How to Make a Model Old-Four Monoplane
By RALPH M. BROWN
The old-four monoplane model, made famous by its wonderful flights, is one of the most graceful that has been built. Its large size and slow, even glide make it a much more desirable flier than the ordinary dartlike model. It gives one a true insight into the phenomena of heavier-than-air flight. This machine, when complete, should weigh 9 oz. and fly 1,200 ft., rising from the ground under its own power and landing lightly. Its construction is simple, and with careful reference to the sketches, an exact reproduction may be made.
For the motor bases, A, [Fig. 1], secure two spruce sticks, each 48 in. long, ³⁄₈ in. wide, and ¹⁄₄ in. thick, and fasten a wire hook on one end of each stick with thread wound around after giving it a coat of glue. These hooks are to hold one end of the rubber bands that act as the motive power, and are designated by the letter B. At the opposite ends of the sticks, at C, bearings are provided, which consist of blocks of wood, each 1 in. long, 1 in. wide, and ³⁄₈ in. thick. These are also bound in place with thread after gluing them. Holes are drilled through the blocks lengthwise and then lined with bushings made of brass tubing, ¹⁄₁₆ in. in inside diameter. The two motor bases A are connected with four cross sticks, D, each 9 in. long and ³⁄₁₆ in. square. These are bound and glued on the under side, one near each end and the others equidistant each from the other and from the nearest end stick. The front bumper E is made of round rattan, ¹⁄₈ in. in diameter.
The Mechanical Bird will Run About Five Feet on the Ground and Then Rise and Fly
The alighting gear is next in order of construction. This is made as shown entirely of bamboo, ³⁄₁₆ in. square. The pieces marked F are 11 in. long; G, 9¹⁄₂ in. long, and the cross bar H, 11 in. long. At the rear, the pieces J are 13 in. long; K, 4¹⁄₂ in. long, and the cross piece L, 11 in. long. The distance between the points M and N, [Fig. 2], is 6 in., and between O and P, 9 in. The bamboo is easily curved by wetting and holding it for an instant in the flame of a candle. It will hold its shape just as soon as it becomes cold. The wheels are made of tin, 1¹⁄₂ in. in diameter, borrowed from a toy automobile. The axles are made from wire, ¹⁄₁₆ in. in diameter.
The wing spars Q are made of spruce, ³⁄₁₆ in. wide and ¹⁄₄ in. thick. Those for the front are 30 in. long, and for the rear, 36 in. long. The ribs R are made of bamboo pieces, ¹⁄₁₆ in. square, 5 in. long for the front plane, and 6 in. for the rear. These are bound and glued on top of the spars, 3 in. apart. They are given a slight upward curve. The round ends are made of ¹⁄₁₆-in. rattan.
Fig. 1
The Motor Base is Made of Two Spruce Sticks Joined Together with Four Cross Sticks, Bound and Glued to the Under Side