Notwithstanding the work already in progress on the big Handley Page O/100 heavy bomber, the Admiralty issued a requirement in mid-1915 for a smaller, single-engine, land-based bomber, possessing a range of about 700 miles, capable of lifting 800 lb of bombs with a crew of two and a speed of 80 mph. Shorts had been quickest to produce a contender to this requirement, and accordingly received production orders. However, both Grahame-White and J Samuel White also produced prototypes, although none of the three aircraft tendered fully satisfied the performance demands.

 

Design of the big Grahame-White Type 18 (G.W.18) occupied much of the summer and autumn of 1915 and centred on the choice of a single 285hp Sunbeam Maori 12-cylinder water-cooled engine, the bearers being extensions of the upper fuselage longerons. The wooden box girder, which constituted the fuselage primary structure, carried formers to fair the fuselage to oval section. The three-bay wings were built up on twin spruce spars with closely-spaced ribs and four pairs of interplane struts, the inboard pairs (which replaced conventional centre section struts) providing the rigidity required for the wing-folding attachments.

 

The wings, of parallel chord and equal span, featured ailerons on upper and lower surfaces, and the twin mainwheel undercarriage with V-struts and spreader bar was augmented by a small balancing nosewheel. Bomb racks, capable of supporting two 230 lb or four 112 lb bombs were attached under the lower wings immediately outboard of the fold axis. A large fuel tank was located forward of the pilot's cockpit, and the gunner/observer was evidently provided with a Lewis gun on what appears to be a ring mounting.

 

The Type 18 was probably completed in the spring or summer of 1916, by which time the Handley Page O/100 was confounding its critics by demonstrating the practicality of large bombing aeroplanes and, of the three bomber designs tendered, only the Short Bomber entered production, while the Wight Bomber was developed further by conversion into a floatplane, for which production orders were placed. By contrast, work was evidently halted on the Grahame-White Type 18 soon after completion, and no record of flight performance has been traced.