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Studies of Basin-Range Structure

Description: From preface: This paper represents the partial fruition of a broad plan to reexamine critically the subject of Basin-Range structure.
Date: 1928
Creator: Gilbert, Grove Karl
Partner: UNT Libraries Government Documents Department

Report of the Twenty-First National Conference on Weights and Measures, 1928

Description: Report of the annual conference on weights and measures, hosted by the U.S. National Bureau of Standards in Washington D.C. It includes conference proceedings, a list of attendees, information about committees and officers, and other reports or commentaries discussed at the meetings.
Date: May 1928
Creator: United States. National Bureau of Standards.
Partner: UNT Libraries Government Documents Department

On the take-off of heavily loaded airplanes

Description: This report examines the take-off conditions of airplanes equipped with tractive propellers, and particularly the more difficult take-off of airplanes heavily loaded per unit of wing area (wing loading) or per unit of engine power (power loading).
Date: November 1, 1928
Creator: Breguet, Louis
Partner: UNT Libraries Government Documents Department

Preliminary biplane tests in the variable density wind tunnel

Description: Biplane cellules using the N.A.C.A.-M6 airfoil section have been tested in the variable density wind tunnel of the National Advisory Committee for Aeronautics. Three cellules, differing only in the amount of stagger, were tested at two air densities, corresponding to pressures of one atmosphere and of twenty atmospheres. The range of angle of attack was from -2 degrees to +48 degrees. The effect of stagger on the lift and drag, and on the shielding effect of the upper wing by the lower at high angles of attack was determined.
Date: June 1, 1928
Creator: Shoemaker, James M
Partner: UNT Libraries Government Documents Department

Preliminary report on the flat-top lift curve as a factor in control at low speed

Description: This report is concerned with the importance of the flat-top lift curve as a factor contributing to safety and control at low speed. An analysis of existing airfoil data indicated definite relations between the shape of the lift curve and certain section dimensions.
Date: September 1, 1928
Creator: Knight, Montgomery & Bamber, Millard J
Partner: UNT Libraries Government Documents Department

Preliminary flight tests of the N.A.C.A. Roots type aircraft engine supercharger

Description: An investigation of the suitability of the N.A.C.A. Roots type aircraft engine supercharger to flight-operating conditions, as determined the effects of the use of the supercharger upon engine operation and airplane performance, is described in this report. Attention was concentrated on the operation of the engine-supercharger unit and on the improvement of climbing ability; some information concerning high speeds at altitude was obtained. The supercharger was found to be satisfactory under flight-operating conditions. Although two failures occurred during the tests, the causes of both were minor and have been eliminated. Careful examination of the engines revealed no detrimental effects which could be attributed to supercharging. Marked improvements in climbing ability and high speeds at altitude were effected. It was also found that the load which could be carried to a given moderate or high altitude in a fixed time was considerably augmented. A slight sacrifice of low-altitude performance was necessitated, however, by the use of a fixed-pitch propeller. From a consideration of the very satisfactory flight performance of the Roots supercharger and of its inherent advantages, it is concluded that this type is particularly attractive for use in certain classes of commercial airplanes and in a number of military types.
Date: January 1, 1928
Creator: Gardiner, Arthur W & Reid, Elliott G
Partner: UNT Libraries Government Documents Department

The measurement of pressure through tubes in pressure distribution tests

Description: The tests described in this report were made to determine the error caused by using small tubes to connect orifices on the surface of aircraft to central pressure capsules in making pressure distribution tests. Aluminum tubes of 3/16-inch inside diameter were used to determine this error. Lengths from 20 feet to 226 feet and pressures whose maxima varied from 2 inches to 140 inches of water were used. Single-pressure impulses for which the time of rise of pressure from zero to a maximum varied from 0.25 second to 3 seconds were investigated. The results show that the pressure recorded at the capsule on the far end of the tube lags behind the pressure at the orifice end and experiences also a change in magnitude. For the values used in these tests the time lag and pressure change vary principally with the time of rise of pressure from zero to a maximum and the tube length. Curves are constructed showing the time lag and pressure change. Empirical formulas are also given for computing the time lag. Analysis of pressure distribution tests made on airplanes in flight shows that the recorded pressures are slightly higher than the pressures at the orifice and that the time lag is negligible. The apparent increase in pressure is usually within the experimental error, but in the case of the modern pursuit type of airplane the pressure increase may be 5 per cent. For pressure-distribution tests on airships the analysis shows that the time lag and pressure change may be neglected.
Date: January 1, 1928
Creator: Hemke, Paul E
Partner: UNT Libraries Government Documents Department

