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Supermarine Type 307

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Adapted from the English Wikipedia article Supermarine Type 307, available under CC BY-SA 4.0Updated 29 November 202516 sources
Supermarine
IndustryAerospace, Defence
Founded1913
FounderReginald J. Mitchell (chief designer)
Headquarters
Woolston, Southampton
,
United Kingdom
ProductsAircraft (including Supermarine Walrus)

Overview

The Supermarine Walrus is a British amphibious biplane powered by a single engine, developed by Supermarine under the guidance of designer R. J. Mitchell. It was primarily deployed for maritime patrol missions and holds the distinction of being the first British squadron aircraft to feature a fully retractable landing gear, an enclosed cockpit for the crew, and an all-metal fuselage.

Initially designated as the Supermarine Seagull V, the aircraft was later renamed Walrus. Its maiden flight took place in 1933, following a design phase that began four years earlier as a private initiative. The Walrus retained a similar configuration to the earlier Seagull. Designed to function as a fleet spotter launched via catapult from cruisers or battleships, it was widely utilized for maritime reconnaissance. The early models featured a metal hull to enhance durability in tropical environments, whereas the subsequent Supermarine Walrus II variant incorporated a wooden hull to reduce reliance on scarce light alloys.

The Royal Australian Air Force was the first to introduce the Supermarine Seagull V into service in 1935. Subsequently, the aircraft was adopted by the Fleet Air Arm, Royal Air Force, Royal New Zealand Navy, and Royal New Zealand Air Force. Throughout the Second World War, Walruses played an active role in anti-submarine operations and were also employed by the RAF Search and Rescue Force for air-sea rescue missions. Although plans existed to replace the Walrus with the more advanced Supermarine Sea Otter, this transition did not materialize. Following the war, the Walrus remained operational, with some units serving in civilian roles across regions including Australia and Antarctica. Eventually, helicopters from the first generation succeeded the Walrus in its air-sea rescue duties.

Development

Initially named the Supermarine Seagull V, the Supermarine Walrus was developed by Supermarine as a private initiative to fulfill a Royal Australian Air Force (RAAF) demand for an observation seaplane capable of being catapult-launched from cruisers. The design, led by Supermarine's chief engineer R.J. Mitchell, bore a resemblance in overall configuration to Mitchell's earlier Supermarine Seagull III model.

Work on a prototype began in 1930, but due to other urgent projects, Supermarine did not complete it until 1933. The prototype, designated Type 228 after design alterations, was first piloted by "Mutt" Summers on 21 June 1933. Shortly thereafter, five days later, the aircraft—now identified as N-1—was showcased at the SBAC exhibition at Hendon. During this event, Summers performed an unplanned loop, surprising the audience including Mitchell himself.

On 29 July, Supermarine delivered the aircraft, now re-marked as N-2, to the Marine Aircraft Experimental Establishment at Felixstowe. Over subsequent months, it underwent extensive testing, including shipborne trials aboard the Renown-class battlecruiser HMS Repulse and the Queen Elizabeth-class battleship HMS Valiant, conducted on behalf of the Royal Australian Navy. Additionally, catapult launch tests were performed by the Royal Aircraft Establishment at Farnborough, where the Seagull V became the first piloted aircraft globally to be catapult-launched, with Flight Lieutenant Sydney Richard Ubee at the controls.

The aircraft's robustness was proven in October 1935 when a Seagull V carrying the Commander-in-Chief of the Home Fleet, Roger Backhouse, executed a water landing in Portland Harbour with its landing gear extended. The hull flooded upon impact and flipped over; however, Backhouse and his crew escaped with only minor injuries. This incident led to the installation of an automatic horn and indicator lights designed to alert pilots to verify wheel position before landing. The aircraft was subsequently repaired and returned to active duty. Shortly thereafter, it became one of the earliest planes equipped with an undercarriage position indicator integrated into the instrument panel. Test pilot Alex Henshaw later remarked that while the Walrus could withstand wheels-up landings on grass with minimal damage, it was "the noisiest, coldest and most uncomfortable" aircraft he had ever piloted.

