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Tests of large airfoils in the propeller research tunnel, including two with corrugated surfaces

Description: This report gives the results of the tests of seven 2 by 12 foot airfoils (Clark Y, smooth and corrugated, Gottingen 398, N.A.C.A. M-6, and N.A.C.A. 84). The tests were made in the propeller research tunnel of the National Advisory Committee for Aeronautics at Reynolds numbers up to 2,000,000. The Clark Y airfoil was tested with three degrees of surface smoothness. Corrugating the surface causes a flattening of the lift curve at the burble point and an increase in drag at small flying angles.
Date: May 24, 1929
Creator: Wood, Donald H.
Partner: UNT Libraries Government Documents Department

Interferometric observation of flow about an isentropic (reverse Prandtl-Meyer streamline) compression wedge at Mach 3.0

Description: Report presenting an interferometric study of the flow over a two-dimensional isentropic compression surface at a Mach number of 3.0. The flow field was essentially that of a strong-branch-shock configuration resulting from a surface flow turning that corresponded to an empirical limiting value of free-stream normal-shock pressure rise.
Date: March 28, 1955
Creator: Connors, James F.; Woollett, Richard R. & Blue, Robert E.
Partner: UNT Libraries Government Documents Department

Characteristics of thin triangular wings with constant-chord partial-span control surfaces at supersonic speeds

Description: Report presenting a theoretical analysis of the characteristics of constant-chord partial-span control surfaces on thin triangular wings at supersonic speeds by use of methods based on the linearized theory for supersonic flow. Two cases were treated with the analysis. Results regarding lift coefficient, rolling-moment coefficient, and hinge-moment coefficient due to flap deflection, hinge-moment coefficient due to angle of attack, and the pitching-moment coefficient due to flap lift.
Date: July 1948
Creator: Tucker, Warren A. & Nelson, Robert L.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of horizontal tail surfaces

Description: From Summary: "Collected data are presented on the aerodynamic characteristics of 17 horizontal tail surfaces including several with balanced elevators and two with end plates. Curves are given for coefficients of normal force, drag, and elevator hinge moment. A limited analysis of the results has been made. The normal-force coefficients are in better agreement with the lifting-surface theory of Prandtl and Blenk for airfoils of low aspect ratio than with the usual lifting-line theory. Only partial agreement exists between the elevator hinge-moment coefficients and those predicted by Glauert's thin-airfoil theory."
Date: 1940
Creator: Silverstein, Abe & Katzoff, S
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of thin empirical profiles and their application to the tail surfaces and ailerons of airplanes

Description: From Introduction: "The increasing use of airplane wings equipped with ailerons and the importance of knowing the aerodynamic characteristics of tail units (empennages) provided with movable parts (rudders and elevators) impart some interest to the so-called "empirical profiles." For this purpose we thought best to employ the method proposed by Munk for the approximate theoretical study of thin, slightly curved profiles, assimilable, from an aerodynamic view-point, to their mean camber line."
Date: December 1928
Creator: Toussaint, A & Carafoli, E
Partner: UNT Libraries Government Documents Department

Effect of shallow water on the hydrodynamic characteristics of a flat-bottom planing surface

Description: Report presenting an investigation on the tank no. 2 monorail to determine the effect of shallow water on the hydrodynamic characteristics of a flat-bottom planing surface. Values of lift, drag, and trimming moment at a constant speed over a range of trim, wetted lengths, and clearances between the model and a false bottom in the tank.
Date: April 1956
Creator: Christopher, Kenneth W.
Partner: UNT Libraries Government Documents Department

A method for calculation of hydrodynamic lift for submerged and planing rectangular lifting surfaces

Description: A method is presented for the calculation of lift coefficients for rectangular lifting surfaces of aspect ratios from 0.125 to 10 operating at finite depths beneath the water surface, including the zero depth or planing condition. Theoretical values are compared with experimental values obtained at various depths of submergence with lifting surfaces of aspect ratios from 0.125 to 10. The method can also be applied to hydrofoils with dihedral. Lift coefficients computed by this method are in good agreement with existing experimental data for aspect ratios from 0.125 to 10 and dihedral angles up to 10 degrees.
Date: January 1958
Creator: Wadlin, Kenneth L. & Christopher, Kenneth W.
Partner: UNT Libraries Government Documents Department

Low-speed static lateral and rolling stability characteristics of a series of configuration composed of intersecting triangular plan-form surfaces

Description: Report presenting the static lateral and rolling stability derivatives of a series of cruciform, inverted T-, V-, and Y-configurations composed of low-aspect-ratio triangular surfaces at low speed in the rolling-flow test section. Comparisons have been made to indicate the extent of agreement between experiment and existing theory. Results regarding sideslip characteristics and steady rolling characteristics are provided.
Date: October 1955
Creator: Thomas, David F., Jr.
Partner: UNT Libraries Government Documents Department

The planing characteristics of a surface having a basic angle of dead rise of 40 degrees and horizontal chine flare

Description: Report presenting an experimental investigation with a surface with a dead rise angle of 40 degrees and horizontal chine flare to determine the effects of increasing the angle of dead rise on the planing characteristics of horizontally flared prismatic surfaces. Wetted length, resistance, center-of-pressure location, and draft were determined for a range of speed coefficients and trims. Planing characteristics for a given trim were found to depend mainly on lift coefficient.
Date: December 1952
Creator: Blanchard, Ulysse J.
Partner: UNT Libraries Government Documents Department

