and bomb-bay configuration was used with a streamlined store shape of a fineness ratio of 6.00. Simulated altitudes were 3,400 feet at M(sub o) = 0.8, 3,400, and 29,000 feet at M(sub o) = 1.4, and 29,000 feet at M(sub o) = 1.98" (p. 1).

Memorandum presenting a generalized analysis of a pressure-jet powerplant. The effect of changes in ambient conditions on the powerplant performance is provided in a series of charts using parameters containing temperatures and pressures. Some of the variables investigated included the pressure-jet powerplant performance in helicopter and pressure-jet-helicopter performance.

Report presenting data from which the effects of transpiration air flow on average skin-friction coefficients and pressure drag of a conical model were evaluated. The model consisted of a truncated porous nose cone with a solid ogival nose section. Results regarding the pressure distribution, base pressure drag, average skin-friction coefficients, effects of transpiration air, and comparison with theory.

Report presenting the tendencies of 14 different fuels and three fuel blends to produce high-frequency oscillatory combustion (screaming) in a 200-pound-thrust, water-cooled, liquid-oxygen-fuel rocket engine. The fuels, in order of increasing screaming tendency, were hydrazines, branched-chain paraffins, aromatics, and amines, and straight-chain paraffins. Results regarding screaming tendency and screaming amplitude are provided.

Memorandum presenting the subsonic and transonic longitudinal handling qualities of the Douglas D-558-II research airplane with several wing modifications designed to alleviate swept-wing instability and pitch-up. The airplane configurations investigated included the basic wing configuration and two wing-fence configurations in combination with retracted, free-floating, or extended slat,s and a wing leading-edge chord-extension configuration.

Report presenting an investigation of three phases: an experimental investigation of a thin airfoil with blowing over a trailing-edge flap, a comparison of the results of the experimental investigation with the results of other similar investigations, and a theoretical study of the relationships among the air-flow and power parameters for the general blowing case. The investigation utilized a two-dimensional model of the NACA 0006 airfoil equipped with a nose flap and six alternate trailing-edge flaps.

Report presenting surveys made through a turbulent boundary layer on a flat plate by means of a pitot probe, an X-ray densitometer, and hot-wire and cold-wire probes. Results were analyzed to determine the reliability of basic data and how well the distributions of properties in the boundary layer compare with those assumed in theoretical analyses.

Report presenting an acceleration control that operates on fuel flow and uses directly measured acceleration as the control signal as applied to an axial-flow turbojet engine. A study to determine the feasibility and dynamic characteristics of the control was undertaken. Results regarding the open-loop characteristics and closed-loop characteristics are provided.

Various dummy stings were tested on the rear of a related series of afterbody shapes for Mach numbers from 0.80 to 1.10 and Reynolds numbers based on body length from 15.0 x 16 to the 6th power to 17.4 x 10 to the 6th power. A method is presented whereby approximate sting interference corrections can be made to models having afterbody shapes and sting supports similar to those of these tests if the Reynolds numbers are of the same order of magnitude and a turbulent boundary layer exists at the model base. Also presented is an analysis of jet duplication by use of a sting.

Report presenting testing of a 4.5 inch by 4.5 inch tunnel with slots in two opposite walls in order to determine the effects of various slot exit shapes, mixing sections, and diffusers on power requirements. Some of the data obtained included measurements of the pressure ratio required to operate the tunnel, the effects of auxiliary bleed flow, diffuser static-pressure ratios and distributions, and diffuser total pressure distributions.

"Experimental results of lifts and moments about the quarter chord of a two-dimensional wing at subsonic Mach numbers are presented. A comparison of the experimental magnitude of the lift vector with the theory as given by Dietze showed good agreement. Comparisons of the moments and the quadrature component of lift with theory indicated that some refinements in the testing technique are necessary for the experimental determination of these quantities in the transonic range" (p. 1).

Report presenting an investigation in the 8- by 6-foot supersonic tunnel to determine the external-stream effects on the gross thrust and pumping characteristics of ejectors operating at off-design Mach numbers. Results regarding the pumping, thrust, and base characteristics, boattail drag characteristics, and stream effects on jet thrust for typical ejector installations are provided.

Memorandum presenting an investigation to devise an air-cooled turbine blade which eliminated the difficulties encountered with brazing in air-cooled-blade fabrication. Techniques were developed for casting air-cooled blades with a large number of relatively small cooling passages near the airfoil surface; two such blades of HS-21 material were operated in a turbojet engine modified for air cooling. Results regarding the heat-transfer characteristics, stress and durability results, and evaluation of cast-cored-blade potential are provided.

Report presenting fatigue testing in rotating bending on severely notched bars machined from 2024-T4 aluminum-alloy extruded round rods. Two sizes of specimens were studied.

Note presenting an investigation using rocket-powered models to provide an experimental comparison with linearized theoretical calculations for zero-lift drag of sweptback tapered wings with thin, symmetrical, double-wedge airfoil sections. The linearized theory compared very favorably with the experimental results over most of the test range.

"Flight tests of fifteen T-231 70-mm HEAA rocket projectiles (flight components of the T-263 HEAA rounds) were made at the Langley Pilotless AIrcraft Research Station at Wallops Island, VA., to obtain flight trajectories at high quadrant elevation launchings and to obtain drag data. Although all rounds were of the same general type, there were differences in nozzle cant angles, number of nozzles per round, shape of head and fuse, motor case length, and type of propellant. All projectiles were launched at an elevation angle of 60 deg" (p. 1).