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Duralumin
Various properties of duralumin as used in aircraft construction are discussed, including the effects of temperature, working, tempering, and strength.
Notes on the Design of Supercharged and Over-dimensioned Aircraft Engines
The author discusses the limited benefits of supercharging motors and some of the factors that make supercharging less beneficial than it initially appears.
Static Testing and Proposed Standard Specifications
Static tests fall into two groups, the first of which is designed to load all members of the structure approximately in accordance with the worst loads which they carry in flight, while the second is directed to the testing of specific members which are suspected of weakness and which are difficult to analyze mathematically. The nature of the loading in the second type is different for every different test, but the purpose of the first is defined clearly enough to permit the adoption of some standard set of loading specifications, at least for airplanes of normal design. Here, an attempt is made to carry through an analysis leading to such a standard, the goal being the determination of a load which will simultaneously impose on every member of the airplane structure a stress equal to the worst it will carry in flight.
Theory of Lifting Surfaces
The general basis of the theory of lifting surfaces is discussed. The problem of the flow of a fluid about a lifting surface of infinite span is examined in terms of the existence of vortexes in the current. A general theory of permanent flow is discussed. Formulas for determining the influence of aspect ratio that may be applied to all wings, whatever their plane form, are given.
Abacus for the Reduction of English Measures to the Metric System and Vice Versa
This report presents a description of an abacus with three scales: one for English measures, one for metric measures, and one with the "points of reduction", as well as construction details. There is also a detailed description on how to use the abacus.
The Caproni Seaplane
The Caproni Company recently built a seaplane of unusual design. The main supporting surfaces consisted of three triplanes in tandem, the lower wings being attached to the hull, which was described as providing accommodation for a hundred passengers. On one of the first flights, the seaplane fell into a lake, nose down, and was destroyed. The authors wish to show that this failure could have been predicted.
The Drawing of Experimental Curves
This report presents a discussion of how to determine the location of a line or surface from experimental data. What we desire to know practically is the number of ordinates required to obtain a certain probable precision in drawing a line or surface.
The Dynamometer Hub for the Testing Propellers and Engines During Flight
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 skill.
Flexible Petrol Pipe
Report presenting an examination of flexible piping and some of the difficulties involved in creating satisfactory flexible pipe. The joint used to assist in the flexibility of the pipe is illustrated and described.
The Problem of Fuel for Aviation Engines
Note presenting the physical properties which may be demanded of fuels for aviation use and the means that may be adopted by the engine manufacturers to properly meet the demands necessitated by the use of the fuel. Some of the factors that must be considered include its composition, the quantity available, the price per heat unit, and the possibility of keeping stocks in aerial ports both at home and abroad.
Theory of the ideal windmill
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.
Aerial navigation by dead reckoning
Report discussing the problem to be solved, as presented to the pilot or observer of an aircraft, is as follows: The aircraft starting from A must land at B, the only data being the speed of the airplane, the altitude and the orientation D of the course. The above data would be amply sufficient, were it not for the fact that the airplane is constantly subjected to a wind of variable direction and strength.
Aerodynamics and Ballistics
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.
Airplane Stability Calculations and Their Verification by Flight Tests
For some time, the designers of airplanes have begun to occupy themselves with the question of longitudinal stability. In their quest to simplify calculation and data collection, the designers have attached the greatest importance to the coefficient of initial longitudinal stability. In this study a diagram was constructed from the data of the tunnel tests, which depends neither on the position of the center of gravity nor of the angle of deflection of the elevators. This diagram is constructed by means of straight lines drawn through the metacenters of the complete airplane, in a direction parallel to the tangents to the polar of the airplane relative to a system of axes fixed with reference to the airplane.
Aviation in the Belgian Congo
The establishment of air service in the Belgian Congo is detailed in this report. The airplanes, landing fields, and air routes are all discussed.
Beacon Lights for Air Traffic
A beacon light manufactured by the Julius Pintsch Company is described and the arrangement of these lights on a landing field is discussed.
European Air Travel in 1922
This article discusses the different passenger air transport services offered in Europe. The author deals mainly with the service offered between different cities, in terms of time and cost.
The Future of the Airship
The author discusses the safety record of airships in light of the accidents with the Roma and the ZR2.
General Problem of the Airplane
A series of equations relating to airplanes are given and examples listed. Some of the equations listed include: the speed, altitude and carrying capacity of various airplanes; weight of an airplane; weight of various parts of an airplane; the polars of the wings; speeds of airplanes; radius of action.
Laying out of a practical air route
Unfortunately the problem of laying out an air route has been approached by all who give it consideration as one of the hardest tasks in the world. Whereas, as a matter of fact, a very serviceable air route can be laid out with an absolute minimum of ground work.
Maritime Aviation
This report presents some studies of maritime aviation which cover the following principal points: employment of landplanes on maritime aerial warfare; their adaption to peculiar requirements of the Navy; and the establishment of a method of aerial pursuit and bombardment, likewise adapted to military aviation over land.