Airframe

The Type 236 Supermarine Walrus is an amphibious biplane powered by a single engine, primarily engineered for maritime reconnaissance tasks. Its hull, crafted entirely from metal—a pioneering feature at the time—utilized an anodised alloy, with stainless steel components employed for the catapult spools and their mountings. The choice of metal construction stemmed from prior experience indicating that wooden airframes deteriorated quickly in tropical environments.

Although normally operated by a single pilot, the aircraft was equipped with dual pilot stations. The control column was designed to be removable and could be inserted into either of two floor sockets, allowing it to be transferred between pilots as needed. Positioned behind the cockpit was a compact cabin housing workstations dedicated to the navigator and radio operator.

Wings

The wings, covered with fabric, are symmetrical in span and feature a distinctive sweepback. Their structure incorporates stainless steel spars combined with wooden ribs. The lower wings are mounted at shoulder height, each supporting a stabilising float beneath them. The elevators are positioned high on the tail fin and supported by pairs of struts on both sides. To facilitate storage, the wings were designed to fold, reducing the aircraft’s width to slightly more than that of the tailplane.

Notably, the Seagull V marked a first in British military aviation by incorporating a retractable undercarriage. This innovation originated from a senior technical assistant at Supermarine who proposed fully retracting the wheels into the wings to enhance aerodynamic efficiency.

Powerplant

The aircraft is powered by a single Bristol Pegasus radial engine mounted at the rear of a nacelle supported by four struts above the lower wing and further braced by four shorter struts connecting to the upper wing’s center section. This engine drives a four-bladed wooden propeller arranged in a pusher configuration. Inside the nacelle are housed the oil tank—designed around an air intake at its front which serves as an oil cooler—alongside electrical systems, with multiple access panels provided for maintenance purposes. An additional oil cooler is installed on the starboard side. Fuel is stored in two tanks located within the upper wings.

The pusher layout offers several benefits: it keeps both engine and propeller clear of water spray during aquatic operations, lowers noise levels inside the cabin, and positions the propeller safely away from crew members standing on the forward deck when attaching hoisting cables. To counteract yaw caused by asymmetric forces on the rudder due to propeller vortices, the engine is angled three degrees to starboard. A solid aluminium tailwheel is enclosed within a small water rudder assembly.

Armament

The Walrus was equipped with two .303 in (7.7 mm) Vickers K machine guns, positioned in open mounts located at the front nose and rear fuselage sections. Additionally, it was capable of carrying bombs or depth charges under the lower wings.

Operation from ships

A2-7 being positioned on the catapult of HMAS Hobart, a RAN Leander class cruiser, in 1939

Before the 1930s, any naval vessel able to launch aircraft was fitted with catapults; by 1934, catapult launches accounted for a quarter of the Fleet Air Arm's aircraft. When operating from a warship, the Walrus would land on water beside the vessel and then be hoisted aboard using the ship’s crane. The aircraft’s lifting gear was stored within a compartment on the wing section above the engine, where a crew member would climb atop the upper wing to secure it to the crane hook.

While landing and recovery were straightforward in calm seas, rough conditions could complicate these operations. Typically, just before touchdown, the ship would turn approximately 20° to generate a calm 'slick' on its lee side, allowing the Walrus to land smoothly and taxi quickly toward the vessel before the slick vanished.

Similar to other flying boats, the Walrus carried marine equipment for water operations, such as an anchor and boat-hook.

Production

photograph of an early Walrus
Supermarine Walrus I, serial number K5783, from the first production batch. The aircraft served with the Royal New Zealand Navy cruisers HMNZS Achilles and HMNZS Leander.

In 1933, the RAAF placed an order for 24 Seagull Vs intended as spotter-reconnaissance planes for the RAN; deliveries occurred during 1935 and 1936, with most units sent to Point Cook, Victoria for use by the Seaplane Training Flight RAAF.

The RAF’s initial order of 12 aircraft was made in May 1935; the first production model, bearing serial number K5772, took its maiden flight on 16 March 1936. Within RAF service, this type was designated as Walrus. Early production models were powered by Pegasus II M2 engines, while from 1937 onwards they received 750 hp (560 kW) Pegasus VI engines. Compared to prototypes, production aircraft featured subtle modifications: a smoother transition between upper decking and fuselage sides, reduction of tailplane bracing struts from three to two, lower wings hinged to fold upward 90° instead of downward 180°, and removal of the external oil cooler.

