Technical Report Archive and Image Library (TRAIL) - 21 Matching Results

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The quiescent-chamber type compression-ignition engine

Description: Report presents the results of performance tests of a single-cylinder 4-stroke-cycle compression-ignition engine having a vertical disk form of combustion chamber without air flow. The number, size, and direction of the orifices of the fuel-injection nozzles used were independently varied. A table and graphs are presented showing the performance of the engine with different nozzles; results of tests at different compression ratios, boost pressures, and coolant temperatures are also included.
Date: April 30, 1936
Creator: Foster, H. H.
Partner: UNT Libraries Government Documents Department

The Column Strength of Two Extruded Aluminum-Alloy H-Sections

Description: "Extruded aluminum-alloy members of various cross sections are used in aircraft as compression members either singly or as stiffeners for aluminum-alloy sheet. In order to design such members, it is necessary to know their column strength or, in the case of stiffeners, the value of the double modulus, which is best obtained for practical purposes from column tests. Column tests made on two extruded h-sections are described, and column formulas and formulas for the ratio of the double modulus to Young's modulus, based on the tests, are given" (p. 289).
Date: September 30, 1938
Creator: Osgood, William R. & Holt, Marshall
Partner: UNT Libraries Government Documents Department

High-Speed Tests of Conventional Radial-Engine Cowlings

Description: The drag characteristics of eight radial-engine cowlings have been determined over a wide speed range in the NACA 8-foot high-speed wind tunnel. The pressure distribution over all cowlings was measured, to and above the speed of the compressibility burble, as an aid in interpreting the force tests. One-fifth-scale models of radial-engine cowlings on a wing-nacelle combination were used in the tests.
Date: March 30, 1939
Creator: Robinson, Russell G. & Becker, John V.
Partner: UNT Libraries Government Documents Department

Determination of optimum plan forms for control surfaces

Description: Solutions found for a range of airfoil plan forms indicate that, regardless of the characteristics of the tail surface, the chord of the rudder or of the elevator should be very nearly constant over its span. The optimum ailerons are also of a characteristic shape, varying little with the plan form of the wing.
Date: January 30, 1941
Creator: Jones, Robert T. & Cohen, Doris
Partner: UNT Libraries Government Documents Department

Pressure distribution over an NACA 23012 airfoil with a fixed slot and a slotted flap

Description: Report presents the results of a pressure-distribution investigation conducted in the Langley Memorial Aeronautical Laboratory 7 by 10-foot wind tunnel to determine the air loads on an NACA 23012 airfoil in combination with a fixed leading-edge slot and a slotted flap. Pressures were measured over the upper and lower surfaces of the component parts of the combination for several angles of attack and at several flap settings. The data, presented as pressure diagrams and graphs of section coefficients, are applicable to rib, slat, and flap designs for the combination.
Date: July 30, 1941
Creator: Harris, Thomas A. & Lowry, John G.
Partner: UNT Libraries Government Documents Department

A General Small-Deflection Theory for Flat Sandwich Plates

Description: "A small-deflection theory is developed for the elastic behavior of orthotropic flat plates in which deflections due to shear are taken into account. In this theory, which covers all types of flat sandwich construction, a plate is characterized by seven physical constants (five stiffnesses and two Poisson ratios) of which six are independent. Both the energy expression and the differential equations are developed. Boundary conditions corresponding to simply supported, clamped, and elastically restrained edges are considered" (p. 1).
Date: September 30, 1947
Creator: Libove, Charles & Batdorf, S. B.
Partner: UNT Libraries Government Documents Department

Stability derivatives at supersonic speeds of thin rectangular wings with diagonals ahead of tip Mach lines

Description: The investigation includes steady and accelerated vertical and longitudinal motions and steady rolling, yawing, sideslipping, and pitching for Mach numbers and aspect ratios greater than those for which the Mach line from the leading edge of the tip section intersects the trailing edge of the opposite tip section. The stability derivatives are derived with respect to principal body axes and then transformed to a system of stability axes. Theoretical results are obtained, by means of the linearized theory, for the surface-velocity-potential functions, surface-pressure distributions, and stability derivatives for various motions at supersonic speeds of thin flat rectangular wings without dihedral.
Date: June 30, 1948
Creator: Harmon, Sidney M.
Partner: UNT Libraries Government Documents Department

