National Advisory Committee for Aeronautics (NACA) - 744 Matching Results

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An analysis of the full-floating journal bearing

Description: Report discussing an analysis of the operating characteristics of a full-floating journal bearing, a bearing in which a floating sleeve is located between the journal and bearing surfaces, is presented together with charts from which the performance of such bearings may be predicted.
Date: 1947
Creator: Shaw, M. C. & Nussdorfer, T. J., Jr,
Partner: UNT Libraries Government Documents Department

Charts for determining the characteristics of sharp-nose airfoils in two-dimensional flow at supersonic speeds

Description: Solutions of the Hugoniot shock equations and Meyer expansion equations are plotted in such a manner as to permit the pressure distribution, the local Mach number, and the angles of shock waves on arbitrary sharp-nose airfoils at supersonic speeds to be obtained directly. (author).
Date: January 1947
Creator: Ivey, H. Reese; Stickle, George W. & Schuettler, Alberta
Partner: UNT Libraries Government Documents Department

Column and plate compressive strengths of aircraft structural materials: Extruded 0-1HTA magnesium alloy

Description: Column and plate compressive strengths of extruded 0-1HTA magnesium alloy were determined both within and beyond the elastic range from tests of flat end H-section columns and from local instability tests of H-, Z-, and channel section columns. These tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.
Date: January 1947
Creator: Heimerl, George J. & Niles, Donald E.
Partner: UNT Libraries Government Documents Department

Compressible Flow Tables for Air

Description: This paper contains a tabulation of functions of the Mach number which are frequently used in high-speed aerodynamics. The tables extend from M = 0 to M = 10.0 in increments of 0.01 and are based on the assumption that air is a perfect gas having a specific heat ratio of 1.400.
Date: January 1, 1947
Creator: Burcher, Marie A.
Partner: UNT Libraries Government Documents Department

Determination of elastic stresses in gas-turbine disks

Description: A method is presented for the calculation of elastic stresses in symmetrical disks typical of those of a high-temperature gas turbine. The method is essentially a finite-difference solution of the equilibrium and compatibility equations for elastic stresses in a symmetrical disk. Account can be taken of point-to-point variations in disk thickness, in temperature, in elastic modulus, in coefficient of thermal expansion, in material density, and in Poisson's ratio. No numerical integration or trial-and-error procedures are involved and the computations can be performed in rapid and routine fashion by nontechnical computers with little engineering supervision. Checks on problems for which exact mathematical solutions are known indicate that the method yields results of high accuracy. Illustrative examples are presented to show the manner of treating solid disks, disks with central holes, and disks constructed either of a single material or two or more welded materials. The effect of shrink fitting is taken into account by a very simple device.
Date: 1947
Creator: Manson, S. S.
Partner: UNT Libraries Government Documents Department

Effect of brake forming in various tempers on the strength of Alclad 75S-T aluminum-alloy sheet

Description: Results are presented of tests to determine the effect of brake forming in various tempers on the strength of Alclad 75S-T aluminum alloy sheet in the direction parallel to the brake. The tensile and compressive strengths of Alclad 75S-T sheet, formed in the O and W tempers, were either increased or little affected compared with those of similarly treated unformed material. When Alclad 75S-T sheet 'as received' was formed, however, the tensile yield stress was reduced about 7 percent for the with-grain direction and 1 percent for the cross-grain direction, whereas the tensile ultimate and compressive yield stresses were increased somewhat. The elongation was always slightly reduced as a result of forming.
Date: January 1947
Creator: Woods, Walter & Heimerl, George J.
Partner: UNT Libraries Government Documents Department

Effect of rivet or bolt holes on the ultimate strength developed by 24S-T and Alclad 75S-T sheet in incomplete diagonal tension

Description: From Summary: "Strength tests were made of a number of 24S-T and Alclad 75S-T aluminum alloy shear webs to determine the effect of rivet or bolt holes on the shear strength. Data were obtained for webs which approached a condition of pure shear stress as well as for webs with well-developed diagonal tension. The rivet factor (pitch minus diameter), divided by pitch, was varied from approximately 0.81 to 0.62. These tests indicated that the shear stresses on the gross section were nearly constant for all values of the rivet factor investigated if the other properties of the web were not changed."
Date: January 1947
Creator: Levin, L. Ross & Nelson, David H.
Partner: UNT Libraries Government Documents Department

