UNT Libraries Government Documents Department - 22 Matching Results

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Bending of Rectangular Plates with Large Deflections

Description: The solution of von Karman's fundamental equations for large deflections of plates is presented for the case of a simply supported rectangular plate under combined edge compression and lateral loading. Numerical solutions are given for square plates and for rectangular plates with a width-span ratio of 3:1. The effective widths under edge compression are compared with effective widths according to von Karman, Bengston, Marguerre, and Cox and with experimental results by Ramberg, McPherson, and Levy. The deflections for a square plate under lateral pressure are compared with experimental and theoretical results by Kaiser. It is found that the effective widths agree closely with Marguerre's formula and with the experimentally observed values and that the deflections agree with the experimental results and with Kaiser's work.
Date: May 1942
Creator: Levy, Samuel

A Brief Study of the Speed Reduction of Overtaking Airplanes by Means of Air Brakes, Special Report

Description: As an aid to airplane designers interested in providing pursuit airplanes with decelerating devices intended to increase the firing time when overtaking another airplane, formulas are given relating the pertinent distances and speeds in horizontal flight to the drag increase required. Charts are given for a representative parasite-drag coefficient from which the drag increase, the time gained, and the closing distance may be found. The charts are made up for three values of the ratio of the final speed of the pursuing airplane to the speed of the pursued airplane and for several values of the ratio of the speed of the pursued airplane to the initial speed of the pursuing airplane. Charts are also given indicating the drag increases obtainable with double split flaps and with conventional propellers. The use of the charts is illustrated by an example in which it is indicated that either double split flaps or, under certain ideal conditions, reversible propellers should provide the speed reductions required.
Date: May 1942
Creator: Pearson, H. A. & Anderson, R. F.

Effect of additions of aromatics on the knocking characteristics of several 100-octane fuels at two engine speeds

Description: Report presenting testing at two engine speeds on six representative fuels rated at 100-octane number by the C.F.R. aviation method. Blends of the fuels with benzene, toluene, xylene, and isopropyl comprise nine other fuels, leading to testing on 15 fuels. Results regarding the tests at 2000 rpm and 250 degrees Fahrenheit inlet-air temperature, at 3100 rpm and 250 degrees Fahrenheit inlet-air temperature, 2000 rpm and 150 degrees Fahrenheit inlet-air temperature, and 3100 rpm and 150 degrees Fahrenheit inlet-air temperature, effect of speed on knock rating, effect of inlet-air temperature on knock rating, and effect of spark advance on knock rating are provided.
Date: May 1942
Creator: Biermann, Arnold E.; Corrington, Lester C. & Harries, Myron L.

Effect of inlet-air velocity distribution on the metering pressure of an injection-type aircraft carburetor

Description: Report presenting tests of a three-barrel pressure carburetor to determine the effect of nonuniformity of the air flow in the intake duct on the metering of the carburetor. Measurements were made in the air side of the metering system and in the carburetor barrels for a variety of flow distributions. Results regarding the metering pressure, altitude compensation, effect of throttle on the metering characteristics, and flow of air around the bends are provided
Date: May 1942
Creator: Kinghorn, George F.

A flight investigation of internally balanced sealed ailerons in the presence of a balanced split flap

Description: Report presenting flight tests made with a modified Ryan ST airplane to determine the effect on aileron characteristics of various arrangements of balanced split flaps covering that portion of the wing span occupied by the ailerons. With the flaps fully extended, the aileron effectiveness was reduced by approximately 18 percent of the effectiveness measured with ailerons alone.
Date: May 1942
Creator: Williams, W. C.

A flight investigation of short-period longitudinal oscillations of an airplane with free elevator

Description: Report presenting a flight investigation to check the results of a theoretical analysis of longitudinal stability of an airplane with free controls. Tests used a Fairchild XR2K-1 airplane on which the weight moment and the aerodynamic balance of the elevator were varied to bring it into a condition where unstable short-period oscillations were encountered.
Date: May 1942
Creator: Phillips, William H.

Generalized selection charts for bombers with four 2000-horsepower engines

Description: Report presenting a study of the performance of bombers powered by four 2000-horsepower engines supercharged to 25,000 feet. A series of charts is provided with the coordinates of power loading and wing loading in order to simplify the selection of the best airplane for a given purpose.
Date: May 1942
Creator: Brevoort, Maurice J.; Stickle, George W. & Hill, Paul R.

