Supermarine Type 545

Supermarine

Industry	Aerospace, Defence
Founded	1913
Fate	Incorporated into British Aircraft Corporation (BAC)
Headquarters	United Kingdom
Products	Aircraft

Template:Infobox aircraft The Supermarine 545 was a British supersonic jet fighter concept developed by the aircraft manufacturer Supermarine. Although one prototype was constructed, it never undertook flight testing, primarily because the project lost political support.

Initiated in the early 1950s, the development responded to the Royal Air Force’s growing interest in transonic aircraft. Supermarine, which was simultaneously working on the Supermarine Swift fighter, based the Type 545 design on this earlier model. Key modifications included implementing a crescent wing design and equipping it with a more powerful Rolls-Royce Avon turbojet engine fitted with afterburning (reheat) capability. Supermarine asserted that the new fighter could comfortably reach speeds of up to Mach 1.3.

In February 1952, Supermarine secured a contract to produce two prototypes. Nevertheless, by the time the first prototype was finished, political enthusiasm had waned due to the Swift's significant performance issues. Confidence in Supermarine had diminished, leading to cancellation of the project on 25 March 1956 before any flight tests occurred. Following a short period in storage, the sole Type 545 airframe was handed over to the College of Aeronautics at Cranfield Airport, Bedfordshire, where it served as an instructional model until being scrapped in 1967. Not long after, Supermarine ceased operating as an independent entity.

Background

The inception of the Type 545 dates back to the early 1950s, when the Royal Air Force (RAF) sought to develop transonic aircraft as an interim solution pending the arrival of the next generation of supersonic fighters. Two competing aircraft manufacturers, Supermarine and Hawker, independently proposed designs based on their existing fighters, the Type 545 evolving from the Swift and the Hawker P.1083 deriving from the Hunter. Supermarine submitted its design in February 1951, which was officially approved by the Air Ministry about a month later.

At this point, the Swift programme was still underway and its limitations had not yet been fully recognized. Derek Wood, an aviation historian, attributes this timely circumstance as a key factor in why Supermarine's proposal gained greater favour over Hawker's among RAF evaluators.

The Type 545 was developed to meet the criteria outlined in the Air Ministry's Specification F.105D. It was anticipated to reach speeds up to Mach 1.3 and was expected to outperform its competitor, the P.1083. While externally reminiscent of the Swift, the Type 545 was extensively reworked, featuring an area-ruled fuselage among other significant modifications.

A distinctive visual hallmark of the Type 545 was its unconventional crescent-shaped wing, which was designed to enhance aerodynamic performance, especially at supersonic velocities. The fuselage exhibited a streamlined, bullet-like form; notably, its lower section was flattened where it joined the wings to improve airflow and mitigate the poor low-speed handling issues experienced by the Swift. The airframe consisted of a relatively thick outer skin supported by a closely spaced spanwise web beneath it, reportedly granting the structure a superior strength-to-weight ratio compared to contemporary aircraft. Propulsion came from a single Rolls-Royce Avon turbojet engine equipped with an afterburning system and receiving air through an elliptical intake located near the nose. Aviation author Francis Mason notes that this uniquely shaped intake marked a clear departure from its predecessor’s side intakes.

The crescent wing itself was segmented into three parts: an inboard section with a sweep angle of 50°, a middle section at 40°, and an outboard segment swept at 30°. The average aspect ratio measured approximately 7.5 per cent, while the thickness-to-chord ratio tapered from 8 per cent at the root down to 6 per cent towards the wing tips.

Order and cancellation

In February 1952, Supermarine was commissioned to build two prototype Type 545 aircraft under contract 6/Acft/7711. By 1955, it was declared that the Type 545 project would be terminated. Wood attributes this decision partly to the significant unresolved challenges encountered with the Swift aircraft. He noted that by early 1955, the Swift had become a national embarrassment, damaging not only its own reputation but also that of the RAF and the British aerospace sector. This widespread disapproval among government officials and the public fostered a more cautious attitude toward aviation initiatives, placing the Type 545—closely linked to the Swift—under particular scrutiny. Additionally, public statements at the time cited financial limitations as a factor necessitating reductions in such projects.

The first prototype, bearing serial number XA181, was finalized at Hursley Park and was undergoing preparations for its initial flight when the official cancellation of the contract was announced on 25 March 1956. The second prototype, XA186, which was intended to be equipped with an enhanced Avon engine variant capable of reaching speeds up to Mach 1.6, was cancelled before any airframe construction began. Approximately two years later, Supermarine ceased to exist as an independent entity after being incorporated into what would later become the British Aircraft Corporation (BAC).

Following its completion, the sole finished prototype was placed into storage by Supermarine during the mid-1950s. Several years afterward, it was donated to the College of Aeronautics at Cranfield Airport in Bedfordshire, where it served as a practical teaching tool for aeronautical engineering students. In 1967, this only Type 545 prototype was dismantled.

Specifications (performance estimated)

Bibliography

• Andrews, C.F. and E.B. Morgan. Supermarine Aircraft Since 1914. London: Putnam, 1981. ISBN 0-370-10018-2.
• Andrews, C.F. and E.B. Morgan. Supermarine Aircraft since 1914. London: Putnam, 1987, ISBN 0-85177-800-3.
• Halley, J.J. Royal Air Force Aircraft XA100 to XZ999. Air-Britain (Historians) Ltd, 2001, ISBN 0-85130-311-0.
• Mason, Francis K. The British Fighter since 1912. Annapolis, Maryland, USA: Naval Institute Press, 1992. ISBN 1-55750-082-7.
• Wood, Derek. Project Cancelled. Macdonald and Jane's Publishers, 1975. ISBN 0-356-08109-5

External links

• 1963 mention of the Type 545 in Flight magazine