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4,212 Matching Results
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The effects of fuel and cylinder gas densities on the characteristics of fuel sprays for oil engines
"This investigation was conducted as a part of a general research on fuel-injection engines for aircraft. The purpose of the investigation was to determine the effects of fuel and cylinder gas densities with several characteristics of fuel sprays for oil engines. The start, growth, and cut-off of single fuel sprays produced by automatic injection valves were recorded on photographic film by means of special high-speed motion-picture apparatus" (p. 491).
Date:
June 14, 1927
Creator:
Joachim, W. F. & Beardsley, Edward G.
System:
The UNT Digital Library
The prediction of airfoil characteristics
This report describes and develops methods by which the aerodynamic characteristics of an airfoil may be calculated with sufficient accuracy for use in airplane design. These methods for prediction are based on the present aerodynamic theory and on empirical formulas derived from data obtained in the N. A. C. A. variable density wind tunnel at a Reynolds number corresponding approximately to full scale. (author).
Date:
March 14, 1928
Creator:
Higgins, George J.
System:
The UNT Digital Library
Flight tests on U.S.S. Los Angeles Part 1: full scale pressure distribution investigation
The primary purpose of this investigation was to obtain simultaneous data on the loads and stress experience in flight by the U. S. S. Los Angeles which could be used in rigid airship structure design. A secondary object of the investigation was to determine the turning and drag characteristics of the airship. The aerodynamic loading was obtained by measuring the pressure at 95 locations on the tail surfaces, 54 on the hull, and 5 on the passenger car. These measurements were made during a series of maneuvers consisting of turns and reversals in smooth air and during a cruise in rough air which was just short of squall proportions.
Date:
August 14, 1928
Creator:
De France, S. J.
System:
The UNT Digital Library
Airfoil Pressure Distribution Investigation in the Variable Density Wind Tunnel
Report presents the results of wind tunnel tests of pressure distribution measurements over one section each of six airfoils. Pressure distribution diagrams, as well as the integrated characteristics of the airfoils, are given for both a high and a low dynamic scale or, Reynolds number VL/V, for comparison with flight and other wind-tunnel tests, respectively. It is concluded that the scale effect is very important only at angles of attack near the burble.
Date:
January 14, 1930
Creator:
Jacobs, Eastman N.; Stack, John & Pinkerton, Robert M.
System:
The UNT Digital Library
The Gaseous Explosive Reaction: The Effect of Pressure on the Rate of Propagation of the Reaction Zone and Upon the Rate of Molecular Transformation
This study of gaseous explosive reaction has brought out a number of important fundamental characteristics of the explosive reaction indicating that the basal processes of the transformation are much simpler and corresponds more closely to the general laws and principles of ordinary transformations than is usually supposed. The report calls attention to the point that the rate of molecular transformation within the zone was found in all cases to be proportional to pressure, that the transformation within the zone is the result of binary impacts. This result is of unusual interest in the case of the reaction of heavy hydrocarbon fuels and the reaction mechanism proposed by the recent kinetic theory of chain reactions.
Date:
June 14, 1930
Creator:
Stevens, F. W.
System:
The UNT Digital Library
Effect of moderate air flow on the distribution of fuel sprays after injection cut-off
"High-speed motion pictures were taken of fuel sprays with the NACA spray-photographic apparatus to study the distribution of the liquid fuel from the instant of injection cut-off until about 0.05 second later. The fuel was injected into a glass-walled chamber in which the air density was varied from 1 to 13 times atmospheric air density (0.0765 to 0.99 pound per cubic foot) and in which the air was at room temperature. The air in the chamber was set in motion by means of a fan, and was directed counter to the spray at velocities up to 27 feet per second" (p. 163).
Date:
February 14, 1934
Creator:
Rothrock, A. M. & Spencer, R. C.
System:
The UNT Digital Library
A description and test results of a spark-ignition and a compression-ignition 2-stroke-cycle engine
This report presents performance results of air cooled and water-cooled engines. The results obtained were sufficiently promising to warrant further investigation with fuel injection and spark ignition, with the same arrangement of inlet ports and exhaust valves at the bottom of the cylinder and the exhaust gases discharged through two poppet valves in the cylinder head. The displacement of the engine was 118 cubic inches. Optimum performance was obtained with the inlet air directed into the cylinder at an angle of 20 degrees to the radial.
Date:
May 14, 1934
Creator:
Spanogle, J. A. & Whitney, E. G.
