The Bow Hooks support the bow ends of the rubber motor, and are made upon the ends of a piece of heavy piano-wire bent V-shaped to fit over the ends of sticks A ([Fig. 39]). Bind the wire to the sticks with thread, coating the thread with glue to make it hold fast ([Fig. 37]).
The Main Plane has a framework built as shown in [Fig. 40], with the front or entering-edge, and the rear or following-edge, made of sticks of white pine or other light-weight wood, and the ribs and tips on the ends made of No. 16 gauge aluminum wire. The ends of the frame sticks are cut away on their outer edge, to receive the ends of the wire forming the tips, and the ends of these wires, and the laps of the wire ribs, are bound in position with thread, and the thread then coated with glue to hold it in position.
The Elevator, or front plane, has a framework made as shown in [Fig. 41]. Its entering-edge is a stick, and its following-edge, ribs, and end tips, are made of No. 16 gauge aluminum wire. You will notice by [Fig. 41] that the center ribs cross the following-edge of the frame and are bent up in the form of a flat loop. This loop rests against the under side of the fuselage, and gives the elevator its proper angle for stability ([Fig. 36]). The tips are bent up to add stability.
The frames of the main plane and elevator are covered with china-silk, which may either be sewed or glued in place, and this is given a thin coat of shellac to make it air-tight and taut. The covering must be put on smoothly to reduce to a minimum what is known as skin resistance—the resistance that the plane makes to the air while passing through it.
The main plane and elevator are held to the fuselage by means of rubber-bands slipped beneath them and over the fuselage, and unlike the planes of the majority of models, are fastened to the under side of the fuselage. [Figure 36] shows the approximate position of the elevator. That of the main plane will vary under different air conditions, sometimes being placed over the separator C, and at other times closer to separator B than is shown in [Fig. 35]. Therefore, you must adjust your plane and elevator—this operation is known as tuning—to suit the condition of the atmosphere, until you find the positions where they will give the machine the greatest stability. A great factor in the successful flight of a model aeroplane lies in properly tuning the planes, both laterally and longitudinally, and of course the planes must balance at their centers, in order to make the machine balance properly.
Fig. 40.—Detail of the Main Plane Framework of the Wells Model.
Fig. 41.—Detail of the Elevator Framework.
Fig. 42.—Detail of Fin.
The Fin directly over the center of the elevator ([Figs. 34] and [36]) is provided for stability, and may be used as a rudder by turning it slightly to one side or the other. It is made of No. 34 gauge sheet aluminum, cut to the form shown in [Fig. 42]. Its vertical edge is bent around a piece of heavy wire, as shown in the plan detail of [Fig. 42], and the lower end of the wire is fastened upright between the bow ends of sticks A.