UNT Libraries Government Documents Department - 226 Matching Results

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N.A.C.A. Stall-Warning Device

Description: With some airplanes the approach to the stall is accompanied by changes in the behavior, such as tail buffeting or changes in the control characteristics of the airplane so that the pilot obtains a warning of the impending stall. Vith other airplanes it is possible to approach the stall without any perceptible warning other than the reading of the air-speed meter, in which case the danger of inadvertent stalling is considerably greater. Although it is not within the scope of this paper to discuss stalling characteristics, it is desired to point out that in general the danger of inadvertent stalling is greatest with those airplanes that behave worse when the stalling occurs; that is, with airplanes in which the stall starts at the wing tips. A warning of the impending stall is desirable in any case, but is particularly desirable with airplanes of the latter type.
Date: February 1938
Creator: Thompson, F. L.

N.A.C.A. Stall-Warning Indicator

Description: "The stall-warning indicator employs a total-head tube located close to the wing surface in a region wherein local stalling occurs before the main portion of the wing stalls. The artificial production of a localized stalled region is accomplished by means of a sharp leading edge extending a few inches along the span. An abrupt drop in the total pressure relative to a static reference taken at some convenient point occurs at the stall in this region" (p. 1).
Date: October 1938
Creator: Thompson, F. L.

Aerodynamic Characteristics of a 4-Engine Monoplane Showing Effects of Enclosing the Engines in the Wing and Comparisons of Tractor- and Pusher-Propeller Arrangements

Description: Report presenting testing in the full-scale wind tunnel on a model of a large 4-engine monoplane to determine the overall aerodynamic efficiency of a conventional wing-nacelle-engine installation as compared with power-plant installations enclosed in the wing with extension shafts to the propellers. Results regarding power-on and power-off performance for the installations as well as propeller noise are provided.
Date: April 1938
Creator: Silverstein, Abe & Wilson, Herbert A., Jr.

Aerodynamic characteristics of a large number of airfoils tested in the variable-density wind tunnel

Description: From Summary: "The aerodynamic characteristics of a large number of miscellaneous airfoils tested in the variable-density tunnel have been reduced to a comparable form and are published in this report for convenient reference. Plots of the standard characteristics are given in tabular form. Included is a tabulation of important characteristics for the related airfoils reported in NACA report 460. This report, in conjunction with NACA report 610, makes available in comparable and convenient form the aerodynamic data for airfoils tested in the variable-density tunnel since January 1, 1931."
Date: 1938
Creator: Pinkerton, Robert M. & Greenberg, Harry

The aerodynamic characteristics of four full-scale propellers having different plan forms

Description: From Introduction: "Its main purpose is to present propeller data for four full-scale propellers of Navy design, three of which have somewhat unusual plan forms and the other one has a normal (usual present-day type) plan form. These data may give some clue as to what may be expected from fundamental changes in blade plan form."
Date: 1938~
Creator: Hartman, Edwin P. & Biermann, David

The Aerodynamic Characteristics of Full-Scale Propellers Having 2, 3, and 4 Blades of Clark Y and R.A.F. 6 Airfoil Sections

Description: "Aerodynamic tests were made of seven full-scale 10-foot-diameter propellers of recent design comprising three groups. The first group was composed of three propellers having Clark Y airfoil sections and the second group was composed of three propellers having R.A.F. 6 airfoil sections, the propellers of each group having 2, 3, and 4 blades. The third group was composed of two propellers, the 2-blade propeller taken from the second group and another propeller having the same airfoil section and number of blades but with the width and thickness 50 percent greater" (p. 1).
Date: 1938
Creator: Hartman, Edwin P. & Biermann, David

The Aerodynamic Drag of Five Models of Side Floats N.A.C.A. Models 51-E, 51-F, 51-G, 51-H, 51-J

Description: "The drag of five models of side floats was measured in the N.A.C.A. 7- by 10-foot wind tunnel. The most promising method of reducing the drag of floats indicated by these tests is lowering the angle at which the floats are rigged. The addition of a step to a float does not always increase the drag in the flying range, floats with steps sometimes having lower drag than similar floats without steps" (p. 1).
Date: December 1938
Creator: House, R. O.

Air Flow in the Boundary Layer of an Elliptic Cylinder

Description: From Introduction: "The present investigation was carried out for the purpose of supplementing the earlier work with information on the boundary layer under such conditions of air speed and turbulence that transition occurs and the layer is partly laminar and partly turbulent. In the work reported in reference 1, the air speed was about 12 feet per second, and it was assumed that the boundary layer remained in the laminar condition until after separation because the separation point remained fixed and the pressure distribution about the cylinder was unaffected until an air speed of 15 feet per second was reached."
Date: August 6, 1938
Creator: Schubauer, G. B.

Airfoil section characteristics as applied to the prediction of air forces and their distribution on wings

Description: From Introduction: "The system presented herein yields, within the limitations of our present knowledge of aerodynamics, a general solution of the resultant wing forces and moments and their distribution. For the sake of completeness and facility in use, the report contains a table of the important section parameters for many commonly used sections and all other necessary data required to solve the most practical design problems coming within the scope of the system."
Date: 1938
Creator: Jacobs, Eastman N. & Rhode, R. V.

