https://en.wikipedia.org/wiki/Supermarine_Walrus
The Supermarine Walrus (originally known as the Supermarine Seagull V) was a
British single-engine amphibious biplane reconnaissance aircraft designed by R.
J. Mitchell and first flown in 1933. Designed for use as a fleet spotter to be
catapult launched from cruisers or battleships, the Walrus was later employed in
other roles, notably as a rescue aircraft for aircrew in the sea. The Walrus
continued in service throughout the Second World War, with the Fleet Air Arm
(FAA), Royal Air Force (RAF), Royal Australian Air Force (RAAF), Royal New
Zealand Navy (RNZN) and Royal New Zealand Air Force (RNZAF). It was the first
British squadron-service aircraft to incorporate in one airframe a fully
retractable main undercarriage, completely enclosed crew accommodation and
all-metal fuselage.
The Walrus was initially developed as a private venture in response to a 1929
Royal Australian Air Force (RAAF) requirement for an aircraft to be
catapult-launched from cruisers and was originally called the Seagull V,
although it only resembled the earlier Supermarine Seagull III in general
layout. Construction was started in 1930 but owing to other commitments
Supermarine did not complete the aircraft 1933.
The single-step hull was constructed from aluminium alloy, with stainless-steel
forgings for the catapult spools and mountings. Metal construction was used
because experience had shown that wooden structures deteriorated rapidly under
spars, wooden ribs which were covered in fabric. The lower wings were set in the
shoulder position with a stabilising float mounted under each. The elevators
were high on the tail-fin and braced on either side by N struts. The wings could
be folded, giving a stowage width of 17 ft 6 in (5.33 m). The single 620 hp (460
kW) Pegasus II M2 radial engine was housed at the rear of a nacelle mounted on
four struts above the lower wing and braced by four shorter struts to the
centre-section of the upper wing. This powered a four-bladed, wooden pusher
propeller. The nacelle contained the oil tank, arranged around the air intake at
the front as an oil cooler; electrical equipment and had a number of access
panels for maintenance. A supplementary oil cooler was mounted on the starboard
side.
When flying from a warship, the Walrus would be recovered by touching-down
alongside, then lifted from the sea by a ship's crane. The Walrus lifting-gear
was kept in a compartment in the section of wing directly above the engine. A
crewmember would climb onto the top wing and attach this to the crane hook.
Landing and recovery was a straightforward procedure in calm waters but could be
very difficult if the conditions were rough. The usual procedure was for the
creating a 'slick' to the lee side of ship on which the Walrus could alight,
this being followed by a fast taxi up to the ship before the 'slick' dissipated.
A total of 740 Walruses were built in three major variants: the Seagull V,
Walrus I and the Walrus II. The Mark IIs were constructed by Saunders-Roe and
the prototype first flew in May 1940. This aircraft had a wooden hull, which was
heavier but economised on the use of light metal alloys. Saunders-Roe
license-built 270 metal Mark Is and 191 wooden-hulled Mark IIs. The successor to
the Walrus was the Supermarine Sea Otter, a similar but more powerful design.
Sea Otters never completely replaced the Walrus and both were used for air-sea
rescue during the latter part of the war. A post-war replacement for both
aircraft, the Supermarine Seagull, was cancelled in 1952, with only prototypes
being constructed. By that time, air-sea rescue helicopters were taking over
from small flying-boats. The Walrus was known as the "Shagbat" or sometimes
"Steam-pigeon"; the latter name coming from the steam produced by water striking
the hot Pegasus engine.
Role
Amphibious reconnaissance aircraft
National origin
United Kingdom
Manufacturer
Supermarine
Designer
R. J. Mitchell
First flight
21 June 1933
Introduction
1935
Primary users
Royal Navy
Irish Air Corps
Royal Air Force
Royal Australian Air Force
Produced
Number built
740
Developed from
Supermarine Seagull
The first Seagull V, A2-1, was handed over to the Royal Australian Air Force in
1935, with the last, A2-24 delivered in 1937. The type served aboard HMA Ships
Australia, Canberra, Sydney, Perth and Hobart. Walrus deliveries to the RAF
started in 1936 when the first example to be deployed was assigned to the New
cruisers that carried one Walrus each. The Royal Navy Town-class cruisers
carried two Walruses during the early part of the war and Walruses also equipped
the York-class and County-class heavy cruisers. Some battleships, such as
Warspite and Rodney carried Walruses, as did the monitor Terror and the seaplane
tender Albatross.
By the start of World War II the Walrus was in widespread use. Although its
principal intended use was gunnery spotting in naval actions, this only occurred
twice: Walruses from Renown and Manchester were launched in the Battle of Cape
Spartivento and a Walrus from Gloucester was used in the Battle of Cape Matapan.
The main task of ship-based aircraft was patrolling for Axis submarines and
surface-raiders and by March 1941, Walruses were being deployed with Air to
Surface Vessel (ASV) radars to assist in this. During the Norwegian Campaign and
the East African Campaign, they also saw very limited use in bombing and
strafing shore targets. In August 1940, a Walrus operating from Hobart bombed
and machine-gunned an Italian headquarters at Zeila in Somalia. By 1943,
catapult-launched aircraft on cruisers and battleships were being phased out;
their role at sea was taken over by much-improved radar. Also, a hangar and
catapult occupied a considerable amount of valuable space on a warship. However,
Walruses continued to fly from Royal Navy carriers for air-sea rescue and
general communications tasks. Their low landing speed meant they could make a
carrier landing despite having no flaps or tailhook.
Walruses also found civil and commercial use. They were briefly used by a
whaling company, United Whalers. Operating in the Antarctic, they were launched
from the factory ship FF Balaena, which had been equipped with a surplus navy
aircraft catapult. The aircraft used were slightly modified; they were fitted
with electrical sockets to power the electrically heated suits, worn by the crew
under their immersion suits. A small, petrol-burning cabin heater was fitted to
help keep the crews comfortable during flights that could last over five hours.
A Dutch whaling company embarked Walruses, but never flew them. Four aircraft
were bought from the RAAF by Amphibious Airways of Rabaul. Licensed to carry up
to ten passengers, they were used for charter and air ambulance work, remaining
in service until 1954.
Specifications (Supermarine Walrus)
General characteristics
Length: 37 ft 7 in (11.45 m)
Wingspan: 45 ft 10 in (14.0 m)
Height: 15 ft 3 in (4.6 m)
Empty weight: 4,900 lb (2,220 kg)
Loaded weight: 7,200 lb (3,265 kg)
Max. takeoff weight: 8,050 lb (3,650 kg)
Performance
Maximum speed: 135 mph (215 km/h) at 4,750 ft (1,450 m)
Range: 600 mi (965 km)
Service ceiling: 18,500 ft (5,650 m)
Rate of climb: 1,050 ft/min (5.3 m/s)
Power/mass: 0.094 hp/lb (0.16 kW/kg)
Armament
Bombs: 6 100 lb (45 kg) bombs or 2 250 lb (110 kg) bombs or 2 250 lb (110 kg)
Mk.VIII depth charges
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