143 Matching Results

Search Results

prev Results: 73 - 96 next
open access

Gordon Bennett Airplane Cup 1920

Description: The characteristics of the airplanes built for the Gordon Bennett Airplane Cup race that took place on September 28, 1920 are described. The airplanes are discussed from a aerodynamical point of view, with a number of new details concerning the French machines. Also discussed is the regulation of future races. The author argues that there should be no limitations on the power of the aircraft engines. He reasons that in the present state of things, liberty with regard to engine power does not le… more
Date: April 1921
Creator: Margoulis, W.
Partner: UNT Libraries Government Documents Department
open access

The optical wing aligning device of the Langley Field tunnel

Description: Described here is a convenient and accurate method of aligning the wing chord with the airflow. The device was developed to permit rapid and accurate alignment of airfoils and models with the airstream passing through the tunnel. It consists of three main parts: a projector, a reflector, and a target. The arrangement, which is shown in a figure, has proven satisfactory in operation. It is far better than the old method of sighting across a long batten, as the operator of a balance may see the t… more
Date: January 1921
Creator: Norton, F. H. & Bacon, D. L.
Partner: UNT Libraries Government Documents Department
open access

The Dynamometer Hub for the Testing Propellers and Engines During Flight

Description: The need for a device to measure flight resistance, engine and propeller power, and efficiency during flight grew in proportion to the demand for increased flying capacity in military types of aircraft. Here, a dynamometer hub was inserted between the engine and the propeller. Taken as a whole, the tests that were conducted show that though the dynamometer is a sensitive instrument liable to numerous derangements, it is undeniably useful even in its present form, when handled with care and skil… more
Date: July 1921
Creator: Enoch, O.
Partner: UNT Libraries Government Documents Department
open access

On a New Type of Wind Tunnel

Description: Discussed here is a new type of wind tunnel, its advantages, the difficulties attendant upon its use, and the special methods required for its operation. The main difference between the new type of wind tunnel and the ones now in operation is the use of a different fluid. The idea is to diminish the effect of viscosity.
Date: May 1921
Creator: Munk, Max
Partner: UNT Libraries Government Documents Department
open access

A New Method of Testing in Wind Tunnels

Description: Now, in existing wind tunnels, using a horsepower of 100 to 300, the models are generally made to a 1/10 scale and the speed is appreciably lower than the speeds currently attained by airplanes. The Reynolds number realized is thus 15 to 25 times smaller than that reached by airplanes in free flight, while the ratio of speed to the velocity of sound is between a third and three quarters of the true ratio. The necessary increases in either the diameter of the wind tunnel or the velocity of the a… more
Date: August 1921
Creator: Margoulis, W.
Partner: UNT Libraries Government Documents Department
open access

Similitude tests on wing sections

Description: Report presenting an exploration of the application of model test results to full size construction, which assumes that either the resistance varies as the square of the speed within, the range of speeds in question or that the mechanical similarity law is fulfilled by the model test. The latter requires that the relation of airflow to the model be exactly like that for the large machine.
Date: April 1921
Creator: Kumbruch, H. & Bacon, D. L.
Partner: UNT Libraries Government Documents Department
open access

N.A.C.A. Langley field wind tunnel apparatus: The tilting manometer

Description: A description is given of a tilting manometer designed to meet the requirements of a manometer for use in the wind tunnel at the Langley Memorial Aeronautical Laboratory. This gauge was designed to meet the requirements of a manometer in use in connection with a static pressure plate to indicate the wind speed in the tunnel. The requirements are noted. The sensitivity of the gauge must be made inversely proportional to the pressure to be measured. The gauge must be accurately and quickly set fo… more
Date: January 1921
Creator: Norton, F. H. & Bacon, D. L.
Partner: UNT Libraries Government Documents Department
open access

Experiments With Slotted Wings

Description: Note presenting an investigation of various aspects of slotted wings, including some theoretical and experimental results and characteristics of certain slotted wings currently in production.
Date: November 1921
Creator: Lachmann, G.
Partner: UNT Libraries Government Documents Department
open access

Effect of the Reversal of Air Flow Upon the Discharge Coefficient of Durley Orifices

Description: Experiments were conducted to obtain information on the relationship between the coefficients for flow in two directions through thin plate orifices at low velocities. The results indicate that the ratio of the orifice discharge coefficient from standard orifice C(sub s)(sup 1) to the discharge coefficient from the reverse flow C(sub s) is always less than unity with increasing ratio of box area to orifice area. Even for areas as low as twenty, the ratios of the coefficients are not much less t… more
Date: February 1921
Creator: Ware, Marsden
Partner: UNT Libraries Government Documents Department
open access

Aneroid investigations in Germany

Description: Report presenting an experiment of aneroid development and a theoretical study of the equilibrium of forces acting on the vacuum box.
Date: October 1921
Creator: Hersey, M. D.
Partner: UNT Libraries Government Documents Department
open access

Influence of Span and Load Per Square Meter on the Air Forces of the Supporting Surface

