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Compressibilities of gases

Description: Reproduction of thirteen graphs for computing compressibilities of various gases and for computing the volumes delivered from cylinders containing various gases.
Date: November 21, 1925
Creator: Pickering, Samuel Fisher
Partner: UNT Libraries Government Documents Department

The Flettner rotor ship in the light of the Kutta-Joukowski theory and of experimental results

Description: In this paper the fundamental principles of the Flettner rotor ship (Reference I) are discussed in the light of the Kutta-Joukowski theory and available experimental information on the subject. A brief exposition of the Kutta-Joukowski theory is given and the speed of the rotor ship Buckau computed, first by using effective propulsive force obtained by the above theory, and then by direct application of wind tunnel data.
Date: October 1, 1925
Creator: Rizzo, Frank
Partner: UNT Libraries Government Documents Department

Interference tests on NACA pitot tubes

Description: In connection with the standardization of instruments used in the wind tunnel, this investigation was undertaken to determine the nature and magnitude of the errors inherent in the measurement of air speed by a pitot tube when the instrument is mounted close to some other body. The mounting of the instrument in proximity to some other body is so frequent in flight and in wind tunnel research that it seemed advisable to investigate thoroughly the magnitude of the possible errors caused by such proximity. The results of this investigation will facilitate comparisons of the errors due to interference which have been reduced to percentages of the air-speed readings obtained under conditions of no interference.
Date: January 1, 1925
Creator: Reid, Elliott G
Partner: UNT Libraries Government Documents Department

The influence of the form of a wooden beam on its stiffness and strength III : stresses in wood members subjected to combined column and beam action

Description: The general purpose in this study was to determine the stresses in a wooden member subjected to combined beam and column action. What may be considered the specific purpose, as it relates more directly to the problem of design, was to determine the particular stress that obtains at maximum load which, for combined loading, does not occur simultaneously with maximum stress.
Date: January 1, 1925
Creator: Newlin, J A & Trayer, G W
Partner: UNT Libraries Government Documents Department

Investigation of slipstream velocity

Description: These experiments were made at the request of the Bureau of Aeronautics, Navy Department, to investigate the velocity of the air in the slipstream in horizontal and climbing flight to determine the form of expression giving the slipstream velocity in terms of the airspeed of the airplane. The method used consisted in flying the airplane both on a level course and in climb at full throttle and measuring the slipstream velocity at seven points in the slipstream for the whole speed range of the airplane in both conditions. In general the results show that for both condition, horizontal and climbing flights, the slipstream velocity v subscript 3 and airspeed v can be represented by straight lines and consequently the equations are of the form: v subscript s = mv+b where m and b are constant. (author).
Date: January 1925
Creator: Crowley, J. W., Jr.
Partner: UNT Libraries Government Documents Department

A method for the direct determination of wing-section drag

Description: In order that the method may be more easily understood, we will first consider the simpler case when there is no lift, but only drag, and when the streamlines at the measuring point behind the obstacle are nearly parallel. Moreover, the flow is assumed not to deviate much from the two-dimensional flow.
Date: November 1925
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department

The "Navigraph"

Description: Commander Le Prieur, whose flight experience in a low-speed seaplane we related in our number of September 27, 1924, invented, four years ago, an instrument destined to render very great service to aviators, namely, the "navigraph", designed to correct errors of orientation due to the effect of the winds during flight.
Date: June 1, 1925
Creator: Le Prieur, Ives
Partner: UNT Libraries Government Documents Department

The problem of fuel measurement : the Schiske "Konsummeter"

Description: Any measuring device, which immediately indicates the rate of fuel consumption in the desired units, has the advantage of saving considerable time and fuel, besides facilitating the adjustment of the carburetor. The Schiske "Konsummeter" (made by the "PS-Vergaser and Apparatebau A. G.") was designed from the above viewpoint.
Date: May 1, 1925
Creator: Praetorius, K. R. H.
Partner: UNT Libraries Government Documents Department

Law of similitude for the surface resistance of lacquered planes moving in a straight line through water

Description: The proof of the validity of the Reynolds law of similitude for the surface resistance of planes has been developed with an accuracy hitherto unattained and for a large range of lengths and speeds. It has been shown that, in addition to the form resistance, the resistance of the longitudinal edges must be taken into account.
Date: April 1, 1925
Creator: Gebers, Friedrich
Partner: UNT Libraries Government Documents Department

Latecoere Air Lines

Description: This article presents the observations of the authors on an inspection trip of the Latecoere Air Lines routes from Southern France into North Africa.
Date: August 1, 1925
Creator: Van Zandt, J Parker
Partner: UNT Libraries Government Documents Department

Note on the air forces on a wing caused by pitching.

