AN EFFICIENT SINGLE STICKER. A very light single-stick model may be built of bamboo rods, which will stand an immense amount of wear and tear. It consists of a single longitudinal member with crossed pieces at either end, braced against the central stick to withstand the pull of the motor. Select a bamboo stick about half an inch in diameter and three feet long. An old fish pole will answer. The cross pieces at the ends should be of some light, strong wood, such as poplar, whitewood or ash, since they must be mortised and drilled, and the bamboo is likely to split under the operation. Use a three-eighth-inch strip, cutting a piece ten inches long for the rear and another six inches in length for the front of the base. Fasten these rigidly in position at right angles by mortising, glueing and tying in position. Run diagonal pieces cut from quarter-inch strips from the ends of both cross sticks to the central frame. Be careful not to cut away the wood in mortising it, for a bad break is likely to occur at the weakened point. Build two serviceable planes. The larger one, which should be carried in the rear, should measure about twenty-four inches by eight, and the front plane twelve by four inches. Since your frame is very light and strong, there is no need to economize weight. By carrying the braces running from the cross sticks well out on the stick, you can provide a broad support for the planes. Tie the wings on the motor base with strands of rubber. In landing they will then give enough to save a bad smash. [Illustration: One of the best models of the year, built by John Caresi] [Illustration: An excellent model, showing careful attention to details. Built by L. V. Brooks] The propellers are mounted by passing the axles through holes drilled through the center of the rear stick about one inch from the ends. The rubber strands may be simply passed around the front stick and tied in position, or may be looped about a hook inserted in the stick. Use a fairly high pitch propeller, since the base will carry a powerful motor. Select some simple form of skid, for the model will be comparatively light, say within ten ounces. A ONE-PLANE MODEL. Interesting experiments have been made this season by altering the angle at which the main planes are set to the motor base. The theory of these designs is, of course, that the resistance offered by an entering angle is less than that of a straight edge. In some models, the main planes are carried backward until the rear tips are on a line with the propellers. The model is driven tail first by twin propellers. The planes are besides set at a slight dihedral angle so that the angle of incidence is greater at the ends.