Technical Report Archive and Image Library (TRAIL) - 48 Matching Results

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Airfoil profiles for minimum pressure drag at supersonic velocities -- general analysis with application to linearized supersonic flow

Description: From Summary: "A theoretical investigation is made of the airfoil profile for minimum pressure drag at zero lift in supersonic flow. In the first part of the report a general method is developed for calculating the profile having the least pressure drag for a given auxiliary condition, such as a given structural requirement or a given thickness ratio. To illustrate the general method, the optimum airfoil, defined as the airfoil having minimum pressure drag for a given auxiliary condition, is calculated in a second part of the report using the equations of linearized supersonic flow."
Date: 1952
Creator: Chapman, Dean R.
Partner: UNT Libraries Government Documents Department

Axisymmetric Supersonic Flow in Rotating Impellers

Description: "General equations are developed for isentropic, frictionless, axisymmetric flow in rotating impellers with blade thickness taken into account and with blade forces eliminated in favor of the blade-surface function. It is shown that the total energy of the gas relative to the rotating coordinate system is dependent on the stream function only, and that if the flow upstream of the impeller is vortex-free, a velocity potential exists which is a function of only the radial and axial distances in the impeller. The characteristic equations for supersonic flow are developed and used to investigate flows in several configurations in order to ascertain the effect of variations of the boundary conditions on the internal flow and the work input" (p. 1).
Date: 1952
Creator: Goldstein, Arthur W.
Partner: UNT Libraries Government Documents Department

Chordwise and compressibility corrections to slender-wing theory

Description: Corrections to slender-wing theory are obtained by assuming a spanwise distribution of loading and determining the chordwise variation which satisfies the appropriate integral equation. Such integral equations are set up in terms of the given vertical induced velocity on the center line or, depending on the type of wing plan form, its average value across the span at a given chord station. The chordwise distribution is then obtained by solving these integral equations. Results are shown for flat-plate rectangular, and triangular wings.
Date: January 1, 1952
Creator: Lomax, Harvard & Sluder, Loma
Partner: UNT Libraries Government Documents Department

Comparison of high-speed operating characteristics of size 215 cylindrical-roller bearings as determined in turbojet engine and in laboratory test rig

Description: A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made by means of a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and the outer-race bearing operating temperatures are computed for the laboratory test rig and the turbojet engine. A method is given that enables the designer to predict the inner- and outer-race turbine roller-bearing temperatures from single curves, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter, or any combination of these parameters.
Date: 1952
Creator: Macks, E. Fred & Nemeth, Zolton N.
Partner: UNT Libraries Government Documents Department

Detailed computational procedure for design of cascade blades with prescribed velocity distributions in compressible potential flows

Description: A detailed step-by-step computational outline is presented for the design of two-dimensional cascade blades having a prescribed velocity distribution on the blade in a potential flow of the usual compressible fluid. The outline is based on the assumption that the magnitude of the velocity in the flow of the usual compressible nonviscous fluid is proportional to the magnitude of the velocity in the flow of a compressible nonviscous fluid with linear pressure-volume relation.
Date: 1952
Creator: Costello, George R.; Cummings, Robert L. & Sinnette, John T., Jr.
Partner: UNT Libraries Government Documents Department

Effects of compressibility on the performance of two full-scale helicopter rotors

Description: Report presents the results of an investigation conducted on the Langley helicopter test tower to determine experimentally the effects of compressibility on the performance and blade pitching moments of two full-scale helicopter rotors. Two sets of rotor blades were tested which differed only in that the blades of one set incorporated -8 degrees of linear twist, whereas the blades of the other set were untwisted. The tests covered a range of tip speeds from 350 to 770 feet per second and a range of pitch angles from 0 degrees to the limit imposed by extreme vibration.
Date: 1952
Creator: Carpenter, Paul J.
Partner: UNT Libraries Government Documents Department

Experimental Aerodynamic Derivatives of a Sinusoidally Oscillating Airfoil in Two-Dimensional Flow