Tank tests of flat and v-bottom planning surfaces

Description: "Four planing surfaces, all having beams of 16 inches and lengths of 60 inches but varying in dead rise by 10 degrees increments from 0 degrees to 30 degrees, were tested in the N.A.C.A. tank. The results cover a wide range of speed, loads, and trim angles, and are applicable to a variety of problems encountered in the design of seaplanes. The data are analyzed to determine the characteristics of each surface at the trim angle giving minimum resistance for all the speed and loads tested. A planing coefficient intended to facilitate the application of the results to design work is developed and curves of resistance, wetted length, and center of pressure are plotted against this coefficient" (p. 1).
Date: November 1934
Creator: Shoemaker, James M.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of self-excited vibrations of single planing surfaces

Description: "A preliminary investigation was made of self-excited vibrations of single planing surfaces. A self-excited oscillation requiring freedom in rise but not in trim occurred with high aspect ratio (order of 10) of the wetted portion. This vibration could be controlled most successfully by methods (such as the use of dead rise) which limited the wetted aspect ratio" (p. 1).
Date: June 1956
Creator: Mottard, Elmo J.
Partner: UNT Libraries Government Documents Department

General Characteristics of the Flow through Nozzles at Near Critical Speeds

Description: The characteristics of the position and form of the transition surface through the critical velocity are computed for flow through flat and round nozzles from subsonic to supersonic velocity. Corresponding considerations were carried out for the flow about profiles in the vicinity of sonic velocity.
Date: June 1947
Creator: Sauer, R.
Partner: UNT Libraries Government Documents Department

A Summary of the results obtained in the LDRD project "Interaction of a magnetized plasma with structured surfaces- from devices to spacecraft"

Description: Our work was directed towards developing a basic understanding of a new class of phenomena: effects of surface structure on the processes in a magnetized plasma near surfaces and at some distances for them. The surface structures can be of various kinds: topographic features ranging from smooth �waviness� to a coarse �roughness,� non-uniformities of the secondary emission coefficient, dielectric impregnations into conducting surface, etc. The expected effects are strongest when the magnetic field forms a shallow angle with the surface. The current and future applications of this new branch of plasma physics include fusion devices, gas-discharge and plasma-processing devices, large spacecraft, and physical phenomena in the vicinity of celestial bodies without atmospheres. We have developed a methodology that allows one to study in a unified way effects of rough surfaces with arbitrary scales of topographic features, from sizes exceeding the ion gyro-radius, to sizes much below the electron gyro-radius, in the most interesting case of a grazing magnetic field. The results can be presented in a dimensionless form, so that they would be equally applicable to the micrometer-scale roughness of the divertor plates of fusion devices, and to 10-km-scale structures of a Lunar surface. We have identified the following new effects: 1) the plasma is absorbed by only a small fraction of the total surface, near the �mountain tops� of the bumps; 2) regions inaccessible for one or both plasma species (�shadows�) are formed behind the bumps; the size of these inaccessible domains is, generally speaking, different for the electrons and ions; 3) this latter circumstance leads to formation of fine potential structure both near the surface and in the bulk plasma, leading to enhanced plasma transport. We have investigated the processes that may lead to plasma penetration into the shadows and concluded that most probable candidates are (depending on ...
Date: February 23, 1999
Creator: Cohen, R H; Porter, G D & Ryutov, D D
Partner: UNT Libraries Government Documents Department

Hovering performance of a helicopter rotor using NACA 8-H-12 airfoil sections

Description: Report presenting an investigation of a helicopter rotor employing an NACA 8-H-12 airfoil section that has been tested in the helicopter test tower. Two blade surface conditions, one with a filled blade using a plastic filler and one with the filler removed. The performance of the blades in the condition they arrived in was about what would be expected from good practical-construction rotor blades.
Date: August 1954
Creator: Powell, Robert D., Jr.
Partner: UNT Libraries Government Documents Department

Theory of lifting surfaces

Description: The general basis of the theory of lifting surfaces is discussed. The problem of the flow of a fluid about a lifting surface of infinite span is examined in terms of the existence of vortexes in the current. A general theory of permanent flow is discussed. Formulas for determining the influence of aspect ratio that may be applied to all wings, whatever their plane form, are given.
Date: July 1920
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department

Transonic lateral and longitudinal aerodynamic characteristics of a lateral-control system employing rotatable airfoils mounted vertically at the wing tips of an unswept wing-fuselage-tail combination

Description: Report presenting the aerodynamic characteristics of a new type of lateral control through a range of Mach numbers. The control consisted of airfoils mounted vertically at the tips of the wing and could be rotated to induce rolling moments or lift on the wing surface. Results regarding lateral-control characteristics and lift-control characteristics are provided.
Date: January 7, 1958
Creator: Axelson, John A.
Partner: UNT Libraries Government Documents Department

Sulfur-induced Corrosion at Metal and Oxide Surfaces and Interfaces

Description: Sulfur adsorbed on metallic and oxide surfaces, whether originating from gaseous environments or segregating as an impurity to metallic interfaces, is linked to the deterioration of alloy performance. This research dealt with investigations on the interactions between sulfur and iron or iron alloy metallic and oxide surfaces under ultrahigh vacuum conditions. Sulfur was either intentionally dosed from a H2S source on an atomically clean metal surface, or segregated out as an impurity from the bulk to the metal surface by annealing at elevated temperatures.
Date: August 1997
Creator: Cabibil, Hyacinth (Hyacinth Liesl)
Partner: UNT Libraries

Investigation of flutter characteristics of three low-aspect-ratio all-movable half-span control surfaces at Mach numbers from 1.49 to 2.87

Description: Report presenting the results of a supersonic flutter investigation of three low-aspect-ratio control surfaces, two which had all-movable controls and one with a fixed cutout. Experimental results are provided and compared to calculations using the piston theory for plan form 2. Modifications for improving the flutter of the various control surfaces are also described.
Date: May 2, 1958
Creator: Morgan, Homer G.; Figge, Irving E. & Presnell, John G., Jr.
Partner: UNT Libraries Government Documents Department