The Second Boys' Book of Model Aeroplanes

by Francis A. Collins

Your propeller should measure four inches in diameter. A propeller cut from a blank one by four inches and one-half of an inch thick will give a good pitch. Either a propeller of wood or metal such as has already been described will answer. The propeller should be mounted upon an axle and adjusted to the bearings, and the hook after passing through the bearings in the support turned into a hook for the rubber strands. Select from the detailed instructions the method which appeals to you. Be sure that the propeller spins smoothly. It should be so delicately adjusted that it will turn literally at a breath.

Before stringing the rubber strands between the two hooks of your motor, be sure that the hooks are bent back, so that the strands will be in a line with the bands. The bearings should be carefully oiled. In flying out of doors, there is danger of getting fine sand or dirt in the bearings which, of course, greatly increases the friction. Try out your motor with four strands of rubber one-eighth of an inch square. The rubber sold for one-eighth inch is often a trifle under this measurement. The propeller should, of course, be mounted with the shorter or curved edge forward. In winding your motor, never turn it after the second row of double knots begin to appear, and do not keep your propeller wound a second more than is necessary before a flight.

An American Fleming Williams built by C. McQueen

One of the earlier models built by Cecil Peoli

For a model of this size, wooden planes are entirely practical and very simple to construct. Much depends upon the modeling of the planes and the smoothness of both of their surfaces. For the planes you will need two thin boards, one eight by two inches and another four by two inches, each one-eighth of an inch thick. Select a wood such as poplar or spruce, which will not split easily. The ends of the planes should be rounded in front and cut sharply away at the rear edge, as described elsewhere. If the wood will stand reduction without breaking, plane or sandpaper away the surfaces until they are about one-sixteenth of an inch thick.

The planes may be flexed by steaming, but there is a still simpler method. Paint your planes with a thin glue or varnish, and while they are still wet and pliable, bend them to the desired shape. To shape them, procure a strip of wood one-quarter of an inch square, tack it to a board and bend the planes over it, and fasten them in position with brads driven about the edges and bent over to hold it down. The stick should be placed parallel to the entering edge and one-half an inch back of the line. This will give you planes flexed with a dipping edge. Later you will probably want to experiment by changing this curve, which is very easily done by bending over a stick of different size and altering its position.

The model is driven by the propeller with the small plane forward. Attach the planes to the stick with the curved or entering edge forward by tying them with a rubber band. This will hold them in position and allow them to give when they fall. Slip the planes back and forth until the proper position has been found. A small block of wood may be inserted between the planes and the stick to raise the wing to the desired elevation. Practise throwing the model as a glider until it sails across the room on an even keel, when the motor may be installed.

Directional stability may be gained by adding a vertical rudder. It may be made from a thin board similar to that used in the planes. Cut a piece two inches square and round off the corners, and shave to a knife edge. Attach this, curved edge downward, to the edge of the stick directly beneath the rear plane, taking care that the motor does not touch it. To complete the model, attach skids to the under surface at the front and rear. These should be of light reed, cane or bamboo, glued to the main frame and curved downward and backward like runners.