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Wind-Tunnel Tests of Four Curtiss Propellers Embodying Different Blade Sections

Description: Tests of four 10-foot propellers were made in the propeller-research tunnel for the Army Air Corps to check flight and static thrust test results made on several propellers embodying Clark Y and modified NACA 16-series sections. These propellers were identical as to diameter and activity factor and very closely identical in thickness ratio and pitch distribution. The blades embodied sections with both single- and double-cambered Clark Y, modified NACA 16-series, and a combination of Clark Y and… more
Date: August 1941
Creator: Gray, W. H.
Partner: UNT Libraries Government Documents Department
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Determination of control-surface characteristics from NACA plain-flap and tab data

Description: From Summary: "The data from previous NACA pressure-distribution investigations of plain flaps and tabs have been analyzed and are presented in this paper in a form readily applicable to the problems of control-surface design. The experimentally determined variation of aerodynamic parameters with flap chord and tab chord are given in chart form and comparisons are made with the theory. With the aid of these charts and the theoretical relationships for a thin airfoil, the aerodynamic characteris… more
Date: February 1941
Creator: Ames, Milton B., Jr. & Sears, Richard I.
Partner: UNT Libraries Government Documents Department
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Correction of the Lifting-Line Theory for the Effect of the Chord

Description: "It is shown that a simple correction for the chord of a finite wing can be deduced from the three-dimensional potential flow around an elliptic plate. When this flow is compared with the flow around a section of an endless plate, it is found that the edge velocity is reduced by the factor 1/E, where E is the ratio of the semiperimeter to the span. Applying this correction to the circulation brings the theoretical lift into closer agreement with experiments" (p. 1).
Date: July 1941
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department
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Wind-tunnel investigation of an NACA 23012 airfoil with several arrangements of slotted flaps with extended lips

Description: "An investigation was made in the NACA 7- by 10-foot wind tunnel to determine the effect of slot-lip location on the aerodynamic section characteristics of an NACA 23012 airfoil with a 30-percent-chord slotted flap. Tests were made with slot lips located at 90 and 100 percent of the airfoil chord and with two different flap shapes. The results are compared with a slotted flap previously developed by the National advisory Committee for Aeronautics with a slot lip located at 83 percent of the air… more
Date: May 1941
Creator: Lowry, John G.
Partner: UNT Libraries Government Documents Department
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The aerodynamics of a wind-tunnel fan

Description: From Introduction: "This paper deals only with the aerodynamics of the fan proper and demonstrates the manner in which the radial distribution of axial velocity of fluid through a fan is governed by geometry of the fan itself."
Date: August 1941
Creator: Corson, Blake W.
Partner: UNT Libraries Government Documents Department
open access

Notes on the Stability and Control of Tailless Airplanes

Description: "Problems involved in the stability and control of tailless airplanes are discussed. Such factors as the location of the aerodynamic center and its effect on the longitudinal stability, longitudinal trim with high-lift devices, the effects of various changes in the shape of the wing on lateral stability, and the effects of nacelles are covered. It appears that sufficient stability and controllability can be secured without sweepback" (p. 1).
Date: December 1941
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department
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Damping characteristics of dashpots

Description: An investigation of the damping characteristics of dashpots was carried out combining theory and experiment. Laminar flow was assumed and three equations for the steady velocity of a piston moving in a cylinder filled with liquid were derived. In the first equation, the piston was assumed coaxial in the cylinder and, in the second equation, the piston was assumed eccentric in the cylinder with an element of the piston in contact with the cylinder wall. The third equation is for a piston of circ… more
Date: October 1941
Creator: Peterson, John B.
Partner: UNT Libraries Government Documents Department
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The theoretical lateral motions of an automatically controlled airplane subjected to a yawing moment disturbance

Description: Report presenting an investigation of the lateral motion resulting from a disturbance of the type produced by asymmetric loss of thrust for a hypothetical average airplane equipped with an automatic pilot. Plots of the resultant motion and various modes that constitute the motion are presented for fixed controls and for various amounts of autopilot.
Date: June 1941
Creator: Imlay, Frederick H.
Partner: UNT Libraries Government Documents Department
open access