Description: Experimental measurements of the aerodynamic reactions on a symmetrical airfoil oscillating harmonically in a two-dimensional flow are presented and analyzed. Harmonic motions include pure pitch and pure translation, for several amplitudes and superimposed on an initial angle of attack, as well as combined pitch and translation. The apparatus and testing program are described briefly and the necessary theoretical background is presented. In general, the experimental results agree remarkably well with the theory, especially in the case of the pure motions. The net work per cycle for a motion corresponding to flutter is experimentally determined to be zero. Considerable consistent data for pure pitch were obtained from a search of available reference material, and several definite Reynolds number effects are evident.
Date: January 1, 1952
Creator: Halfman, Robert L.
Partner: UNT Libraries Government Documents Department

Experimental Determination of the Effect of Horizontal-Tail Size, Tail Length, and Vertical Location on Low-Speed Static Longitudinal Stability and Damping Pitch of a Model Having 45 Degree Sweptback Wing and Tail Surfaces

Description: Report presents the results of an investigation conducted in the Langley stability tunnel to determine the effects of horizontal tails of various sizes and at various tail lengths (when loaded on the fuselage center line) and also the effects of vertical location of the horizontal tail relative to the wing on the low-speed static longitudinal stability and on the steady-state rotary damping in pitch for a complete-model configuration. The wing and tail surfaces had the quarter-chord lines swept back 45 degrees and had aspect ratios of 4. The results of the investigation showed that, in agreement with analytical considerations, the contribution of the horizontal tail to static longitudinal stability was related directly to the tail size and length; whereas, its contribution to damping in pitch was related directly to tail size and the square of tail length.
Date: January 1, 1952
Creator: Lichtenstein, Jacob H.
Partner: UNT Libraries Government Documents Department

An experimental investigation of transonic flow past two-dimensional wedge and circular-arc sections using a Mach-Zehnder interferometer

Description: Report presents the results of interferometer measurements of the flow field near two-dimensional wedge and circular-arc sections of zero angle of attack at high-subsonic and low-supersonic velocities. Both subsonic flow with local supersonic zone and supersonic flow with detached shock wave have been investigated. Pressure distributions and drag coefficients as a function of Mach number have been obtained. The wedge data are compared with the theoretical work on flow past wedge sections of Guderley and Yoshihara, Vincenti and Wagner, and Cole. Pressure distributions and drag coefficients for the wedge and circular-arc sections are presented throughout the entire transonic range of velocities.
Date: January 1, 1952
Creator: Bryson, Arthur Earl, Jr.
Partner: UNT Libraries Government Documents Department

Flight investigation of a mechanical feel device in an irreversible elevator control system of a large airplane

Description: Report presents the results of measurements of the longitudinal stability and control characteristics of a large airplane using a mechanical feel device in combination with a booster incorporated in the elevator-control system. Tests were made to investigate the feasibility of eliminating the aerodynamic control forces through use of a booster and of providing control-feel forces mechanically. The feel device consisted of a centering spring which restrained the control stick through a linkage which was changed as a function of the dynamic pressure. Provisions were made for trimming and for manual adjustment of the force gradient. The system was designed to approximate the control-force characteristics that would result with a conventional elevator control with linear hinge-moment characteristics.
Date: 1952
Creator: Brown, B. Porter; Chilton, Robert G. & Whitten, James B.
Partner: UNT Libraries Government Documents Department

Generalization of Boundary-Layer Momentum-Integral Equations to Three-Dimensional Flows Including Those of Rotating System

Description: The Navier-Stokes equations of motion and the equation of continuity are transformed so as to apply to an orthogonal curvilinear coordinate system rotating with a uniform angular velocity about an arbitrary axis in space. A usual simplification of these equations as consistent with the accepted boundary-layer theory and an integration of these equations through the boundary layer result in boundary-layer momentum-integral equations for three-dimensional flows that are applicable to either rotating or nonrotating fluid boundaries. These equations are simplified and an approximate solution in closed integral form is obtained for a generalized boundary-layer momentum-loss thickness and flow deflection at the wall in the turbulent case. A numerical evaluation of this solution carried out for data obtained in a curving nonrotating duct shows a fair quantitative agreement with the measures values. The form in which the equations are presented is readily adaptable to cases of steady, three-dimensional, incompressible boundary-layer flow like that over curved ducts or yawed wings; and it also may be used to describe the boundary-layer flow over various rotating surfaces, thus applying to turbomachinery, propellers, and helicopter blades.
Date: January 1, 1952
Creator: Mager, Arthur
Partner: UNT Libraries Government Documents Department

