Technical Report Archive and Image Library (TRAIL) - 1,437 Matching Results

Search Results

Aerodynamic principles of the direct lifting propeller

Description: From Summary: "The purpose of this report is to make the complicated processes on the direct-lift propeller amenable to analysis and observation. This is accomplished by placing the physical phenomena, starting with the most elementary process, in the foreground, while limiting the mathematical treatment to the most essential in view of the fundamental defects of the theorems. Comparison with model experiments supplements and corroborates the theoretical results."
Date: January 1934
Creator: Schrenk, Martin
Partner: UNT Libraries Government Documents Department

Aerodynamic Research on Fuselages with Rectangular Cross Section

Description: The influence of the deflected flow caused by the fuselage (especially by unsymmetrical attitudes) on the lift and the rolling moment due to sideslip has been discussed for infinitely long fuselages with circular and elliptical cross section. The aim of this work is to add rectangular cross sections and, primarily, to give a principle by which one can get practically usable contours through simple conformal mapping. In a few examples, the velocity field in the wing region and the induced flow produced are calculated and are compared with corresponding results from elliptical and strictly rectangular cross sections.
Date: July 1958
Creator: Maruhn, K.
Partner: UNT Libraries Government Documents Department

The aerodynamic safety of airplanes

Description: This report presents several hypotheses regarding airplane safety, mainly concerning the nondimensional coefficient of air, speed, acceleration, and wing area on aerodynamic considerations of safety.
Date: September 1932
Creator: Kahn, Louis
Partner: UNT Libraries Government Documents Department

The aerodynamic wind vane and the inherent stability of airplanes

Description: Report discussing the design of the wind vane described rests on the following line of reasoning: An airplane, originally in equilibrium about its C.G. is assumed to be deflected from this position through an angle (delta)i, the variation (delta)i being so sudden that the path of the C.G. and the airplane speed do not change while it is taking place. The aerodynamic forces acting on the wings, tail surfaces, fuselage, etc., which, as a whole, exerted a zero moment (M(sub G) = 0) about the center of gravity at the instant of equilibrium, now exert a moment M(sub G) not equal to 0.
Date: February 1931
Creator: Lapresle, A
Partner: UNT Libraries Government Documents Department

Aerodynamics and ballistics

Description: Ballistics is a science hundreds of years old and this report is an attempt to show how these older principles can be used in the newer science of aerodynamics.
Date: July 1922
Creator: Burzio, Filippo
Partner: UNT Libraries Government Documents Department

Aerodynamics of rotating-wing aircraft with blade-pitch control

Description: From Introduction: "In the present report, with the aid of the usual computation methods, a rotor is investigated the pitch of whose blades is capable of being controlled in such a manner that it varies linearly with the flapping angle. To test the effect of this linkage on the aircraft performance, the theory is applied to an illustrative example."
Date: February 1940
Creator: Pfluger, A
Partner: UNT Libraries Government Documents Department

Aerodynamics of the Fuselage

Description: The present report deals with a number of problems, particularly with the interaction of the fuselage with the wing and tail, on the basis of simple calculating method's derived from greatly idealized concepts. For the fuselage alone it affords, in variance with potential theory, a certain frictional lift in yawed flow, which, similar to the lift of a wing of small aspect ratio, is no longer linearly related to the angle of attack. Nevertheless there exists for this frictional lift something like a neutral stability point the position of which on oblong fuselages appears to be associated with the lift increase of the fuselage in proximity to the zero lift, according to the present experiments. The Pitching moments of the fuselage can be determined with comparatively great reliability so far as the flow conditions in the neighborhood of the axis of the fuselage can be approximated if the fuselage were absent, which, in general, is not very difficult. For the unstable contribution of the fuselage to the static longitudinal stability of the airplane it affords comparatively simple formulas, the evaluation of which offers little difficulty. On the engine nacelles there is, in addition a very substantial wing moment contribution induced by the nonuniform distribution of the transverse displacement flow of the nacelle along the wing chord; this also can be represented by a simple formula. A check on a large number of dissimilar aircraft types regarding the unstable fuselage and nacelle moments disclosed an agreement with the wind-tunnel tests, which should be sufficient for practical requirements. The errors remained throughout within the scope of instrumental accuracy.
Date: December 1942
Creator: Multhopp, H.
Partner: UNT Libraries Government Documents Department

