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 Serial/Series Title: NACA Technical Reports
 Collection: National Advisory Committee for Aeronautics Collection
Measurements of free-space oscillating pressures near propellers at flight Mach numbers to 0.72

Measurements of free-space oscillating pressures near propellers at flight Mach numbers to 0.72

Date: January 1, 1958
Creator: Kurbjun, Max C & Vogeley, Arthur W
Description: In the course of a short flight program initiated to check the theory of Garrick and Watkins (NACA rep. 1198), a series of measurements at three stations were made of the oscillating pressures near a tapered-blade plan-form propeller and rectangular-blade plan form propeller at flight Mach numbers up to 0.72. In contradiction to the results for the propeller studied in NACA rep. 1198, the oscillating pressures in the plane ahead of the propeller were found to be higher than those immediately behind the propeller. Factors such as variation in torque and thrust distribution, since the blades of the present investigation were operating above their design forward speed, may account for this contradiction. The effect of blade plan form shows that a tapered-blade plan-form propeller will produce lower sound-pressure levels than a rectangular-blade plan-form propeller for the low blade-passage harmonics (the frequencies where structural considerations are important) and produce higher sound-pressure levels for the higher blade-passage harmonics (frequencies where passenger comfort is important).
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The mechanism of thermal-gradient mass transfer in the sodium hydroxide-nickel system

The mechanism of thermal-gradient mass transfer in the sodium hydroxide-nickel system

Date: January 1, 1958
Creator: May, Charles E
Description: "Thermal-gradient mass transfer" was investigated in the molten sodium hydroxide-nickel system. Possible mechanisms (physical, electrochemical, and chemical) are discussed in terms of experimental and theoretical evidence. Experimental details are included in appendixes.
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A method for simulating the atmospheric entry of long-range ballistic missiles

A method for simulating the atmospheric entry of long-range ballistic missiles

Date: January 1, 1958
Creator: Eggers, A J , Jr
Description: It is demonstrated with the aid of similitude arguments that a model launched from a hypervelocity gun upstream through a special supersonic nozzle should experience aerodynamic heating and resulting thermal stresses like those encountered by a long-range ballistic missile entering the earth's atmosphere. This demonstration hinges on the requirements that model and missile be geometrically similar and made of the same material, and that they have the same flight speed and Reynolds number (based on conditions just outside the boundary layer) at corresponding points in their trajectories. The hypervelocity gun provides the model with the required initial speed, while the nozzle scales the atmosphere, in terms of density variation, to provide the model with speeds and Reynolds numbers over its entire trajectory. Since both the motion and aerodynamic heating of a missile tend to be simulated in the model tests, this combination of hypervelocity gun and supersonic nozzle is termed an atmosphere entry simulator.
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A method of computing the transient temperature of thick walls from arbitrary variation of adiabatic-wall temperature and heat-transfer coefficient

A method of computing the transient temperature of thick walls from arbitrary variation of adiabatic-wall temperature and heat-transfer coefficient

Date: January 1, 1958
Creator: Hill, P R
Description: A method of calculating the temperature of thick walls has been developed in which the time series and the response to a unit triangle variation of surface temperature concepts are used, together with essentially standard formulas for transient temperature and heat flow into thick walls. The method can be used without knowledge of the mathematical tools of its development. The method is particularly suitable for determining the wall temperature in one-dimensional thermal problems in aeronautics where there is a continuous variation of the heat-transfer coefficient and adiabatic-wall temperature. The method also offers a convenient means for solving the inverse problem of determining the heat-flow history when temperature history is known.
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Methods for obtaining desired helicopter stability characteristics and procedures for stability predictions

Methods for obtaining desired helicopter stability characteristics and procedures for stability predictions

Date: January 1, 1958
Creator: Gustafson, F B & Tapscott, Robert J
Description: Part I of this report presents a brief review of methods available to the helicopter designer for obtaining desired stability characteristics by modifications to the airframe design. The discussion is based on modifications made during the establishment of flying-qualities criteria and includes sample results of theoretical studies of additional methods. The conclusion is reached that it is now feasible to utilize combinations of methods whereby stability-parameter values are realized which in turn provide the desired stability characteristics. Part II reviews some of the methods of predicting rotor stability derivatives. The procedures by which these rotor derivatives are employed to estimate helicopter stability characteristics have been summarized.
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NACA research on slurry fuels