Effect of Various Methods of Boundary-Layer Control on Performance of V-1710-93 Engine-Stage Supercharger

Description: Four methods of boundary-layer control were tried during an investigation to improve the flow in the impeller passages of a V-1710-93 engine-stage supercharger. The boundary layer along the impeller front shroud was removed by suction. In one method the removal was accomplished by recirculation of the air to the impeller inlet; in another method, by external removal. In the other methods, slots were cut through the impeller-blade faces first at 30 percent and then at 30 and 70 percent of the mean-flow-path length measured from leading edges of the rotating inlet guide vanes to introduce air from the high-pressure side of the blades into the region where stagnation and separation were suspected. A slight improvement in performance was obtained when the boundary layer was removed through the impeller front shroud. In general, this improvement become more pronounced as the amount of air removed was increased even though the excessive impeller frontal clearance maintained for these tests, together with an exaggerated negative pressure gradient, apparently induced flow separation on the diffuser front and rear walls as well as on the impeller front shroud. The use of slots in the impellers at the locations selected had a detrimental effect on the supercharger performance characteristics.
Date: January 1947
Creator: Kohl, Robert C. & Diggs, Donald R.
Partner: UNT Libraries Government Documents Department

Evaluation of Gust and Draft Velocities from Flights of P-61C Airplanes within Thunderstorms: September 5, 1946 to September 10, 1946 at Orlando, Florida

Description: Tables I and II of this report summarize the gust and draft velocity data for thunderstorm flights 31, 32, and 33 of September 5, 1946, September 6, 1946, and September 10, 1946, respectively. These data were evaluated from records of NACA instruments installed in P-61C airplanes and are of the type presented for previous flights. Table III summarizes the readings of a milliammeter which was used in conjunction with other equipment to indicate ambient air temperature during thunderstorm surveys. These data were read from motion-picture records of the instrument and include all cases in which variations in the instrument indications were noted for the present flights.
Date: 1947
Creator: Tolefson, H. B.
Partner: UNT Libraries Government Documents Department

Flight Investigation on a Fighter-Type Airplane of Factors Which Affect the Loads and Load Distributions on the Vertical Tail Surfaces During Rudder Kicks and Fishtails

Description: "Results are presented of a flight investigation conducted on a fighter-type airplane to determine the factors which affect the loads and load distributions on the vertical tail surfaces in maneuvers. An analysis is made of the data obtained in steady flight, rudder kicks, and fishtail maneuvers. For the rudder kicks, the significant loads were the "deflection load" resulting from an abrupt control deflection and the "dynamic load" consisting of a load corresponding to the new static equilibrium condition for the rudder deflected plus a load due to a transient overshoot" (p. 1).
Date: 1947
Creator: Boshar, John
Partner: UNT Libraries Government Documents Department

Free-Spinning-Tunnel Tests of a 1/27-Scale Model of the Douglas XF3D-1 Airplane, TED No. NACA DE 312

Description: Free-spinning-tunnel tests have been made on a 1/27-scale model of the Douglas XF3D-1 airplane to confirm a preliminary evaluation made of the airplane spin and recovery characteristics and previously reported. Recovery characteristics were satisfactory for erect and inverted spins when the model was in the clean condition. When the slow-down brakes were open, recoveries were slow. The pedal force necessary to reverse the airplane rudder during a spin will be within the physical capabilities of the pilot. A 10-foot-diameter parachute attached to the tail of the airplane (laid-out-flat diameter, drag coefficient 0.7) or a 4.5-foot-diameter parachute attached to the outboard wing tip will be satisfactory for emergency spin recovery from demonstration spins. If it becomes necessary for the crew to abandon the airplane during a spin, they should leave from the outboard side of the cockpit. The test results indicated spin and recovery characteristics generally similar to those indicated in the preliminary evaluation.
Date: 1947
Creator: Scher, Stanley H.
Partner: UNT Libraries Government Documents Department