Aeroelastic Problems of Airplane Design

Description: The technical memorandum briefly summarizes the growth of interest in aeroelastic phenomena as aircraft speed increased and wing designs changed for faster aircraft. Different types of aircraft vibrations are then introduced, and the mathematical basis for the theory behind them is described. Special attention is given to static oscillations, wing flutter, and the flutter of skin panels. The last section of the memorandum deals with the prevention of flutter by design specifications.
Date: November 1956
Creator: Kuessner, H. G.
Partner: UNT Libraries Government Documents Department

Aeronautic instruments

Description: The development of aeronautic instruments. Vibrations, rapid changes of the conditions of flight and of atmospheric conditions, influence of the air stream all call for particular design and construction of the individual instruments. This is shown by certain examples of individual instruments and of various classes of instruments for measuring pressure, change of altitude, temperature, velocity, inclination and turning or combinations of these.
Date: February 1924
Creator: Koppe, H & Everling, E
Partner: UNT Libraries Government Documents Department

Aeronautic insurance

Description: The problem of insuring the emerging commercial aeronautic industry is detailed. The author also motes that a complete solution cannot be obtained until the necessary statistics are compiled.
Date: March 1922
Creator: Neal, Erik
Partner: UNT Libraries Government Documents Department

Aeronautical education and research at the Swiss Institute of Technology in Zurich

Description: Progress in the scientific and practical fields of aviation has caused the Swiss Institute of Technology to organize lectures and practical training courses in all three branches of aeronautics and to found centers of scientific research, laboratories, etc., in order to supply the government and industries with scientifically and technically trained engineers.
Date: April 1931
Creator: Karner, L & Ackeret, J
Partner: UNT Libraries Government Documents Department

Aeronautical record : no. 1 (to June, 1923)

Description: "...considerations have prompted us to pay special attention to the development of aeronautical industries and aerial navigation as a commercial enterprise and to publish an analytical review of events in the aeronautical world and of the attendant problems.".
Date: December 1923
Partner: UNT Libraries Government Documents Department

Air admixture to exhaust jets

Description: From Introduction: "The problem of thrust increase for jet engines by air mixture to the exhaust jet was introduced into aviation techniques by the suggestions of Melot (ref.1). Due to a too general interpretation of several theoretical investigations of A. Busemann (ref.2), so far no practical use has been made of these suggestions. The following considerations show that, in the case of low-pressure mixing according to Melot's suggestions, probably no thrust increase of technical significance will occur for the flight speeds of interest (however, the low-pressure mixture is highly promising for ground test setups and for special power plants of relatively slow sea and land vehicles."
Date: July 1953
Creator: Sanger, Eugen
Partner: UNT Libraries Government Documents Department

Air-flow experiments

Description: This report describes the apparatus used to take air-flow photographs. The photographs show chiefly the spiral course of the lines of flow near the tip of the wing. They constitute therefore a visual presentation of the phenomena covered by airfoil theory.
Date: May 1924
Creator: Wieselsberger, C
Partner: UNT Libraries Government Documents Department

Air forces and air-force moments at large angles of attack and how they are affected by the shape of the wing

Description: From Summary: "The present report is, in the first place, a compilation of the test results now available from wing tests up to angles of attack 90^o. Reports are also given of tests with monoplane and auxiliary wings in the Gottingen wind tunnel for the purpose of plotting a steadily rising curve of the normal force as a foundation of the angle of attack."
Date: July 1930
Creator: Fuchs, Richard & Schmidt, Wilhelm
Partner: UNT Libraries Government Documents Department

Air Forces Exerted on Streamlined Bodies with Round or Square Cross- Sections, When Placed Obliquely to the Airstream

Description: The question of behavior of a streamlined body with round or square cross-sections is of importance in determining the shape to give an airplane fuselage. It is our task here to show how the lift and drag are affected, with the object placed obliquely to the air stream.
Date: June 1924
Creator: Wieselsberger, C
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 reactions to objects moving at rates above the velocity of sound with application to the air propeller

Description: From Discussion: "To meet these unusual conditions three sets of ball-bearings were employed and arranged in tandem, thereby reducing their speeds by the ratio of the number of sets used, as shown in Fig.3. This proved to be a complete success. The results obtained in experiments with a two-blade, 4 foot propeller of series 2, are given in Fig. 9."
Date: November 1922
Creator: Reed, S. Albert
Partner: UNT Libraries Government Documents Department