NACA research on slurry fuels

Date: January 1, 1958
Creator: Pinns, M L; Olson, W T; Barnett, H C & Breitwieser, R
Description: An extensive program was conducted to investigate the use of concentrated slurries of boron and magnesium in liquid hydrocarbon as fuels for afterburners and ramjet engines. Analytical calculations indicated that magnesium fuel would give greater thrust and that boron fuel would give greater range than are obtainable from jet hydrocarbon fuel alone. It was hoped that the use of these solid elements in slurry form would permit the improvement to be obtained without requiring unconventional fuel systems or combustors. Small ramjet vehicles fueled with magnesium slurry were flown successfully, but the test flights indicated that further improvement of combustors and fuel systems was needed.
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On flow of electrically conducting fluids over a flat plate in the presence of a transverse magnetic field

On flow of electrically conducting fluids over a flat plate in the presence of a transverse magnetic field

Date: January 1, 1958
Creator: Rossow, Vernon J
Description: The use of a magnetic field to control the motion of electrically conducting fluids is studied. The incompressible boundary-layer solutions are found for flow over a flat plate when the magnetic field is fixed relative to the plate or to the fluid. The equations are integrated numerically for the effect of the transverse magnetic field on the velocity and temperature profiles, and hence, the skin friction and rate of heat transfer. It is concluded that the skin friction and the heat-transfer rate are reduced when the transverse magnetic field is fixed relative to the plate and increased when fixed relative to the fluid. The total drag is increased in all of the areas.
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Origin and Prevention of Crash Fires in Turbojet Aircraft

Origin and Prevention of Crash Fires in Turbojet Aircraft

Date: January 1, 1958
Creator: Pinkel, I. Irvin; Weiss, Solomon; Preston, G. Merritt & Pesman, Gerard J.
Description: The tendency for the jet engine rotor to continue to rotate after crash presents the probability that crash-spilled combustibles suspended in the air or puddled on the ground at the engine inlet may be sucked into the engine. Studies with jet engines operating on a test stand and full-scale crashes of turbojet-powered airplanes showed that combustibles drawn into the engine in this way ignite explosively within the engine. Experiment showed that the gas flow through the engine is too rapid to permit the ignition of ingested combustibles on the hot metal in contact with the main gas stream. Ignition will occur on those hot surfaces not in the main gas stream. The portion of the engine airflow is diverted for cooling and ventilation to these zones where the gas moves slowly enough for ignition to occur.
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A phenomenological relation between stress, strain rate, and temperature for metals at elevated temperatures

A phenomenological relation between stress, strain rate, and temperature for metals at elevated temperatures

Date: January 1, 1958
Creator: Stowell, Elbridge Z
Description: It is shown that for one material, 7075-Tm aluminum-alloy sheet, the information yielded by the relation for these four applications agrees reasonably well with test data.
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The response of an airplane to random atmospheric disturbances

The response of an airplane to random atmospheric disturbances

Date: January 1, 1958
Creator: Diederich, Franklin W
Description: The statistical approach to the gust-load problem, which consists in considering flight through turbulent air to be a stationary random process, is extended by including the effect of lateral variation of the instantaneous gust intensity on the aerodynamic forces. The forces obtained in this manner are used in dynamic analyses of rigid and flexible airplanes free to move vertically, in pitch, and in roll. The effect of the interaction of longitudinal, normal, and lateral gusts on the wind stresses is also considered.
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The similarity rules for second-order subsonic and supersonic flow

The similarity rules for second-order subsonic and supersonic flow

Date: January 1, 1958
Creator: Van Dyke, Milton D
Description: The similarity rules for linearized compressible flow theory (Gothert's rule and its supersonic counterpart) are extended to second order. It is shown that any second-order subsonic flow can be related to "nearly incompressible" flow past the same body, which can be calculated by the Janzen-Rayleigh method.
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A simplified method for approximating the transient motion in angles of attack and sideslip during a constant rolling maneuver

A simplified method for approximating the transient motion in angles of attack and sideslip during a constant rolling maneuver

Date: January 1, 1958
Creator: Sternfield, Leonard
Description: The transient motion in angles of attack and sideslip during a constant rolling maneuver has been analyzed. Simplified expressions are presented for the determination of the pertinent modes of motion as well as the modal coefficient corresponding to each mode. Calculations made with and without the derivatives for side force due to sideslip and lift-curve slope indicate that although these derivatives increase the total damping of the system they do not markedly affect the transient motion.
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A study of the motion and aerodynamic heating of ballistic missiles entering the earth's atmosphere at high supersonic speeds

