National Advisory Committee for Aeronautics (NACA) - 87 Matching Results

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Aerodynamic characteristics of thin empirical profiles and their application to the tail surfaces and ailerons of airplanes

Description: From Introduction: "The increasing use of airplane wings equipped with ailerons and the importance of knowing the aerodynamic characteristics of tail units (empennages) provided with movable parts (rudders and elevators) impart some interest to the so-called "empirical profiles." For this purpose we thought best to employ the method proposed by Munk for the approximate theoretical study of thin, slightly curved profiles, assimilable, from an aerodynamic view-point, to their mean camber line."
Date: December 1928
Creator: Toussaint, A & Carafoli, E
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

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

Airplane drag

Description: It has been less well understood that the induced drag (or, better said, the undesired increase in the induced drag as compared with the theoretical minimum calculated by Prandtl) plays a decisive role in the process of taking off and therefore in the requisite engine power. This paper seeks to clarify the induced drag.
Date: December 1929
Creator: Topfer, Carl
Partner: UNT Libraries Government Documents Department

Automatic stability of airplanes

Description: It is endeavored in this report to give a full outline of the problem of airplane stability and to classify the proposed solutions systematically. Longitudinal stability, which can be studied separately, is considered first. The combination of lateral and directional stabilities, which cannot be separated, will be dealt with later.
Date: December 1932
Creator: Haus, FR
Partner: UNT Libraries Government Documents Department

Automatic stabilization

Description: This report lays more stress on the principles underlying automatic piloting than on the means of applications. Mechanical details of servomotors and the mechanical release device necessary to assure instantaneous return of the controls to the pilot in case of malfunction are not included. Descriptions are provided of various commercial systems.
Date: December 1936
Creator: Haus, FR
Partner: UNT Libraries Government Documents Department

The balance of moments and the static longitudinal stability of airplanes

Description: A nomogram is developed which renders it possible by drawing a few lines, to determine: the location of the center of gravity for zero wing and tail moments; the longitudinal dihedral angle; the tail coefficient F(sub h) iota/F(sub t). Moreover there is no difficulty in determining the magnitude of the restoring moment or of the unstable moment.
Date: December 1, 1929
Creator: Muller, Horst
Partner: UNT Libraries Government Documents Department

Balloon fabrics made of Goldbeater's skins

Description: Goldbeater's skin, which is the prepared outside membrane of the large intestine of an ox, is examined as a balloon fabric and details of how goldbeater's skin is prepared for use are provided. The construction techniques employed by Germany, France, and England are all discussed.
Date: December 1, 1922
Creator: Chollet, L
Partner: UNT Libraries Government Documents Department

The Breda wind tunnel

Description: A description of the design and construction of the Breda wind tunnel. The tunnel is equipped with a two-meter throat diameter and a 310 kph velocity potential.
Date: December 1, 1939
Creator: Pittoni, Mario
Partner: UNT Libraries Government Documents Department

Calculating thrust distribution and efficiency of air propellers

Description: I am now proposing a method for the preliminary approximate calculation of the thrust distribution and efficiency of air propellers under any operating conditions. Our task becomes the following, namely, to determine the speed relations and the forces developed on a section with a given direction and velocity of the air current, a problem which can be solved with the aid of the momentum theory.
Date: December 1, 1927
Creator: Bienen, Theodor
Partner: UNT Libraries Government Documents Department

Calculation of the pressures on aircraft engine bearings

Description: For aircraft engines the three principal operating conditions are idling speed, cruising speed, and diving with the engine stopped. In what follows, we will discuss a method which affords a good idea of the course of pressure for the above mentioned operating conditions. The pressures produced in the driving gear are of three kinds; namely, the pressure due to gases, the pressure due to the inertia of the rotating masses, and the pressure due to the inertia of the reciprocating masses.
Date: December 1, 1929
Creator: Steigenberger, O
Partner: UNT Libraries Government Documents Department

The cetene scale and the induction period preceding the spontaneous ignition of diesel fuels in bombs

Description: In the present report a comparison is made between the scale obtained with mixtures of cetane and l-methyl naphthalene in a bomb, and that obtained with the same fuels in a Waukesha engine. The tests were conducted in a metal bomb heated by a Nichrome spiral. The fuel was injected into the bomb from a Bosch jet by means of a specially constructed plunger pump. The instant injection and the pressure curve in the bomb were registered by a beam of light which was reflected from a mirror connected to the needle of the jet and to a membrane indicator.
Date: December 1, 1936
Creator: Michailova, M N & Neumann, M B
Partner: UNT Libraries Government Documents Department

Chordwise load distribution of a simple rectangular wing

Description: The chordwise distribution theory was taken over from the theory of the infinite wing. Since in this work a series expansion in b/t was used, the computation converges only for large aspect ratios. In this paper a useful approximate solution will be found also for wings with large chord - i.e., small aspect ratio.
Date: December 1, 1940
Creator: Wieghardt, Karl
Partner: UNT Libraries Government Documents Department

