Hawker Nimrod The Hawker Nimrod was 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 / 6 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 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 , 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 Hawker ' s familiar curved shape , with a deep , wide chord , unbalanced rudder extending to the keel . The Nimrod had a conventional undercarriage of cross axle type on trailing struts , with compression legs almost at right angles to the fuselage and a tailskid aft . It could also operate as a floatplane on single step , cross braced floats mounted on N - form struts . With floats fitted the maximum speed was reduced by 47 mph ( 76 km / h ) , or 25 % . The Kestrel engine ' s bath type radiator was mounted on the lower fuselage between the undercarriage struts . After testing in 1930 , the prototype went with HMS " Eagle " to Buenos Aires , flying as part of the British Empire Trade Exhibition there in March 1931 . It returned to RAF Martlesham Heath for final testing . A production order for 35 was placed and the first of these flew on 31 October 1931 . In the following year , another contract for a further 19 Nimrod Is was signed . With a top speed of 193 mph ( 311 km / h ) it was only marginally slower than its land - based counterpart , the Hawker Fury . A headrest fairing was added retrospectively to the Nimrod Is , to ease pilot strain during catapult launches . Aircraft from the later production batch were fitted with arrester hook s . Experiments with the first of this batch , refitted with swept upper and lower wings , lead to the Nimrod II . As well as the swept wings , this had at first an uprated Kestrel II engine . Later , these were replaced with Kestrel Vs . Later Nimrod IIs had a slight increase in rudder area to improve spin recovery of inverted , float equipped aircraft . Originally it was intended that the Nimrod II should have a corrosion resistant stainless steel , but only three of these were built . The first of 27 / 33 Nimrod IIs was delivered in March 1933 . Operational history . The first production Nimrod Is entered service in 1932 with No . 408 Flight on . Others went to No . s 402 and 409 Flights soon after . Fleet Air Arm flights were reorganized into Squadrons early in 1933 , with the Nimrods joining No . s 801 , 802 and 803 Squadrons RAF . The Nimrod II followed in September 1934 . Few Nimrods were exported , though one aircraft was supplied to Japan and one to Portugal . Two went to Denmark , where they were known as the " Nimrodderne " . They were intended as pattern aircraft for proposed licence building and were essentially Nimrod Is , though powered by Kestrel IIIS engines . One , unusually , was fitted with spats . The Nimrod had been replaced by more modern designs such as the Sea Gladiator by May 1939 , before the start of World War II . Survivors . Two Nimrods survive , both airworthy and both based at the Imperial War Museum ' s Duxford Aerodrome , Cambridgeshire . Both served with No . 802 Squadron Nimrod I ; Nimrod II ;