Technical Report Archive and Image Library (TRAIL) - 117 Matching Results

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Pitot-static tubes for determining the velocity of air

Description: On the occasion of the formulation of the rules for testing the efficiency of ventilators and compressors, experiments were instituted by the subcommittee on ventilators for the production of suitable tubes for velocity and pressure measurements.
Date: February 1, 1925
Creator: Kumbruch, H.
Partner: UNT Libraries Government Documents Department

Pressure Distribution on Joukowski Wings and Graphic Construction of Joukowski Wings

Description: In the first article, in connection with a lecture on the hydrodynamic basis of flight and the potential flow about a Joukowski wing, the pressure distribution on several wings is computed and plotted. The diagrams of the pressure distributions are presented accompanied with a qualitative discussion of the pressure distribution. In the second article, the the cross-sectional outline (or profile) a Joukowski wing are plotted.
Date: October 1, 1925
Creator: Blumenthal, Otto & Trefftz, E.
Partner: UNT Libraries Government Documents Department

Airplane Parachutes

Description: The "Bulletin Technique", of March, 1919, gave the results of tests and studies made up to that date in connection with airplane parachutes. This work has been continued.
Date: August 1925
Creator: Mazer
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

Experimental determination of pressure drop caused by wire gauze in an air stream

Description: For several kinds of wire gauze the difference in static, dynamic and total or absolute pressure in front of and behind the gauze were determined for comparison with the pressure drop caused by an airplane radiator, such gauze being used on airplane models to represent the radiator.
Date: January 1, 1925
Partner: UNT Libraries Government Documents Department

Results of recent experiments with slotted wings

Description: This report gives the results of a recent series of experiments performed on a wing designed for a cantilever monoplane. Both wings were trapezial in their ground plan, with their tips rounded elliptically. These wing sections combine all known devices for increasing the lift, namely, the slot, the increased camber and angle of attack by means of an aileron running the whole length of the span. The last advance included in the wing section was an increase in wing area by means of an auxiliary wing adjusted by a sort of rectangular joint.
Date: January 1, 1925
Creator: Lachmann, G
Partner: UNT Libraries Government Documents Department

Hulls for large seaplanes

Description: In reality, the principle of similitude is not applicable to the hulls, the designing of which increases in difficulty with increasing size of the seaplanes. In order to formulate, at least in a general way, the basic principles of calculation, we must first summarize the essential characteristics of a hull with reference to its gradual enlargement. In this study, we will disregard hulls with wing stubs, as being inapplicable to large seaplanes.
Date: January 1, 1925
Creator: Magaldi, Giulio
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

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 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 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

Determination of the lift and drag characteristics of an airplane in flight

Description: Flight tests to determine lift and drag characteristics are discussed. A review is given of the fundamental principles on which the tests are based and on the forces acting on an airplane in the various conditions of steady flight. Glide with and without propeller thrust and the relation between angle of attack and the indicated airspeed for different conditions of steady flight are discussed. The glide test procedure and the problem of the propeller are discussed.
Date: August 1, 1925
Creator: Green, Maurice W
Partner: UNT Libraries Government Documents Department

The estimation of airplane performance from wind tunnel tests on conventional airplane models

Description: Calculations of the magnitude of the correction factors and the range of their variations for wind tunnel models used in making aircraft performance predictions were made for 23 wind tunnel models. Calculated performances were compared with those actually determined for such airplanes as have been built and put through flight test. Except as otherwise noted, all the models have interplane struts and diagonal struts formed to streamwise shape. Wires were omitted in all cases. All the models were about 18 inches in span and were tested in a 4-foot wind tunnel. Results are given in tabular form.
Date: May 1, 1925
Creator: Warner, Edward P. & Ober, Shatswell
Partner: UNT Libraries Government Documents Department

Propeller scale effect and body interference

Description: This note shows that the main part of the discrepancy between full flight propeller performance and the performance of models in a wind tunnel is due to a scale effect, and that a minor part is caused by body interference. Analyses are made of propeller performances on several standard airplanes, and the actual brake horsepower compared with the power as calculated from model test data. The calculated power is based on that absorbed by a wind tunnel propeller model which is geometrically similar to the full scale propeller and is operating under the same ratio of V/nD.
Date: September 1, 1925
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

Simplified propeller design for low-powered airplanes

Description: The object of this report is to furnish the designer and builder of small airplanes a simple system for designing the propeller and making the drawing. An empirical design method is used, based on tests of model propellers in a wind tunnel and full scale tests of propellers in flight.
Date: January 1, 1925
Creator: Weick, Fred E.
Partner: UNT Libraries Government Documents Department

The comparison of well-known and new wing sections tested in the variable density wind tunnel

Description: Three groups of airfoils have been tested in the variable density wind tunnel. The first group contains three airfoils. The second group is a systematic series of twenty-seven airfoils. The third group consists of several frequently used wing sections.
Date: May 1925
Creator: Higgins, George J.
Partner: UNT Libraries Government Documents Department

Pressure distribution on the nose of an airship in circling flight

Description: In recent tests on the pressures occurring on the envelope and control surfaces of the naval airship C-7, it was noted that the pressures on the nose of the airship, while flying in level circling flight, were symmetrically distributed. Such a condition can only occur when the nose of the airship is pointed directly into the wind, and to accomplish this in circling flight, the axis of the airship must then be parallel to the direction of the motion of the nose. The question was raised as to whether the same conditions occur generally on all airships in circling flight. It appears that airships flying in a constant, level, circling flight path will generally head very closely into the wind, and any deviation will be so slight that the distribution of pressure over the nose will be but slightly, if at all, changed from a symmetrical distribution.
Date: August 1, 1925
Creator: Fairbanks, Karl J
Partner: UNT Libraries Government Documents Department

An altitude chamber for the study and calibration of aeronautical instruments

Description: The design and construction of an altitude chamber, in which both pressure and temperature can be varied independently, was carried out by the NACA at the Langley Memorial Aeronautical Laboratory for the purpose of studying the effects of temperature and pressure on aeronautical research instruments. Temperatures from +20c to -50c are obtained by the expansion of CO2from standard containers. The chamber can be used for the calibration of research instruments under altitude conditions simulating those up to 45,000 feet. Results obtained with this chamber have a direct application in the design and calibration of instruments used in free flight research.
Date: November 1925
Creator: Reid, J E & Kirchner, Otto E
Partner: UNT Libraries Government Documents Department

Model tests on the economy and effectiveness of helicopter propellers

Description: The average velocity of helicopter blades relative to the air is greater than that of airplane wings. The helicopter may turn out to be more economical than the airplane wing for extreme velocities of horizontal flight, the airplane then requiring a very great speed range.
Date: January 1, 1925
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department