One-Dimensional Flows of an Imperfect Diatomic Gas

Description: "With the assumptions that Berthelot's equation of state accounts for molecular size and intermolecular force effects, and that changes in the vibrational heat capacities are given by a Planck term, expressions are developed for analyzing one-dimensional flows of a diatomic gas. The special cases of flow through normal and oblique shocks in free air at sea level are investigated. It is found that up to a Mach number 10 pressure ratio across a normal shock differs by less than 6 percent from its ideal gas value; whereas at Mach numbers above 4 the temperature rise is considerable below and hence the density rise is well above that predicted assuming ideal gas behavior" (p. 239).
Date: December 30, 1948
Creator: Eggers, A. J., Jr.
Partner: UNT Libraries Government Documents Department

Investigations at supersonic speeds of 22 triangular wings representing two airfoil sections for each of 11 apex angles

Description: The results of tests of 22 triangular wings, representing two leading-edge shapes for each of 11 apex angles, at Mach numbers 1.62, 1.92, and 1.40 are presented and compared with theory. All wings have a common thickness ratio of 8 percent and a common maximum-thickness point at 18 percent chord. Lift, drag, and pitching moment are given for all wings at each Mach number. The relation of transition in the boundary layer, shocks on the wing surfaces, and characteristics of the pressure distributions is discussed for several wings.
Date: March 30, 1949
Creator: Love, Eugene S.
Partner: UNT Libraries Government Documents Department

Effect of tunnel configuration and testing technique on cascade performance

Description: "An investigation has been conducted to determine the influence of aspect ratio, boundary-layer control by means of slots and porous surfaces, Reynolds number, and tunnel end-wall condition upon the performance of airfoils in cascades. A representative compressor-blade section (the NACA 65-(12)(10) of aspect ratios of 1, 2, and 4 has been tested at low speeds in cascades with solid and with porous side walls. Two-dimensional flow was established in porous-wall cascades of each of the three aspect ratios tested; the flow was not two-dimensional in any of the solid-wall cascades" (p. 263).
Date: November 30, 1949
Creator: Erwin, John R. & Emery, James C.
Partner: UNT Libraries Government Documents Department

Hydrodynamic impact of a system with a single elastic mode 2: comparison of experimental force and response with theory

Description: From Summary: "Hydrodynamic impact tests were made on an elastic model approximating a two-mass spring system to determine experimentally the effects of structural flexibility on the hydrodynamic loads encountered during seaplane landing impacts and to correlate the results with theory. A flexible seaplane was represented by a two-mass spring system consisting of a rigid prismatic float connected to a rigid upper mass by an elastic structure. The model had a ratio of sprung mass to hull mass of 0.6 and a natural frequency of 3.0 cycles per second. The tests were conducted in smooth water at fixed trims and included both high and low flight-path angles and a range of velocity. Theoretical and experimental comparisons indicated that the theoretical results agreed well with the experimental results."
Date: January 30, 1951
Creator: Miller, Robert W. & Merten, Kenneth F.
Partner: UNT Libraries Government Documents Department

Experimental and theoretical studies of area suction for the control of the laminar boundary layer on an NACA 64A010 airfoil

Description: From Summary: "A low-turbulence wind-tunnel investigation was made of an NACA 64A010 airfoil having a porous surface to determine the reduction in section total-drag coefficient that might be obtained at large Reynolds numbers by the use of suction to produce continuous inflow through the surface of the airfoil (area suction). In addition to the experimental investigation, a related theoretical analysis was made to provide a basis of comparison for the test results."
Date: March 30, 1951
Creator: Braslow, Albert L.; Burrows, Dale L.; Tetervin, Neal & Visconti, Fioravante
Partner: UNT Libraries Government Documents Department

Spectrum of turbulence in a contracting stream

Description: The spectrum concept is employed to study the selective effect of a stream contraction on the longitudinal and lateral turbulent velocity fluctuations of the stream. By a consideration of the effect of the stream contraction on a single plane sinusoidal disturbance wave, mathematically not dissimilar to a triply periodic disturbance treated by G. I. Taylor, the effect on the spectrum tensor of the turbulence and hence on the correlation tensor is determined.
Date: August 30, 1951
Creator: Ribner, H. S. & Tucker, M.
Partner: UNT Libraries Government Documents Department

Application of a channel design method to high-solidity cascades and tests of an impulse cascade with 90 degrees of turning

Description: From introduction: "A technique for application of the channel design methods of reference 11 to the design of high-solidity cascades with prescribed velocity distributions as a function of arc length along the blade-element profiles is presented herein."
Date: November 30, 1951
Creator: Stanitz, John D. & Sheldrake, Leonard J.
Partner: UNT Libraries Government Documents Department

Experimental investigation of free-convection heat transfer in vertical tube at large Grashof numbers

