It is very important that the frame should be properly braced to withstand the strain brought upon it. In the glider this bracing is less important, but the action of the motor changes the situation. The rapid movement of the propellers wracks the entire frame, and the impact on landing is naturally greater when the weight is increased. A thin copper wire, No. 32, 34, or 36, should be used, which will be found strong and flexible, while adding little to the weight. After constructing your aëroplane go over it carefully and cut away the wood wherever it may be lightened, and then strengthen it by bracing. Wherever a joint may be strengthened or a strut or a plane be made more rigid by bracing, do not spare the wire.
The accompanying drawing, with the photographs of models, will indicate how these braces may best be applied. To begin with, braces should be run, wherever possible, from the corners of the planes to the central frame and the skids. In the monoplane forms you will find it worth while to add posts or perpendiculars to the upper side of the frame and run wire braces diagonally to the ends of the planes. The extreme ends of the planes should also be connected.
Splitting the Cigar Box Cover to Build the Propeller.
No matter how carefully you have constructed your aëroplane, you will find the planes have a tendency to sag and become wrinkled. These braces give you the opportunity to pull them taut and hold them in this position. This is commonly called “tuning up” the aëroplane. It will be found convenient to fasten small rings to the ends of the braces whenever they may be slipped over the ends of the frame to save the trouble of winding. The more perfectly your aëroplane is tuned up, the greater will be its speed and distance qualities.
THE DIAGRAM OF A MONOPLANE.
Planes measure 20 inches by 8 inches. The motor base is 36 inches in length.
Plate C.
An excellent monoplane for the beginner is shown in drawing. (Plate C.) It is very simple and easily adjusted, and when well tuned up will fly upward of two hundred feet. The two planes are built separately in the proportion indicated. The frame consists of a central stick supported by triangular skids. An ordinary hat-pin run through the supports near the ground serves as an axle for wooden disks or wheels. The front skids are made somewhat higher to give the front planes the proper angle of elevation.
The bracing of the planes is simple but effective, and should be copied carefully, particularly the double bracing in the rear, using ordinary wire for the purpose. A double support is used for the axle of the propeller, an excellent idea, which keeps the shaft rigidly in place. It is formed by fastening two blocks drilled to hold the axle to the bottom of the main frame. The planes are held taut by wires running from the corners to a post at the middle of the plane. The front plane is hinged at its rear edge, and may be tilted by pulling back a piece of whalebone fastened at its center, which is tacked to the top of the frame. The rudder turns on a triangular frame attached to the top of the rear plane. A string passes through the rear end of the rudder to the rear edge of the plane, forming a triangle, which makes it possible to adjust the rudder-plane and fix it rigidly in position.
After you have built one or two models you will find yourself confronted by a bewildering number of schemes for constructing new forms. It will be found a very simple matter to use stiff wire for many parts of your model instead of wood or reed. In building rounded planes the wire will be a convenience. The wire may be attached to the wooden frame by embedding it in the wood and binding it fast. And, by the way, you can get a surprising effect by painting your wooden frame with silver paint, as the Wrights do. To all appearance you will have an aluminium frame.