The RAF received 40, which entered
service in 1954; Malaysia bought nine and Sri
Lanka had a pair.LARGER DERIVATIVE
Having achieved a modicum of success with
the Pioneer, SAL proceeded to a twin-engined
derivative, the Twin Pioneer with a selling
price of £25,000. A model of the project was
exhibited at the 1952 Farnborough Airshow
and received such interest that design began
the following year.
The workforce was doubled to 1,500 and
tooling began, but SAL needed additional
financial support for such a large scheme.
Additional financial support was provided
in October 1954 when SAL received a £1m
loan from the Finance Corporation for Industry
(FCI). The first prototype G-ANTP made its
official maiden flight at Prestwick, piloted by
Noel Capper, on June 25, 1955, though it hadmade a few preparatory hops on the runway
the previous day.
Its outer-wing panels, large leading-edge
slats and flaps were almost identical to those
of the single-engined version. When the flaps
were extended to 12 ̊, the slats opened. The
fuselage was roomier and could carry up to
16 passengers, or well over a ton (1,016kg)
of freight, while retaining a short takeoff
and landing (STOL) performance almost as
remarkable as that of the smaller aircraft.
The airframe was a simple, stressed-
skin, light-alloy structure built from sheet
strip and plate. To maintain controllability
at low speeds, it had triple fins and triple
rudders. Especially notable, was the degree
of interchangeability achieved, for example,
the fins and rudders, slats, outer flaps, main
undercarriage, nacelles, oil and outer-fuel
tanks were all interchangeable.
The Twin Pioneer was designed to besuitable for differing roles: heavy freight,
photographic survey, or as a feederliner.SALES TOURS
Initial flight-testing with ’NTP indicated a
major problem as the Twin Pioneer could not
climb on one engine. This was rectified by
exchanging the 540hp Alvis Leonides 503/8s
for more powerful 560hp 514/8s. Other
alterations were to shorten the span of the
ailerons, remove the inboard fixed leading-
edge slats, change the angle of incidence of
the tail by 3 ̊ and streamline the wing struts.
These modifications were incorporated on
the second aircraft, G-AOEN, the first of four
pre-production aircraft that flew on April 28,- It was painted in the blue, white and
red livery of De Kroonduif, KLM’s Dutch East
Indies subsidiary. The next aircraft G-AOEO
flew on August 26 bearing Swissair colours
and these two aircraft jointly appeared at
http://www.aviation-news.co.uk 17Above: Twin Pioneer prototype G-ANTP
waiting to take off at the 1955 Farnborough
Air Show. Its large leading-edge slats
and flaps which gave it superlative STOL
performance are visible. BAE Systems
Right: The first of four pre-production Twin
Pioneers, G-AOEN, which flew on April 28,
1956, in Scottish Aviation’s house livery with
the rampant lion on the tail. Key Collection
Below: The second pre-production aircraft
G-AOEO was trialled by Swissair for internal
flights within Alpine Switzerland from
January to March 1957. However, no order
was forthcoming. Key Collection16-20_pioneerDC.mfDC.indd 17 05/01/2018 15: