The Hawker Nimrod is a British carrier-based single-engine, single-seat biplane fighter aircraft built in the early 1930s by Hawker Aircraft. Design and development In 1926 the Air Ministry specification N.21/26 was intended to produce a successor to the Fairey Flycatcher, then in its fourth year of Naval service. By the time it was replaced by the Nimrod in 1932, the Flycatcher had become so obsolete in terms of its speed that RAF officers who flew it often joked that a sprightly fly might actually give the aircraft a run for its money. None of the aircraft designed to this specification were selected for production after trials in 1928, but the radial-engined Hawker Hoopoe, not actually designed to N.21/26, was considered promising enough to be further developed. Despite the Navy's traditional preference for radial engines, Hawker's designer Sydney Camm was convinced by his experience with the landplane Hawker Fury that the future for shipborne aircraft also lay with inline engines and began such a design, powered by a Rolls-Royce Kestrel. Before it was completed Air Ministry specification 16/30 was written around it. It flew under the initial name "Norn" early in 1930, received a production contract and was renamed Nimrod. The Nimrod had an overall similarity to the Fury: it was a single-seater biplane with an open cockpit, fixed undercarriage and guns firing through the propeller. Its unswept, constant chord, round-tipped wings had an unequal span and strong stagger, the latter partly to enhance the pilot's view. It was a single bay biplane braced with outward-leaning N-form interplane struts, with the upper plane held a little above the upper fuselage by cabane struts. The fabric-covered wings had metal spars and spruce ribs and carried balanced ailerons only on the upper wings. The Nimrod's fuselage was a Warren girder structure of tubular steel and aluminium, surrounded by stringers which defined its oval cross section. The Rolls-Royce F.9MS engine, later renamed the Kestrel IIMS was closely cowled in aluminium and the rest of the fuselage fabric covered. As with the Fury, the upper fuselage line was highest at the cockpit, placed between the trailing edges of the upper and lower planes. Its twin machine guns were mounted in the upper fuselage between pilot and engine, firing through the propeller using the standard interrupter gear. The tailplane was mounted on top of the fuselage and carried split horn balanced elevators; the vertical tail had