Notes on Aerodynamic Forces 2: Curvilinear Motion
"The laws of curvilinear motion are established and the transverse forces on elongated airship hulls along a curved path are investigated" (p. 1).
Notes on Aerodynamic Forces 3: The Aerodynamic Forces on Airships
"The results of the two preceding notes are applied to airships and checked with wind tunnel tests" (p. 1).
Notes on Aerodynamic Forces I: Rectilinear Motion
"The study of the motion of perfect fluids is of paramount importance for the understanding of the chief phenomena occurring in the air surrounding an aircraft, and for the numerical determination of their effects. The author recently successfully employed some simple methods for the investigation of the flow of a perfect fluid that have never been mentioned in connection with aeronautical problems. These methods appeal particularly to the engineer who is untrained in performing laborious mathematical computations, as they do away with these and allow one to obtain many interesting results by the mere application of some general and well-known principles of mechanics" (p. 1-2).
Propeller Tests on Airplanes
In order to determine the efficiency of a propeller as accurately as possible, its revolution speed, thrust and power absorbed must be measured during flight. Unfortunately, these measurements can only be made with very complicated equipment. To surmount this problem the testers contented themselves with approximate results obtainable in two or three hours of flight.
Resume of the Activities of the Aeronautical Experimental Institute, Rome, During the Months of May, June, July and August 1921
This report is a listing of the different studies conducted by the Institute in May thru August of 1921. The aerodynamical section studied: the aerodynamical characteristics of a very thick concave-convex wing; the disturbance caused in a tunnel by the presence of a disk, placed in relation with a transversely infinite barrier; vertical pressure in a wing of low head resistance; the drag caused by two small doors in the sides of the fuselage. Some other studies conducted by the Institute included: depressions in the interior of the model of a wing; the influence of a conical casing fitted with helicoidal flanges centered on the hub of the propeller; the influence of the velocity of translation on the aerodynamical effects of the propeller; and the influence of a honeycomb placed in the tunnel.
Skin frictional resistance of plane surfaces in air: Abstract of recent German tests, with notes
Given here is the most recent research on skin frictional resistance of plane surfaces in air that was conducted by Dr. Wieselsberger under the direction of Dr. Prandtl of Gottingen University. In all, 16 models were tested. These were divided into four groups, as follows: 1) cloth, in the original condition; 2) cloth, with the nap singed off; 3) cloth, with three coats of dope; and 4) cloth, with six coats of dope. Each group consisted of four models of uniform width, 1 meter, and of lengths of 0.5, 1.0, 1.5, and 2.0 meters.
The Stresses in Columns Under Combined Axial and Side Loads
The problem before us is to determine the total stresses in an axially loaded column of any degree of restraint which is also subject to transverse bending both from a uniformly distributed load and from concentrated loads. The solution of this problem is of special importance in the design of aircraft which consist of slender columns" (p. 1).
This Summer's Gliding Meets
This article discusses the upcoming gliding meets in France and Germany in the summer of 1922. Restrictions of design, prize money, and new innovations are all discussed.
Politics of Aviation Fields
In short, the "politics of aviation" lies in a few propositions: the need of having as large a number of fields as possible and of sufficient area; the utilization of the larger part of the existing military fields; the selection of uncultivated or unproductive fields, whenever technical conditions permit; ability to disregard (save in exceptional cases) objections of an agricultural nature.
The "Autogiro"
Report presenting a description of the autogiro, which is a flying machine built and designed in Spain. A history of the device and the reasons why it is safer and more stable than a typical aircraft are provided.
Control Operating Mechanisms for Airplanes
The connections between the cockpit and the control surfaces are examined. An examination of the pros and cons of using stick control, the problems of control in giant aircraft, an effort to find a substitute for these controls, and a proposed concept for mechanically operated gear are provided.
Control Problems on Large Airplanes
The development of more efficient control surfaces requiring less force to operate are presented. Some of the control surfaces explored include the De Havilland gear, Flettner rudder, and some other possible control methods.
The flexible mounting of an airplane engine
Discussed here is the suggested installation of the 'unbalanced' 8-cylinder VE-engine. The suggestion was that a flexible mounting be used instead of bolting the engine rigidly to the airplane structure. It was concluded that a flexible connection between the engine and the airplane is probably possible. A flexible connection primarily diminishes the vibrations due to inertia and, to a lesser degree, those due to torque variation. However, engines vibrate more when freely suspended than when rigidly mounted, and this vibration has a detrimental effect on all connections between the engine and the airplane. Therefore, in view of the relatively insignificant advantages which may be derived from the elastic suspension of the engine, the present rigid mounting is to be preferred. Vibration reduction can be achieved by incorporating in the fuselage as many of the rigid airplane parts as possible.
Influences in the Selection of a Cycle for Small High Speed Engines Running on Solid or Airless Injection With Compression Ignition
Note presenting an investigation undertaken to answer the question of what cycle of heat phases should be selected for small high speed engines running on solid or airless injection with compression ignition, and what the relative proportions of the heat phases should be.
