Technical Report Archive and Image Library (TRAIL) - 59 Matching Results

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Analysis of means of improving the uncontrolled lateral motions of personal airplanes

Description: From Summary: "A theoretical analysis has been made of means of improving the uncontrolled motions of personal airplanes. The purpose of this investigation was to determine whether such airplanes could be made to fly uncontrolled for an indefinite period of time without getting into dangerous attitudes and for a reasonable period of time (1 to 3 min) without deviating excessively from their original course. The results of this analysis indicated that the uncontrolled motions of a personal airplane could be made safe as regards spiral tendencies and could be greatly improved as regards maintenance of course without resort to an autopilot."
Date: 1951
Creator: McKinney, Marion O., Jr.
Partner: UNT Libraries Government Documents Department

Analysis of plane-plastic stress problems with axial symmetry in strain-hardening range

Description: From Introduction: "A simple method of solving plane-plastic-stress problems with axial symmetry in the strain-hardening range for finite strains were developed at the NACA Lewis laboratory during 1949-1950. This method is based on the deformation theory of Hencky and Nadai (references 7 to 9), which is derived for the condition of constant directions and ratios of the principal stresses during loading."
Date: 1951
Creator: Wu, M. H. Lee
Partner: UNT Libraries Government Documents Department

Analysis of the effects of boundary-layer control in the take-off and power-off landing performance characteristics of a liaison type of airplane

Description: From Summary: "A performance analysis has been made to determine whether boundary-layer control by suction might reduce the minimum take-off and landing distances of a four-place or five-place airplane or a liaison type of airplane below those obtainable with conventional high-lift devices. The airplane was assumed to have a cruise duration of 5 hours at 60-percent power and to be operating from airstrips having a ground friction coefficient of 0.2 or a combined ground and braking coefficient of 0.4. The payload was fixed at 1500 pounds, the wing span was varied from 25 to 100 feet, the aspect ratio was varied from 5 to 15, and the power was varied from 300 to 1300 horsepower."
Date: 1951
Creator: Horton, Elmer A.; Loftin, Laurence K., Jr.; Racisz, Stanley F. & Quinn, John H., Jr.
Partner: UNT Libraries Government Documents Department

Analysis of turbulent free-convection boundary layer on flat plate

Description: With the use of Karman's integrated momentum equation for the boundary layer and data on the wall-shearing stress and heat transfer in forced-convection flow, a calculation was carried out for the flow and heat transfer in the turbulent free-convection boundary layer on a vertical flat plate. The calculation is for a fluid with a Prandtl number that is close to 1. A formula was derived for the heat-transfer coefficient that was in good agreement with experimental data in the range of Grashof numbers from 10sup10 to 10sup12. Because of the good agreement between the theoretical formula and the experimental data, the formula may be used to obtain data for high Grashof numbers. The calculation also yielded formulas for the maximum velocity in the boundary layer and for boundary-layer thickness.
Date: 1951
Creator: Eckert, E. R. G. & Jackson, Thomas W.
Partner: UNT Libraries Government Documents Department

Analytical determination of coupled bending-torsion vibrations of cantilever beams by means of station functions

Description: From Summary: "A method based on the concept of Station Functions is presented for calculating the modes and the frequencies of nonuniform cantilever beams vibrating in torsion, bending, and coupled bending-torsion motion. The method combines some of the advantages of the Rayleigh-Ritz and Stodola methods, in that a continuous loading function for the beam is used, with the advantages of the influence-coefficient method, in that the continuous loading function is obtained in terms of the displacements of a finite number of stations along the beam."
Date: 1951
Creator: Mendelson, Alexander & Gendler, Selwyn
Partner: UNT Libraries Government Documents Department

Blockage Corrections for Three-Dimensional-Flow Closed-Throat Wind Tunnels, with Consideration of the Effect of Compressibility

Description: Theoretical blockage corrections are presented for a body of revolution and for a three-dimensional, unswept wing in a circular or rectangular wind tunnel. The theory takes account of the effects of the wake and of the compressibility of the fluid, and is based on the assumption that the dimensions of the model are small in comparison with those of the tunnel throat. Formulas are given for correcting a number of the quantities, such as dynamic pressure and Mach number, measured in wind tunnel tests. The report presents a summary and unification of the existing literature on the subject.
Date: January 1, 1951
Creator: Herriot, J. G.
Partner: UNT Libraries Government Documents Department

Buckling of thin-walled cylinder under axial compression and internal pressure

Description: An investigation was made of a thin-walled cylinder under axial compression and various internal pressures to study the effect of the internal pressure on the compressive buckling stress of the cylinder. A theoretical analysis based on a large-deflection theory was also made. The theoretically predicted increase of compressive buckling stress due to internal pressure agrees fairly well with the experimental results. (author).
Date: 1951
Creator: Lo, Hsu; Crate, Harold & Schwartz, Edward B.
Partner: UNT Libraries Government Documents Department

Comparison of theoretical and experimental heat-transfer characteristics of bodies of revolution at supersonic speeds