Description: "It should be clear that in order to obtain a lift it is necessary that the air which flows past an aerofoil be given a downward acceleration; indeed the lift can be only the reaction produced by the downward acceleration of the flowing air. The motion of the air in the neighborhood of an aerofoil may be followed theoretically with great exactness. In the following, it will be undertaken to make understood, through the simplest possible considerations, the effect of span and loading on the air … more
Date: March 1921
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department
open access

The Choice of Wing Sections for Airplanes

Description: "The subject of the choice of an airfoil section is by no means a closed one, and despite the impossibility of making a single rule serve, it is quite practicable to deduce in a strictly rational manner a series of rules and formulas which are capable of being of the greatest use if we but confine ourselves to the consideration of one element of performance at a time. There are seven such elements of performance which are here taken up in turn. The seven are of different relative importance in … more
Date: November 1921
Creator: Warner, Edward P.
Partner: UNT Libraries Government Documents Department
open access

Mutual Influence of Wings and Propeller

Description: Report presenting an experiment consisting of an aerofoil and propeller in order to discover the mutual influence between the two components and variations in moment due to the propeller influence.
Date: December 1921
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department
open access

Effects of Varying the Relative Vertical Position of Wing and Fuselage

Description: "The object of this series of experiments was to determine the influence of the relative vertical position of wing and fuselage on the efficiency of the wing. Since the longitudinal position of the wing can be varied but slightly with reference to the center of gravity in a normal airplane, it was kept constant in the experiments to be described and only the vertical position of the wing with reference to the fuselage was varied" (p. 1).
Date: December 1921
Creator: Prandtl, L.
Partner: UNT Libraries Government Documents Department
open access

Extract From a Report on the Resistance of Spheres of Small Diameter in an Airstream of High Velocity

Description: Much attention is given here to the design of the wind tunnel and the experimental set-up. In comparing their results on the wind resistance of spheres to the results of other researchers, the authors find wide discrepancies. They are unable to explain the cause of the discrepancies, concluding, as they do, that the differing results could not be explained by the action of the wind tunnel walls.
Date: March 1921
Creator: Toussaint & Hayer
Partner: UNT Libraries Government Documents Department
open access

Theory of the ideal windmill

Description: Report presenting the theory of the ideal propeller, which is important for solving the problem of the action of propellers. Several different theories of propeller action are described and compared to determine which ones seem to be the most accurate.
Date: July 1921
Creator: Hoff, Wilhelm
Partner: UNT Libraries Government Documents Department
open access

Recent European Developments in Helicopters

Description: Descriptions are given of two captured helicopters, one driven by electric power, the other by a gasoline engine. An account is given of flight tests of the gasoline powered vehicle. After 15 successful flight tests, the gasoline powered vehicle crashed due to the insufficient thrust. Also discussed here are the applications of helicopters for military observations, for meteorological work, and for carrying radio antennas.
Date: April 1921
Partner: UNT Libraries Government Documents Department
open access

A Mechanical Device for Illustrating Airplane Stability

Description: An instrument is described which will illustrate completely in a qualitative sense the longitudinal stability characteristics of an airplane. The instrument is primarily of use for the lecture room, but it is hoped that ultimately it will be possible to obtain quantitative results from it.
Date: December 1921
Creator: Norton, F. E.
Partner: UNT Libraries Government Documents Department
open access

The determination of downwash

Description: It is obvious that, in accordance with Newton's second law, the lift on an aerofoil must be equal to the vertical momentum communicated per second to the air mass affected. Consequently a lifting aerofoil in flight is trailed by a wash which has a definite inclination corresponding to the factors producing the lift. It is thought that sufficient data, theoretical and experimental, are now available for a complete determination of this wash with respect to the variation of its angle of inclinati… more
Date: January 1921
Creator: Diehl, Walter S.
Partner: UNT Libraries Government Documents Department
open access

Design of Wind Tunnels and Wind Tunnel Propellers, 2

Description: Report presenting a continuation of a previous study in order to supply further data to the designers of wind tunnels. Particular emphasis was placed on the study of directional variation in the wind stream. The results indicated that placing radial vanes directly before the propeller actually increased the efficiency of the tunnel to a considerable extent.
Date: 1921
Creator: Norton, F. H. & Warner, E. P.
Partner: UNT Libraries Government Documents Department
open access

Effect of the Reversal of Air Flow Upon the Discharge Coefficient of Durley Orifices

Description: Note presenting an experiment to obtain information regarding the relationship between the coefficients for flow in the two directions through an inlet. The results indicate that the ratio of the orifice discharge coefficient from standard orifice to the discharge coefficient from reverse flow is always less than unity, but approaches unity with increasing ratio of box area to orifice area, and that even for a ratio of areas as low as twenty the ratios of the coefficients is not much less than … more
Date: February 1921
Creator: Ware, Marsden
Partner: UNT Libraries Government Documents Department
open access

The Lacasa Area, Ranger District North-Central Texas

Description: This document reports the economic geology of the Lacasa area, Ranger district in North-Central Texas, with fieldwork done in April and May of 1919.
Date: December 23, 1921
Creator: Ross, Clarence S.
Partner: UNT Libraries Government Documents Department
Back to Top of Screen