Figs. 227, 228. [↑]
A Good Model. A simple and effective model is shown in [Fig. 226]. Lay out a light framework, as shown in [Fig. 227]. It is the combination of a tailless kite and a triangular box-kite. Three long sticks, a, b, c, are used for the triangular portion and three cross-sticks, d, e, f, are for the wing supports. A vertical post, g, about ¼” × ⅜” × 8” is used in the center of the rear (the wide part), to stiffen the frame and give an anchorage for the propeller shaft. Four light braces, h, i, j, and k, make it possible to use lighter material than one would suspect for the entire framework. In a model 3’ long, a, b, and c, need not be larger than 3/16” square, but there must be no split or uneven places in a stick so small. The braces ⅛” × 3/16” would be plenty large. The two upper pieces, b, c, should be flattened on the inside of the front end so as to make them join together, terminating in a point. The lower spine, a, should be flattened on the upper side for the same reason. All three should be glued and lashed together with linen thread. A triangular block, l, should be placed about 4” back from the front end with a strong cup-hook screwed in the side toward the rear, on which the ring of the rubber motor is attached. The block, l, must be well secured to the triangular framework with glue and thread. The cross-piece, d, is 30” long and is bowed upward as is shown by [Fig. 228]. Piece e is 24” long, 5” in front of d, and both are 3/16” × ¼”. ⅛” × 3/16” will be heavy enough for f, and this should be bowed much more than d, and e. It will be necessary to steam this piece a little. Chinese rice tissue will be good for covering. Cover the underside of the two planes, and the underside of the triangular framework which is similar to the hull of a boat, and acts as a keel. Test out well as a glider. Put more and less curve to bows, and experiment for poise of model. A small piece of tin on each side of the support will give a good bearing for the propeller shaft. The hole in the wood should be a trifle larger than the shaft. String is run from both ends of d and e to the front end of the framework but is not attached to f.
Fig. 229. [↑]
When long models are made with single spine, they need some simple wire supports to prevent springing up or down, and from left to right. [Fig. 229] is 4’ long and the spine is only ¼” × ¼” at the small end ¼” × ⅜” at the larger end. A little 1/16” oak veneer cut in strips 3/16” wide would be very serviceable for the purpose of support in trussing the long spine. It should stand 2” above and below the spine, and the same amount for the right and left brace, [Fig. 230]. The wires for these should extend about a foot on each side of these posts, and be attached to the spine with little tin anchors, as shown in [Fig. 230], a.
Figs. 230, 231, 232. [↑]
The propeller shaft bearing is of metal and is lashed to the cross-piece, called the base, [Fig. 231]. It is not necessary to have two points of bearing for the shaft. The metal is about 1/16” × ¼” × 1”, bent as in [Fig. 232], and lashed to the under side of the base. The planes are similar to those in the next model. 1” × 1½” × 7½” propeller blanks are used. Try about fourteen strands of 1/16” string rubber for each motor, seven rounds.