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 an aft tailskid. It could also operate as a floatplane on single-step, crossbraced 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 there as part of the British Empire Trade Exhibition 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 arrestor hooks. Experiments with the first of this batch, refitted with swept upper and lower wings, led 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 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 reorganised 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