UNT Libraries Government Documents Department - 39 Matching Results

Search Results

Results: 1 - 24 next
open access

Lifting-Surface-Theory Aspect-Ratio Corrections to the Lift and Hinge-Moment Parameters for Full-Span Elevators on Horizontal Tail Surfaces

Description: "A limited number of lifting-surface-theory solutions for wings with chordwise loadings resulting from angle of attack, parabolic-arc camber, and flap deflection are now available. These solutions were studied with the purpose of determining methods of extrapolating the results in such a way that they could be used to determine lifting-surface-theory values of the aspect-ratio corrections to the lift and hinge-moment parameters for both angle-of-attack and flap-deflection-type loading that coul… more
Date: 1948
Creator: Swanson, Robert S. & Crandall, Stewart M.
Item Type: Refine your search to only Report
open access

Theoretical and Experimental Analysis of Low-Drag Supersonic Inlets Having a Circular Cross Section and a Central Body at Mach Numbers 3.30, 2.75, and 2.45

Description: Contains theoretical and experimental analysis of circular inlets having a central body at Mach numbers of 3.30, 2.75, and 2.45. The inlets have been designed in order to have low drag and high pressure recovery. The pressure recoveries obtained are of the same order of magnitude as those previously obtained by inlets having very large external drag.
Date: August 13, 1948
Creator: Ferri, Antonio & Nucci, Louis M.
Item Type: Refine your search to only Report
open access

Calculation of the aerodynamic loading of swept and unswept flexible wings of arbitrary stiffness

Description: A method is presented for calculating the aerodynamic loading, the divergence speed, and certain stability derivatives of swept and unswept wings and tail surfaces of arbitrary stiffness. Provision is made for using either stiffness curves and root rotation constants or structural influence coefficients in the analysis. Computing forms, tables of numerical constants required in the analysis, and an illustrative example are included to facilitate calculations by means of the method.
Date: December 24, 1948
Creator: Diederich, Franklin W.
Item Type: Refine your search to only Report
open access

The Method of Characteristics for the Determination of Supersonic Flow Over Bodies of Revolution at Small Angles of Attack

Description: "The method of characteristics has been applied for the determination of the supersonic-flow properties around bodies of revolution at a small angle of attack. The system developed considers the effect of the variation of entropy due to the curved shock and determines a flow that exactly satisfies the boundary conditions in the limits of the simplifications assumed. Two practical methods for numerical calculations are given" (p. 1039).
Date: November 22, 1948
Creator: Ferri, Antonio
Item Type: Refine your search to only Report
open access

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… more
Date: December 30, 1948
Creator: Eggers, A. J., Jr.
Item Type: Refine your search to only Report
open access

Linearized compressible-flow theory for sonic flight speeds

Description: The partial differential equation for the perturbation velocity potential is examined for free-stream Mach numbers close to and equal to one. It is found that, under the assumptions of linearized theory, solutions can be found consistent with the theory for lifting-surface problems both in stationary three-dimensional flow and in unsteady two-dimensional flow. Several examples are solved including a three dimensional swept-back wing and two dimensional harmonically-oscillating wing, both for a … more
Date: December 12, 1948
Creator: Heaslet, Max A.; Lomax, Harvard & Spreiter, John R.
Item Type: Refine your search to only Report
open access

Accuracy of Airspeed Measurements and Flight Calibration Procedures

Description: From Summary: "The sources of error that may enter into the measurement of airspeed by pitot-static methods are reviewed in detail together with methods of flight calibration of airspeed installations. Special attention is given to the problem of accurate measurements of airspeed under conditions of high speed and maneuverability required of military airplanes." (author).
Date: 1948
Creator: Huston, Wilber B.
Item Type: Refine your search to only Report
open access

Experiments on Stability of Bunsen-Burner Flames for Turbulent Flow

Description: "The results of a study of the stability of propane-air flames on bunsen-burner tubes are presented. Fuel-air ratio, tube diameter, and Reynolds number were the primary variables. Regions of stability are outlined in plots of fuel-air ratio as a function of Reynolds number for flames seated on the burner lip and for flames suspended well above the burner" (p. 1).
Date: 1948
Creator: Bollinger, Lowell M. & Williams, David T.
Item Type: Refine your search to only Report
open access

Theoretical comparison of several methods of thrust augmentation for turbojet engines