Cooling and Performance Tests of a Continental A-75 Engine

Description: Note presenting an investigation to determine the performance of a small airplane with two Continental A-75 air-cooled engines enclosed in the wings. The object of the tests was to determine the quantity of air and the pressure difference required for satisfactory cooling of the engine at sea level and at altitude. The engine could be cooled satisfactorily at sea level with wide-open throttle and maximum-power mixture with a pressure difference of 4.5 inches of water and 1.06 pounds of cooling … more
Date: July 1941
Creator: Ellerbrock, Herman H., Jr. & Bullock, Robert O.
Partner: UNT Libraries Government Documents Department
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The Tensile Elastic Properties at Low Temperatures of 18:8 Cr-Ni Steel as Affected by Heat Treatment and Slight Plastic Deformation

Description: Note presenting the relationship between stress, strain, and permanent set for 18:8 Cr-Ni steel as measured at -110 degrees Fahrenheit. The influence of annealing and slight plastic extension upon the derived elastic properties is also discussed.
Date: July 1941
Creator: Mebs, R. W. & McAdam, D. J., Jr.
Partner: UNT Libraries Government Documents Department
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Minimum Induced Drag in Wing-Fuselage Interference

Description: Note presenting a method for obtaining the minimum induced drag of airfoils in the proximity of ideal internal boundaries. The theorem is applied to the case of an ideal wing-fuselage combination consisting of a lifting line intersecting an infinitely long circular cylindrical fuselage to determine the effect of wing height on the minimum induced drag. The analysis used can be modified for combinations with different fuselage cross sections.
Date: September 1941
Creator: Pepper, Perry A.
Partner: UNT Libraries Government Documents Department
open access

Cooling Effects of an Airplane Equipped With an NACA Cowling and a Wing-Duct Cooling System

Description: Report presenting cooling tests of a Northrop A-17A attack airplane equipped with a conventional NACA cowling and then with a wing-duct cooling system. Ground cooling for the wing-duct system without cowl flap was better than for the cowling with flap, but was improved by installing a cowl flap. Satisfactory temperatures were maintained in climb and high-speed flight, but a greater quantity of cooling air was needed for the wing-duct system.
Date: June 1941
Creator: Turner, L. I., Jr.; Bierman, David & Boothby, W. B.
Partner: UNT Libraries Government Documents Department
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Preliminary Stability and Control Tests in the NACA Free-Flight Wind Tunnel and Correlation With Full-Scale Flight Tests

Description: Note presenting a study of stability and control of airplanes by means of dynamic scale models in the 12-foot free-flight wind tunnel. Tests of a scale model of the F-36A airplane were used to develop the testing technique and to afford a comparison of tests of a model in the tunnel with flight tests of the corresponding airplane. Results regarding longitudinal stability and control and lateral stability and control are provided.
Date: June 1941
Creator: Shortal, Joseph A. & Osterhout, Clayton J.
Partner: UNT Libraries Government Documents Department
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The Effect of Methods of Testing on the Ultimate Loads Supported by Stiffened Flat Sheet Panels Under Edge Compression

Description: Note presenting testing of two series of stiffened flat sheet specimens tested under edge compression using various end conditions: round ends, flat ends, and continuous panels. The specimens consisted of aluminum-alloy flat sheet stiffened by three hat-shaped extruded aluminum-alloy stiffeners. The results indicated that the length of the specimen has an insignificant effect on the ultimate compressive load.
Date: June 1941
Creator: Holt, Marshall
Partner: UNT Libraries Government Documents Department
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The Effects of Aerodynamic Heating on Ice Formations on Airplane Propellers

Description: Report presenting an investigation of the effect of aerodynamic heating on propeller-blade temperatures and its relation to propeller icing. Test results indicate that the outermost station at which ice formed on a propeller blade as determined by the blade temperature rise resulting from the aerodynamic heating at that point.
Date: March 1941
Creator: Rodert, Lewis A.
Partner: UNT Libraries Government Documents Department
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Comparison of stress-strain curves obtained by single-thickness and pack methods

Description: Report presenting an apparatus for supporting a single thickness of sheet against buckling so that its compressive yield strength can be determined by the single-thickness method. The results of testing are compared with those from two other methods. This method results in substantial cost savings as compared to the pack method.
Date: August 1941
Creator: Paul, D. A.; Howell, F. M. & Grieshaber, H. E.
Partner: UNT Libraries Government Documents Department
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Some comparative tests of plain and alclad 24S-T sheet