A study of the motion and aerodynamic heating of ballistic missiles entering the earth's atmosphere at high supersonic speeds

Date: January 1, 1958
Creator: Allen, H Julian & Eggers, A J , Jr
Description: A simplified analysis of the velocity and deceleration history of ballistic missiles entering the earth's atmosphere at high supersonic speeds is presented. The results of this motion analysis are employed to indicate means available to the designer for minimizing aerodynamic heating. The heating problem considered involves not only the total heat transferred to a missile by convection, but also the maximum average and local time rates of convective heat transfer.
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A summary of preliminary investigations into the characteristics of combustion screech in ducted burners

A summary of preliminary investigations into the characteristics of combustion screech in ducted burners

Date: January 1, 1958
Creator: unknown
Description: Increasing demands for higher afterburner performance have required operation at progressively higher fuel-air ratios, which has increased the occurrence and intensity of screeching combustion. The onset of screech may be followed by rapid destruction of the combustor shell and other combustor parts. Because of its destructive characteristics, considerable effort has been expended to understand and eliminate screech. NACA work on the screeching combustion problem prior to 1954 is summarized herein. These studies showed that resonant acoustic oscillations are a primary component of the screech mechanism in the burners thus far investigated.
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Survey of hydrogen combustion properties

Survey of hydrogen combustion properties

Date: January 1, 1958
Creator: Drell, Isadore L & Belles, Frank E
Description: This literature digest of hydrogen-air combustion fundamentals presents data on flame temperature, burning velocity, quenching distance, flammability limits, ignition energy, flame stability, detonation, spontaneous ignition, and explosion limits. The data are assessed, recommended values are given, and relations among various combustion properties are discussed. New material presented includes: theoretical treatment of variation in spontaneous ignition lag with temperature, pressure, and composition, based on reaction kinetics of hydrogen-air composition range for 0.01 to 100 atmospheres and initial temperatures of 0 degrees to 1400 degrees k.
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Systematic two-dimensional cascade tests of NACA 65-series compressor blades at low speeds

Systematic two-dimensional cascade tests of NACA 65-series compressor blades at low speeds

Date: January 1, 1958
Creator: Emery, James C; Herrig, L Joseph; Erwin, John R & Felix, A Richard
Description: The performance of NACA 65-series compressor blade section in cascade has been investigated systematically in a low-speed cascade tunnel. Porous test-section side walls and for high-pressure-rise conditions, porous flexible end walls were employed to establish conditions closely simulating two-dimensional flow. Blade sections of design lift coefficients from 0 to 2.7 were tested over the usable angle-of-attack range for various combinations of inlet-flow angle. A sufficient number of combinations were tested to permit interpolation and extrapolation of the data to all conditions within the usual range of application. The results of this investigation indicate a continuous variation of blade-section performance as the major cascade parameters, blade camber, inlet angle, and solidity were varied over the test range. Summary curves of the results have been prepared to enable compressor designers to select the proper blade camber and angle of attack when the compressor velocity diagram and desired solidity have been determined.
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Theoretical analysis of total-pressure loss and airflow distribution for tubular turbojet combustors with constant annulus and liner cross-sectional areas

Theoretical analysis of total-pressure loss and airflow distribution for tubular turbojet combustors with constant annulus and liner cross-sectional areas

Date: January 1, 1958
Creator: Graves, Charles C & Grobman, Jack S
Description: Compressible and incompressible flow calculations were made of the combustor total-pressure-loss coefficient and liner airflow distribution for tubular turbojet combustors having constant annulus and liner cross-sectional areas along the combustor axis. Information on static and total pressure distribution and liner air-jet entrance angles along the length of the combustor was obtained as an intermediate step in the calculations. The calculations include the effects of heat release, annulus wall friction, and variation in discharge coefficients of the liner wall openings along the combustor. The combustor total-pressure-loss coefficient and liner air-flow distribution are presented graphically in terms of the following dimensionless parameters: (1) combustor reference Mach number, (2) ratio of combustor-exit to inlet total temperature, (3) fraction of total airflow passing through the liner dome, (4) ratio of total open hole area in liner wall to total combustor cross-sectional area, and (5) ratio of liner cross-sectional area to total combustor cross-sectional area.
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A theoretical and experimental study of planing surfaces including effects of cross section and plan form

A theoretical and experimental study of planing surfaces including effects of cross section and plan form

