The tank is guided by the pilot wheel, shown in [Fig. 1]. The sheet-metal armor, with its turret, is fitted over the mechanism, and can be removed quickly. It bears on angles bent up, as detailed in [Fig. 2], to fit on the ends of the wooden center crosspiece of the main frame, and is held by removable pins at the ends of this frame. While the rubber motor is easy to make and install, the range of the tank can be increased by using a strong spring motor, the construction otherwise being similar.
The construction is best begun by making the wooden frame which supports the armor. The perspective sketch, [Fig. 1], used in connection with the working and detailed drawings, will aid in making the latter clear. Make the frame C, as detailed in [Figs. 5 and 6], ³⁄₈ by 1³⁄₄ by 11 in. long, with an opening cut in the center, 1 in. wide, 1 in. from the rear, and 1¹⁄₄ in. from the front end. Make the crosspiece D ³⁄₈ by 1³⁄₄ by 5⁷⁄₈ in. long; the gun support E, as detailed in [Fig. 4], ³⁄₈ by 1⁵⁄₁₆ by 6¹⁄₄ in. long. Shape the support E as shown. Fasten the frame C and the crosspiece D with screws, setting the piece D 5³⁄₄ in. from the front, and its left end 3 in. from the side of the frame, as shown in Fig. 5. This is important, as the fitting of the other parts depends on the position of these wooden supports.
| Fig. 3 | Fig. 4 |
| Fig. 1 | |
| Fig. 2 | |
Perspective Sketch, Showing the Arrangement of the Parts, with the Armor and the Tractor Bands Removed, and Details of the Gun Mechanism and the Armor
The drive-wheel axles are carried in sheet-metal hangers, F, shown in [Figs. 1] and [5], and detailed in [Fig. 6]. These hangers also carry bearing wheels, G, Fig. 1, which are held between the hanger F and a metal angle, as detailed at G, Fig. 6. These wheels are cut on a broomstick, and mounted on nail axles. The metal for the hangers F is drilled as shown, and bent double at the ends to make a strong bearing for the drive-wheel axles. The upper portion is bent at a right angle and fits over the top surface at the end of the crosspiece D, and is fastened to it with small screws or nails. Cut the stock for the hangers 2 by 6³⁄₈ in. long.
Next make the sheet-metal support H, [Fig. 1], for the flywheel, the rim of which is wrapped with wire to give it added weight. Cut the stock, as detailed in [Fig. 6], 1³⁄₄ by 4³⁄₁₆ in. long, and notch it to form the spring arrangement, which holds the flywheel so that the belt will be tight. The other sheet-metal support may then be made also. Cut the stock for the front support J, for the rubber motor, 4¹⁄₈ by 3³⁄₄ in. long, and shape it as shown in the detail, Fig. 6. Make the support K from a piece of sheet metal, in general shape similar to that used for support H, the dimensions being made as required, and no spring arrangement being provided. Drill these metal fittings, as indicated, for the points of fastening, and mark the places for the holes in which shafts or axles run very carefully.
The driving mechanism can then be made, as shown in [Fig. 1], and detailed in [Figs. 5 and 6]. The driving shafts and their parts, as well as the pulleys, can be turned in a lathe, or made from spools, round rods, etc. Make the front axle L, and wheels, joined solidly, 5³⁄₄ in. over all, the grooved wheels being ³⁄₄ in. thick, and 1⁷⁄₁₆ in. in diameter. Wires are used as bearings for shafts for the driving axles. If the rear axle is turned in a lathe, it is cut down to the shape indicated, thinner at the middle, to provide a place for the cord connected to the rubber motor. The grooved pulley and the fluted drive wheel at the winding-key end, shown in Fig. 5, are then cut loose; the drive wheel on the other end is cut loose, forming three sections, mounted on the wire axle, one end of which is the winding key. Ratchet wheels, M, are fitted between the ends of the center section and the adjoining pieces, the ratchet wheels being nailed to the center section and soldered to the wire axle. Pawls, U, are fitted to the inside of the two end sections, as indicated in Fig. 1 and in Fig. 5. When the rubber motor is wound up on the drum, the tractor bands are gripped until it is desired to start the tank on its trip. Then the power is communicated from the drum, or center section of the axle, to the drive wheels by means of the ratchet wheels, acting on the pawls.
Mount the hangers F on the center crosspiece D, fitting the axles of the drive wheels into place. Make the weighted flywheel, and mount it on its shaft, as shown, lining it up with the pulley on the rear drive shaft. Fit the supports J and K into place, setting spools for the rubber-motor cord in place, on wire axles. Arrange the belt from the flywheel to the drive shaft, and connect the rubber bands for the rubber motor as shown. Fasten one end in the hook of support J, and pass the winding cord through the spools, and fix it to the drive shaft. The device can then be operated with the fluted drive wheels, bearing on strips of wood for tracks.
The tractor bands N are fitted over the drive wheels, as shown in [Fig. 6]. They are built up of canvas strips, on which wooden shoes are glued and sewed, as detailed in [Fig. 5]. The stitches which reinforce the gluing are taken in the order indicated by the numerals. The pilot wheel is 2 in. in diameter, and sharpened at its circumference. Make a metal shell, O, for it, as detailed in Fig. 6. Solder the shell to the double wire, which supports the wheel and gives it a spring tension to take obstructions nicely. The wire is fastened to the crosspiece D, as shown in Fig. 5.