1. Propellers carved out of solid and laminated blocks.
2. Metal propellers with curved or twisted surfaces.
3. Built up propellers. In this type a small block is used as a hub, and the wood or metal fans are projected out from this. The fans are attached on the diagonal.
4. Propellers made of pressed wood veneer. These are excellent, but require more skill and more apparatus to make.
Figs. 244-251. [↑]
The carved out propeller is the one most generally used and is not only a good exercise in modeling with a knife, but is a good serviceable kind. There are a number of types of propellers, named mostly by men who have designed them. For simplicity in laying out and carving, I like the Langley type. A rectangle is made of wood, say ¾” × 1½” × 6”. [Fig. 244]. Draw the diagonals, as in [Fig. 245]. With a radius of ¼”, and center at the intersection of the diagonals, draw a half-inch circle. Connect the diagonal lines and the circumference of the circle, as in [Fig. 246], and cut down to the outline as it now appears. The blank is now as shown in [Fig. 247]. We will now take off two big slices, not all in one cut, but in several. [Fig. 248] has the dotted lines showing the depth to be cut, and [Fig. 249] shows these same parts cut away. Now cut away x and x until the blade is curved back to edges z and z. The cut away portions will be as in [Fig. 250]. Cut the opposite side the same way, and cut away the back corners a little, giving the result as shown in [Fig. 251]. Sandpaper well and shellac. Drill hole carefully for the propeller shaft.