Description: The following contains information on the air forces on a wing produced by it's pitching at a finite rate of angular velocity. The condition of smooth flow at the region of the trailing edge is maintained. The wing then experiences the same lift as if moving with the momentary velocity of the rear edge.
Date: March 1, 1925
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

Note on the Katzmayr effect on airfoil drag

Description: The reduction of drag of an airfoil when the air stream is oscillating is called the Katzmayr effect. The purpose here is to offer a simple explanation of the cause of the Katzmayr effect.
Date: February 1, 1925
Creator: Ober, Shatswell
Partner: UNT Libraries Government Documents Department

The effect of changes in compression ratio upon engine performance

Description: This report is based upon engine tests made at the Bureau of Standards during 1920, 1921, 1922, and 1923. The majority of these tests were of aviation engines and were made in the Altitude Laboratory. For a small portion of the work a single cylinder experimental engine was used. This, however, was operated only at sea-level pressures. The report shows that an increase in break horsepower and a decrease in the pounds of fuel used per brake horsepower hour usually results from an increase in compression ratio. This holds true at least up to the highest ratio investigated, 14 to 1, provided there is no serious preignition or detonation at any ratio. To avoid preignition and detonation when employing high-compression ratios, it is often necessary to use some fuel other than gasoline. It has been found that the consumption of some of these fuels in pounds per brake horsepower hour is so much greater than the consumption of gasoline that it offsets the decrease derived from the use of the high-compression ratio. The changes in indicated thermal efficiency with changes in compression ratio are in close agreement with what would be anticipated from a consideration of the air cycle efficiencies at the various ratios. In so far as these tests are concerned there is no evidence that a change in compression ratio produces an appreciable, consistent change in friction horsepower, volumetric efficiency, or in the range of fuel-air ratios over which the engine can operate. The ratio between the heat loss to the jacket water and the heat converted into brake horsepower or indicated horsepower decreases with increase in compression ratio. (author).
Date: January 1, 1925
Creator: Sparrow, Stanwood W
Partner: UNT Libraries Government Documents Department

The drift of an aircraft guided towards it's destination by directional receiving of radio signals transmitted from the ground

Description: Following a curved path increases the distance to be flown, and a type of radio navigation that forces the adoption of such a path is therefore less efficient than one that marks out a definite straight line between the point of departure and the intended destination, and holds the airplane to that line. To determine the loss of efficiency resulting from curvature of the path, calculations were made for two particular cases by the method of step-by-step integration. The calculations were based on the assumption that the pilot makes straightforward use of his radio for navigation and makes no allowance for drift. Results are given in tabular form for two airplanes flying 200 miles at 100 mph, one with a cross wind of 50 mph wind across course, and the other with a 20 mph wind across course. It is shown that the following of the curved path increases the time of flight and the air distance flown by 17 percent and 2.5 percent in the two cases.
Date: June 1, 1925
Partner: UNT Libraries Government Documents Department

Determination of ignition points of liquid fuels under pressure

Description: Two series of experiments were tried, in order to determine the ignition point at any desired pressure, the first series at constant and the second at varying pressure. The results differ greatly and indicate that testing under pressure, in the investigation of liquid fuels, can be done best in the laboratory and that the determination of the ignition points in an open vessel furnishes no certain indication of the behavior of the fuel in the engine.
Date: January 1, 1925
Creator: Tausz, J & Schulte, F
Partner: UNT Libraries Government Documents Department

Determination and classification of the aerodynamic properties of wing sections

Description: The following note, prepared for the NACA, contains several remarks on the possible improvement of the experimental determination of the aerodynamic properties of wing sections. It shows how errors of observation can subsequently be partially eliminated, and how the computation of the maxima or minima of aerodynamic characteristics can be much improved.
Date: September 1, 1925
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

Air forces on airfoils moving faster than sound

Description: We are undertaking the task of computing the air forces on a slightly cambered airfoil in the absence of friction and with an infinite aspect ratio. We also assume in advance that the leading edge is very sharp and that its tangent lies in the direction of motion.
Date: June 1925
Creator: Ackeret, J
Partner: UNT Libraries Government Documents Department

Air flow investigation for location of angle of attack head on a JN4h airplane

Description: The technical staff of the NACA at Langley Field, has made a series of free flight tests with a JN4h airplane in order to find the best place for an instrument for measuring the angle of attack. A "neutral zone" was found where the air remains either at rest relative to the undisturbed air beyond the influence of the airplane, or is set in motion parallel to the motion of the airplane. This zone is about midway between the two wings and slightly in front of, or at the vertical plane through the leading edges of the wings but the exact position as well as the outlines of the zone varies considerably as the conditions of flight change.
Date: August 1925
Creator: Freeman, R. G.
Partner: UNT Libraries Government Documents Department

Aircraft engine design

Description: From Introduction: "The subject of this paper is so broad in scope that a large volume might be devoted to it. In a short paper of this kind it is possible simply to sketch in the high lights of aircraft engine design showing the development to date, the possibilities of the future, and the underlying fundamental principles. Summarizing this development and referring to the graph (Fig.1), we that there is now a water-cooled engine in every power from 150 to 800 HP. and an air-cooled engine in the 200 to 400 HP. classes."
Date: January 1, 1925
Creator: Wilson, E E
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of airfoils at high speeds

Description: From Summary: "This report deals with an experimental investigation of the aerodynamical characteristics of airfoils at high speeds. Lift, drag, and center of pressure measurements were made on six airfoils of the type used by the air service in propeller design, at speeds ranging from 550 to 1,000 feet per second. The results show a definite limit to the speed at which airfoils may efficiently be used to produce lift, the lift coefficient decreasing and the drag coefficient increasing as the speed approaches the speed of sound. The change in lift coefficient is large for thick airfoil sections (camber ratio 0.14 to 0.20) and for high angles of attack. The change is not marked for thin sections (camber ratio 0.10) at low angles of attack, for the speed range employed. At high speeds the center of pressure moves back toward the trailing edge of the airfoil as the speed increases. The results indicate that the use of tip speeds approaching the speed of sound for propellers of customary design involves a serious loss in efficiency."
Date: 1925~
Creator: Briggs, L. J.; Hull, G. F. & Dryden, H. L.
Partner: UNT Libraries Government Documents Department