Scottish Aviation Twin Pioneer


The Scottish Aviation Twin Pioneer was a British STOL transport aircraft built by Scottish Aviation Limited at Prestwick Airport, Scotland, during the 1950s. It was designed for both civil and military operators. It was conceived as a twin-engined version of the Pioneer light transport. Both aircraft required "an area only 30m by 275m in which to operate."

Design and development

Powered by two Alvis Leonides radial engines, the Twin Pioneer was a high-wing cabin monoplane with a triple fin and rudder assembly and fixed tailwheel undercarriage. The prototype Twin Pioneer, registered G-ANTP, first flew at Prestwick Airport on 25 June 1955. Flight trials demonstrated that the aircraft had a very short landing run and the aircraft was displayed at the September 1955 Society of British Aircraft Constructors Show at Farnborough.
Three pre-production aircraft were built for trials, and sales and demonstrations.
In 1958, the 33rd aircraft was used as a prototype for the Series 2 with Pratt & Whitney Wasp R-1340 radial engines of which 5 had been ordered by Philippine Air Lines. In 1959, a Series 3 version was developed to use the improved Alvis Leonides 531 radial engine.
Early in its operational life in 1957 the Twin Pioneer suffered two fatal accidents due to fatigue failure which caused the outer panel of the wing to detach from the aircraft in flight. This issue required significant re-design of the structure and adversely impacted sales.

Operational history

The military version could carry external stores such as bombs under the stub wings. One aircraft became the first aircraft for the newly formed Royal Malaysian Air Force when it was delivered on 16 January 1962; the type served with the air force for 12 years.
The Royal Air Force ordered 39 aircraft, which were built between 1958 and 1959, deployed in Aden and the Far East. It was used extensively by British forces in the Malayan Emergency and the later confrontation in Borneo. In August 1959, No. 78 Squadron RAF at Khormaksar received some Twin Pioneers to supplement its single engine Pioneers. The Twin Pioneers were employed in moving troops and supplies around the wilderness and on occasions lending support to the Sultan of Oman. A series of double engine failures caused problems with the squadron losing two aircraft on the same day. Unsuitable soft and hard landing strips were also causes of failures during landings.
Other squadrons that operated the Twin Pioneers were No. 152 Squadron RAF based at Muharraq in Bahrain and No. 21 Squadron RAF, which reformed with the type at Benson in May 1959. The squadron then moved to Kenya and in June 1965 to Aden. No. 152 operated around the Persian Gulf and in 1959, No. 209 Squadron RAF based at Seletar began to receive Twin Pioneers. These operated in Borneo and Malaya. The SRCU at RAF Odiham also flew three Twin Pioneers for aircrew training. RAF No. 230 Squadron in the UK was the last military operator of the Twin Pioneer. The squadron operated the type in an interesting sand-colour camouflage scheme.
Although mainly used in military operations, the Twin Pioneer was also successful as a commercial transport for operation in areas without proper airfields, where unprepared surfaces were often the norm. Twin Pioneers were sold as survey aircraft to oil exploration companies with some of the first sales to Rio Tinto Finance and Exploration Limited, and the Austrian and Swiss government survey departments. Three were used by the 'Kroonduif' in Dutch New Guinea.
One Twin Pioneer served as a STOL training aircraft with the Empire Test Pilot School at RAE Farnborough for many years.

Variants

Many Series 1 aircraft were subsequently converted to Series 3 standard, including the prototype and all the remaining RAF CC.Mk 1 aircraft.

Operators

Civil Operators

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Scottish Aviation Twin Pioneer Srs3
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Crown Colony of North Borneo
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Australia

;Airworthy
;On display
;On display
;On display
;Stored or under restoration