System:
The UNT Digital Library
Scale Effect on Clark Y Airfoil Characteristics From NACA Full-Scale Wind-Tunnel Tests
This report presents the results of wind tunnel tests conducted to determine the aerodynamic characteristics of the Clark Y airfoil over a large range of Reynolds numbers. Three airfoils of aspect ratio 6 and with 4, 6, and 8 foot chords were tested at velocities between 25 and 118 miles per hour, and the characteristics were obtained for Reynolds numbers (based on the airfoil chord) in the range between 1,000,000 and 9,000,000 at the low angles of attack, and between 1,000,000 and 6,000,000 at maximum lift. With increasing Reynolds number the airfoil characteristics are affected in the following manner: the drag at zero lift decreases, the maximum lift increases, the slope of the lift curve increases, the angle of zero lift occurs at smaller negative angles, and the pitching moment at zero lift does not change appreciably.
Date:
June 14, 1934
Creator:
Silverstein, Abe
System:
The UNT Digital Library
Aircraft compass characteristics
From Summary: "A description of the test methods used at the National Bureau of Standards for determining the characteristics of aircraft compasses is given. The methods described are particularly applicable to compasses in which mineral oil is used as the damping liquid. Data on the viscosity and density of certain mineral oils used in United States Navy aircraft compasses are presented. Results of flight tests are presented."
Date:
December 14, 1935
Creator:
Peterson, John B. & Smith, Clyde W.
System:
The UNT Digital Library
Blower Cooling of Finned Cylinders
"Several electrically heated finned steel cylinders enclosed in jackets were cooled by air from a blower. The effect of the air conditions and fin dimensions on the average surface heat-transfer coefficient q and the power required to force the air around the cylinders were determined. Tests were conducted at air velocities between the fins from 10 to 130 miles per hour and at specific weights of the air varying from 0.046 to 0.074 pound per cubic foot. The fin dimensions of the cylinders covered a range in pitches from 0.057 to 0.25 inch average fin thicknesses from 0.035 to 0.04 inch, and fin widths from 0.67 to 1.22 inches" (p. 269).
Date:
November 14, 1936
Creator:
Schey, Oscar W. & Ellerbrock, Herman H., Jr.
System:
The UNT Digital Library
Wind-Tunnel Investigation of Tapered Wings With Ordinary Ailerons and Partial-Span Split Flaps
Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel to determine the aerodynamic properties of tapered wings having partial-span flaps for high lift and ordinary ailerons for lateral control. Each of two Clark-y wings, tapered 5:1 and 5:3, was equipped with partial-span split flaps of two lengths and with ordinary ailerons extending from the outboard ends of the flap to the wing tips. Measurements of wing forces and moments and of aileron hinge moments were made for the two conditions of flaps neutral and deflected.
Date:
January 14, 1937
Creator:
Wenzinger, Carl J.
System:
The UNT Digital Library
An analysis of the factors that determine the periodic twist of an autogiro rotor blade, with a comparison of predicted and measured results
Report presents an analysis of the factors that determine the periodic twist of a rotor blade under the action of the air forces on it. The results of the analysis show that the Fourier coefficients of the twist are linear expressions involving only the tip-speed ratio, the pitch setting, the inflow coefficient, the pitching-moment coefficient of the blade airfoil section, and the physical characteristics of the rotor blade and machine.
Date:
April 14, 1937
Creator:
Wheatley, John B.
System:
The UNT Digital Library
The variation with Reynolds number of pressure distribution over an airfoil section
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 section indicated that the pressure distribution is practically unaffected by changes in Reynolds number except where separation is involved.
Date:
July 14, 1937
Creator:
Pinkerton, Robert M.
System:
The UNT Digital Library
Tests of Two Full-Scale Propellers With Different Pitch Distributions, at Blade Angles Up to 60 Degrees
"Two 3-blade 10-foot propellers were operated in front of a liquid-cooled engine nacelle. The propellers differed only in pitch distribution; one had normal distribution (nearly constant pitch for a blade angle of 15 degrees at 0.75 radius), and the other had the pitch of the tip sections decreased with respect to that for the shank sections (blade angle of 35 degrees for nearly constant pitch distribution). Propeller blade angles at 0.75r from 15 degrees to sixty degrees, corresponding to design speeds up to 500 miles per hour, were investigated" (p. 327).
Date:
April 14, 1938
Creator:
Biermann, David & Hartman, Edwin P.
System:
The UNT Digital Library
Design Charts for Predicting Downwash Angles and Wake Characteristics Behind Plain and Flapped Wings
"Equations and design charts are given for predicting the downwash angles and the wake characteristics for power-off conditions behind plain and flapped wings of the types used in modern design practice. The downwash charts cover the cases of elliptical wings and wings of taper ratios 1, 2, 3, and 5, with aspect ratios of 6, 9, and 12, having flaps covering 0, 40, 70, and 100 percent of the span. Curves of the span load distributions for all these cases are included" (p. 1).
Date:
July 14, 1938
Creator:
Silverstein, Abe & Katzoff, S.