Description: "A theoretical investigation of tail-pipe burning, water injection at the compressor inlet, combination tail-pipe burning plus water injection, bleedoff, and rocket-assist methods thrust augmentation for turbojet engines was made for an engine representative of those in current use. The effect of augmented liquid ratio on augmented thrust ratio and the effects of altitude and flight Mach number on the performance of various methods were determined. The additional take-off weight involved by the… more
Date: October 27, 1948
Creator: Hall, Eldon W. & Wilcox, E. Clinton
Item Type: Refine your search to only Report
open access

Prediction of the Effects of Propeller Operation on the Static Longitudinal Stability of Single-Engine Tractor Monoplanes with Flaps Retracted

Description: "The effects of propeller operation on the static longitudinal stability of single-engine tractor monoplanes are analyzed, and a simple method is presented for computing power-on pitching-moment curves for flap-retracted flight conditions. The methods evolved are based on the results of powered-model wind-tunnel investigations of 28 model configurations. Correlation curves are presented from which the effects of power on the downwash over the tail and the stabilizer effectiveness can be rapidly… more
Date: July 13, 1948
Creator: Weil, Joseph & Sleeman, William C., Jr.
Item Type: Refine your search to only Report
open access

The Longitudinal Stability of Elastic Swept Wings at Supersonic Speed

Description: "The longitudinal stability characteristics of elastic swept wings of high aspect ratio experiencing bending and torsional deformations are calculated for supersonic speed by the application of linearized lifting-surface theory. A parabolic wing deflection curve is assumed and the analysis is simplified by a number of structural approximations. The method is thereby limited in application to wings of high aspect ratio for which the root effects are small" (p. 1).
Date: December 3, 1948
Creator: Frick, C. W. & Chubb, R. S.
Item Type: Refine your search to only Report
open access

Some theoretical low-speed span loading characteristics of swept wings in roll and sideslip

Description: The Weissinger method for determining additional span loading for incompressible flow is used to find the damping in roll, the lateral center of pressure of the rolling for wing plan forms of various aspect ratios, taper ratios, and sweep angles. In addition, the applicability of the method to the determination of certain other aerodynamic derivatives is investigated, and corrections for the first-order effects of compressibility are indicated. The agreement obtained between experimentally and … more
Date: December 22, 1948
Creator: Bird, John D.
Item Type: Refine your search to only Report
open access

Theoretical Stability Derivatives of Thin Sweptback Wings Tapered to a Point with Sweptback or Sweptforward Trailing Edges for a Limited Range of Supersonic Speeds

Description: "The stability derivatives valid for a limited range of supersonic speeds are presented for a series of sweptback wings tapered to a point with sweptback or sweptforward trailing edges. These wings were derived by modifying the trailing edge of a basic triangular wing so that it coincided with lines drawn from the wing tips to the wing axis of symmetry. The stability derivatives were formulated by using the pressure distributions previously obtained for the basic triangular wing for angle of at… more
Date: September 23, 1948
Creator: Malvestuto, Frank S., Jr. & Margolis, Kenneth
Item Type: Refine your search to only Report
open access

The calculation of downwash behind supersonic wings with an application to triangular plan forms

Description: A method is developed consistent with the assumptions of small perturbation theory which provides a means of determining the downwash behind a wing in supersonic flow for a known load distribution. The analysis is based upon the use of supersonic doublets which are distributed over the plan form and wake of the wing in a manner determined from the wing loading. The equivalence in subsonic and supersonic flow of the downwash at infinity corresponding to a given load distribution is proved.
Date: November 9, 1948
Creator: Lomax, Harvard; Sluder, Loma & Heaslet, Max A.
Item Type: Refine your search to only Report
open access

The application of Green's theorem to the solution of boundary-value problems in linearized supersonic wing theory

Description: From Introduction: "The present paper is restricted to a discussion of wing theory subject to the assumptions of linearized compressible flow. It therefore employs solutions of Laplace's equation and the wave equation for cases where the boundary condition are specified in the plane of the wing."
Date: December 22, 1948
Creator: Heaslet, Max A. & Lomax, Harvard
Item Type: Refine your search to only Report
open access

Theoretical symmetric span loading at subsonic speeds for wings having arbitrary plan form

Description: From Summary: "A method is shown by which the symmetric span loading for a certain class of wings can be simply found. The geometry of these wings is limited only to the extent that they must have symmetry about the root chord, must have a straight quarter-chord line over the semispan, and must have no discontinuities in twist. A procedure is shown for finding the lift-curve slope, pitching moment, center of lift, and induced drag from the span load distribution. A method of accounting for the … more
Date: 1948
Creator: DeYoung, John & Harper, Charles W.
Item Type: Refine your search to only Report
open access