Across three primary variants—the Seagull V, Walrus I, and Walrus II—a total of 740 Walruses were manufactured. Of these, Saunders-Roe constructed 462 units at their Weybridge facility in Surrey, with fuselages produced by Elliotts of Newbury. This version incorporated a wooden hull that was heavier but conserved light alloy materials. Saunders-Roe produced under license 270 metal Mark I models and 191 wooden-hulled Mark II versions. Crews affectionately nicknamed the Walrus as "Shagbat," "Steam Pigeon," among other monikers.

The Supermarine Sea Otter succeeded the Walrus with a similar design but enhanced power; however, Sea Otters never fully replaced their predecessor. Both types served in air-sea rescue roles during World War II's later stages. A post-war successor—the Supermarine Seagull (1948)—was cancelled in 1952 after only prototype development. By that period, helicopters had begun supplanting small flying boats in air-sea rescue missions.

Early deployment

The Royal Australian Air Force received the first Seagull V, designated A2-1, in 1935, with the final unit delivered by 1937. This aircraft operated from the County-class cruisers HMAS Australia and Canberra, as well as the Leander-class cruisers Sydney, Perth, and Hobart.

The Royal Air Force began receiving Walrus aircraft in 1936, with the first deployment on the New Zealand Division of the Royal Navy's Achilles, one of the Leander-class light cruisers which each carried a single Walrus. During the Second World War, Town-class cruisers of the Royal Navy typically carried two Walruses, while these aircraft also equipped the York-class and County-class heavy cruisers. Additionally, certain battleships such as the Queen Elizabeth-class HMS Warspite and the Nelson-class battleship Rodney operated Walruses, alongside the seaplane tender HMAS Albatross.

By the outbreak of hostilities, Walruses were extensively utilized. Although their primary role was intended to be gunnery spotting during naval engagements, this function was performed only on two occasions: Walruses launched from the battlecruiser Renown, the lead ship of her class, and from the Town-class cruiser Manchester took part in the Battle of Cape Spartivento, while another Walrus from the Town-class Gloucester was deployed during the Battle of Cape Matapan. The predominant mission for shipborne aircraft was to conduct patrols against Axis submarines and surface raiders. By March 1941, Walruses were equipped with ASV radar systems to enhance this capability. Throughout campaigns such as the Norwegian Campaign and the East African Campaign, Walruses had limited roles in bombing and strafing enemy shore positions. Notably, in August 1940, a Walrus operating from HMAS Hobart attacked and machine-gunned Italian command facilities at Zeila in British Somaliland.

By 1943, radar technology had begun to supplant catapult-launched aircraft aboard cruisers and battleships due to its more compact footprint on vessels. Nevertheless, Walruses continued to operate from Royal Navy carriers, primarily fulfilling air-sea rescue duties and general communication tasks. Their ability to land on carriers was facilitated by their low landing speeds despite lacking flaps or a tailhook.

Other military applications

photograph of a Walrus landing on a ship
A Walrus touches down on a Royal Navy carrier in the Indian Ocean, after rescuing a pilot under fire who was shot down during an attack on Japanese positions in the Nicobar Islands

The Royal Navy and Royal Air Force deployed the Walrus for air-sea rescue operations. Dedicated RAF Air Sea Rescue Service units operated various aircraft types: Spitfires and Boulton Paul Defiants conducted patrols to locate downed airmen, Avro Ansons dropped essential supplies and inflatable dinghies, while Walruses performed water recoveries.[1] RAF air-sea rescue squadrons were assigned to cover maritime zones around the United Kingdom, the Mediterranean, and the Bay of Bengal.[2] These missions resulted in over 1,000 aircrew rescues, with 277 Squadron credited for 598 recoveries.[3]

In 1939, two Walruses stationed at Lee-on-Solent underwent ASV equipment trials,[4] featuring a dipole antenna mounted on the aircraft's interplane struts. By 1940, one Walrus was modified with a forward-firing Oerlikon 20 mm cannon as a defensive measure against German submarines. Although the weapon was successfully operated, the concept was discontinued when it was discovered that muzzle flash impaired pilot vision.[5]

A Walrus was transported to Arkhangelsk alongside other supplies aboard British Convoy PQ 17. It was allocated to the 16th air transport detachment, remaining operational through late 1943.[6]