Description: Report presents the results of an investigation conducted to study free-convection heat transfer in a stationary vertical tube closed at the bottom. The walls of the tube were heated, and heated air in the tube was continuously replaced by fresh cool air at the top. The tube was designed to provide a gravitational field with Grashof numbers of a magnitude comparable with those generated by the centrifugal field in rotating-blade coolant passages (10(8) to 10(13)). Local heat-transfer coefficients in the turbulent-flow range and the temperature field within the fluid were obtained.
Date: June 30, 1952
Creator: Eckert, E. R. G. & Diaguila, A. J.
Partner: UNT Libraries Government Documents Department

Generalized Theory for Seaplane Impact

Description: "The motions, hydrodynamic loads, and pitching moments experienced by V-bottom seaplanes during step-landing impacts are analyzed and the theoretical results are compared with experimental data. In the analysis, the primary flow about the immersed portion of a keeled hull or float is considered to occur in transverse flow planes and the concept of virtual mass is applied to determined the reaction of the water to the motions of the seaplane. The entire immersion process is analyzed from the instant of initial contact until the seaplane rebounds from the water surfaces" (p. 953).
Date: October 30, 1952
Creator: Milwitzky, Benjamin
Partner: UNT Libraries Government Documents Department

Secondary flows and boundary-layer accumulations in turbine nozzles

Description: An investigation of secondary-flow loss patterns originating in three sets of turbine nozzle blade passages was conducted by means of flow-visualization studies and detailed flow measurements. For all cases, high loss values were measured in the fluid downstream of the corners formed by the suction surfaces of the blades and the shrouds, and these losses were accompanied by discharge-angle deviations from design values. Despite the size of the loss regions and angle gradients, over-all mass-average blade efficiencies were of the order of 0.99 and 0.98 and, therefore, are not a good index of blade performance.
Date: April 30, 1953
Creator: Rohlik, Harold E.; Kofskey, Milton G.; Allen, Hubert W. & Herzig, Howard Z.
Partner: UNT Libraries Government Documents Department

Comparison of performance of experimental and conventional cage designs and materials for 75-millimeter-bore cylindrical roller bearings at high speed

Description: From Summary: "The results of two investigations, one to determine the relative merits of four experimental and two conventional design 75-millimeter-bore (size 215) cylindrical roller bearings and one to determine the relative merits of nodular iron and bronze as cage materials for this size and type of bearing, are presented in this report. Nine test bearings were operated over a range of dn values (product of bearing bore in mm and shaft speed in r.p.m) from 0.3 x 10(6) to 2.3 x 20(6), radial loads for 7 to 1613 pounds, and oil flows from 2 to 8 pounds per minute with a single-jet circulatory oil feed. Of the six bearings used to evaluate designs, four were experimental types with outer-race-riding cages and inner-race-guided rollers, and two were conventional types, one with outer-race-guided rollers and cage and one with inner-race-guided rollers and cage."
Date: June 30, 1954
Creator: Anderson, William J.; Macks, E. Fred & Nemeth, Zolton N.
Partner: UNT Libraries Government Documents Department

Generalized Indical Forces on Deforming Rectangular Wings in Supersonic Flight

Description: "A method is presented for determining the time-dependent flow over a rectangular wing moving with a supersonic forward speed and undergoing small vertical distortions expressible as polynomials involving spanwise and chordwise distances. The solution for the velocity potential is presented in a form analogous to that for steady supersonic flow having the familiar "reflected area" concept discovered by Evvard. Particular attention is paid to indicial-type motions and results are expressed in terms of generalized indicial forces. Numerical results for Mach numbers equal to 1.1 and 1.2 are given for polynomials of the first and fifth degree in the chordwise and spanwise directions, respectively, on a wing having an aspect ratio of 4" (p. 595).
Date: June 30, 1954
Creator: Lomax, Harvard; Fuller, Franklyn B. & Sluder, Loma
Partner: UNT Libraries Government Documents Department

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

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.
Date: November 30, 1956
Creator: Gustafson, F. B. & Tapscott, Robert J.
Partner: UNT Libraries Government Documents Department

Blowing-type boundary-layer control as applied to the trailing-edge flaps of a 35 degree swept-wing airplane

Description: A wind-tunnel investigation was made to determine the effects on the aerodynamic characteristics of a 35 degree swept-wing airplane of applying blowing-type boundary-layer control to the trailing-edge flaps. Flight tests of a similar airplane were then conducted to determine the effects of boundary-layer control on the handling qualities and operation of the airplane, particularly during landing and take-off. The wind-tunnel and flight tests indicated that blowing over the flaps produced large increases in flap lift increment, and significant increases in maximum lift. The use of blowing permitted reductions in the landing approach speeds of as much as 12 knots.
Date: April 30, 1958
Creator: Kelly, Mark W.; Anderson, Seth B. & Innis, Robert C.
Partner: UNT Libraries Government Documents Department