Frequency-Response Method for Determination of Dynamic Stability Characteristics of Airplanes With Automatic Controls

Description: "A frequency-response method for determining the critical control-gearing and hunting oscillations of airplanes with automatic pilots is presented. The method is graphical and has several advantages over the standard numerical procedure based on Routh's discriminant. The chief advantage of the method is that direct use can be made of the measured response characteristics of the automatic pilot. This feature is especially useful in determining the existence, amplitude, and frequency of the hunting oscillations that may be present when the automatic pilot has nonlinear dynamic characteristics" (p. 1).
Date: 1947
Creator: Greenberg, Harry
Partner: UNT Libraries Government Documents Department

High-Speed Wind-Tunnel Tests of a 1/16-Scale Model of the D-558 Research Airplane Air-Stream Fluctuations at the Tail of the D-558-1 Airplane

Description: An investigation of the air-stream fluctuations at the tail of the D-558-1 airplane has been made at high speed for the purpose of determining the vertical region in which the horizontal tail may be placed without becoming subject to tail buffeting. The investigation was made for a range of Mach numbers from 0.775 to 0.907, and a range of vertical positions at the tall to include two proposed horizontal-tail positions. The tests were made at two angles of attack, 0,2 deg. and 4.2 deg., representative, of the angles of attack for high-speed level flight and a pull-out condition.
Date: January 1, 1947
Creator: Pendley, Robert E.
Partner: UNT Libraries Government Documents Department

Investigations of Compression Shocks and Boundary Layers in Gases Moving at High Speed

Description: The mutual influences of compression shocks and friction boundary layers were investigated by means of high speed wind tunnels.Schlieren optics provided a clear picture of the flow phenomena and were used for determining the location of the compression shocks, measurement of shock angles, and also for Mach angles. Pressure measurement and humidity measurements were also taken into consideration.Results along with a mathematical model are described.
Date: January 1947
Creator: Ackeret, J.; Feldmann, F. & Rott, N.
Partner: UNT Libraries Government Documents Department

Isolated and Cascade Airfoils With Prescribed Velocity Distribution

Description: "An exact solution of the problem of designing an airfoil with a prescribed velocity distribution on the suction surface in a given uniform flow of an incompressible perfect fluid is obtained by replacing the boundary of the airfoil by vortices. By this device, a method of solution is developed that is applicable both to isolated airfoils and to airfoils in cascade. The conformal transformation of the designed airfoil into a circle can then be obtained and the velocity distribution at any angle of attack computed. Numerical illustrations of the method are given for the airfoil in cascade" (p. 1).
Date: 1947
Creator: Goldstein, Arthur W. & Jerison, Meyer
Partner: UNT Libraries Government Documents Department

Lateral-control characteristics of various spoiler arrangements as measured in flight

Description: Report presenting an investigation of the lateral-control characteristics of several spoiler arrangements located near the wing trailing edge in flight. In all cases, the control response was satisfactory and the variation of rolling effectiveness with control deflections was smooth and nearly linear. Results regarding response characteristics, rolling effectiveness, control-force and hinge-moment characteristics, yawing characteristics, effects of altitude, characteristics near the stall, and characteristics in inverted flight are provided.
Date: January 1947
Creator: Spahr, J. Richard
Partner: UNT Libraries Government Documents Department

Longitudinal Stability and Stalling Characteristics of a 1/8.33-Scale Model of the Republic XF-12 Airplane

Description: The XF-12 airplane is a high performance, photo-reconnaissance aircraft designed by the Republic Aviation Corporation for Army Air Forces. A series of tests of a 1/8.33-scale powered model was conducted in the Langley 9-foot pressure tunnel to obtain information relative to the aerodynamic design of the airplane. This report presents the results of tests to determine the static longitudinal stability and stalling characteristics of the model. From this investigation it was indicated that the airplane will possess a positive static margin for all probable flight conditions. The stalling characteristics are considered satisfactory in that the stall initiates near the root section and progresses toward the tips. Early root section stalling occurs, with the flaps retracted and may cause undesirable tail buffeting and erratic elevator control in the normal flight range. From considerations of sinking speed landing flap deflections of 40 degrees may be preferable to 55 degrees of 65 degrees.
Date: 1947
Creator: Pepper, Edward & Foster, Gerald V.
Partner: UNT Libraries Government Documents Department