Approximate Stress Analysis of Multistringer Beams With Shear Deformation of the Flanges

Description: "The problem of the skin-stringer combinations used as axially loaded panels or as covers for box beams is considered from the point of view of the practical stress analyst. By a simple substitution the problem is reduced to the problem of the single-stringer structure, which has been treated in NACA Report no. 608. The method of making this substitution is essentially empirical; in order to justify it, comparisons are shown between calculations and strain-gage tests of three beams tested by the author and of one compression panel and three beams tested and reported elsewhere" (p. 469).
Date: April 20, 1938
Creator: Kuhn, Paul

Behavior of a Plate Strip Under Shear and Compressive Stresses Beyond the Buckling Limit

Description: The present report is an extension of previous theoretical investigations on the elastic behavior of a plate under compression and shear in the region above the critical. The main object is the clarification of the behavior immediately above the buckling limit since no theoretical expressions for this range have thus far been found and since experimentally, too, any degree of regularity in the behavior of the plate in the range between the critical load and about three to four times the critical, is discernible only with difficulty.
Date: July 1938
Creator: Kromm, A. & Marguerre, K.

Behavior of Static Pressure Heads at High Speeds

Description: "Memorandum presenting the development of a static pressure head for high speeds. These tests proved the practicability of static pressure heads at speeds up to 400 km/h (248.5 mph). It weighs 6.5 kg or 2.5 times as much as the old head. The position of the pressure head below the airplane was determined by bearing method at different speeds and for different lengths of suspension" (p. 1).
Date: June 1938
Creator: Danielzig, Helmut

Breeds of dogs.

Description: Provides information to assist the reader in selecting dogs for breeding for various purposes. Includes only the "best known" breeds.
Date: 1938
Creator: Speelman, S. R. (Sanford Reed), 1894- & Williams, J. O. (John Oscar), 1885-

The Buckling of Curved Tension-Field Girders

Description: "The present paper reports on experiments made to determine the buckling load under shear of circular curved tension-field webs. The buckling load of the webs may be expressed with reference to the buckling load of the stiffeners. It is found that within the explored range the buckling load is approximately twice as great as that of the identically stiffened flat wall of equal web depth" (p. 1).
Date: January 1938
Creator: Limpert, G.

Calculation of Load Distribution in Stiffened Cylindrical Shells

Description: "Thin-walled shells with strong longitudinal and transverse stiffening (for example, stressed-skin fuselages and wings) may, under certain simplifying assumptions, be treated as static systems with finite redundancies. In this report the underlying basis for this method of treatment of the problem is presented and a computation procedure for stiffened cylindrical shells with curved sheet panels indicated. A detailed discussion of the force distribution due to applied concentrated forces is given, and the discussion illustrated by numerical examples which refer to an experimentally determined circular cylindrical shell" (p. 1).
Date: June 1938
Creator: Ebner, H. & K├Âller, H.

Calculation of the chordwise load distribution over airfoil sections with plain, split, or serially hinged trailing-edge flaps

Description: From Summary: "A method is presented for the rapid calculation of the incremental chordwise normal-force distribution over an airfoil section due to the deflection of a plain flap or tab, a split flap, or a serially hinged flap. This report is intended as a supplement to NACA Report no. 631, wherein a method is presented for the calculation of the chordwise normal-force distribution over an airfoil without a flap or, as it may be considered, an airfoil with flap (or flaps) neutral. The method enables the determination of the form and magnitude of the incremental normal-force distribution to be made for an airfoil-flap combination for which the section characteristics have been determined. A method is included for the calculation of the flap normal-force and hinge-moment coefficients without necessitating a determination of the normal-force distribution."
Date: 1938
Creator: Allen, H. Julian

Carbonizing Properties of West Virginia Coals and Blends of Coals From the Alma, Cedar Grove, Dorothy Powellton A, Eagle, Pocahontas and Beckley Beds

Description: From Introduction: "The composition and carbonizing properties of 33 coals previously tested have been given in technical papers of the Bureau of Mines and in short reports published for the most part in the Proceedings of the American Gas Association. A complete list of publications on the work previous to 1937 is appended to this report. The present report gives the composition and carbonizing properties of seven additional coals from West Virginia. The data include results of blending test in which Beckley bed low-volatile coal was used with all the high-volatile coals except the Alma coal, with which Pocahontas No. 4 coal was used."
Date: 1938
Creator: Fieldner, A. C.; Davis, J. D.; Selvig, W. A.; Thiessen, R.; Reynolds, D. A.; Holmes, C. R. et al.

The City Home Garden

Description: Revised edition. "Fresh vegetables for an average family may be grown upon a large back yard or city lot.... Thousands of acres of idle land that may be used for gardens are still available within the boundaries of our large cities. Some of the problems that confront the city gardener are more difficult than those connected with the farm garden, and it is the object of this bulletin to discuss these problems from a practical standpoint." -- p. 2. Soil preparation, tools, seeding, watering, diseases and pests, and space issues are all discussed and brief descriptions of several vegetables are given.
Date: 1938
Creator: Beattie, W. R. (William Renwick), b. 1870