Biplane and Monoplane Compared: Full Details of the Two Blackburn Civil Aeroplanes Built to the Same Specification

THE biplane wings are braced in two bays, the top and bottom planes being of equal span and chord. The inner bays consist of a wide centre‐section system, the engine mountings being situated in the plane of the inner gap struts which are fitted at the centre‐section extremities. The top centre section is mounted above the fuselage on four steel tubular struts attached to fittings at the top corners of the rectangular section fuselage, the rear pair forming an inverted vee and the front pair a slightly wider angle. Streamline wire cross‐bracing is fitted between the front pair of struts and drag bracing between the two pairs. The bottom centre section, which consists of two separate units, is attached directly to the fuselage at the bottom corners and supported by sloping struts in the front bay only from the top fuselage fittings to their extremities. Double flying wires are used in the front bay and single cross‐bracing wires in the rear bay. The outer bays are braced normally as regards flying, landing and incidence bracing by single streamline wires. Frise type ailerons are fitted to top and bottom planes and connected on each side by inter‐aileron struts.