An Iterative Transformation Procedure for Numerical Solution of Flutter and Similar Characteristics-Value Problems

Description: An iterative transformation procedure suggested by H. Wielandt for numerical solution of flutter and similar characteristic-value problems is presented. Application of this procedure to ordinary natural-vibration problems and to flutter problems is shown by numerical examples. Comparisons of computed results with experimental values and with results obtained by other methods of analysis are made.
Date: January 1, 1952
Creator: Gossard, Myron L.
Partner: UNT Libraries Government Documents Department

On a solution of the nonlinear differential equation for transonic flow past a wave-shaped wall

Description: The Prandtl-Busemann small-perturbation method is utilized to obtain the flow of a compressible fluid past an infinitely long wave-shaped wall. When the essential assumption for transonic flow (that all Mach numbers in the region of flow are nearly unity) is introduced, the expression for the velocity potential takes the form of a power series in the transonic similarity parameter. On the basis of this form of the solution, an attempt is made to solve the nonlinear differential equation for transonic flow past the wavy wall. The analysis utilized exhibits clearly the difficulties inherent in nonlinear-flow problems.
Date: January 1, 1952
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department

On Reflection of Shock Waves from Boundary Layers

Description: Measurements are presented at Mach numbers from about 1.3 to 1.5 of reflection characteristics and the relative upstream influence of shock waves impinging on a flat surface with both laminar and turbulent boundary layers. The difference between impulse and step waves is discussed and their interaction with the boundary layer is compared. General considerations on the experimental production of shock waves from wedges and cones and examples of reflection of shock waves from supersonic shear layers are also presented.
Date: January 1, 1952
Creator: Liepmann, H. W.; Roshko, A. & Dhawan, S.
Partner: UNT Libraries Government Documents Department

Preliminary Investigation of a New Type of Supersonic Inlet

Description: "A supersonic inlet with supersonic deceleration of the flow entirely outside of the inlet is considered a particular arrangement with fixed geometry having a central body with a circular annular intake is analyzed, and it is shown theoretically that this arrangement gives high pressure recovery for a large range of Mach number and mass flow and, therefore, is practical for use on supersonic airplanes and missiles. Experimental results confirming the theoretical analysis give pressure recoveries which vary from 95 percent for Mach number 1.33 to 86 percent for number 2.00. These results were originally presented in a classified document of the NACA in 1946" (p. 1).
Date: 1952
Creator: Ferri, Antonio & Nucci, Louis M.
Partner: UNT Libraries Government Documents Department

Single-degree-of-freedom-flutter calculations for a wing in subsonic potential flow and comparison with an experiment

Description: The effect of Mach number and structural damping on single-degree-of-freedom pitching of a wing is presented. Some experimental results are compared with theory and good agreement is found for certain ranges of an inertia parameter.
Date: 1952
Creator: Runyan, Harry L.
Partner: UNT Libraries Government Documents Department

Some Features of Artificially Thickened Fully Developed Turbulent Boundary Layers with Zero Pressure Gradient

Description: Report gives an account of an investigation conducted to determine the feasibility of artificially thickening a turbulent boundary layer on a flat plate. A description is given of several methods used to thicken artificially the boundary layer. It is shown that it is possible to do substantial thickening and obtain a fully developed turbulent boundary layer, which is free from any distortions introduced by the thickening process, and, as such, is a suitable medium for fundamental research.
Date: January 1, 1952
Creator: Klebanoff, P. S. & Diehl, Z. W.
Partner: UNT Libraries Government Documents Department

A Study of Second-Order Supersonic Flow Theory

Description: Second-order solutions of supersonic-flow problems are sought by iteration, using the linearized solution as the first step. For plane and axially symmetric flows, particular solutions of the iteration equation are discovered which reduce the second-order problem to an equivalent linearized problem. Comparison of second-order solutions with exact and numerical results shows great improvement over linearized theory. For full three-dimensional flow, only a partial particular solution is found. The inclined cone is solved, and the possibility of treating more general problems is considered.
Date: January 1, 1952
Creator: Van Dyke, Milton D.
Partner: UNT Libraries Government Documents Department