Date: January 1, 1958
Creator: Shuford, Charles L , Jr
Description: A summary is given of the background and present status of the pure-planing theory for rectangular flat plates and v-bottom surfaces. The equations reviewed are compared with experiment. In order to extend the range of available planing data, the principal planing characteristics for models having sharp bottom surfaces having constant angles of dead rise of 20 degrees and 40 degrees. Planing data were also obtained for flat-plate surfaces with very slightly rounded chines for which decreased lift and drag coefficients are obtained.
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Theoretical combustion performance of several high-energy fuels for ramjet engines

Theoretical combustion performance of several high-energy fuels for ramjet engines

Date: January 1, 1958
Creator: Tower, Leonard K; Breitwieser, Roland & Gammon, Benson E
Description: An analytical evaluation of the air and fuel specific-impulse characteristics of magnesium, magnesium octene-1 slurries, aluminum, aluminum octene-1 slurries, boron, boron octene-1 slurries, carbon, hydrogen, alpha-methylnaphthalene, diborane, pentaborane, and octene-1 is presented. While chemical equilibrium was assumed in the combustion process, the expansion was assumed to occur at fixed composition.
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Theory of self-excited mechanical oscillations of helicopter rotors with hinged blades

Theory of self-excited mechanical oscillations of helicopter rotors with hinged blades

Date: January 1, 1958
Creator: Coleman, Robert P & Feingold, Arnold M
Description: 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.
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Thin airfoil theory based on approximate solution of the transonic flow equation

Thin airfoil theory based on approximate solution of the transonic flow equation

Date: January 1, 1958
Creator: Spreiter, John R & Alksne, Alberta Y
Description: A method is presented for the approximate solution of the nonlinear equations of transonic flow theory. Solutions are found for two-dimensional flows at a Mach number of 1 and for purely subsonic and purely supersonic flows. Results are obtained in closed analytic form for a large and significant class of nonlifting airfoils. At a Mach number of 1 general expressions are given for the pressure distribution on an airfoil of specified geometry and for the shape of an airfoil having a prescribed pressure distribution. Extensive comparisons are made with available data, particularly for a Mach number of 1, and with existing solutions.
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A variational theorem for creep with applications to plates and columns

A variational theorem for creep with applications to plates and columns

Date: January 1, 1958
Creator: Sanders, J Lyell, Jr; Mccomb, Harvey G , Jr & Schlechte, Floyd R
Description: A variational theorem is presented for a body undergoing creep. Solutions to problems of the creep behavior of plates, columns, beams, and shells can be obtained by means of the direct methods of the calculus of variations in conjunction with the stated theorem. The application of the theorem is illustrated for plates and columns by the solution of two sample problems.
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A wind-tunnel investigation of the aerodynamic characteristics of a full-scale supersonic-type three-blade propeller at Mach numbers to 0.96

A wind-tunnel investigation of the aerodynamic characteristics of a full-scale supersonic-type three-blade propeller at Mach numbers to 0.96

Date: January 1, 1958
Creator: Evans, Albert J & Liner, George
Description: An investigation of the characteristics of a full-scale supersonic-type propeller has been made in the Langley 16-foot transonic tunnel with the 6000-horsepower propeller dynamometer. The tests covered a range of blade angles from 20.2 degrees to 60.2 degrees at forward Mach numbers up to 0.96. The results showed that envelope efficiency at an advance ratio of 2.8 decreased from 86 percent to 72 percent when the forward Mach number was increased from 0.70 to 0.96. A comparison of the experimental results with calculated results showed that maximum propeller efficiency can be calculated with good accuracy by using ordinary subsonic strip theory when the blade-section speeds are supersonic. The investigation also showed favorable power-absorption properties of the supersonic-type propeller at high speeds.
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Aerodynamic characteristics at high speeds of related full-scale propellers having different blade-section cambers

Aerodynamic characteristics at high speeds of related full-scale propellers having different blade-section cambers

Date: January 1, 1957
Creator: Maynard, Julian D & Salters, Leland B , Jr
Description: Wind-tunnel tests of a full-scale two-blade NACA 10-(10)(08)-03 (high camber) propeller have been made for a range of blade angles from 20 degrees to 55 degrees at airspeeds up to 500 miles per hour. The results of these tests have been compared with results from previous tests of the NACA 10-(3) (08)-03 (low camber) and NACA 10-(5)(08)-03 (medium camber) propellers to evaluate the effects of blade-section camber on propeller aerodynamic characteristics.
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