Performance characteristics of underslung vertical wedge inlet with porous suction at Mach numbers of 0.63 and 1.5 to 2.0.

Memorandum presenting a low-speed investigation in the free-flight tunnel to determine the effect of small canard surfaces on the directional stability of a fighter-airplane model with an aspect ratio of 3.4 and a 42 degree sweptback wing. The canard surfaces were found to be generally ineffective at angles of attack below 20 degrees.

Memorandum presenting a generalized analysis of the effects of turbojet propulsion system development and fuel selection on ability of a strategic bomber to perform desired and minimum missions. The variation of bomber performance using a hydrocarbon, boron, or nuclear fuel is discussed.

Report presenting an investigation in the transonic pressure tunnel to determine the afterbody pressure distribution and fin loading characteristics of two configurations of the TX-21 special weapon. The only different in the two configurations was the nose contour, with one having a hemispherical-flat shape and one with a double-radius ogive-flat shape. Results regarding the pressure port, fin loads, and force measurements are provided.

Memorandum presenting an experimental investigation on a production-model turbojet engine modified by the substitution of special combustors and air-cooled turbine stator and rotor assemblies to determine some of the problems pertinent to the operation of air-cooled engines at turbine-inlet temperatures over 2200 degrees R. The investigation was conducted in an altitude chamber at simulated altitudes of 50,000 and 60,000 feet and a simulated flight Mach number of 0.8. Results regarding the combustion system, turbine stator, turbine rotor blades, turbine disks, and tailcone and other engine parts are provided.

Free flight test of tailless missile configuration with 45-deg sweptback wing of aspect ratio 4 - stability at transonic speeds. The longitudinal flexible-wing results indicated a gradual transonic trim change a lift-curve slope comparable with that for the same configuration with a wing of aspect ratio 5.5. Results regarding trim characteristics, lift and longitudinal stability, and side-force and lateral stability are provided.

Memorandum presenting an investigation conducted on the size and density of the boric oxide exhaust cloud from a J47-25 turbojet engine operating on trimethyl-borate fuel at sea-level static conditions. Movies and still photographs were taken from the ground and from a helicopter. Results regarding the visual observation and oxide fallout and concentration are provided.

Memorandum presenting a computation and comparison of the thrust augmentation and accompanying total fuel flow for four afterburner fuels and a rocket. Four turbojet engines burning JP-4 primary fuel and several operating conditions were selected for the analyses.

Report presenting an investigation in the altitude test chamber to evaluate the performance of a 16-inch-long combustor designed for use with gaseous-hydrogen fuel. The investigation covered a range of combustor pressures and simulated altitudes at Mach number 0.8. Results regarding operational characteristics, combustor performance, and temperature profiles are provided.

An investigation of the effect of extremely high altitude operation on the performance and operating characteristics of two turbojet engines using gaseous hydrogen and JP-4 fuels. At extremely high altitude conditions, engine performance was significantly poorer than at low altitudes. The majority of performance losses were due to the compressor because of low Reynolds number and the combustor because of low combustion efficiency.

Note presenting tables of thermal properties of stream that have been prepared in an NBS-NACA series. They include, for real gas, the compressibility factor, the density, the specific heat at constant pressure, the enthalpy, the entropy, the free-energy function, the viscosity, and the thermal conductivity.

"A method is presented for obtaining the attenuation of a shock wave in a shock tube due to the unsteady boundary layer along the shock-tube walls. It is assumed that the boundary layer is thin relative to the tube diameter and induces one-dimensional longitudinal pressure waves whose strength is proportional to the vertical velocity at the edge of the boundary layer. The contributions of the various regions in a shock tube to shock attenuation are indicated" (p. 1).

Report presenting a combination of two previously published reports with an extension of the data to cover properties of fuels up to temperatures as high as 400 degrees Fahrenheit.

From Summary: "An investigation was made in the Langley low-turbulence pressure tunnel to determine the effect of size and location of a sandpaper type of roughness on the Reynolds number for transition. Transition was observed by means of a hot-wire anemometer located at various chordwise stations for each position of the roughness. These observations indicated that when the roughness is sufficiently submerged in the boundary layer to provide a substantially linear variation of boundary-layer velocity with distance from the surface up to the top of the roughness, turbulent "spots" begin to appear immediately behind the roughness when the Reynolds number based on the velocity at the top of the roughness height exceeds a value of approximately 600. At Reynolds numbers even slightly below the critical value (value for transition), the sandpaper type of roughness introduced no measurable disturbances into the laminar layer downstream of the roughness. The extent of the roughness area does not appear to have an important effect on the critical value of the roughness Reynolds number."