Notes on the N.A.C.A. Control Force Recorder
Emphasized here is the desirability of using recording instruments in the investigation of the characteristics of airplanes with particular reference to the National Advisory Committee for Aeronautics (NACA) control force recorder. Given here are photographs, records, and a description of the instrument developed by NACA for investigations on different types of aircraft. Described here is an instrument for recording control forces.
Speed Measurements Made by Division "A" of the Airplane Directorate (Flugzeugmeisterei), Subdivision for Flight Experiments
"The various speeds of an airplane can only be measured in horizontal flight, since there are no means for measuring the angle of ascent or descent. The measurements must be corrected for the density of the air. This is obtained by simultaneous pressure and temperature measurements during flight" (p. 1).
Variable Pitch Propeller
The advantages of variable pitch propellers over constant pitch propellers is presented along with different methods of varying the pitch. The technique of varying the shape of the propeller is presented as the most efficient one.
Balloon Flight and Atmospheric Electricity
"The air is known to be charged with electricity (chiefly positive) with reference to the earth, so that its potential increases with the altitude and the difference in potential between two points in the same vertical line, divided by the distance between them, gives a value called the "potential gradient," which may vary greatly with the altitude, the nature of the ground and the atmospheric conditions" (p. 1).
Experiments on the Resistance of Airplane Wheels and Radiators
Experiments were made on the resistance of four airplane wheels of different sizes and coverings and two Lamblin radiators. The results show the important influence of the wheel coverings. The closing of a shutter, which was fitted to one of the radiators, considerably lessened the resistance.
Experiments With a Device for Shortening the Glide and Landing Run of an Airplane
The improvement of airplanes and increased safety of air traffic can be sought in various ways. In the experiments described below, the aim was to find some simple and inexpensive method of modifying present-day airplanes, so as to improve and simplify the process of landing.
The Problem of Liquid Fuels (for Aircraft Engines)
"The crisis which troubles the world market for liquid fuel in general and for carburants in particular is doubtless one of the most serious ever experienced by modern industry. It is a national crisis of economic and political independence for countries like Italy and France. The solutions suggested for meeting the lack of liquid fuel may be summed up under two general headings: the economical use of the petroleum now available; creation of petroleum substitutes from natural sources within the country" (p. 1).
Some Tables of the Factor of Apparent Additional Mass
"This note, prepared for publication by the National Advisory Committee for Aeronautics, is a collection of the tables of the factor of apparent mass that have been published up to now. The theory of the motion of solids in a perfect fluid is of the greatest value for the study of most aerodynamic problems, and the additional apparent mass of an immersed solid is the most important characteristic for such theoretical numerical computations. It will therefore be helpful to have the most important values of the apparent mass - for some elementary cases - collected in a convenient form" (p. 1).
Velocity and Pressure Distribution Behind Bodies in an Air Current
The following experiments on the air flow behind bodies were made for the purpose of assisting in the explanation of the phenomena connected with air resistance. The first two series of experiments dealt with the phenomena behind a cylinder. The third series of experiments was carried out behind a streamlined strut.
Computation of Cantilever Airplane Wings
The purpose of this treatise is, first of all, the determination of the effect of variously loaded spars on one another, since the neglect of this effect would present an economically very unfavorable computation method. The system of spars and cross-bars alone (whether solid or built-up) does not matter at first, the original assumption being that the spars are rigidly braced by the cross-bars.
Increasing the Power of Internal Combustion Engines
This report presents various methods for increasing the power of engines such as supercharging and turbocharging.
Recent experiments at the Gottingen Aerodynamic Institute
This report presents the results of various experiments carried out at the Gottingen Aerodynamic Institute. These include: experiments with Joukowski wing profiles; experiments on an airplane model with a built-in motor and functioning propeller; and the rotating cylinder (Magnus Effect).
Relation Of "Lilienthal Effect" to Dynamic Soaring Flight
"In this article, the phenomena of the upward component in the case of flat surfaces will be referred to as the "Lilienthal effect." The Lilienthal effect will be distinguished from the Knoller-Betz effect which is explained by means of vertical wind oscillations, at the basis of which, however, there lie air motions which the Lilienthal effect could not produce. It will be shown that the same cause, which can produce the Lilienthal effect on flat airfoils, considerably strengthens the thrust due to the Knoller-Betz effect" (p. 1).
The Blackburn "Sprat": A Training Airplane Convertible Into Landplane or Seaplane
The Sprat is similar the Blackburn Swift and Dart models but is designed as a trainer. It is powered with a smaller 275 HP Rolls-Royce Falcon engine. It is a 2 seat biplane with equal sized upper and lower wings. It can quickly convert from a land to a seaplane.
Development of Light and Small Airplanes
Memorandum presenting an overview of the development of light and small airplanes. Some of the characteristics explored include the development of airplanes of medium weight, development in countries other than Germany, development of light airplanes, general constructive fiducial lines, safety problems, the economy problem, and some special structural considerations are provided.
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