UNT Libraries Government Documents Department - 1,346 Matching Results

Search Results

prev Results: 1249 - 1272 next
open access

Turbulent Boundary Layer of an Airfoil

Description: A need has arisen for a new determination of the velocity profiles in the boundary layer. Assuming that the character of the velocity distribution depends to a large extent on the character of the shear distribution across the boundary layer, we shall consider the nature of the shear distribution for a boundary layer with a pressure gradient.
Date: April 1937
Creator: Fediaevsky, K.
Item Type: Refine your search to only Report
open access

Turbulent Jet Expansion

Description: This report was made to study the velocity distribution in an open, in a partially open, and in a partially expanding jet. The open-jet observations reveal minor systematic discrepancies from Tollmien's theoretical velocity distribution. The shearing-stress distribution for the partially open jet was determined. The value derived for the ratio of mixing distance to jet width was found to be in close agreement with the corresponding value for the open-jet boundary.
Date: March 1936
Creator: Förthmann, E.
Item Type: Refine your search to only Report
open access

Twelfth Rhon Soaring Contest, 1931

Description: The crew of the "Fafnir" was given an excellent opportunity for collecting first-hand data as to the usefulness of gliders in the Alps. It is necessary to recount the remarkable glider achievements ahead of the Rhon Soaring Contest, in order to understand the tension and expectation with which the Rhon contest was anticipated. A description of some of the aircraft present at the event is provided.
Date: May 1932
Creator: Georgii, Walter
Item Type: Refine your search to only Report
open access

Twisting Failure of Centrally Loaded Open-Section Columns in the Elastic Range

Description: In the following report a complete theory of twisting failure by the energy method is developed, based on substantially the same assumptions as those employed by Wagner and Bleich. Problems treated in detail are: the stress and strain condition under St. Venant twist and in twist with axial constraint; the concept of shear center and the energy method for problems of elastic stability.
Date: March 1938
Creator: Kappus, Robert
Item Type: Refine your search to only Report
open access

Twisting of Thin Walled Columns Perfectly Restrained at One End

Description: "Proceeding from the basic assumptions of the Batho-Bredt theory on twisting failure of thin-walled columns, the discrepancies most frequently encountered are analyzed. A generalized approximate method is suggested for the determination of the disturbances in the stress condition of the column, induced by the constrained warping in one of the end sections" (p. 1).
Date: March 1938
Creator: Lazzarino, Lucio
Item Type: Refine your search to only Report
open access

The Twisting of Thin-Walled, Stiffened Circular Cylinders

Description: On the basis of the present investigation of the twisting of thin-walled, stiffened cylinders the following conclusions can be reached: 1) there is as yet no generally applicable formula for the buckling moment of the skin; 2) the mathematical treatment of the condition of the shell after buckling of the skin is based on the tension-field theory, wherein the strain condition is considered homogenous.
Date: October 1938
Creator: Schapitz, E.
Item Type: Refine your search to only Report
open access

Two-Dimensional Subsonic Compressible Flow Past Elliptic Cylinders

Description: "The method of Poggi is used to calculate, for perfect fluids, the effect of compressibility upon the flow on the surface of an elliptic cylinder at zero angle of attack and with no circulation. The result is expressed in a closed form and represents a rigorous determination of the velocity of the fluid at the surface of the obstacle insofar as the second approximation is concerned. Comparison is made with Hooker's treatment of the same problem according to the method of Janzen and Rayleight an… more
Date: February 11, 1938
Creator: Kaplan, Carl
Item Type: Refine your search to only Report
open access

Universal Logarithmic Law of Velocity Distribution as Applied to the Investigation of Boundary Layer and Drag of Streamline Bodies at Large Reynolds Number

Description: In the present paper we shall consider a figure of revolution, so that the formulas applicable to the more simple cases as, for example, a wing or flat plate will follow from our equations as corollaries. For checking the results of our theory, we made use of the data derived from the tests of Freeman on a 1/40-scale model of the airship "Akron" conducted in the large NACA wind tunnel. In the first part we shall derive the fundamental equation for a body of revolution according to the Karman th… more
Date: November 1937
Creator: Gurjienko, G.
Item Type: Refine your search to only Report
open access

The Unsteady Lift of a Finite Wing

Description: Note discussing the lift of a finite wing including the calculations and constants for each step of the lift. This information is compared against the lift of an infinite wing. From Summary: "Unsteady lift function for wings of finite aspect ratio have been calculated by approximate methods involving corrections of the aerodynamic inertia and of the angle of the infinite wing. The starting lift of the finite wing is found to be only slightly less than that of the infinite wing; whereas the fina… more
Date: January 1939
Creator: Jones, Robert T.
Item Type: Refine your search to only Report
open access

The unsteady lift of a wing of finite aspect ratio

Description: "Unsteady-lift functions for wings of finite aspect ratio have been calculated by correcting the aerodynamic inertia and the angle of attack of the infinite wing. The calculations are based on the operational method. The starting lift of the finite wing is found to be only slightly less than that of the infinite wing; whereas the final lift may be considerably less" (p. 1).
Date: June 15, 1939
Creator: Jones, Robert T.
Item Type: Refine your search to only Report
open access