High-Speed Tests of a Ducted Body with Various Air-Outlet Openings

Description: Test of a ducted body with Internal flow were made in the 8-foot high-speed wind tunnel for the purpose of studying the effects on external drag and an critical speed of the addition of efficient inlet and outlet openings to a basic streamline shape. Drag tests of a 13.6- inch-diameter streamline body of fineness ratio 6.14 were made at Mach numbers ranging from 0.20 to 0.75. The model was centrally mounted on a 9-percent-thick airfoil and was designed to have an efficient airfoil-body juncture and a high critical speed.
Date: May 1942
Creator: Becker, John V. & Baals, Donald D.

High-speed tests of radial-engine nacelles on a thick low-drag wing

Description: Report presenting testing in the high-speed wind tunnel to determine the drag characteristics of several types of radial-engine nacelle on a low-drag airfoil. The drag coefficients of nacelles incorporating cowling-nose shapes shown by previous tests to be efficient and afterbodies of adequate length were about the same magnitude as commonly obtained for comparable installations on conventional wings. Results regarding the reduction of data, effect of nacelles on lift, and pressures at wing-nacelle juncture are provided.
Date: May 1942
Creator: Becker, John V.

Investigation of lubricants under boundary friction

Description: Numerous observations of such lubrication processes within range of boundary friction on journal bearings and gear tooth profiles have strengthened the supposition that it should be possible to study the attendant phenomena with engineering methods and equipment. These considerations formed the basis of the present studies, which have led to the discovery of relations governing the suitability of bearing surfaces and the concept of "lubricating quality.".
Date: May 1, 1942
Creator: Heidebroek, E. & Pietsch, E.

Observations of the improvement in vision brought about by the application of a rain-repellent lacquer on an airplane windshield

Description: From Introduction: "A rain-repellent lacquer was submitted to the National Advisory Committee for Aeronautics by Captain K.H. Kalberer, of Lorr Laboratories, and preliminary tests and observations have been made to determine its value in improving the vision through an airplane windshield during rain. The tests and observations were carried out at Ames Aeronautical Laboratory, Moffett Field, California, over a period of about a week. The results are reported herein."
Date: May 1942
Creator: McAvoy, William H. & Clousing, Lawrence A.

The Porpoising Characteristics of a Planing Surface Representing the Forebody of a Flying-Boat Hull

Description: Porpoising characteristics were observed on V-body fitted with tail surfaces for different combinations of load, speed, moment of inertia, location of pivot, elevator setting, and tail area. A critical trim was found which was unaltered by elevator setting or tail area. Critical trim was lowered by moving pivot either forward or down or increasing radius or gyration. Increase in mass and moment of inertia increased amplitude of oscillations. Complete results are tabulated and shown graphically.
Date: May 1942
Creator: Benson, James M.

Recording rapidly changing cylinder-wall temperatures

Description: The present report deals with the design and testing of a measuring plug suggested by H. Pfriem for recording quasi-stationary cylinder wall temperatures. The new device is a resistance thermometer, the temperature-susceptible part of which consists of a gold coating applied by evaporation under high vacuum and electrolytically strengthened. After overcoming initial difficulties, calibration of plugs up to and beyond 400 degrees C was possible. The measurements were made on high-speed internal combustion engines. The increasing effect of carbon deposit at the wall surface with increasing operating period is indicated by means of charts.
Date: May 1, 1942
Creator: Meier, Adolph

Square plate with clamped edges under normal pressure producing large deflections

Description: A theoretical analysis is given for the stresses and deflections of a square plate with clamped edges under normal pressure producing large deflections. Values of the bending stress and membrane stress at the center of the plate and at the midpoint of the edge are given for center deflections up to 1.9 times the plate thickness. The shape of the deflected surface is given for low pressures and for the highest pressure considered. Convergence of the solution is considered and it is estimated that the possible error is less than 2 percent. The results are compared with the only previous approximate analysis known to the author and agree within 5 percent. They are also shown to compare favorably with the known exact solutions for the long rectangular plate and the circular plate.
Date: May 1942
Creator: Levy, Samuel

A summary of results of various investigations of the mechanical properties of aluminum alloys at low temperatures

Description: The available sources of data on the mechanical properties of aluminum alloys at low temperatures are listed and a summary of the material to be found in each source is given. There is included a discussion of the results of recent tests of aluminum alloys at low temperatures made at the Aluminum Research Laboratories.
Date: May 1942
Creator: Hartmann, E. C. & Sharp, W. H.

Test of NACA 66,2-116, a = 0.6 airfoil section fitted with pressure balanced and slotted flaps for the wing of the XP-63 airplane

Description: Report presenting tests in the two-dimensional low-turbulence pressure tunnel of a model of the NACA 66,2-116, a = 0.6 airfoil section representing the root section of the wing for the XP-63 airplane. The model was of 24-inch chord, built of wood with dural slot cover plates for the flap.
Date: May 1942
Creator: Underwood, William J. & Abbott, Frank T., Jr.