Westland Wyvern - Design and Development

Design and Development

The Wyvern began as a Westland project for a naval strike fighter, with the engine located behind the pilot and driving a propeller in the nose via a long shaft that passed under the cockpit floor. This enabled the pilot to be located in a position that conferred the best possible visibility over the nose for carrier operations. Official interest resulted in Air Ministry Specification N.11/44, for a long range naval fighter using the Rolls-Royce Eagle 22 24-cylinder H-block piston engine — unrelated to the First World War-era engine of the same name — being issued to cover Westland's design. The specification also called for an airframe design that would be able to take a turboprop engine as and when a suitable unit was available. There was a parallel specification for the Royal Air Force, F.13/44, for which Hawker submitted the competing P.1027; a development of the Tempest. The RAF variant was cancelled when in 1945 it was decided that all future fighter aircraft would be jet powered.

The original design soon matured into the more conventional Westland W.34, with the 3,500 hp (2,610 kW) Eagle engine in the nose driving large contra-rotating propellers and the pilot sitting high in a humped fuselage to improve visibility. The design was otherwise orthodox, with a low wing, tail-wheel undercarriage and double-folding wings fitted with both Youngman flaps on the inner wing section and conventional flaps on the outer section. The W.34 was to be armed with four Hispano 20 mm cannon in the wings and have the ability to carry a torpedo under the fuselage or a selection of bombs and rockets under the wings.

The prototype W.34; the Wyvern TF Mk 1, first flew on 12 December 1946 with Westland's test pilot Harald Penrose at the controls. This aircraft was lost on 15 October 1947 when the propeller bearings failed in flight. Westland's assistant test pilot Sqn. Ldr. Peter Garner was killed attempting to make an emergency landing. From prototype number 3 onwards, the aircraft were navalised and carried their intended armament.

At around this time, the Eagle engine was cancelled and it was found that there were insufficient pre-production engines available to complete all the prototype and pre-production aircraft. Specification N.12/45 was therefore issued for the Wyvern TF.Mk.2, to be powered by a turboprop engine: either the Rolls-Royce Clyde or the Armstrong Siddeley Python. A single Clyde-powered prototype was ordered along with two with Pythons. A Clyde-powered TF 2 first flew on 18 January 1949. Both the piston-powered and turboprop versions shared many common components including wing and tail units, and essentially the same basic cockpit structure. The flight was cut short to only three minutes when shortly after takeoff, the cockpit filled with smoke from a fuel leak onto the exhaust ducting. The Clyde was cancelled after only 50 hours of flight time for the TF 2, and the aircraft was delivered to Napier & Son to be fitted with the Nomad turbo-compound engine. The latter engine never materialised, however and this aircraft was used for crash barrier trials.

The first Python-powered TF.2 flew on 22 March 1949 and this aircraft introduced the ejection seat to the Wyvern. Twenty TF.2s were completed to the Python design although after three years of testing what was then a revolutionary aircraft design, a myriad of detailed aerodynamic changes resulted. The Python engine responded poorly to minor throttle adjustments, so control was exercised by running the engine at a constant speed and varying the pitch of the propellers. The aircraft was declared ready for service in 1952, but never reached an operational squadron.

The definitive Wyvern mark was the TF.Mk.4, later S.Mk.4. Initially, 50 Mark 4s were ordered and were joined by the last seven TF.2s, which were altered while still under construction. Mk.4s reached limited shore-based front line service in May 1953 with 813 Naval Air Squadron at RNAS Ford, replacing the somewhat similar (and equally troubled) Blackburn Firebrand. Several second line squadrons also received Wyverns around this time.

Total production was 127 airframes with 124 aircraft completed, as the last three Eagle piston engined airframes, VR138/VR140, were never completed.