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An Introduction to the Laws of Air Resistance of Aerofoils

Description: Report presents methods of calculating air resistance of airfoils under certain conditions of flow phenomena around the airfoil.
Date: September 1918
Creator: de Bothezat, George
Partner: UNT Libraries Government Documents Department
open access

A flight evaluation of the longitudinal stability characteristics associated with the pitch-up of a swept-wing airplane in maneuvering flight at transonic speeds

Description: This report presents the results of flight measurements of longitudinal stability and control characteristics made on a swept-wing jet aircraft to determine the origin of the pitch-up encountered in maneuvering flight at transonic speeds. For this purpose measurements were made of elevator angle, tail angle of attack, and wing-fuselage pitching moments (obtained from measurements of the balancing tail loads).
Date: September 12, 1951
Creator: Anderson, Seth B. & Bray, Richard S.
Partner: UNT Libraries Government Documents Department
open access

The dynamic-response characteristics of a 35 degree swept-wing airplane as determined from flight measurements

Description: From Summary: "The longitudinal and lateral-directional dynamic-response characteristics of a 35 degree swept-wing fighter-type airplane determined from flight measurements are presented and compared with predictions based on theoretical studies and wind-tunnel data. Flights were made at an altitude of 35,000 feet covering the Mach number range of 0.50 to 1.04. A limited amount of lateral-directional data were also obtained at 10,000 feet. The flight consisted essentially of recording transient… more
Date: September 17, 1952
Creator: Triplett, William C.; Brown, Stuart C. & Smith, G. Allan
Partner: UNT Libraries Government Documents Department
open access

A wind-tunnel test technique for measuring the dynamic rotary stability derivatives at subsonic and supersonic speeds

Description: "A method is described for measuring the dynamic stability derivatives of a model airplane in a wind tunnel. The characteristic features of this system are that single-degree-of-freedom oscillations were used to obtain combinations of rolling, yawing and pitching motions; that the oscillations were excited and controlled by velocity feedback which permitted operation under conditions unfavorable for more conventional types of oscillatory testing; and that data processing was greatly simplified … more
Date: September 20, 1954
Creator: Beam, Benjamin H.
Partner: UNT Libraries Government Documents Department
open access

Impingement of Cloud Droplets on a Cylinder and Procedure for Measuring Liquid-Water Content and Droplet Sizes in Supercooled Clouds by Rotating Multicylinder Method

Description: "Evaluation of the rotating multicylinder method for the measurement of droplet-size distribution, volume-median droplet size, and liquid-water content in clouds showed that small uncertainties in the basic data eliminate the distinction between different cloud droplet-size distributions and are a source of large errors in the determination of the droplet size. Calculations of the trajectories of cloud droplets in incompressible and compressible flow fields around a cylinder were performed on a… more
Date: September 5, 1952
Creator: Brun, R. J.; Lewis, W.; Perkins, P. J. & Serafini, J. S.
Partner: UNT Libraries Government Documents Department
open access

Preknock vibrations in a spark-ignition engine cylinder as revealed by high-speed photography

Description: "The high-speed photographic investigation of the mechanics of spark-ignition engine knock recorded in three previous reports has been extended with use of the NACA high-speed camera and combustion apparatus with a piezoelectric pressure pickup in the combustion chamber. The motion pictures of knocking combustion were taken at the rate of 40,000 frames per second. Existence of the preknock vibrations in the engine cylinder suggested in Technical Report no.727 has been definitely proved and the … more
Date: September 11, 1944
Creator: Miller, Cearcy D. & Logan, Walter O., Jr.
Partner: UNT Libraries Government Documents Department
open access

On the flow of a compressible fluid by the hodograph method 2: fundamental set of particular flow solutions of the Chaplygin differential equation

Description: From Summary: "The differential equation of Chaplygin's jet problem is utilized to give a systematic development of particular solutions of the hodograph flow equations, which extends the treatment of Chaplygin into the supersonic range and completes the set of particular solutions. The particular solutions serve to place on a reasonable basis the use of velocity correction formulas for the comparison of incompressible and compressible flows. It is shown that the geometric-mean type of velocity… more
Date: September 29, 1944
Creator: Garrick, I. E. & Kaplan, Carl
Partner: UNT Libraries Government Documents Department
open access

