The blades forming the fan are of half-inch wood, one V-shaped piece and two end slats cut as shown in the illustration. They are all held in position by the two rails that extend back from the pinion block and two that are set at right angles to them, and which hold the upper and lower edge blades.
This wheel may be placed at the top of a post two or three inches square or round, in which a half-inch iron rod or long pin has been driven, leaving about six or eight inches of it projecting above the top of the post. On this the block turns as the wind acts on the fan-tail.
A Pumping Windmill
A simple wheel, with spokes and sails, that is commonly employed on canal-boats and barges, and in a small way for raising water in a suction-pump, is shown in the illustration of a pumping windmill. Fig. 18.
It consists of a hub, six spokes, a fan-tail, and a trunk or upright to which the wheel is attached. The hub is a hexagon of six inches and six inches long, so that one spoke can be driven into a hole made in each side, as shown in Fig. 19. The spokes are three feet long, three by one inch and a half at the hub end, and one by one inch and a half at the outer end. They are driven snugly into holes in the hub three inches long and one inch and a half wide, and pinned to hold them in place.
The hub should be made of hard wood, and it would be well to have a blacksmith put a thin iron band around each end to prevent it from splitting. The holes may be cut with a mortise chisel and mallet, and care must be taken to shape them evenly, so that the spokes will line properly.
Triangular pieces of twilled muslin sheeting are tacked to the face of each spoke, and the loose corner of each is caught to the next spoke end with a rope and snap. This makes an outlet between the leech and spoke of each space between spokes for the wind to pass through, thereby causing the wheel to revolve.
The wheel is held in place to the head of the supporting post by a shaft which passes through the hub and is bolted fast at the front of it with a nut. A blacksmith will make this shaft, as it is somewhat beyond a boy’s ability unless he has had some experience in blacksmithing. It should be shaped as shown in Fig. 20.
The shaft is an inch square where it passes through the hub, and at the front end it is threaded and provided with a nut and washer. At the end of the square part, A, where the rear of the hub will stop, a shoulder, B, should be welded on to hold the hub in the proper place.