Issue No 22 THE AVIATION HISTORIAN 97
ABOVE The test crew assembles for the tethered engine run, and the Wyvern is fuelled from a small Brockhouse-
type bowser. The battery trolley has also been plugged in. Note the square carburettor intake under the nose,
wedged between the annular intercooler intakes, and the staining along the forward fuselage from the exhaust.
the Wyvern until early 1947), serial TS371, first
flew in December 1946. The flight took place
at Boscombe Down rather than Westland’s
own test airfield at Yeovil, probably because
Boscombe Down’s considerably greater space
and long concrete runway offered greater safety
and practicality than the small grass runway at
Yeovil for such a large, powerful and complex
aircraft. After a tethered engine run on December
16 that year, Westland’s chief test pilot Harald
Penrose took TS371 into the air. It was not until
September 10, 1947, however, that the next
prototype, TS375, made its maiden flight.
These photographs show a tethered engine run
by TS375, around the time of its first flight. These
procedures were not always straightforward
with the Wyvern. During a later tethered run
with the engine eventually chosen for service
use, the Python, the aircraft slipped its bonds
and jumped forward, whereupon the propeller
completely destroyed the engine manufacturer
representative’s 1929 Armstrong Siddeley
saloon. Fortunately, nothing so dramatic appears
to have taken place on this occasion!
Best of the breed?
Wyvern TS375 was central to Westland’s
development of the aircraft, especially after
the loss of TS371 in late 1947. It was retained
by Westland until March 1949 when it went
to the Aeroplane & Armament Experimental
Establishment (A&AEE) at Boscombe Down
for handling trials, being fitted with an ejection
seat in June 1950. It was also fitted with features
under development for service aircraft, such as a
dihedral tailplane and outer-wing airbrakes.
By the late 1940s Rolls-Royce wished to
concentrate on jet engines, and the Eagle
never really underwent anything more than
preliminary development before it was axed.
Most of the engines built were installed in the
six prototype and seven “production” Wyvern
TF.1s. The turboprop alternatives were the
Rolls-Royce Clyde and as already mentioned,
the Python, and trial aircraft fitted with these
engines were initially designated TF.2 regardless
of engine. (Some sources refer to the Clyde-
engined examples as TF.2As, but this appears to
have been unofficial.)
The Eagle-engined Wyverns, designated
TF.1 (for Torpedo Fighter, a classification
later changed to S for Strike) were in many
ways the most impressive of the entire breed,
outperforming the later Python-engined variants
in top speed — 456 m.p.h. (734km/h) as against
383 m.p.h. (616km/h); rate of climb — 2,900ft
(883m)/min versus 2,350ft (716m)/min; range —
1,180 miles (1,900km) versus 910 miles (1,465km)
and ceiling — 32,000ft (9,800m) as against
28,000ft (8,500m). However, the Python-engined
S.4 did have the edge in cruising speed — 348
m.p.h. (560km/h) versus 295 m.p.h. (475km/h)
and speed at sea level — 383 m.p.h. (616km/h)
as against 365 m.p.h. (587km/h), the TF.1
offering its best speed at 23,000ft (7,000m).
The Python, a very bulky engine originally
developed for large bombers, required
significant alteration of the Westland fighter’s
airframe, including a longer, deeper nose to
accommodate the engine, a taller mid-fuselage
to raise the cockpit and improve the pilot’s
view, and a much larger fin and rudder to retain
directional stability.
Possibly the most promising Wyvern, however,