Description: An investigation of the three important factors that determine convective heat-transfer characteristics at supersonic speeds, location boundary-layer transition, recovery factor, and heat-transfer parameter has been performed at Mach numbers from 1.49 to 1.18. The bodies of revolution that were tested had, in most cases, laminar boundary layers, and the test results have been compared with available theory. Boundary-layer transition was found to be affected by heat transfer. Adding heat to a laminar boundary layer caused transition to move forward on the test body, while removing heat caused transition to move rearward. These experimental results and the implications of boundary-layer-stability theory are in qualitative agreement.
Date: January 1, 1951
Creator: Scherrer, Richard
Partner: UNT Libraries Government Documents Department

Compressive strength of flanges

Description: The maximum compressive stress carried by a hinged flange is computed from a deformation theory of plasticity combined with the theory for finite deflections for this structure. The computed stresses agree well with those found experimentally. Empirical observation indicates that the results will also apply fairly well to the more commonly used flanges which are not hinged.
Date: 1951
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

Diffusion of chromium in alpha cobalt-chromium solid solutions

Description: Diffusion of chromium in cobalt-chromium solid solutions was investigated in the range 0 to 40 atomic percent at temperatures of 1360 degrees, 1300 degrees, 1150 degrees, and 10000 degrees c. The diffusion coefficients were found to be relatively constant within the composition range covered by each specimen. The activation heat of diffusion was determined to be 63,000 calories per mole. This value agrees closely with the value of 63,400 calories per mole calculated by means of the Dushman-Langmuir equation.
Date: 1951
Creator: Weeton, John W.
Partner: UNT Libraries Government Documents Department

Formulas for the supersonic loading, lift, and drag of flat swept-back wings with leading edges behind the Mach line

Description: The method of superposition of linearized conical flows has been applied to the calculation of the aerodynamic properties, in supersonic flight, of thin flat, swept-back wings at an angle of attack. The wings are assumed to have rectilinear plan forms, with tips parallel to the stream, and to taper in the conventional sense. The investigation covers the moderately supersonic speed range where the Mach lines from the leading-edge apex lie ahead of the wing. The trailing edge may lie ahead of or behind the Mach lines from its apex. The case in which the Mach cone from one tip intersects the other tip is not treated. Formulas are obtained for the load distribution, the total lift, and the drag due to lift. For the cases in which the trailing edge is outside the Mach cone from its apex the formulas are complete. For wings with both leading and trailing edges behind their respective Mach lines, a degree of approximation is necessary. Charts of some of the functions derived are included to facilitate computing, and several examples are worked out in outline.
Date: January 1, 1951
Creator: Cohen, Doris
Partner: UNT Libraries Government Documents Department

A general integral form of the boundary-layer equation for incompressible flow with an application to the calculation of the separation point of turbulent boundary layers

Description: A general integral form of the boundary-layer equation, valid for either laminar or turbulent incompressible boundary-layer flow, is derived. By using the experimental finding that all velocity profiles of the turbulent boundary layer form essentially a single-parameter family, the general equation is changed to an equation for the space rate of change of the velocity-profile shape parameter. The lack of precise knowledge concerning the surface shear and the distribution of the shearing stress across turbulent boundary layers prevented the attainment of a reliable method for calculating the behavior of turbulent boundary layers.
Date: January 1, 1951
Creator: Tetervin, Neal & Lin, Chia Chiao
Partner: UNT Libraries Government Documents Department

Investigation of Separation of the Turbulent Boundary Layer

Description: An investigation was conducted on a turbulent boundary layer near a smooth surface with pressure gradients sufficient to cause flow separation. The reynolds number was high, but the speeds were entirely within the incompressible flow range. The investigation consisted of measurements of mean flow, three components of turbulence intensity, turbulent shearing stress, and correlations between two fluctuation components at a point and between the same component of different points. The results are given in the form of tables and graphs. The discussion deals first with separation and then with the more fundamental question of basic concepts of turbulent flow.
Date: January 1, 1951
Creator: Schubauer, G. B. & Klebanoff, P. S.
Partner: UNT Libraries Government Documents Department

Investigation of Spoiler Ailerons for Use as Speed Brakes or Glide-Path Controls on Two NACA 65-Series Wings Equipped with Full-Span Slotted Flaps

Description: A wind-tunnel investigation was made to determine the characteristics of spoiler ailerons used as speed brakes or glide-path controls on an NACA 65-210 wing and an NACA 65-215 wing equipped with full-span slotted flaps. Several plug aileron and retractable-aileron configurations were investigated on two wing models with the full-span flaps retracted and deflected. Tests were made at various Mach numbers between 0.13 and 0.71. The results of this investigation have indicated that the use of plug or retractable ailerons, either alone or in conjunction with wing flaps, as speed brakes or glide-path controls is feasible and very effective.
Date: January 1, 1951
Creator: Fischel, Jack & Watson, James M.
Partner: UNT Libraries Government Documents Department

A recurrence matrix solution for the dynamic response of aircraft in gusts

Description: "A systematic procedure developed for the calculation of the structural response of aircraft flying through a gust by use of difference equations in the solution of dynamic problems is first illustrated by means of a simple-damped-oscillator example. A detailed analysis is then given which leads to a recurrence matrix equation for the determination of the response of an airplane in a gust. The method takes into account wing bending and twisting deformations, fuselage deflection, vertical and pitching motion of the airplane, and some tail forces" (p. 1).
Date: 1951
Creator: Houbolt, John C.
Partner: UNT Libraries Government Documents Department

