MODEL AEROPLANING
INTRODUCTION.
§ 1. Model Aeroplanes are primarily divided into two classes: first, models intended before all else to be ones that shall fly; secondly, models, using the word in its proper sense of full-sized machines. Herein model aeroplanes differ from model yachts and model locomotives. An extremely small model locomotive built to scale will still work, just as a very small yacht built to scale will sail; but when you try to build a scale model of an "Antoinette" monoplane, including engine, it cannot be made to fly unless the scale be a very large one. If, for instance, you endeavoured to make a 1/10 scale model, your model petrol motor would be compelled to have eight cylinders, each 0·52 bore, and your magneto of such size as easily to pass through a ring half an inch in diameter. Such a model could not possibly work.[1]
Note.—Readers will find in the "Model Engineer" of June 16, 1910, some really very fine working drawings of a prize-winning Antoinette monoplane model.
§ 2. Again, although the motor constitutes the chief, it is by no means the sole difficulty in scale model aeroplane building. To reproduce to scale at scale weight, or indeed anything approaching it, all the necessary—in the case of a full-sized machine—framework is not possible in a less than 1/5 scale.
§ 3. Special difficulties occur in the case of any prototype taken. For instance, in the case of model Blériots it is extremely difficult to get the centre of gravity sufficiently forward.
§ 4. Scale models of actual flying machines that will fly mean models at least 10 or 12 feet across, and every other dimension in like proportion; and it must always be carefully borne in mind that the smaller the scale the greater the difficulties, but not in the same proportion—it would not be twice as difficult to build a ¼-in. scale model as a ½-in., but four, five or six times as difficult.
§ 5. Now, the first requirement of a model aeroplane, or flying machine, is that it shall FLY.