The Second Boys' Book of Model Aeroplanes

by Francis A. Collins

It will be found an easy matter to obtain long, graceful glides from this model from the first. By launching it upward, it may rise to a considerable height. When you have caught the trick of launching your glider with sufficient force, try a spectacular flight. Set your forward plane at an angle by inserting a block of wood between the stick. In the case of metal planes, bend up the front edge.

A very slight upward elevation will answer. Gradually increase this angle until the model sweeps upward and turns on itself. You will soon be able to make the glider describe a complete circle or loop the loop twice before landing. When traveling at such a high rate of speed, your glider is likely to be dangerous and might inflict a bad cut, and the flight should only be attempted where one has plenty of room.

These flights may be still further varied by adjusting the rear edge of the vertical plane or rudder. By turning the rudder to the right, for instance, the glider may be made to travel to the right or the direction may be reversed. In this way the glider may be made to describe a complete horizontal circle or several circles. By launching the glider upward with this adjustment, it may be made to fly in a graceful spiral.

The success of a glider depends more upon its modeling and finish of its planes than in the case of the model aeroplane. It must gain as much support as possible from the air, since it has no motive power to keep it aloft. Its head resistance must also be cut down. The ordinary cloth-covered planes, which serve well enough for an ordinary model aeroplane, will not carry a glider far. The planes must, therefore, be of metal or wood, or when built-up planes are used they must be of the most careful workmanship.

The simplest form of glider, excepting, of course, the paper model, is made entirely of wood. A glider two feet in length will be found a good size to experiment with. The model should be much heavier than an aeroplane so that one need not take the care in its construction to reduce weight which may make the construction of a model tedious. A glider of this size may weigh upward of one pound. Under favorable conditions, it will glide for two hundred feet, when launched from the hand, while if it is thrown from an elevation, an upper window or a hill top, it may travel considerably further.

Select a stout stick for your base, one inch square and two feet in length. The main plane should measure fifteen inches in width by six in depth, and the smaller plane ten inches by four inches. A thin board about three-sixteenths of an inch thick may be used for the planes.

The front corners should be slightly rounded, and the rear edges cut sharply away. These planes may be flexed by steaming. Hold the section to be bent over the spout of a tea kettle until the wood is soft and pliable enough to bend. If it does not soften sufficiently, immerse the wood in boiling water. The plane should be flexed slightly upward just back of the forward edge. A good curve may be obtained by heating the under surface over a flame.

To hold it in position until it has dried and assumed shape, bend it over a stick laid on a board and fasten the plane down by driving brads around the edges and bending them over to keep it down. Leave it in this position until it is dry and hard.

Your glider will fly better with a vertical rudder, as in the case of the paper models. The rudder should be cut from a thin board of the same material about six inches square. Round off one corner and plane or sandpaper this front edge, which will be the entering edge. The entering edges of the front plane should be prepared in the same way to reduce the head resistance as much as possible. Nail this rudder to the side of the stick directly beneath the rear or larger plane. It will be still better if you mortise it neatly into the center of the stick.

The glider is thrown with the smaller end forward. For the trial flight, mount the smaller plane at the extreme forward end and then move it backward as you test it out, until the glider moves on an even keel. To launch the glider, grasp the central stick from beneath at the point where it balances, and throw it forward with all your might. Since it travels at a much higher speed than a power-driven model aeroplane, it requires much less supporting surface, while the planes may be spaced much further apart.