THE simplest form of heavier-than-air machine is the stiff card or letter which you may spin across the room. If you give it just the right twirl it will glide on a level for many feet. There are many ways besides of folding a sheet of stiff paper which will convert it into a surprisingly clever little airship. With a little practice these gliders may be made to fly ten or twenty times their own length, which would be a very creditable flight for the best aëroplane models.
There is no better way to begin the construction of a model aëroplane than by study and experiment with these paper ships. The most famous aëronauts of the day, the Wright brothers, Curtiss, Herring, and many others, have spent years working with gliders before attempting to build or fly an aëroplane. It is in this way that they discovered what form of wing would support the greatest weight, whether the passenger should stand up or lie down, how to place the propeller and the rudder, and hundreds of other details which have made possible the actual conquests of the air.
Following in their footsteps, or rather their flights, the amateur aëronaut should first build and fly only gliders or aëroplanes without means of self-propulsion. The simplest form of glider may be made by cutting a broad oval from a sheet of stiff letter-paper and creasing it down the middle. The experiment may be made more interesting, however, by cutting out the plane like the outstretched wings of a bird, as suggested in the accompanying illustration. Try as you may, this sheet will not fly. Now add a trifling weight to the front of the plane. This may be done by fastening one or more paper clips to the edge, pasting a match or a toothpick, or by dropping a little tallow or sealing-wax.
At first you will underestimate the weight your little airship will carry. Add more weight in the same way, and test its gliding powers until the little airship will glide gracefully across the floor. Keep the length of these models under six inches. If you increase it beyond this, the model loses steadiness and flutters about ineffectively.
An interesting model may be made by folding a sheet of stiff paper in an arrow-like form. The idea is to form a series of planes which will support the weight of the tiny craft and, at the same time, enable it to fly or dart in a straight line. It will be found that the vertical surfaces lend stability and keep the ship moving in a straight line. You will soon learn, in this way, more of the principles of aëroplane construction than mere reading from books can teach you. Be careful, meanwhile, to remember just how you have launched the various forms of models, whether you have thrown them with an upward or downward motion, and how hard a push you have given them. The skill you acquire in this way will be valuable later on when you come to launch your regular model aëroplane.
Dowel Strips of Different Sizes.
We are now ready to begin the construction of the frames of aëroplane models. The first model will be merely a glider. The frame and wings or planes of an aëroplane are built much the same as a kite. The idea in all such work is to combine the greatest possible strength or stability with extreme lightness. Remember, however, that the aëroplane during its flights is racked and shaken by its motor, and is likely to land with a bump. The materials used must be stronger than in the case of an ordinary kite, the joints more securely formed, and the entire structure braced in every possible way.
The best materials for constructing these gliders or aëroplanes are very cheap and easily obtained. At almost any hardware-store you will find a variety of “dowel-sticks,” which seem especially made for this work. They are smooth, round sticks a yard in length and of a variety of diameter. The sticks three sixteenths of an inch in diameter will be found most serviceable, while the larger sticks are just the thing for the backbones of your aëroplane. These sticks will not split at the ends and may be readily worked. They cost one cent apiece.
Some boys find that the reed or cane suits their purpose better than the dowel-sticks, since it is more flexible and a trifle lighter. The cane is easy to work when you wish to build planes with curved lines. It can be readily shaped to any desired form by first wetting it and allowing it to dry after working. Care must be taken in using it, since the ends are likely to split. Bundles of this cane may be bought at most hardware-stores or in department-stores. Enough material for constructing a model may be bought for a few cents.