page_title: Nieuport Nighthawk
section_title: Gloster variants
hierarchical_section_title: Nieuport Nighthawk / Operational history / Gloster variants
caption_attribution_description: English: The Gloster Mars I G-EAXZ , the only Mk I. Later renamed Gloster I. Set a British speed record of 196 mph (315 km/h) This December 1921 image shows it with twin Hamblin radiators for its Napier Lion II engine. Late used on floats as J7284 to train Schneider Trophy pilots for the 1925 and 1927 contests.
context_page_description: The Nieuport Nighthawk was a British fighter aircraft developed by the Nieuport & General Aircraft company for the Royal Air Force towards the end of the First World War. Although ordered into production before the aircraft first flew, it did not enter large scale service with the RAF owing to unreliable engines. Re-engined aircraft did see service in Greece, serving from 1923 to 1938.
context_section_description: Nieuport & General closed down in August 1920, and the rights to the Nighthawk were purchased by the Gloster Aircraft Company, who also hired Folland as chief designer. Gloster proceeded to produce a number of derivatives of the Nighthawk, using stocks of Nighthawk components acquired by the company from the cancelled production run, calling them the Gloster Mars.
  The first of these derivatives was the Mars I (or Bamel) racing aircraft. Powered by a 450 hp (336 kW) Napier Lion II engine, this used a Nighthawk undercarriage, rear fuselage and tail with new, single-bay wings, first flying on 20 June 1921. It was modified progressively to reduce drag and increase speed, with the wing area at one stage being reduced from the original 205 ft² (19.0m²) to 165 ft² (15.3 m²), in this form setting a British speed record of 196.4 mph (313.3 km/h).  In 1922, the aircraft made an attempt on the world air speed record. Although the recorded speed of 212.15 mph (342 km/h) was faster than the existing record, it did not exceed it by the required margin, so the record was not recognised. In 1923, this aircraft was modified with new wings and a more powerful Lion engine as the Gloster I. The Gloster I was sold to the RAF in December 1923, being fitted with floats and used as a Trainer for the High Speed Flight RAF, being scrapped in 1927.
  The Mars I, after conversion to the Gloster I, was fitted with floats and used as a training seaplane for the British 1925 and 1927 Schneider Trophy teams, remaining in use until 1930.
  The Gloster Sparrowhawk (or Mars II, III and IV) was a naval fighter for Japan, powered by the Bentley BR2 rotary engine. The Japanese Sparrowhawks were flown from the Yokosuka Naval Base as well as from platforms built on gun turrets of warships.  The Nightjar (known as the Mars X) was a similar carrier fighter for the RAF.
  A further factory conversion of a Mars III (civil registered as G-EAYN) led to the Gloster Grouse I powered by a 185 hp Siddeley Lynx, that became the prototype for a small production run of Grouse II for Sweden. The Grouse series was the progenitor of the later Gloster Grebe.
  The Gloster Nighthawk, or Mars VI, replaced the Dragonfly with either an Armstrong-Siddeley Jaguar or a Bristol Jupiter radial. In 1922, the RAF acquired 29 aircraft converted from Nieuport Nighthawks, powered by both Jaguar and Jupiter engines, while Greece purchased 25 Jaguar powered fighters.
  Three of the RAF's Gloster Nighthawks were sent to Iraq in 1923 for more extensive evaluation, being tested by No 1, 8 and 55 Squadrons. The 25 Greek aircraft were delivered in 1923, remaining in service until 1938.
  The  final Nighthawk variant was the Mars X or Nightjar naval fighter powered by a 230 hp Bentley B.R. 2. All of the series of 22 Nightjars were converted from available stocks of original Nighthawks. Nightjars were used operationally during the Chanak Crisis in 1922 and were operated from the H.M.S. Argus from 1922–1924.
caption: The Gloster Mars I
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