De Havilland Gyron

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The PS.23 or PS.52 Gyron, also known as the Halford H-4, was Frank Halford's last turbojet design while working for de Havilland. Intended to outpower any design then under construction, the Gyron was the most powerful engine of its era, producing 20,000 lbf "dry", and 27,000 lbf with afterburner ("reheat" in British terminology). The engine was actually too large for most roles and saw no production use. It was later scaled down to 45% of its original size to produce the de Havilland Gyron Junior, which was somewhat more successful.

The Gyron was Halford's first axial-flow design, a complete departure from his earlier centrifugal-flow engines based on Whittle-like designs, the Goblin (H-1) and Ghost (H-2). The Gyron was also one of the first engines designed specifically for supersonic flight.

The Gyron first ran in 1953. Flight testing started in 1955 on modified Short Sperrins (a bomber design that was instead turned into an experimental aircraft), replacing the lower two Rolls-Royce Avons with the much larger Gyrons.

The Gyron was selected for a number of projects, most notably the Hawker P.1121 (sometimes referred to as the Hurricane) supersonic attack aircraft that was to have been the replacement for the Hawker Hunter. However, this project was eventually cancelled. Another design potentially based on the Gyron was the Operational Requirement F.155 interceptor, which optionally used the Rolls-Royce RB.106. F.155 was also cancelled, part of the 1957 Defence White Paper.

An example of the Gyron is held by the Science Museum[1], another was held by the de Havilland Heritage Museum, St Albans [2]

The Gyron Junior was the initial powerplant of the Blackburn Buccaneer before the type was re-engined with the Rolls-Royce Spey, and it was also used in the Bristol 188 supersonic research aircraft.

[edit] External links

• "British Jet Engine Website" entry