Vibrations of rotary-wing aircraft may derive their energy from the rotation of the rotor rather than from the air forces. A theoretical analysis of these vibrations is described and methods for its application are explained in Chapter one. Chapter two reports the results of an investigation of the mechanical stability of a rotor having two vertically hinged blades mounted upon symmetrical supports, that is, of equal stiffness and mass in all horizontal directions. Chapter three presents the theory of ground vibrations of a two-blade helicopter rotor on anisotropic flexible supports.

"The concept of the adhesive power of a tire with respect to the road involves several properties which result from the purpose of the tire; namely, connecting link between vehicle and road: (1) The tire must transfer the tractive and braking forces acting in the direction of travel (tractive and braking adhesion); (2) The tire is to prevent lateral deviations of the vehicle from the desired direction of travel (track adhesion)" (p. 1).

In some applications, aluminum alloys are subjected to intermittent heating at elevated temperature. It is generally considered that the effects of such intermittent heating are cumulative, and therefore are the same as if the heating had been continuous for the same total length of time. The object of these tests was to determine the effects of intermittent and continuous heating at 300 and 400 F, for total periods of 100 and 200 hr, upon the tensile properties of 2024-T4 and 6061-T6 alloy rolled-and-drawn rod and 7075-T6 alloy extrusions, at room temperature and at the temperature of heating.

This report is a compilation of practical rules, derived at the same time from theory and from experience, intended to guide the aeronautical engineer in the design of flutter-free airplanes. Rules applicable to the wing, the ailerons, flaps, tabs,tail surfaces, and fuselage are discussed.

"An investigation has been completed in the Langley 20-foot free-spinning tunnel on a 1/24-scale model of the Grumman F11F-1 airplane to determine its spin and recovery characteristics. An interim report, Research Memorandum SL55G20, was published earlier and the present report concludes the presentation of results of the investigation. Primarily, the present report presents results obtained with engine gyroscopic moments simulated on the model. Also, the current results were obtained with a revised larger vertical tail recently incorporated on the airplane" (p. 1).

"An investigation has been made in the Langley 4- by 4-foot supersonic pressure tunnel at a Mach number of 1.41 to determine the aerodynamic characteristics of an 0.03-scale model of the Avro CF-105 airplane. The investigation included the determination of the static longitudinal and lateral stability, the control and the hinge-moment characteristics of the elevator, the aileron, and the rudder, as well as the vertical-tail-load characteristics. The results indicated a minimum drag coefficient of about 0.0270, and a maximum trimmed lift-drag ratio of about 4.25 which occurs at a lift coefficient of 0.16" (p. 1).

"Internal performance of an XJ79-GE-1 variable ejector was experimentally determined with the primary nozzle in a representative nonafterburning position. Jet-thrust and air-handling data were obtained in quiescent air for 11 selected ejector configurations over a wide range of operation. Additional data, at specific operating conditions, were obtained which indicate the ejector diameter ratio for peak jet-thrust performance. The experimental ejector data are presented in both graphical and tabulated form" (p. 1).

"An investigation has been made in the Langley 4 by 4-foot supersonic pressure tunnel at Mach numbers of 1.82 and 2.01 to determine the longitudinal and lateral static-stability characteristics of a 0.04-scale model of the Lockheed F-104A airplane. The effects of a modified vertical tail, several ventral-fin arrangements, and several external store arrangements were also determined. The tests were made at Reynolds numbers of 1.02 (exp 6) and 1.382 (exp 6), respectively, based on the wing mean geometric chord" (p. 1).

Chapters XI to XIII concern the unsteady compressor operation arising when compressor blade elements stall. The fields of compressor stall and surge are reviewed in Chapters XI and XII, respectively. The part-speed operating problem in high-pressure-ratio multistage axial-flow compressors is analyzed in Chapter XIII. Chapter XIV summarizes design methods and theories that extend beyond the simplified two-dimensional approach used previously in the report. Chapter XV extends this three-dimensional treatment by summarizing the literature on secondary flows and boundary layer effects. Charts for determining the effects of errors in design parameters and experimental measurements on compressor performance are given in Chapters XVI. Chapter XVII reviews existing literature on compressor and turbine matching techniques.

Performance characteristics of a 16-inch annular-type combustor installed in a full-scale engine using gaseous-hydrogen fuel were obtained at simulated altitudes from 66,000 to 86,000 feet at a flight Mach number of 0.8. Combustion efficiencies of 86 percent were obtained at 86,000 feet (combustor pressure, 420 lb/sq ft abs). Combustor blowout was not encountered during the investigation.