A theoretical analysis of the effects of fuel motion on airplane dynamics

Description: The general equations of motion for an airplane with a number of spherical fuel tanks are derived. The motion of the fuel is approximated by the motion of solid pendulums. The same type of derivation and equations are shown to apply to any type of fuel tank where the motion of the fuel may be represented in terms of undamped harmonic oscillators. Motions are calculated for a present-day high-speed airplane and a free-flying airplane model with two spherical tanks in the symmetry plane.
Date: 1952
Creator: Schy, Albert A.
Partner: UNT Libraries Government Documents Department

Theoretical damping in roll and rolling moment due to differential wing incidence for slender cruciform wings and wing-body combinations

Description: A method of analysis based on slender-wing theory is developed to investigate the characteristics in roll of slender cruciform wings and wing-body combinations. The method makes use of the conformal mapping processes of classical hydrodynamics which transform the region outside a circle and the region outside an arbitrary arrangement of line segments intersecting at the origin. The method of analysis may be utilized to solve other slender cruciform wing-body problems involving arbitrarily assigned boundary conditions. (author).
Date: 1952
Creator: Adams, Gaynor J. & Dugan, Duane W.
Partner: UNT Libraries Government Documents Department

Transonic flow past a wedge profile with detached bow wave

Description: "A theoretical study has been made of the aerodynamic characteristics at zero angle of attack of a thin, doubly symmetrical double-wedge profile in the range of supersonic flight speed in which the bow wave is detached. The analysis utilizes the equations of the transonic small-disturbance theory and involves no assumptions beyond those implicit in this theory. The mixed flow about the front half of the profile is calculated by relaxation solution of boundary conditions along the shock polar and sonic line" (p. 1).
Date: 1952
Creator: Vincenti, Walter G. & Wagoner, Cleo B.
Partner: UNT Libraries Government Documents Department

Effect of Aspect Ratio on the Low-Speed Lateral Control Characteristics of Untapered Low-Aspect-Ratio Wings Equipped With Flap and With Retractable Ailerons

Description: A low-speed wind-tunnel investigation was made to determine the lateral control characteristics of a series of untapered low-aspect-ratio wings. Sealed flap ailerons of various spans and spanwise locations were investigated on unswept wings of aspect ratios 1.13, 1.13, 4.13, and 6.13; and various projections of 0.60-semispan retractable ailerons were investigated on the unsweptback wings of aspect ratios 1.13, 2.13, and 4.13 and on a 45 degree sweptback wing. The retractable ailerons investigated on the unswept wings spanned the outboard stations of each wing; whereas the plain and stepped retractable ailerons investigated on the sweptback wing were located at various spanwise stations. Design charts based on experimental results are presented for estimating the flap aileron effectiveness for low-aspect-ratio, untapered, unswept.
Date: February 8, 1952
Creator: Fischel, Jack; Naeseth, Rodger L.; Hagerman, John R. & O'Hare, William M.
Partner: UNT Libraries Government Documents Department

Reciprocity relations in aerodynamics

Description: "Reverse flow theorems in aerodynamics are shown to be based on the same general concepts involved in many reciprocity theorems in the physical sciences. Reciprocal theorems for both steady and unsteady motion are found as a logical consequence of this approach. No restrictions on wing plan form or flight Mach number are made beyond those required in linearized compressible-flow analysis" (p. 253).
Date: February 19, 1952
Creator: Heaslet, Max A. & Spreiter, John R.
Partner: UNT Libraries Government Documents Department

Displacement Effect of a Three-Dimensional Boundary Layer

Description: "A method is described for determining the "displacement surface" of known three-dimensional compressible boundary-layer flow in terms of the mass-flow defects associated with the profiles of the two velocity components parallel to the surface. The result is a generalization of the plane flow concept of displacement thickness introduced in order to describe how a thin boundary layer distorts the outer nonviscous flow. Numerical values are found for the known three-dimensional boundary-layer flow about a cone at a small angle of attack to a supersonic stream" (p. 367).
Date: March 6, 1952
Creator: Moore, Franklin K.
Partner: UNT Libraries Government Documents Department