Description: Report presenting comparative data on the behavior of plain and alclad 24S-T sheet under several types of structural loading. Results indicated that as far as flexural stiffness and resistance to buckling are concerned, the effect of the soft protective coating on alclad shoot is equivalent to a reduction in thickness of about 7 percent. Results regarding the tensile and compressive properties of materials, bending tests on single thicknesses of sheet, column tests on single thicknesses of shee… more
Date: August 1941
Creator: Moore, R. L.
Partner: UNT Libraries Government Documents Department
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Wind-tunnel investigation of effect of yaw on lateral-stability characteristics 3: symmetrically tapered wing at various positions on circular fuselage with and without a vertical tail

Description: Report presenting testing of model combinations of an NACA 23012 tapered wing and a circular fuselage to determine the effect of longitudinal wing position on the change in lateral stability due to interference. Results regarding wing-fuselage interference and effect of wing-fuselage interference on vertical tail are provided.
Date: September 1941
Creator: Recant, Isidore G. & Wallace, Arthur R.
Partner: UNT Libraries Government Documents Department
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Variation of Properties Throughout Cross Section of Two Extruded Shapes

Description: "Tensile and compressive properties were determined of specimens cut from the fins and the main bodies of two different extruded shapes of 24S-T aluminum alloy. The specimens from the fins as compared with those from the main body of the section showed: tensile strengths from 5000 to 10,000 pounds per square inch lower; tensile yield strengths and compressive yield strengths 4000 to 9000 pounds per square inch lower. The compressive yield strength values for any given location in the cross sect… more
Date: September 1941
Creator: Howell, F. M.
Partner: UNT Libraries Government Documents Department
open access

Tandem Air Propellers - 2

Description: Report presenting testing of three-blade, adjustable-pitch counterrotating tandem model propellers adjusted to absorb equal power at maximum efficiency of the combination. The aerodynamic characteristics were determined for a variety of blade-angle settings and diameter spacings. At maximum efficiency, the tandem propellers absorb about double the power of the three-blade propellers and about 8 percent more power than six-blade propellers with the pitch of the forward propeller of the tandem co… more
Date: August 1941
Creator: Lesley, E. P.
Partner: UNT Libraries Government Documents Department
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Velocity gained and altitude lost in recoveries from inclined flight paths

Description: A series of charts is given showing the variation of the velocity gained and the altitude lost in dive pullouts with the initial indicated air speed and the dive angle. The effects of the maximum load factor, the drag parameter K, the initial altitude, and the type of recovery on the velocity gained and the altitude lost are also considered. The results were obtained from a step-by-step solution of the equations of motion in which mean values of the air density and the airplane drag coefficient… more
Date: October 1941
Creator: Pearson, H. A. & Garvin, J. B.
Partner: UNT Libraries Government Documents Department
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A Method of Determining the Equilibrium Performance and the Stability of an Engine Equipped With an Exhaust Turbosupercharger

Description: "The performance of an exhaust turbine driving a supercharger is investigated by means of a sample calculation based on reasonable assumptions for the purpose of determining whether the assumed installation is stable with respect to changes in the mass of gas handled, boost pressure, etc. The arrangement was found to be stable throughout the entire range of operation. The method developed can be generally applied" (p. 1).
Date: November 1941
Creator: Rea, James Buchanan
Partner: UNT Libraries Government Documents Department
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Relief of Residual Stress in Streamline Tie Rods by Heat Treatment

Description: "About two-thirds of the residual stress in cold-worked SAE 1050 steel tie rods was relieved by heating 30 minutes at 600 degrees Fahrenheit. Cold-worked austenitic stainless-steel tie rods could be heated at temperatures up to 1000 degrees Fahrenheit without lowering the important physical properties. The corrosion resistance, in laboratory corrosion test, of straight 18:8 and titanium-treated 18:8 materials appeared to be impaired after heating at temperatures above 800 degrees or 900 degrees… more
Date: November 1941
Creator: Pollard, R. E. & Reinhart, Fred M.
Partner: UNT Libraries Government Documents Department
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Ultimate Stresses Developed by 24S-T Sheet in Incomplete Diagonal Tension

Description: "Tests were made on 18 shear panels of 24S-T aluminum alloy to verify the dependence of the ultimate stress on the degree of development of the diagonal-tension field. Tests were made on two thicknesses of sheet with the sheet either clamped between the flange angle or riveted to the outside of the angles" (p. 1).
Date: December 1941
Creator: Kuhn, Paul
Partner: UNT Libraries Government Documents Department
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