Supermarine Walrus

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 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 observation seaplane 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 until 1933.

Fuel was carried in two tanks in the upper wings. The pusher configuration had
the advantages of keeping the engine and propeller further out of the way of
spray when operating on water and reducing the noise level inside the aircraft.
The propeller was safely away from any crew standing on the front deck, when
picking up a mooring line. The engine was offset by three degrees to starboard,
to counter any tendency of the aircraft to yaw, due to unequal forces on the
rudder caused by the vortex from the propeller. A solid aluminium tailwheel was
enclosed by a small water-rudder, which could be coupled to the main rudder for
taxiing or disengaged for takeoff and landing. Although the aircraft typically
flew with one pilot, there were positions for two. The left-hand position was
the main one, with the instrument panel and a fixed seat, while the right-hand
seat could be folded away to allow access to the nose gun-position via a
crawl-way. An unusual feature was that the control column was not fixed in the
usual way but could be unplugged from either of two sockets in the floor. It
became a habit for only one column to be in use; when control was passed from
the pilot to co-pilot or vice versa, the control column would simply be
unplugged and handed over. Behind the cockpit, there was a small cabin with work
stations for the navigator and radio operator.

Armament usually consisted of two .303 in (7.7 mm) Vickers K machine guns, one
each in the open positions in the nose and rear fuselage; with provision for
carrying bombs or depth charges mounted beneath the lower wings. Like other
flying boats, the Walrus carried marine equipment for use on the water,
including an anchor, towing and mooring cables, drogues and a boat-hook. The
prototype was first flown by "Mutt" Summers on 21 June 1933; five days later it
made an appearance at the SBAC show at Hendon, where Summers startled the
spectators (R. J. Mitchell among them) by looping the aircraft. Such aerobatics
were possible because the aircraft had been stressed for catapult launching. On
29 July Supermarine handed the aircraft over to the Marine Aircraft Experimental
Establishment at Felixstowe. Over the following months extensive trials were
carried out, including shipborne trials aboard Repulse and Valiant carried out
on behalf of the Royal Australian Navy and catapult trials carried out by the
Royal Aircraft Establishment at Farnborough, becoming the first amphibious
aircraft in the world to be launched by catapult with a full military load,
piloted by Flight Lieutenant Sydney Richard Ubee.

The strength of the aircraft was demonstrated in 1935, when the prototype was
attached to the battleship Nelson at Portland. With the commander-in-chief of
the Home Fleet, Admiral Roger Backhouse, on board the pilot attempted a water
touch-down, forgetting that the undercarriage was in the down position. The
Walrus was immediately flipped over but the occupants only had minor injuries;
the machine was later repaired and returned to service. Soon afterwards, the
Walrus became one of the first aircraft to be fitted with an undercarriage
position indicator on the instrument panel. Test pilot Alex Henshaw later stated
that the Walrus was strong enough to make a wheels-up landing on grass without
much damage (he also commented that it was "the noisiest, coldest and most
uncomfortable" aircraft he had ever flown).

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
1936–1944

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 HMAS
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
Zealand Division of the Royal Navy, on Achilles– one of the Leander-class light
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 HMS
Warspite and Rodney carried Walruses, as did the monitor Terror and the seaplane
tender HMAS Albatross.

By the start of the Second World War 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 British Somaliland. By
1943, catapult-launched aircraft on cruisers and battleships were being replaced
by improved radar. A hangar and catapult occupied a considerable amount of space
on a warship. Walruses continued to fly from Royal Navy carriers for air-sea
rescue and general communications. The low landing speed of the Walrus meant
they could make a carrier landing despite having no flaps or tailhook.

Civil use?

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 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 I)?

General characteristics
Crew: 4
Length: 37 ft 7 in (11.46 m) on wheels
Wingspan: 45 ft 10 in (13.97 m)
Height: 15 ft 3 in (4.65 m) on wheels
Wing area: 610 sq ft (57 m2)
Empty weight: 4,900 lb (2,223 kg)
Gross weight: 7,200 lb (3,266 kg)
Max takeoff weight: 8,050 lb (3,651 kg)
Powerplant: 1 × Bristol Pegasus VI 9-cylinder air-cooled radial piston engine,
750 hp (560 kW)
Propellers: 4-bladed wooden fixed-pitch pusher propeller

Performance
Maximum speed: 135 mph (217 km/h, 117 kn) at 4,750 ft (1,448 m)
Cruise speed: 92 mph (148 km/h, 80 kn) * Alighting speed: 57 mph (50 kn; 92
km/h)
Range: 600 mi (970 km, 520 nmi) at cruise
Service ceiling: 18,500 ft (5,600 m)
Rate of climb: 1,050 ft/min (5.3 m/s)
Time to altitude: 10,000 ft (3,000 m) in 12 minutes 30 seconds
Wing loading: 11.8 lb/sq ft (58 kg/m2)
Power/mass: 0.094 hp/lb (0.155 kW/kg)

Armament

Guns: 2× .303 in (7.7 mm) Vickers K machine guns (one in nose, one behind wings)
Bombs: 6x 100 lb (45 kg) bombs
or 2x 250 lb (110 kg) bombsor 2x 250 lb (110 kg) Mk.VIII depth charges