National Advisory Committee for Aeronautics (NACA) - 10 Matching Results

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AVA monographs. B: Boundary layer

Description: Report discusses several experiments regarding boundary layers and their influence on aircraft. The first experiment investigates how to best design airfoils. The second involves using suction to remove the boundary layer. The third involves surface disturbances and how they may affect the boundary layer.
Date: April 1, 1948
Creator: Holstein, H.; Bete, A. & Tollmein, W.
Partner: UNT Libraries Government Documents Department

A Theoretical Investigation of the Dynamic Lateral Stability Characteristics of the MX-838 (XB-51) Airplane

Description: At the request of the Air Material Command, U. S. Air Force, a theoretical study has been made of the dynamic lateral stability characteristics of the MX-838 (XB-51) airplane. The calculations included the determination of the neutral-oscillatory-stability boundary (R = 0), the period and time to damp to one-half amplitude of the lateral oscillation, end the time to damp to one-half amplitude for the spiral mode. Factors varied in the investigation were lift coefficient, wing incidence, wing loading, and altitude. The results of the investigation showed that the lateral oscillation of the airplane is unstable below a lift coefficient of 1.2 with flaps . deflected 40deg but is stable over the entire speed range with flaps deflected 20deg or 0deg. The results showed that satisfactory oscillatory stability can probably be obtained for all lift coefficients with the proper variation of flap deflection and wing incidence with airspeed. Reducing the positive wing incidence improved the oscillatory stability characteristics. The airplane is spirally unstable for most conditions but the instability is mild and the Air Force requirements are easily met.
Date: January 1, 1948
Creator: Paulson, Jon W.
Partner: UNT Libraries Government Documents Department

The Influence of Dimensional Modifications upon the Spin and Recovery Characteristics of a Tailless Airplane Model Having Its Wings Swept Forward 15 Deg (Cornelius XFG-1)

Description: An investigation has been conducted in the Langley 20-foot free- spinning tunnel scale model of the Cornelius XFG-1 glider, a tailless design having its wings swept forward 15 degrees. It was previously found to possess erratic spin and recovery characteristics, and tests were made to determine modifications which would lead to normal steady spins with consistently good recoveries. The results of the investigation indicated that modifications that aid not appreciably alter the basic design aid not appreciably improve the spin and recovery characteristics. In this instance it appears that the sweptforward wing is the cause of unsatisfactory spin and recovery characteristics.
Date: September 1, 1948
Creator: Stone, Ralph W., Jr. & Daughtridge, Lee T., Jr.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Measurements on the Henschel Missile "Zitterrochen" in Subsonic and Supersonic Velocities

Description: At the request of the Henschel Aircraft Works. A. G. Berlin. three models of the missile "Zitterrochen" were investigated at subsonic velocities.(open jet 215-millimeter diameter) and at supersonic velocities (open jet 110 by 130 millimeters) in order to determine the effect of various wing forms on the air forces and moments. Three-component measurements were taken, and one model was also investigated with deflected control plates.
Date: April 1, 1948
Creator: Weber & Kehl
Partner: UNT Libraries Government Documents Department

Venturi Tube with Varying Mass Flow

Description: Measurements on three tubes with flow regulated by suction at the trainling edge of the tube are described. It was possible to vary the mass of air flowing through the tube over a large range. Such tubes could be used for shrouded propellers.
Date: March 1, 1948
Creator: Regenscheit, B.
Partner: UNT Libraries Government Documents Department

Two-dimensional compressible flow in turbomachines with conic flow surfaces

Description: A general method of analysis is developed for two-dimensional, steady, compressible flow in stators or rotors of radial and mixed flow turbomachines with conic flow surfaces (surfaces of right circular cones generated by center line of flow passage in the axial-radial plane). The variables taken into account are: (1) tip speed of the rotor, (2) flow rate, (3) blade shape, (4) variation in passage height with radius, (5) number of blades, and (6) cone angle of the flow surface. Relaxation methods are used to solve the nonlinear differential equation for the stream function. Two numerical examples are presented; one for compressible and the other for incompressible flow in a centrifugal compressor with thin, straight blades. The results of these examples are given by plots of the streamlines, constant velocity-ratio lines, and constant pressure-ratio line.
Date: November 1, 1948
Creator: Stanitz, John D.
Partner: UNT Libraries Government Documents Department

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 design is shown" (p. 1).
Date: June 1, 1948
Creator: Pinkel, I. Irving
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics at high speeds of a two-blade NACA 10-(3)(062)-045 propeller and of a two-blade NACA 10-(3)(08)-045 propeller

Description: From Introduction: "The aerodynamic characteristics of a series of 10-foot-diameter propellers are being investigated in the Langley 16-foot high-speed tunnel in a comprehensive propeller research program. Using high-critical-speed NACA 16-series airfoil sections (reference 1), these propellers are designed to have Betz minimum induced-energy loss loading (reference 2) for a blade angle of 45^o at the 0.7 radius, when used as a four-blade propeller operating at an advance ratio of approximately 2.1 The ultimate purpose of the program is to determine the influence upon propeller design factors and of compressiblity; the propeller tests reported herein form part of the investigation of the effects of blade-section thickness ratio."
Date: October 1, 1948
Creator: Solomon, William
Partner: UNT Libraries Government Documents Department

Pressure recovery at supersonic speeds through annular duct inlets situated in a region of appreciable boundary layer 1: addition of energy to the boundary layer

Description: Report presenting a model with a nozzle upstream of an annular duct inlet for the purpose of ejecting high-velocity air into the boundary layer of the flow along the forebody tested between Mach numbers of 1.36 and 2.01. Results wind-tunnel data, equivalent pressure recovery, and scale effects are provided.
Date: April 1, 1948
Creator: Davis, Wallace F. & Brajnikoff, George B.
Partner: UNT Libraries Government Documents Department

Investigation of Flow Conditions and the Nature of the Wall-Constriction Effect Near and at Choking by Means of the Hydraulic Analogy

Description: Report presenting an investigation of the closed wind-tunnel phenomenon of choking and the wall-constriction effects in the subsonic Mach number range where supersonic Mach numbers appear using the hydraulic analogy. Application of the results to wind tunnel testing, the subsonic choking phenomena, and effects of the walls are described.
Date: September 1, 1948
Creator: Matthews, Clarence W. & Wright, Ray H.
Partner: UNT Libraries Government Documents Department