Application of Theodorsen's theory to propeller design

Description: A theoretical analysis is presented for obtaining, by use of Theodorsen's propeller theory, the load distribution along a propeller radius to give the optimum propeller efficiency for any design condition. The efficiencies realized by designing for the optimum load distribution are given in graphs, and the optimum efficiency for any design condition may be read directly from the graph without any laborious calculations. Examples are included to illustrate the method of obtaining the optimum loa… more
Date: March 15, 1948
Creator: Crigler, John L.
Item Type: Refine your search to only Report
open access

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 lineari… more
Date: June 30, 1948
Creator: Harmon, Sidney M.
Item Type: Refine your search to only Report
open access

The use of source-sink and doublet distributions extended to the solution of boundary-value problems in supersonic flow

Description: "A direct analogy is established between the use of source-sink and doublet distributions in the solution of specific boundary-value problems in subsonic wing theory and the corresponding problems in supersonic theory. The correct concept of the "finite part" of an integral is introduced and used in the calculation of the improper integrals associated with supersonic doublet distributions. The general equations developed are shown to include several previously published results and particular e… more
Date: January 1948
Creator: Heaslet, Max A. & Lomax, Harvard
Item Type: Refine your search to only Report
open access

Theoretical and experimental data for a number of NACA 6A-series airfoil sections

Description: The NACA 6a-series airfoil sections were designed to eliminate the trailing-edge cusp which is characteristic of the NACA 6a-series sections. Theoretical data are presented for NACA 6a-series basic thickness forms having the position of minimum pressure of 30, 40, and 50 percent chord and with thickness ratios varying from 6 percent to 15 percent. Also presented are data for a mean line designed to maintain straight sides on the cambered sections.
Date: 1948
Creator: Loftin, Laurence K., Jr.
Item Type: Refine your search to only Report
open access

Full-scale investigation of aerodynamic characteristics of a typical single-rotor helicopter in forward flight

Description: From Summary: "As part of the general helicopter research program being undertaken by the National Advisory Committee for Aeronautics to provide designers with fundamental rotor information, the forward-flight performance characteristics of a typical single-rotor helicopter, which is equipped with main and tail rotors, have been investigated in the Langley full-scale tunnel. The test conditions included operation of tip-speed ratios from 0.10 to 0.27 and at thrust coefficients from 0.0030 to 0.… more
Date: 1948
Creator: Dingeldein, Richard C. & Schaefer, Raymond F.
Item Type: Refine your search to only Report
open access

Determination of stresses in gas-turbine disks subjected to plastic flow and creep

Description: A finite-difference method previously presented for computing elastic stresses in rotating disks is extended to include the computation of the disk stresses when plastic flow and creep are considered. A finite-difference method is employed to eliminate numerical integration and to permit nontechnical personnel to make the calculations with a minimum of engineering supervision. Illustrative examples are included to facilitate explanation of the procedure by carrying out the computations on a typ… more
Date: March 5, 1948
Creator: Millenson, M. B. & Manson, S. S.
Item Type: Refine your search to only Report
open access

Equations for the Design of Two-Dimensional Supersonic Nozzles

Description: "Equations are presented for obtaining the wall coordinates of two-dimensional supersonic nozzles. The equations are based on the application of the method of characteristics to irrotational flow of perfect gases in channels. Curves and tables are included for obtaining the parameters required by the equations for the wall coordinates. A brief discussion of characteristics as applied to nozzle design is given to assist in understanding and using the nozzle-design method of this report. A sample… more
Date: June 1, 1948
Creator: Pinkel, I. Irving
Item Type: Refine your search to only Report
open access

Sound-Level Measurements of a Light Airplane Modified to Reduce Noise Reaching the Ground

Description: "An Army liaison-type airplane, representative of personal airplanes in the 150 to 200 horsepower class, has been modified to reduce propeller and engine noise according to known principles of airplane-noise reduction. Noise-level measurements demonstrate that, with reference to an observer on the ground, a noisy airplane of this class can be made quiet -- perhaps more quiet than necessary. In order to avoid extreme and unnecessary modifications, acceptable noise levels must be determined" (p. … more
Date: February 12, 1948
Creator: Vogeley, A. W.
Item Type: Refine your search to only Report
Back to Top of Screen