Three-ply Fuselage.
The third system is typical of the method adopted for the series of German Albatross machines. There are few, if any, examples of its use in this country, although prior to the war a few constructors favoured its use, and one successful monoplane of note was so built. The writer is acquainted with one pioneer designer who very strongly believes in this form of construction, and certain later developments in the use of three-ply confirm this view. The advantages of this form of construction are: (1) quickness of production; (2) great strength in a vertical and horizontal direction; (3) the result of the longeron being shot through would not endanger the structure to the same extent as with a wire-braced system. Against this must be balanced the fact that: (1) it entails a considerable increase in weight; (2) is weak under a torsional strain, such as that produced by the combined actions of elevator and rudder; and (3) cannot be trued up in the event of distortion. Examples of this system in pre-war machines are afforded by the Martinsyde and Blackburn monoplanes, although the framework in both cases was so formed as to constitute a lattice girder. The tail portion of the Martinsyde was lightened by cutting away diamond-shaped pieces from each bay.
The formers of the Albatross are extremely simple. In the fore part they are cut from three-ply, while at the rear they are just simple frames composed of laths, reinforced where the longerons occur by three-ply stiffeners. There are six longerons, the two middle ones being fixed slightly more than halfway up each side, which are really longitudinal stringers to prevent the three-ply buckling between the points of attachment.