Commercial airplanes and seaplanes : thick wings or thin wings - all metal or mixed construction

Description: In this report we will consider, as the dominating characteristic, either the load carried, the speed, the radius of action, the fuel consumption, the activity of transport, or, lastly, the qualities of comfort and safety. The first four factors determine the theoretical efficiency, while the others determine its practical efficiency.
Date: December 1, 1922
Creator: POINT
Partner: UNT Libraries Government Documents Department

Concerning the flow about ring-shaped cowlings Part VI : further measurements on inlet devices

Description: The present report presents as a supplement to the fourth report (available as ATI 5045, Air Materiel Command) in the series of investigations concerning the flow about ring-shaped cowlings further wind-tunnel measurements on inlet devices which are to show the influence of the radius of the nose of the cowling on the flow conditions. Moreover, a simple rule for the design of such arrangements, containing a hub in the interior, is suggested.
Date: December 1, 1951
Creator: Kuchemann, Dietrich & Weber, Johanna
Partner: UNT Libraries Government Documents Department

Contribution to the aerodynamics of rotating-wing aircraft

Description: The chief defect of the investigations up to now was the assumption of a more or less arbitrary "mean" drag coefficient for a section of the blade. This defect is remedied through replacement of the constant coefficient by a function of higher order which corresponds to the polar curve of the employed profile. In that way it is possible to extend the theory to include the entire range from "autogyro" without power input to the driven "helicopter" with forward-tilted rotor axis. The treatment includes the twisted rectangular blade and a non-twisted tapered blade. Proceeding from the air flow and stresses on a section of the blade, the formulas for torque, axial and normal thrust of a linearly twisted rectangular blade, and a non-twisted tapered blade, are derived.
Date: December 1, 1939
Creator: Sissingh, G
Partner: UNT Libraries Government Documents Department

Contribution to the aileron theory

Description: In an attempt to treat theoretically the effect of ailerons, difficulty arises because an aileron may begin at any point of the wing. Hence the question arises as to how the transition of the lift distribution proceeds at such a point, since the effect of the aileron (i.e., the moment generated about the longitudinal axis) depends largely on this distribution. In order to answer this question regarding the lift distribution during irregular variations in the angle of attack at first independently of other influences, especially those of the wing tips, we have taken as the basis of the following theoretical discussion a wing of infinite span and constant chord which exhibits at one point an irregular variation in the angle of attack. As regards the mathematical treatment, we will first consider a wing with periodically recurring angle of attack.
Date: December 1929
Creator: Betz, A. & Petersohn, E.
Partner: UNT Libraries Government Documents Department

Contribution to the theory of tail-wheel shimmy

Description: A basic theoretical and experimental investigation is made of the shimmy behavior of a swiveling landing gear, the experimental tests being conducted with a small wheel mounted over a continuous belt. Effects of wheel loading, rolling velocity, rearward position of the wheel with respect to the swivel axis, tire elasticity, and torsional flexibility of the fuselage are investigated both experimentally and theoretically. A major theoretical conclusion is that the motion of a landing gear moving in a straight line without fuselage elasticity is stable for a sufficiently large rearward position of the wheel behind the swivel axis, and this conclusion is well verified quantitatively by the experimental data.
Date: December 1, 1954
Creator: Melzer, M
Partner: UNT Libraries Government Documents Department

The Coupling of Flexural Propeller Vibrations with the Torsional Crankshaft Vibrations

Description: The exact mathematical treatment of the problem is possible by replacing the propeller blade by a homogeneous prismatic rod. Conclusions can them be drawn as to the behavior of an actual propeller, since tests on propeller blades have indicated a qualitative agreement with the homogeneous rod. The natural frequencies are determined and the stressing of the systems under the various vibration modes are discussed.
Date: December 1943
Creator: Meyer, J.
Partner: UNT Libraries Government Documents Department

Depreciation of aircraft

Description: There is a widespread, and quite erroneous, impression to the effect that aircraft are essentially fragile and deteriorate with great rapidity when in service, so that the depreciation charges to be allowed on commercial or private operation are necessarily high.
Date: December 1, 1922
Creator: Warner, Edward P.
Partner: UNT Libraries Government Documents Department

Determination of the bending and buckling effect in the stress analysis of shell structures accessible from one side only

Description: The present report describes a device for ascertaining the bending and buckling effect in stress measurements on shell structures accessible from one side only. Beginning with a discussion of the relationship between flexural strain and certain parameters, the respective errors of the test method for great or variable skin curvature within the test range are analyzed and illustrated by specimen example.
Date: December 1, 1941
Creator: Dose, A
Partner: UNT Libraries Government Documents Department