A few more mechanical-flight formulas without the aid of polar diagrams

Description: The reliability of the assumption of a parabolic shape of the polar curve is investigated and found satisfactory for all practical purposes. It is further shown that the aerodynamically best possible or "ideal" airplane is produced on this assumption. Lastly, detailed suggestions are given on the possibilities of application of this method of calculation. It especially simplifies the design and evaluation of structural changes and the determination of the limits of technical possibilities. The present report deals only with the relations of the airfoils. The mutual action of the airfoils, engine and propeller will be treated in a subsequent report.
Date: March 1, 1928
Creator: Schrenk, Martin
Partner: UNT Libraries Government Documents Department

Drag of exposed fittings and surface irregularities on airplane fuselages

Description: Measurements of drag were made on fittings taken from a typical fuselage to determine whether the difference between the observed full size fuselage drag and model fuselage drag could be attributed to the effects of fittings and surface irregularities found on the full size fuselage and not on the model. There are wide variations in the drag coefficients for the different fittings. In general those which protrude little from the surface or are well streamlined show very low and almost negligible drag. The measurements show, however, that a large part of the difference between model and full scale test results may be attributed to these fittings.
Date: March 1928
Creator: Wood, Donald H.
Partner: UNT Libraries Government Documents Department

Full scale drag tests on various parts of Sperry Messenger airplane

Description: The drag of a Sperry Messenger airplane with the wings removed, and also the drag of its various component parts, was measured in the 20-foot air stream of the N.A.C.A. propeller research tunnel at air speeds from 50 to 100 m.p.h. It was found that the three-cylinder radial air-cooled engine nearly doubled the drag of the bare fuselage, and the drag of the landing gear was about the same as that of the fuselage and engine combined.
Date: January 1, 1928
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

A full-scale investigation of ground effect

Description: This report describes flight tests which were made with the Vought VE-7 airplane to determine the effects of flying close to the ground. It is found that the drag of an airplane is materially reduced upon approaching the ground and that the reduction may be satisfactorily calculated according to theoretical formulas. Several aspects of ground effect which have had much discussion are explained.
Date: January 1, 1928
Creator: Reid, Elliott G
Partner: UNT Libraries Government Documents Department

The gaseous explosive reaction : the effect of inert gases

Description: Attention is called in this report to previous investigations of gaseous explosive reactions carried out under constant volume conditions, where the effect of inert gases on the thermodynamic equilibrium was determined. The advantage of constant pressure methods over those of constant volume as applied to studies of the gaseous explosive reaction is pointed out and the possibility of realizing for this purpose a constant pressure bomb mentioned. The application of constant pressure methods to the study of gaseous explosive reactions, made possible by the use of a constant pressure bomb, led to the discovery of an important kinetic relation connecting the rate of propagation of the zone of explosive reaction within the active gases, with the initial concentrations of those gases: s = K(sub 1)(A)(sup n1)(B)(sup n2)(C)(sup n3)------. By a method analogous to that followed in determining the effect of inert gases on the equilibrium constant K, the present paper records an attempt to determine their kinetic effect upon the expression given above.
Date: January 1, 1928
Creator: Stevens, F W
Partner: UNT Libraries Government Documents Department

Ignition and combustion phenomena in Diesel engines

Description: Evidences were found that neither gasification nor vaporization of the injected fuel occurs before ignition; also that the hydrogen coefficient has no significance. However the knowledge of the ignition point and of the "time lag" is important. After ignition, the combustion proceeds in a series of reactions, the last of which at least are now known.
Date: October 1, 1928
Creator: Sass, F
Partner: UNT Libraries Government Documents Department

Ignition points and combustion reactions in Diesel engines. Part I

Description: The question of whether the fuel should be adapted to the engine or whether it is possible to improve equipment such as carburetors and engines so that as much of the crude oil as possible may be used without further transformation is examined in this report. Various ignition points and fuel mixtures are investigated in this regard.
Date: October 1, 1928
Creator: Tausz, J & Schulte, F
Partner: UNT Libraries Government Documents Department

