National Advisory Committee for Aeronautics (NACA) - 4,155 Matching Results

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High-altitude cooling. 3 : Radiators

Description: Report details the methods of determining the heat-transfer rate, pressure drop, and drag power of high-altitude radiators. Performance charts are provided for a wide range of design variables.
Date: September 1944
Creator: Nielsen, Jack Norman
Partner: UNT Libraries Government Documents Department

Investigation of Icing Characteristics of Typical Light Airplane Engine Induction Systems

Description: The icing characteristics of two typical light-airplane engine induction systems were investigated using the carburetors and manifolds of engines in the horsepower ranges from 65 to 85 and 165 to 185. The smaller system consisted of a float-type carburetor with an unheated manifold and the larger system consisted of a single-barrel pressure-type carburetor with an oil-jacketed manifold. Carburetor-air temperature and humidity limits of visible and serious Icing were determined for various engine power conditions. Several.methods of achieving ice-free induction systems are discussed along with estimates of surface heating requirements of the various induct ion-system components. A study was also made of the icing characteristics of a typical light-airplane air scoop with an exposed filter and a modified system that provided a normal ram inlet with the filter located in a position to Induce inertia separation of the free water from the charge air. The principle of operation of float-type carburetors is proved to make them inherently more susceptible to icing at the throttle plate than pressure-type carburetors.. The results indicated that proper jacketing and heating of all parts exposed to the fuel spray can satisfactorily reduce or eliminate icing in the float-type carburetor and the manifold. Pressure-type carburetors can be protected from serious Icing by proper location of the fuel-discharge nozzle combined with suitable application of heat to critical parts.
Date: February 1, 1949
Creator: Coles, W. D.
Partner: UNT Libraries Government Documents Department

NACA: University Conference on Aerodynamics, A Compilation of the Papers Presented

Description: This document contains reproductions of the technical papers presented at the NACA - University Conference on Aerodynamics held at the Langley Aeronautical Laboratory on June 21, 22, and 23, 1948. The conference was held in recognition of the difficulties, imposed by security restrictions, in keeping abreast of the rapid advances in aerodynamics. The papers were prepared to review the status of a number of fields of interest, to summarize the more important wartime advances that are no longer classified, and to orient reference material for further study. The papers in this document are in the same form in which they were presented at the conference so that distribution of them might be prompt. The original presentation and this record are considered as complementary to, rather than as substitutes for, the Committee?s system of complete and formal reports.
Date: 1948-06-21/1948-06-23
Partner: UNT Libraries Government Documents Department

Flight tests of the high-speed performance of a P-51B airplane (AAF no. 43-12105)

Description: Report discussing testing to check the improvement of 3 or 4 miles per hour in the maximum speed of the P-51B airplane as a result of sealing the wing-gun access doors and flap-spar lightening holes. Large variations in speed were observed during testing, so additional testing and analysis was carried out to determine the effects of various factors that were suspected of contributing to the inconsistency of the plane's performance.
Date: December 18, 1944
Creator: Voglewede, T. J. & Danforth, E. C. B.
Partner: UNT Libraries Government Documents Department

Icing and De-Icing of a Propeller with Internal Electric Blade Heaters

Description: An investigation has been made in the NACA Cleveland icing research tunnel to determine the de-icing effectiveness of an experimental configuration of an Internal electric propeller-blade heater. Two atmospheric Icing conditions and two propeller operating conditions were Investigated, In experiments with unheated blades and with heat applied to the blades both continuously and cyclically. Data are presented to show the effect of propeller speed., ambient air temperature and liquid-water concentration, and the duration of the heat-on and cycle times on the power requirements and de-Icing performance of the blade heaters. The extent of ice-covered area on the blades for various icing ax4 operating conditions has been determined. The largest iced area was obtained at the higher ambient-air temperatures and at low propeller speed. The ohord.wise extent of Icing In practically every case was greater than that covered by blade heaters. Adequate de-icing in the heated area with continuous application of heat was obtained with the power available but a maximum power, input of 1250 watts per blade was insufficient for cyclic de-Icing for the range of conditions investigated. Blade-surface temperature rates of rise of 0.2 to 0.7 F per second were obtained and the minimum cooling period for cyclic de-icing was found to be approximately 2-1/2 times the heating period.
Date: August 1948
Creator: Lewis, James P. & Stevens, Howard C., Jr.
Partner: UNT Libraries Government Documents Department

Determination of rate, area, and distribution of impingement of waterdrops on various airfoils from trajectories obtained on the differential analyzer

Description: From Summary: "The trajectories of waterdrops in air flowing over airfoils are determined for three airfoil - angle-of-attack combinations using the differential analyzer to solve the differential equations of motion of the waterdrops. From these trajectories the rate of water impingement, the area of impingement, and the distribution of impingement are determined as functions of two dimensionless moduli. Comparisons are made of the rate of water impingement on these airfoils and the rate of water impingement on cylinders."
Date: February 16, 1949
Creator: Guibert, A. G.; Janssen, E. & Robbins, W. M.
Partner: UNT Libraries Government Documents Department

Determination of rate, area, and distribution of impingement of of waterdrops on various airfoils from trajectories obtained on the differential analyzer

Description: From Summary: "The trajectories of waterdrops in air flowing over airfoils are determined for three airfoil-angle-of-attack combinations using the differential analyzer to solve the differential equations of motion of the waterdrops. From these trajectories the rate of water impingement, the area of impingement, and the distribution of impingement are determined as functions of two dimensionless moduli. Comparisons are made of the rate of water impingement on these airfoils and the rate of water impingement on cylinders."
Date: February 16, 1949
Creator: Guibert, A. G.; Janssen, E. & Robbins, W. M.
Partner: UNT Libraries Government Documents Department