System:
The UNT Digital Library
The knocking characteristics of fuels in relation to maximum permissible performance of aircraft engines
An analysis is presented of the relationship of various engine factors to knock in preignition in an aircraft engine. From this analysis and from the available experimental data, a method of evaluating the knocking characteristics of the fuel in an aircraft-engine cylinder is suggested.
Date:
September 14, 1938
Creator:
Rothrock, A. M. & Biermann, Arnold E.
System:
The UNT Digital Library
Critical Compressive Stress for Outstanding Flanges
A chart is presented for the values of the coefficient in the formula for the critical compressive stress at which buckling may be expected to occur in outstanding flanges. These flanges are flat rectangular plates supported along the loaded edges, supported and elastically restrained along one unloaded edge, and free along the other unloaded edge. The mathematical derivations of the formulas required for construction of the chart are given.
Date:
March 14, 1941
Creator:
Lundquist, Eugene E. & Stowell, Elbridge Z.
System:
The UNT Digital Library
Douglas Aircraft Company, Inc. Project 19 Daily Report: August 14, 1942
Daily report for "Project 19" at the Douglas Aircraft Company, outlining information in sections for personnel, planes, and work done.
Date:
August 14, 1942
Creator:
Bradford, Alex
System:
The Portal to Texas History
Establishing Site X: Letter, Arthur H. Compton to Enrico Fermi, September 14, 1942
This letter from Compton to Fermi describes developments bearing on the establishment of ``site X`` (which, as of the letter date, is definitely determined as at the Tennessee Valley) for the construction of a pile and associated pilot plant buildings, describes the situation as of the letter date, and offers counsel as to how to proceed.
Date:
September 14, 1942
Creator:
Compton, A. H.
System:
The UNT Digital Library
Identification of knock in NACA high-speed photographs of combustion in a spark-ignition engine
Report presents the results of a study of combustion in a spark-ignition engine given in NACA Technical Reports 704 and 727. The present investigation was made with the NACA high-speed motion-picture camera, operating at 40,000 photographs a second, and with a cathode-ray oscillograph operating on a piezoelectric pick-up in the combustion chamber. Photographs are presented showing that the origin of knock is not necessarily in the end gas. The data obtained indicates that knock takes place only in a part of the cylinder charge which has been previously ignited either by autoignition or by the passage of the flame fronts but which has not burned to completion. Mottled regions in the high-speed Schlieren photographs are demonstrated to represent combustion regions.
Date:
November 14, 1942
Creator:
Miller, Cearcy D. & Olsen, H. Lowell
System:
The UNT Digital Library
Calculation of the Temperature Distribution in a Slug With a Solid Aluminum Cap
Calculations were made to determine the temperature at various points of a thick disc and cap, on the assumptions that the heat production rate is uniform throughout the slug and that the slug is in perfect thermal contact with the cap. Results obtained by different methods of computation are compared with each other and with results obtained by Drew on the Paschkis electrical network computer at Columbia University.
Date:
April 14, 1944
Creator:
Murray, F. H.; Karush, William; Ginsburg, M. & Young, G.
System:
The UNT Digital Library
The Pile Safety Circuit
The present report is concerned with the electronic relay which, upon the reaching of a pre-determined value of ionization current in the associated chamber, actuates the safety rod release mechanism. The are here proposed two independent suggestions: (1) An improved trip circuit of such sensitivity and stability as to allow it to be actuated by a signal directly from the chamber without the necessity of interposing intermediate amplifier stages. The value of chamber current at which tripping occurs is stable to +- 0.4%. (2) A triple-wound relay to prevent shut-downs of the pile which would otherwise be caused by development of defects in the safety circuits.
Date:
April 14, 1944
Creator:
Nierman, Leonard G.
System:
The UNT Digital Library
Metallurgical Laboratory, Nuclear Physics Division, Report for the Month Ending May 25, 1944
Technical report with short reports from the (1) Experimental Nuclear Physics Group; (2) Theoretical Physics Group ; (3) Lattice Design Group; (4) Pile Design Group; (5) Exponential Experimental Group; (6) Radiation Group; and (7) Shielding Group.
Date:
June 14, 1944
Creator:
Fermi, Enrico, 1901-1954
System:
The UNT Digital Library
Metallurgical Laboratory, Chemical Research - Radiation Chemistry, Report for the Month Ending June 30, 1944
Technical report with short reports on (1) P-9 recovery from UO2F2 solution; (2) Correlation of theories on action of radiation on matter; (3) Literature surveys on organic compounds and on chemistry of UO2F2; (4) effect of radiation on organic compounds; and (5) Effect of radiation on 100 area construction materials.
Date:
July 14, 1944
Creator:
Hogness, T. R. (Thorfin Rusten), 1894- & Burton, Milton, 1902-
System:
The UNT Digital Library