Friction of aviation engines

Description: The first portion of this report discusses measurements of friction made in the altitude laboratory of the Bureau of Standards between 1920 and 1926 under research authorization of the National Advisory Committee for Aeronautics. These are discussed with reference to the influence of speed, barometric pressure, jacket-water temperature, and throttle opening upon the friction of aviation engines. The second section of the report deals with measurements of the friction of a group of pistons differing from each other in a single respect, such as length, clearance, area of thrust face, location of thrust face, etc. Results obtained with each type of piston are discussed and attention is directed particularly to the fact that the friction chargeable to piston rings depends upon piston design as well as upon ring design. This is attributed to the effect of the rings upon the thickness and distribution of the oil film which in turn affects the friction of the piston to an extent which depends upon its design.
Date: January 1, 1928
Creator: Sparrow, S W & Thorne, M A
Partner: UNT Libraries Government Documents Department

Helium tables.

Description: These tables are intended to provide a standard method and to facilitate the calculation of the quantity of "Standard Helium" in high pressure containers. The research data and the formulas used in the preparation of the tables were furnished by the Research Laboratory of Physical Chemistry, of the Massachusetts Institute of Technology.
Date: January 1, 1928
Creator: Havill, Clinton H
Partner: UNT Libraries Government Documents Department

Corrosion embrittlement of duralumin II : accelerated corrosion tests and the behavior of high-strength aluminum alloys of different compositions

Description: The permanence, with respect to corrosion, of light aluminum alloy sheets of the duralumin type, that is, heat-treatable alloys containing Cu, Mg, Mn, and Si is discussed. Alloys of this type are subject to surface corrosion and corrosion of the interior by intercrystalline paths. Results are given of accelerated corrosion tests, tensile tests, the effect on corrosion of various alloying elements and heat treatments, electrical resistance measurements, and X-ray examinations.
Date: April 1, 1928
Creator: Rawdon, Henry S
Partner: UNT Libraries Government Documents Department

Crank case scavenging of a two-stroke-cycle engine

Description: Experiments with a two-stroke-cycle, crank case scavenging engine. Effect of systematic variation of the height of the scavenge and exhaust ports on the scavenging, as determined by gas analysis. The best results were obtained under conditions differing from the usual ones.
Date: January 1, 1928
Creator: Holm, Otto
Partner: UNT Libraries Government Documents Department

Corrosion embrittlement of duralumin III : effect of the previous treatment of sheet material on the susceptibility to this type of corrosion

Description: As a result of testing, it was determined that control of the rate of quenching and the avoidance of accelerated aging by heating are the only means of modifying duralumin itself so as to minimize the intercrystalline form of corrosive attack. It is so simple a means that it should be adopted even though it may not completely prevent, but only reduce, this form of corrosive attack. By so doing, the need for protection of the surface is less urgent.
Date: April 1, 1928
Creator: Rawdon, Henry S
Partner: UNT Libraries Government Documents Department

Corrosion embrittlement of duralumin I : practical aspects of the problem

Description: Since aircraft design is tending toward all-metal construction, the strong heat-treatable light aluminum alloy, duralumin (a generic name for a class of heat-treatable alloys containing Cu, Mg, Mn, and Si), is finding increasing application. Doubt has been expressed concerning the reliability and permanence of these materials. Information is given on the effect of corrosion on the tensile properties of 14-gauge sheet duralumin, heat treated by quenching in hot water after being heated for 15 minutes in a fused nitrate bath at 500 to 510 C. Intercrystalline corrosion and practical aspects of intercrystalline embrittlement are discussed with respect to duralumin.
Date: April 1, 1928
Creator: Rawdon, Henry S
Partner: UNT Libraries Government Documents Department

Corrosion embrittlement of duralumin IV : the use of protective coatings

Description: Although the corrosion resistance of sheet duralumin can be greatly improved by suitable heat treatment, protection of the surface is still necessary if long life under varied service conditions is to be insured. The coatings used for this purpose may be grouped into three classes: the varnish type of coating, the oxide type produced by a chemical treatment of the surface, and metallic coatings, of which aluminum appears to be the most promising. Since the necessary weather exposure tests are not complete, some of the conclusions regarding the value of various surface coatings are necessarily tentative.
Date: April 1, 1928
Creator: Rawdon, Henry S
Partner: UNT Libraries Government Documents Department