Air-Consumption Parameters for Automatic Mixture Control of Aircraft Engines

Description: From Introduction: "The purpose of this analysis was to investigate the use of a function of intake-manifold pressure, exhaust back pressure, intake manifold temperature, and engine speed in place of a venturi as a means of measuring engine air consumption and to determine if this function is suitable for automatic mixture control."
Date: September 1, 1944
Creator: Shames, Sidney J.
Partner: UNT Libraries Government Documents Department
open access

On the Use of Residue Theory for Treating the Subsonic Flow of a Compressible Fluid

Description: "A new mathematical technique, due to Milne-Thomson, is used to obtain an improved form of the method of Poggi for calculating the effect of compressibility on the subsonic flow past an obstacle. By means of this new method, the difficult surface integrals of the original Poggi method can be replaced by line integrals. These line integrals are then solved by the use of residue theory. In this way an equation is obtained giving the second-order effect of compressibility on the velocity of the fl… more
Date: September 8, 1941
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department
open access

Test of single-stage axial-flow fan

Description: "A single-stage axial fan was built and tested in the shop of the propeller-research tunnel of the NACA. The fan comprised a simple 24-blade rotor having a diameter of 21 inches and a solidity of 0.86 and a set of 37 contravanes having a solidity of 1.33. The rotor was driven by a 25-horsepower motor capable of rotating at a speed of 3600 r.p.m. The fan was tested for volume, pressure, and efficiency over a range of delivery pressures and volumes for a wide range of contravane and blade-angle s… more
Date: September 22, 1941
Creator: Bell, E. Barton
Partner: UNT Libraries Government Documents Department
open access

Wind-Tunnel Investigation of an NACA 23012 Airfoil With 30 Percent-Chord Venetian-Blind Flaps

Description: Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel of a NACA 23012 airfoil with 30-percent-chord venetian-blind flaps having one, two, three, and four slats of Clark y section. The three-slat arrangements was aerodynamically the best of those tested but showed practically no improvement over the comparable arrangement used in the preliminary tests published in NACA Technical Report No. 689. The multiple-slat flaps gave slightly higher lift coefficients tha… more
Date: September 17, 1941
Creator: Rogallo, F. M. & Spano, Bartholomew S.
Partner: UNT Libraries Government Documents Department
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
Partner: UNT Libraries Government Documents Department
open access

Attainable Circulation About Airfoils in Cascade

Description: "From consideration of available information on boundary-layer behavior, a relation among profile thickness, maximum surface velocity, Reynolds number, velocity diagram, and solidity is established for a cascade of airfoils immersed in a two-dimensional incompressible fluid flow. Several cascades are computed to show the effect of various cascade design parameters on minimum required cascade solidity. Comparisons with experimentally determined blade performance show that the derived blade loadi… more
Date: September 1949
Creator: Goldstein, Arthur W. & Mager, Artur
Partner: UNT Libraries Government Documents Department
open access

Dislocation Theory of the Fatigue of Metals

Description: "A dislocation theory of fatigue failure for annealed solid solutions is presented. On the basis of this theory, an equation giving the dependence of the number of cycles for failure on the stress, the temperature, the material parameters, and the frequency is derived for uniformly stressed specimens. The equation is in quantitative agreement with the data" (p. 183).
Date: September 12, 1947
Creator: Machlin, E. S.
Partner: UNT Libraries Government Documents Department
open access

Performance of conical jet nozzles in terms of flow and velocity coefficients

Description: Performance characteristics of conical jet nozzles were determined in an investigation covering a range of pressure ratios from 1.0 to 2.8, cone half-angles from 5 degrees to 90 degrees, and outlet-inlet diameter ratios from 0.50 to 0.91. All nozzles investigated had an inlet diameter of 5 inches. The flow coefficients of the conical nozzles investigated were dependent on the cone half-angle, outlet-inlet diameter ratio, and pressure ratio. The velocity coefficients were essentially constant at… more
Date: September 7, 1948
Creator: Grey, Ralph E. & Wilsted, H. Dean
Partner: UNT Libraries Government Documents Department
open access

A Theory of Unstaggered Airfoil Cascades in Compressible Flow

Description: "By use of the methods of thin airfoil theory, which include effects of compressibility, relations are developed which permit the rapid determination of the pressure distribution over an unstaggered cascade of airfoils of a given profile, and the determination of the profile shape necessary to yield a given pressure distribution for small chord/gap ratios. For incompressible flow the results of the theory are compared with available examples obtained by the more exact method of conformal transf… more
Date: September 1947
Creator: Spurr, Robert A. & Allen, H. Julian
Partner: UNT Libraries Government Documents Department
open access

