SHORT SUNDERLAND
- The Short S.25 Sunderlad was a four-engined general-purpose flying-boat
designed during 1933/34 in response to Specification R.2/33, which spelt
out the needs of Operational Requirement 8 as a replacement for the
biplane 'boats then in service. Designed under direction of Arthur Gouge,
S.25 retained overall configuration and geometry of Scion Senior, and
was in many respects the military counterpart of S.23 Empire Boat, which
was the first to fly. A single prototype S.25 ordered in 1934 for competitive
evaluation against Saro A. 33. Powered by four 950 hp Bristol Pegasus
X engines, prototype K4774 first flew on October 16, 1937. After four
flights, sweepback of 4.5 deg introduced on the mainplanes, and 1,010
hp Pegasus XXIIs fitted; testing in this form resumed on March 7, 1938.
Short Sunderland I: Initial production version of S.25, the first 11
being ordered to Specification 22/36 and OR.42 at the same time as 11
Saro A.31s ordered to Specification 21/36 (the latter being cancelled
after A. 31 prototype damaged beyond repair on October 25, 1938). Further
contracts brought total of Short Sunderland Is built to 74 by Shorts
at Rochester and 15 by Blackburn at Dumbarton. First of development
batch flew on April 21, 1938 and 42 Short Sunderland Is flying by September
1939; first by Blackburn flew late-1941. Short Sunderland I was powered
by four 1,010 hp Pegasus XXII engines and carried a crew of 9-10. Armament
comprised a single (later, two) guns in FN11 nose turret, four guns
in FN13 tail turret and (later aircraft) two Vickers 'K' guns in dorsal
hatches, all of 0.303-in (7.7-mm) calibre'. A 2,000 Ib (908 kg) bomb-load
was carried. Service use began June 1938 with No 230 Sqn at Seletar
and No 210 Sqn at Pembroke Dock, the latter unit flying the first wartime
sortie - a convoy patrol - on September 3. At that time, No 228 Sqn
also flying Short Sunderlands at Alexandria, Egypt, and No 204 at Mount
Batten. Nine Mk Is released by RAF to equip No 10 Sqn, RAAF, still in
UK when war began, becoming operational with Australian crews (but retaining
RAF serials in place of A18-1 to A18-9 allocated). Two further squadrons,
Nos 95 and 201, equipped from 1940.
Max speed, 210 mph (338 kmlh). Rate of climb, 1,200 ft/min (6.1 mlsec).
Ceiling, 20,500 ft (6,248 m). Range, 2,910 mis (4,686 km). Empty weight,
28,290 Ib (12,832 kg). Gross weight, 45,700 Ib (20,730 kg). Span, 112
ft 8 in (34.34 m). Length, 85 ft 8 in (26.11 m). Wing area, 1,487 sq
ft (138.14m2).
Short Sunderland II: Operationally-improved Mk I with 815 hp Pegasus
XVIII engines and two-speed superchargers, FN7 two-gun dorsal turret
in place of open 'K'-gun mounts, and FN4A tail turret with double rpg.
Most Mk Us also fitted with ASV Mk II radar, indicated by aerial masts
and transmitter loops on rear fuselage, and central and underwing Yagi
homing aerials. Prototype conversion of (first Blackburn-built) Mk I,
T9083, followed by 23 by Shorts at Rochester, five by Blackburn and
five by Short & Harland in Belfast (where first flew on April 24,
1942). Served alongside Mk Is in four squadrons and as initial equipment
of four more.
Short Sunderland III: Principal war-time production and service version,
featuring impoved low-drag hull design and faired main step. Other features
as Mk II. Prototype (Mk I conversion) T9042 flown at Rochester on June
28, 1941, and first production Mk III, also at Rochester, on December
15, 1941. Production totals, 186 from Rochester, 71 from Belfast, 170
from Blackburn Dumbarton and 35 from Short-operated factory on Lake
Windermere in the English Lake District. The Windermere factory also
did some conversion work upgrading Mark III Sunderlands to Mark Vs (thanks
John Evans, Pembroke Dock, Wales).
Early in 1943, centimetric
ASV Mk III replaced ASV Mk II; later, ASV Mk VIC, with fairings for
underwing scanners, was fitted in Short Sunderland IIIAs. From late
1943, Mk Ills fitted with four additional forward-firing machine guns
in the nose, and a further modification provided pairs of 0.50-in (12.7-mm)
guns to fire through beam hatches aft of dorsal turret, bringing the
total to 18 machine guns. Short Sunderland Ills served with some 15
squadrons of the RAF, including one French-manned, one Norwegian, two
Canadian, one Australian and one New Zealand. Also, No 10 Sqn, RAAF,
progressed from Mk Is to Mk Ills. Between January 1943 and August 1944,
BOAC received 24 Short Sunderland Ills (diverted from RAF contracts),
stripped of armament and military equipment, and fitted with austere
bench-and-mattress seating. First conversion flew at Rochester on December
26, 1942, and these aircraft, in camouflage and with civil registrations,
used initially on the UK-West Africa route to Lagos. Operating later
on the route through Egypt to Karachi, they acquired RAF roundels and
Transport Command style four-letter codes. Four similar austere transport
conversions diverted from RAF to RNZAF late-1944 for use by the Flying
Boat Transport Flight in the Pacific.
Short Sunderland IV: See separate entry for S.45 Seaford.
Short Sunderland V: As Mk III but fitted with 1,200 hp Pratt & Whitney
R-1830-90 engines. Prototype conversions of Mk Ills by Shorts at Rochester
(ML765) and by No 10 Sqn (RAAF) at Mount Batten (ML839), flown in March
and May 1944 respectively. Existing Mk III contracts switched to Mk
Vs, with deliveries starting late-1944, all with ASV Mk VIC and full
18-gun armament. Short built 47 at Rochester where the last one flew
on September 27, 1945; Short and Harland built 47 at Belfast, completed
June 1946; and Blackburn built 60 at Dumbarton, where last Mk V flew
on November 8, 1945. Entered service February 1945 and used (mostly
post-war) by nine RAF squadrons. Max speed, 213 mph (343 kmlh). Rate
of climb, 840 ftlmin (4.27 ml sec). Service ceiling, 17,900 ft (5,455
m). Cruising endurance, over 15 hours. Empty weight, 37,000 Ib (16,783
kg). Gross weight, 60,000 Ib (27,216 kg). Dimensions as Mk I.
