Читать книгу Building and Flying an Aeroplane. A practical handbook covering the design, construction, and operation of aeroplanes and gliders онлайн

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Main Frame. The main frame of the model monoplane consists of two strips A of spruce, each 28 inches long, and measuring in cross section 1/4 by 3/8 of an inch. As shown in Fig. 1, the two strips are tied together at the front with strong thread and are then glued, the glue being spread over and between the windings of the thread, Figs. 1 and 2. The rear ends of these strips are spread apart 4 1/4 inches to form a stout triangular frame, and are tied together by cross bars of bamboo B and C which are secured to the main strips A by strong thread and glue.

Fig. 2. Details of Forward Skids of Aeroplane Model

Propellers. The propellers D are two in number and are carried by the two long strips A. Each propeller is 5 inches in diameter, and is whittled out of a single block of white pine. The propellers have a pitch of about 10 inches. After the whittling is done they are sandpapered and coated with varnish. The thickness of the wood at the hub E₂, Fig. 3, of the propeller should be about 5/8 inch. At the rear ends of the strips A, bearing blocks E₁ are secured. These bearing blocks are simply small pieces of wood projecting about 5/8 inch laterally from the strips A. They are drilled to receive a small metal tube T₂ (steel, brass, or copper), through which tube the propeller shaft T₁ passes.