Method of characteristics for three-dimensional axially symmetrical supersonic flows

Description: An approximation method for three-dimensional axially symmetrical supersonic flows is developed; it is based on the characteristics theory (represented partly graphically, partly analytically). Thereafter this method is applied to the construction of rotationally symmetrical nozzles. (author).
Date: January 1947
Creator: Sauer, R.
Partner: UNT Libraries Government Documents Department

Notes on the theoretical characteristics of two-dimensional supersonic airfoils

Description: The shock expansion method of the NACA TN No. 1143 was used to determine the principal aerodynamic characteristics of two-dimensional supersonic airfoils. A discussion is given of the effect of thickness ratio, free-stream Mach number, angle of attack, camber, thickness distribution, and aileron deflection. The calculations indicated that the minimum drag of supersonic airfoils is obtained when the maximum thickness is behind the 0.50 chord. The center of pressure obtained for a symmetrical supersonic airfoil was found to be ahead of the 0.50 chord.
Date: January 1947
Creator: Ivey, H. Reese
Partner: UNT Libraries Government Documents Department

On the Vortex Sound from Rotating Rods

Description: The motion of different bodies imersed in liquid or gaseous media is accompanied by characteristic sound which is excited by the formation of unstable surfaces of separation behind the body, usually disintegrating into a system of discrete vortices(such as the Karman vortex street due to the flow about an infintely long rod, etc.).In the noise from fans,pumps,and similar machtnery, vortexnQif3eI?Yequently predominates. The purpose of this work is to elucidate certain questions of the dependence ofthis sound upon the aerodynamic parameters and the tip speed of the rotating rods,or blades. Although scme material is given below,insufficientto calculate the first rough approximation to the solution of this question,such as the mechanics of vortex formation,never the less certain conclusions maybe found of practical application for the reduction of noise from rotating blades.
Date: January 1, 1947
Creator: Yudin, E. Y.
Partner: UNT Libraries Government Documents Department

Possibilities of Reducing the Length of Axial Superchargers for Aircraft Motors

Description: Axial blowers are gaining importance as aircraft engine superchargers. However, the pressure head obtainable per stage is small. Due to the necessary great number of stages, the physical length of the blower becomes too great for an airworthy device. This report discusses several types of construction that permit a reduction in the length of the blower.
Date: January 1947
Creator: Eckert, B.
Partner: UNT Libraries Government Documents Department

Preliminary Results of Altitude-Wind-Tunnel Investigation of X24C-4B Turbojet Engine. 5 - Performance of Modified Engine

Description: From Summary: "An investigation has been conducted in the NACA Cleveland altitude wind tunnel to evaluate the performance characteristics of a modified X24C-4B turbojet engine over a range of simulated altitudes from 5000 to 45,000 feet, simulated flight Mach numbers from 0.25 to 1.07, and engine speeds from 4000 to 12,500 rpm. The engine was modified by the manufacturer to improve the velocity and temperature profiles within the engine. Performance data are graphically presented to show the effect of altitude at a flight Mach number of 0.25 and the effect of flight Mach number at an altitude of 25,000 feet."
Date: 1947
Creator: Prince, William R. & Bloomer, Harry E.
Partner: UNT Libraries Government Documents Department

Pressure-Distribution Measurements on a Straight and on a 35 Degree Swept-Back Tapered Wing

Description: The spanwise lift-distribution measurements in straight air flow on a straight and a 35 deg swept-back tapered wing (NACA airfoil section 0012) are compared with theory for two angles of attack each (alpha approx. 6 deg and alpha approx. 12 deg) in the unstalled range of flow. The complete pressure distribution for the greater of the two angles is indicated.
Date: January 1, 1947
Creator: Thiel, A. & Weissinger, J.
Partner: UNT Libraries Government Documents Department