The Use of Elektron Metal in Airplane Construction

Description: Memorandum presenting an evaluation of elektron, which is the lightest of the light metals and is of particular interest for aircraft construction. Some of its chemical properties, particular alloys and wrought materials that can be made using elektron, and some of the potential ways in which the material might be used are provided.
Date: February 1931
Creator: de Ridder, E. I.
Item Type: Refine your search to only Report
open access

The use of large valve overlap in scavenging a supercharged spark-ignition engine using fuel injection

Description: From Summary: "This investigation was conducted to determine the effect of more complete scavenging on the full throttle power and the fuel consumption of a four-stroke-cycle engine. The NACA single-cylinder universal test engine equipped with both a fuel-injection system and a carburetor was used. The engine was scavenged by using a large valve overlap and maintaining a pressure in the inlet manifold of 2 inches of mercury above atmospheric. The maximum valve overlap used was 112 degrees. Test… more
Date: April 1932
Creator: Schey, Oscar W. & Young, Alfred W.
Item Type: Refine your search to only Report
open access

The Use of Slots for Increasing the Lift of Airplane Wings

Description: This report discusses in detail the results obtained with devices for preventing the separation of the boundary layer. In order to give an idea of the order of magnitude of the positive and negative pressures involved, we made a diagram of them, as measured at 15 degrees angle of attack on the Gottigen profile 387. The pressure scale is graduated in terms of the dynamic pressure q, which enables the evaluation of the positive and negative pressures at all velocities.
Date: August 1931
Creator: Haus
Item Type: Refine your search to only Report
open access

Valve-Spring Surge

Description: Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during… more
Date: March 1937
Creator: Marti, Willy
Item Type: Refine your search to only Report
open access

Valve Timing of Engines Having Intake Pressures Higher Than Exhaust

Description: Note presenting an investigation to determine the possible improvement in performance by using a large amount of valve overlap on a supercharged engine. A series of tests was made on the NACA universal single-cylinder engine of 5-inch bore and 7-inch stroke with varying amounts of overlap from 0 to 100 degrees at five different intake pressures.
Date: February 1932
Creator: Taylor, Edward S.
Item Type: Refine your search to only Report
open access

The Variation in Pressure in the Cabin of an Airplane in Flight

Description: From Summary: "The pressure in the cabin of a Fairchild cabin monoplane was surveyed in flight, and was found to decrease with increased air speed over the fuselage and to vary with the number and location of openings in the cabin. The maximum depression of 2.2 inches of water (equivalent pressure altitude at sea level of 152 feet) occurred at the high speed of the airplane in level flight with the cabin closed."
Date: March 1931
Creator: Gough, Melvin N.
Item Type: Refine your search to only Report
open access

The variation with Reynolds number of pressure distribution over an airfoil section

Description: Pressures were simultaneously measured at 54 orifices distributed over the midspan section of a 5 by 30-inch rectangular model of the NACA 4412 airfoil in the variable-density tunnel. These measurements were made at 17 angles of attack from -20 degrees to 30 degrees for eight values of the effective Reynolds number form approximately 100,000 to 8,200,000. Accurate data were thus obtained for studying the variation of pressure distribution with Reynolds number. These results on the NACA 4412 sec… more
Date: July 14, 1937
Creator: Pinkerton, Robert M.
Item Type: Refine your search to only Report
open access

Velocity Distribution in the Boundary Layer of a Submerged Plate

Description: This report deals with the measurement of the velocity distribution of the air in the velocity of a plate placed parallel to the air flow. The measurements took place in a small wind tunnel where the diameter of the entrance cone is 30 cm and the length of the free jet between the entrance and exit cones is about 2.5 m. The measurements were made in the free jet where the static pressure was constant, which was essential for the method of measurement used.
Date: October 1930
Creator: Hansen, M.
Item Type: Refine your search to only Report
open access

Vertical Descent of the Autogiro

Description: The purpose of this report is to show that only part of the system of rotating blades really is in the "windmill decelerating attitude" when the profile drag is sufficiently low. This particular part receives more torque from the air loads than can be absorbed by the profile drag. As a result thereof the rotating autogiro blade, when its torque is zero, is in part a propeller which functions in the "annular vortex attitude.".
Date: June 1932
Creator: Bennett, J. A.
Item Type: Refine your search to only Report
open access

The vertical wind tunnel of the National Advisory Committee for Aeronautics

Description: "The vertical open-throat wind tunnel of the National Advisory Committee for Aeronautics is described in this report. The tunnel was built mainly for studying the spinning characteristics of airplane models, but may be used as well for the usual types of wind-tunnel tests. A special spinning balance is being developed to measure the desired forces and moments with the model simulating the spin of an airplane. Satisfactory air flow has been attained with a velocity that is uniform over the jet t… more
Date: February 9, 1931
Creator: Wenzinger, Carl J. & Harris, Thomas A.
Item Type: Refine your search to only Report
open access

Vibration response of airplane structures

Description: This report presents test results of experiments on the vibration-response characteristics of airplane structures on the ground and in flight. It also gives details regarding the construction and operation of vibration instruments developed by the National Advisory Committee for Aeronautics.
Date: May 10, 1934
Creator: Theodorsen, Theodore & Gelalles, A. G.
Item Type: Refine your search to only Report
Back to Top of Screen