Model aeroplanes The building of model monoplanes, biplanes, etc., together with a chapter on building a model airship — A Closer Reading

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The Building of Model Monoplanes, Biplanes, etc., together with a Chapter on Building a Model Airship

WITH 190 ILLUSTRATIONS

NEW YORK FUNK & WAGNALLS COMPANY

This is a practical handbook on the principles, constructional details and methods of building model aeroplanes, written by a well-known model aeroplane designer and builder. It deals with every part of a machine and describes a number of different types, including monoplanes, biplanes, collapsible machines, tractor monoplanes, hydro-monoplanes, aeroplanes driven by compressed air, etc., etc. The concluding chapter explains how to build a model airship, and, as in the case of all the others, is based on the results of practical experience. Readers in need of further information on the subject should address their inquiries to “Work,” La Belle Sauvage, London, E.C., through whose columns (but not by post), assistance will be gladly given.

1. WHY AN AEROPLANE FLIES 1 2. TYPES OF MODEL AEROPLANES 12 3. PRACTICAL CONSTRUCTION: MODEL AEROPLANE FUSELAGES 19 4. PRACTICAL CONSTRUCTION: CARVING AIR-SCREWS 35 5. PRACTICAL CONSTRUCTION: BENDING AIR-SCREWS 42 6. PRACTICAL CONSTRUCTION: PLANES 47 7. SIMPLE TWIN-SCREW MONOPLANE 54 8. SIMPLE TWIN-SCREW BIPLANE 61 9. WINDERS FOR ELASTIC MOTORS 69 10. COLLAPSIBLE MONOPLANE 73 11. TRACTOR MONOPLANE 80 12. HYDRO-MONOPLANE 87 13. COMPRESSED-AIR ENGINE FOR MODEL AEROPLANE 94 14. BIPLANE DRIVEN BY COMPRESSED-AIR ENGINE 104 15. GENERAL NOTES ON MODEL DESIGNING 120 16. GENERAL NOTES 124 17. EASILY-MADE TAILLESS KITES 136 18. BUILDING A MODEL AIRSHIP 141 INDEX 154

Why an Aeroplane Flies

Why does an aeroplane fly? The question is worthy of close examination. There is one common enemy to aeroplanes—the force of gravity. Were it not for the existence of this force, which, as Newton put it, “is unseen and unheard and yet dominates the universe,” the problem of the aeroplane would have been solved years ago.

Most readers have handled the toy kite, and since the principles governing the flight of a kite are precisely the same as those which apply to the aeroplane, the latter will be the more readily understood if the principles are explained through this medium. Full-size aeroplanes to which certain models approximate are shown in Fig. 1.

If a kite is launched in a wind it speedily attains a certain height or altitude, at which it remains so long as the wind does not drop. The wind is overcoming gravity, which constantly endeavours to bring the kite to earth, and hence, since the kite remains in the air, the forces acting on the kite are said to be in equilibrium—that is, balanced. The forces are shown diagrammatically in Fig. 1A, and include gravity, which is practically constant and remains unaltered under all conditions, the air pressure which, when sufficiently intense, lifts the kite against the action of gravity, and the pull of the string. The air pressure is really a combination of two forces—lift and drift. The drift or resistance tends to move the kite in the direction of the wind, and lift to raise the kite in opposition to gravity. Since, therefore, drift is an undesirable factor, the resistance of the machine must be made as low as possible, as it absorbs power, as will clearly be seen. If the velocity of the wind drops, the kite drops also, increasing its angle with the horizon, thereby causing it to capture and force down more air until equilibrium is again restored. If the string of a kite breaks, the balance of the forces is destroyed, drift and gravity taking command and so bringing the kite to earth.

If it takes a wind of fifteen miles an hour to lift a kite, similarly it would lift to exactly the same elevation if the holder of the kite-string commenced to run at a rate of fifteen miles per hour in calm air.

Now, an aeroplane is merely a kite with a mechanical arrangement (the engine and propeller) which supplies the motion necessary to fly it, and eliminates the necessity for a wind. This statement can easily be followed. In the aforementioned parallel it was seen that it was immaterial whether the kite-flyer was standing still with the wind moving at fifteen miles per hour, or whether he was moving at the rate of fifteen miles per hour in still air. The result in each case is the same—the kite flies.