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 r… more
Date: September 30, 1947
Creator: Libove, Charles & Batdorf, S. B.
Partner: UNT Libraries Government Documents Department
open access

The Flow of a Compressible Fluid Past a Curved Surface

Description: "An iteration method is employed to obtain the flow of a compressible fluid past a curved surface. The first approximation which leads to the Prandtl-Glauert rule, is based on the assumption that the flow differs but little from a pure translation. The iteration process then consists in improving this first approximation in order that it will apply to a flow differing from pure translatory motion to a greater degree. The method fails when the Mach number of the undisturbed stream reaches unity … more
Date: September 13, 1943
Creator: Kaplan, Carl
Partner: UNT Libraries Government Documents Department
open access

Bending and shear stresses developed by the instantaneous arrest of the root of a moving cantilever beam

Description: A theoretical and experimental investigation has been made of the behavior of a cantilever beam in transverse motion when its root is suddenly brought to rest. Equations are given for determining the stresses, the deflections, and the accelerations that arise in the beam as a result of the impact. The theoretical equations, which have been confirmed experimentally, reveal that, at a given percentage of the distance from root to tip, the bending stresses for a particular mode are independent of … more
Date: September 27, 1944
Creator: Stowell, Elbridge Z.; Schwartz, Edward B. & Houbolt, John C.
Partner: UNT Libraries Government Documents Department
open access

A study of elastic and plastic stress concentration factors due to notches and fillets in flat plates

Description: Six large 24s-t3 aluminum-alloy-sheet specimens containing various notches or fillets were tested in tension to determine their stress concentration factors in both the elastic and plastic ranges. The elastic stress concentration factors were found to be slightly higher than those calculated by Neuber's method and those obtained photoelastically by Frocht. The results showed further that the stress concentration factor decreases as strains at the discontinuity enter the plastic range. A general… more
Date: September 7, 1951
Creator: Hardrath, Herbert F. & Ohman, Lachlan
Partner: UNT Libraries Government Documents Department
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Calculations on the forces and moments for an oscillating wing-aileron combination in two-dimensional potential flow at sonic speed

Description: From Summary: "The linearized theory for compressible unsteady flow is used, as suggested in recent contributions to the subject, to obtain the velocity potential and the lift and moment for a thin harmonically oscillating, two-dimensional wing-aileron combination moving at sonic speed. The velocity potential is derived by considering the sonic case as the limit of the linearized supersonic theory. From the velocity potential explicit expressions for the lift and moment are developed for vertic… more
Date: September 4, 1951
Creator: Nelson, Herbert C. & Berman, Julian H.
Partner: UNT Libraries Government Documents Department
open access

Wind-tunnel investigation of air inlet and outlet openings on a streamline body

Description: In connection with the general problem of providing air flow to an aircraft power plant located within a fuselage, an investigation was conducted in the Langley 8-foot high-speed tunnel to determine the effect on external drag and pressure distribution of air inlet openings located at the nose of a streamline body. Air outlet openings located at the tail and at the 21-percent and 63-percent stations of the body were also investigated. Boundary layer transition measurements were made and correla… more
Date: September 11, 1940
Creator: Becker, John V.
Partner: UNT Libraries Government Documents Department
open access

Equations and Charts for the Rapid Estimation of Hinge-Moment and Effectiveness Parameters for Trailing-Edge Controls Having Leading and Trailing Edges Swept Ahead of the Mach Lines

Description: "Existing conical-flow solutions have been used to calculate the hinge-moments and effectiveness parameters of trailing-edge controls having leading and trailing edges swept ahead of the Mach lines and having streamwise root and tip chords. Equations and detailed charts are presented for the rapid estimation of these parameters. Also included is an approximate method by which these parameters may be corrected for airfoil-section thickness" (p. 937).
Date: September 8, 1950
Creator: Goin, Kennith L.
Partner: UNT Libraries Government Documents Department
open access

Some Effects of Nonlinear Variation in the Directional-Stability and Damping-in-Yawing Derivatives on the Lateral Stability of an Airplane

Description: "A theoretical investigation has been made to determine the effect of nonlinear stability derivatives on the lateral stability of an airplane. Motions were calculated on the assumption that the directional-stability and the damping-in-yawing derivatives are functions of the angle of sideslip. The application of the Laplace transform to the calculation of an airplane motion when certain types of nonlinear derivatives are present is described in detail" (p. 1009).
Date: September 19, 1950
Creator: Sternfield, Leonard
Partner: UNT Libraries Government Documents Department
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