1. Box-girder of four longerons or rails, with cross-struts and wire bracing ([Fig. 65]).
Fig. 65.—Arrangement of fuselage members.
2. Tail portion of longerons, struts and wiring; in the front portion the wire bracing is dispensed with, being replaced by diagonal wood bracing, to which is screwed either three-ply or sheet aluminium alloy ([Fig. 66]).
3. In this case wire bracing is entirely dispensed with, the four, and occasionally six, longitudinals being connected together by cross struts or formers cut to the required shape, the whole body being covered with three-ply.
4. Laminated or monocoque type, formed by layers of wood and fabric, crossed alternately and glued together.
Fig. 66.—Arrangement of fuselage members.
Box-Girder Type.
Dealing with each type in greater detail, and in order of classification, the details and methods of manufacture of type 1 may be considered. The longerons are usually of ash or hickory, although latterly silver spruce has come into use for this purpose, this being due to the desire to reduce weight to the absolute minimum.