Tank tests to determine the effect of varying design parameters of planing-tail hulls 2: effect of varying depth of step, angle of after- body keel, length of afterbody chine, and gross load

Description: From Summary: "The second part of a series of tests made in Langley tank no. 2 to determine the effect of varying design parameters of planing-tail hulls is presented. Results are given to show the effects on resistance characteristics of varying angle of afterbody keel, depth of step, and length of afterbody chine. The effect of varying the gross load is shown for one configuration. The resistance characteristics of planing-tail hulls are compared with those of a conventional flying-boat hull. The forces on the forebody and afterbody of one configuration are compared with the forces on a conventional hull."
Date: July 1946
Creator: Dawson, John R.; McKann, Robert & Hay, Elizabeth S.
Partner: UNT Libraries Government Documents Department

Analysis of circular shell-supported frames

Description: From Summary: "This paper deals with the single problem if circular shell-supported frames subjected to concentrated loadings. A mathematical attack is developed and presented in the form of nondimensional-coefficient curves."
Date: May 1944
Creator: Wignot, J. E.; Combs, Henry & Ensrud, A. F.
Partner: UNT Libraries Government Documents Department

Determination of Stresses in Gas-turbine Disks Subjected to Plastic Flow and Creep

Description: From Summary: "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 facilitated explanation of the procedure by carrying out the computations on a typical gas-turbine disk through a complete running cycle."
Date: 1948
Creator: Millenson, M. B. & Manson, S. S.
Partner: UNT Libraries Government Documents Department

Effects of Ice Formations on Airplane Performance in Level Cruising Flight

Description: A flight investigation in natural icing conditions was conducted by the NACA to determine the effect of ice accretion on airplane performance. The maximum loss in propeller efficiency encountered due to ice formation on the propeller blades was 19 percent. During 87 percent of the propeller icing encounters, losses of 10 percent or less were observed. Ice formations on all of the components of the airplane except the propellers during one icing encounter resulted in an increase in parasite drag of the airplane of 81 percent. The control response of the airplane in this condition was marginal.
Date: May 1948
Creator: Preston, G. Merritt & Blackman, Calvin C.
Partner: UNT Libraries Government Documents Department

A profile-drag investigation in flight on an experimental fighter-type airplane the North American XP-51

Description: Report discussing the results of an investigation of the North American XP-51 and its low-drag airfoils. Several surface conditions were tested and the profile-drag coefficients were determined. The surface that was smoothened and faired by filling and sanding had the lowest profile-drag coefficient.
Date: November 1942
Creator: Zalovcik, John A.
Partner: UNT Libraries Government Documents Department

Table of interplanar spacings for crystal-structure determinations by X-ray diffraction with molybdenum, copper, cobalt, iron, and chromium radiations

Description: For a simple diffraction pattern, the time required to calculate interplanar distances from measurements of the pattern is not excessive. If more than a few lines are present, however, or if several patterns are to be studied, it is very advantageous to have available a table giving interplanar spacings directly in terms of the linear measurements made on the film of the lines appearing on the diffraction pattern. The preparation of the table given here was undertaken when the expansion of research activities involving X-ray diffraction techniques indicated that such a table would greatly decrease the time required to analyze diffraction patterns. The table was prepared for use with K alpha(sub 1) radiation from the following target materials: molybdenum, copper, cobalt, iron, and chromium.
Date: October 1, 1945
Creator: Kittel, J Howard
Partner: UNT Libraries Government Documents Department

Tests of a heated low-drag airfoil

Description: Report discusses the results of an experimental investigation into the NACA 65,2-016 heated wing. Information about the effect of heating on the drag coefficients, Reynolds numbers, and stability of the laminar boundary layer.
Date: December 1942
Creator: Frick, Charles W., Jr. & McCullough, George B.
Partner: UNT Libraries Government Documents Department

Effects of sweepback on boundary layer and separation

Description: "Following the law of stress adopted in the Navier-Stokes equations, the configuration of the viscous flow in planes at right angles to the axis of an infinite cylinder is found to be independent of the axial motion of the cylinder. In the limiting case of a yawed or swept wing of very high aspect ratio, certain boundary-layer and separation phenomena are thus determined independently by the crosswise component of velocity" (p. 1).
Date: July 1947
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department

Tests of a gust-alleviating wing in the gust tunnel

Description: "Tests were made in the NACA gust tunnel to determine the effectiveness of a torsionally flexible wing with the torsion axis ahead of the locus of the section aerodynamic centers in reducing airplane accelerations due to atmospheric gusts. For three gust shapes, a series of flights was made with the airplane model equipped with either a torsionally flexible or a rigid wing. The results indicated that the torsionally flexible wing reduced the maximum acceleration increment 5 percent for the sharp-edge gust and about 17 percent for gust shapes with gradient distances of 6.8 and 15 chord lengths" (p. 1).
Date: April 1941
Creator: Shufflebarger, C. C.
Partner: UNT Libraries Government Documents Department

Some effects of rainfall on flight of airplanes and on instrument indications

Description: "Several possible effects of heavy rain on the aerodynamic performance of an airplane and of heavy rain and associated atmospheric phenomena on the indications of flight instruments are briefly considered. It is concluded that the effects of heavy rain on the performance of an airplane are not so great as to force the airplane down from moderate altitudes. Serious malfunctioning of the air-speed indicator may occur, however, as a result of flooding of the pitot-static head and subsequent accumulation of water in the air-speed pressure line" (p. 1).
Date: April 1941
Creator: Rhode, Richard V.
Partner: UNT Libraries Government Documents Department