Relation between inflammables and ignition sources in aircraft environments

Description: From Summary: "A literature survey was conducted to determine the relation between aircraft ignition sources and inflammables. Available literature applicable to the problem of aircraft fire hazards is analyzed and discussed. Data pertaining to the effect of many variables on ignition temperatures, minimum ignition pressures, minimum spark-ignition energies of inflammables, quenching distances of electrode configurations, and size of openings through which flame will not propagate are presented and discussed. Ignition temperatures and limits of inflammability of gasoline in air in different test environments, and the minimum ignition pressures and minimum size of opening for flame propagation in gasoline-air mixtures are included; inerting of gasoline-air mixtures is discussed."
Date: 1951
Creator: Scull, Wilfred E.
Partner: UNT Libraries Government Documents Department

A small-deflection theory for curved sandwich plates

Description: A small-deflection theory that takes into account deformations due to transverse shear is presented for the elastic-behavior analysis of orthotropic plates of constant cylindrical curvature, with consideration of buckling included. The theory is applicable primarily to sandwich construction. (author).
Date: 1951
Creator: Stein, Manuel & Mayers, J.
Partner: UNT Libraries Government Documents Department

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. The types of nonlinearities assumed correspond to the condition in which the values of the directional-stability and damping-in-yawing derivatives are zero for small angle of sideslip.
Date: January 1, 1951
Creator: Sternfield, Leonard
Partner: UNT Libraries Government Documents Department

The stability of the compression cover of box beams stiffened by posts

Description: An investigation is made of the buckling of the compression cover of post-stiffened box beams subjected to end moments. Charts are presented for the determination of the minimum post axial stiffnesses and the corresponding compressive buckling loads required for the compression cover to buckle with nodes through the posts. Application of the charts to design and analysis and the limitations of their use are discussed.
Date: January 1, 1951
Creator: Seide, Paul & Barrett, Paul F
Partner: UNT Libraries Government Documents Department

A study of effects of viscosity on flow over slender inclined bodies of revolution

Description: From Summary: "The observed flow field about slender inclined bodies of revolution is compared with the calculated characteristics based upon potential theory. The comparison is instructive in indicating the manner in which the effects of viscosity are manifest. Based on this and other studies, a method is developed to allow for viscous effects on the force and moment characteristics of bodies. The calculated force and moment characteristics of two bodies of high fineness ratio are shown to be in good agreement, for most engineering purposes, with experiment."
Date: 1951
Creator: Allen, H. Julian & Perkins, Edward W.
Partner: UNT Libraries Government Documents Department

A study of the use of experimental stability derivatives in the calculation of the lateral disturbed motions of a swept-wing airplane and comparison with flight results

Description: An investigation was made to determine the accuracy with which the lateral flight motions of a swept-wing airplane could be predicted from experimental stability derivatives, determined in the 6-foot-diameter rolling-flow test section and 6 by 6-foot curved-flow test section of the Langley stability tunnel. In addition, determination of the significance of including the nonlinear aerodynamic effects of sideslip in the calculations of the motions was desired. All experimental aerodynamic data necessary for prediction of the lateral flight motions are presented along with a number of comparisons between flight and calculated motions caused by rudder and aileron disturbances.
Date: 1951
Creator: Bird, John D. & Jaquet, Byron M.
Partner: UNT Libraries Government Documents Department

Analysis of the effects of wing interference on the tail contributions to the rolling derivatives

Description: From Introduction: "This report presents calculations of the angularity of the air stream with respect to the vertical tail for a rolling airplane, the interference effects of the wing being taken into account. A discussion of the factors which enter into the calculations is given and equations for applying the side-wash results to the determination of the tail contributions to the rolling-stability derivatives are included. The results are compared with some available experimental data."
Date: January 24, 1951
Creator: Michael, William H., Jr.
Partner: UNT Libraries Government Documents Department

Correlation of physical properties with molecular structure for some dicyclic hydrocarbons having high thermal-energy release per unit volume -- 2-alkylbiphenyl and the two isomeric 2-alkylbicyclohexyl series

Description: Three homologous series of related dicyclic hydrocarbons are presented for comparison on the basis of their physical properties, which include net heat of combustion, density, melting point, boiling point, and kinematic viscosity. The three series investigated include the 2-n-alkylbiphenyl, 2-n-alkylbicyclohexyl (high boiling), and 2-n-alkylbiphenyls (low boiling) series through c sub 16, in addition to three branched-chain (isopropyl, sec-butyl, and isobutyl) 2-alkylbiphenyls and their corresponding 2-alkylbicyclohexyls. The physical properties of the low-boiling and high-boiling isomers of 2-sec-butylbicyclohexyl and 2-isobutylbicyclohexyl are reported herein for the first time.
Date: January 25, 1951
Creator: Goodman, Irving A. & Wise, Paul H.
Partner: UNT Libraries Government Documents Department