Prior to World War 2 (1939-1945), the British Air Ministry developed Specification F.9/35 in 1935 to seek out a new, all-modern "turret fighter" with a machine-gun-armed traversing turret as its primary armament. The type would succeed the obsolete line of Hawker "Demon" biplane aircraft then in service and led the storied concern of Hawker, and its legendary designer Sidney Camm, to develop the "Hotspur" around this requirement. However, the aircraft was not a success by any measure and just one flyable prototype was completed before work on the project ended. The contract instead fell to competitor Bolton Paul and their "Defiant" (detailed elsewhere on this site).
The Hotspur appeared at the same time that Hawker was developing its classic Hawker "Hurricane" single-seat, single-engine monoplane fighter. The turret fighter form also took on one engine as its primary propulsion system but sat a crew of two in tandem, the rear gunner in a separate turret enclosure over the aft dorsal spine of the aircraft. The turret was manufactured by Boulton Paul who also incorporated it into their equally-classic Defiant. The Hotspur took on some of the appearance of the Hurricane and sported relative clean lines and a conventional arrangement but was a direct offshoot of the Hawker "Henley", another of the company's flying products which only advanced its career as a target tug through 202 delivered examples.
The Boulton Paul Defiant was developed to the same specification and would find much greater success (over 1,000 units produced) than the Hotspur (single prototype), which labored through a lengthy and unspectacular development process. Work was underway as soon as 1936 and a first-flight, in prototype form, was recorded on June 14th, 1938 (a second contracted-for prototype was eventually cancelled). In comparison, the Defiant recorded its first-flight back on August 11th, 1937 giving the competing design quite the head start.
The Hawker Hotspur was completed with an overall length of 32.9 feet, a wingspan of 40.5 feet and a height of 31.9 feet. Empty weight was 5,800lb against an MTOW of 7,650lb and power was from a single Rolls-Royce Merlin II V-12 inline piston engine of 1,030 horsepower driving a three-bladed propeller unit at the nose. Maximum speed, as tested, reached 316 miles per hour and a service ceiling of 28,000 feet was possible.
In terms of proposed armament, the intended powered turret carried 4 x 7.7mm Browning machine guns which were operated by the rear gunner. The pilot managed a sole 7.7mm Vickers machine gun firing from a nose mounting but this weapon was fixed to fire forward only. There was no bomb-carrying capability built into the Hotspur.
The Hotspur became nothing more than an incomplete combat warplane prototype and even company interest waned as Hawker was fully committed to the much-needed Hurricane fighter for the war effort (and the subsequent Battle of Britain campaign). During what would become the Hotspur's final flight, a gliding test, the engine failed to restart and the pilot successfully crash-landed his aircraft. Though repairable, the Hotspur was not salvaged and was scrapped instead. Before its end, the Hotspur saw its Bolton Paul turret completely removed and the rear position reworked for a more traditional look to better serve testing other components. In this form it was used in evaluating various diving brakes and flaps into 1942 over Farnborough.