 The SPAD S.XIII fighter, while appearing to be a two bay biplane, has only one bay, but has the midpoints of the rigging braced with additional struts; however, these are not structurally contiguous from top to bottom wing.The Sopwith 1½ Strutter has a W shape cabane, however as it does not connect the wings to each other, it does not add to the number of bays.Large transport and bombing biplanes often needed still more bays to provide sufficient strength.