Following World War II, the Walrus saw continued but limited military service with the RAF and foreign naval forces. Argentina operated eight aircraft, with two assigned to the cruiser La Argentina until 1958.[4] Additionally, some units were employed by the French Navy's Aviation navale for training purposes.[7]

Civilian use after the war

During the 1940s, a Supermarine Walrus was trialed by United Whalers, a whaling company operating in Antarctic waters.[8] It was launched from the factory ship Balaena, which featured a surplus naval catapult system.[7] These aircraft were equipped with power sockets to supply electrically heated suits worn beneath crew immersion suits.[4] A cabin heater was installed to maintain warmth during flights lasting over five hours.Template:Ref name="Gri"[9] A Dutch whaling firm also acquired Walruses but did not operate them in flight.[7]

Amphibious Airways of Rabaul purchased four Walruses from the RAAF. Certified to carry up to ten passengers, they served in charter and air ambulance roles until 1954.[4][10] In the early 1960s, the last remaining Walrus A2-4, registered for both private and charter use, received upgraded radio systems and additional seating capacity. It operated transporting tourists and freight to locations such as the Great Barrier Reef and along Australia's eastern seaboard.[11]

Variants

Seagull V
This model features a metal hull and was produced in a total of 27 units.
Walrus I
Constructed with a metal hull, Supermarine manufactured 281 of these aircraft.
Walrus II
Featuring a wooden hull, this version was built by Saunders-Roe, with a production count of 270 aircraft.

Military operators

Template:ARG
Template:AUS
Canada
Egypt
Template:FRA
Template:IRL
Template:NZL
Template:TUR
Template:UK

Civilian operators

Template:AUS
  • Operated by Amphibious Airways
Template:CAN
  • Kenting Aviation
Template:NLD
  • Two aircraft were carried aboard the whaling vessel Willem Barendsz
Template:NOR
  • Utilized by Vestlandske Luftfartsselskap
Template:UK
  • Somerton Airways
  • United Whalers

Surviving aircraft

Apart from one privately owned example, three Walrus aircraft remain preserved within museum collections. In 2008, photographs were taken of what is believed to be the Walrus assigned to the cruiser HMAS Sydney when the wreck of the ship was rediscovered.

Seagull V A2-4

photograph of a Walrus in 2017
A2-4 at the Royal Air Force Museum London in 1980

The Australian-built Seagull V A2-4 is exhibited permanently at the Royal Air Force Museum London. Constructed in Woolston in 1934, it reached Australia in early 1936 and was initially assigned to No. 101 Flight RAAF, which soon became No. 5 Squadron RAAF. Prior to the war, it performed various roles including survey missions and operations from HMAS Sydney. Throughout much of World War II, it operated with No. 9 Squadron RAAF within Australia.

In 1946, the aircraft was sold into civilian hands and was registered as VH–ALB five years later. Throughout the 1950s and 1960s, it was flown by several private Australian owners until it sustained severe damage during a takeoff accident at Taree, New South Wales in 1970. The RAF Museum acquired the damaged plane in exchange for a Supermarine Spitfire along with a payment of AUD 5,000.[note 1] While being transported to the United Kingdom in 1973, it underwent fumigation in Hawaii after black widow spiders were discovered aboard. Restoration efforts began upon its arrival at RAF Henlow, and since 1979 it has been on display at the Royal Air Force Museum London.

Walrus HD874

HD874 at the RAAF Museum in 2014

The Walrus designated HD874 is housed at the RAAF Museum located at RAAF Williams, Point Cook, Victoria. Initially operated by the Fleet Air Arm, it was transferred to the Royal Australian Air Force in 1943. During wartime service, HD874 flew with No. 9 Squadron and the No. 8 Communication Unit.

Following World War II, the aircraft was placed into storage until 1947 when it was assigned to the RAAF's Antarctic Flight for deployment on Heard Island as part of Australia's first Antarctic expedition after the war. Painted a distinctive bright yellow, it flew only once before being severely damaged by a storm. The aircraft was recovered in 1980 and underwent restoration from 1993 through to 2002.

Walrus L2301

photograph of a Walrus in 2011
L2301 at the Fleet Air Arm Museum, Somerset, in 2014

The Walrus exhibited at the Fleet Air Arm Museum located at RNAS Yeovilton is a hybrid aircraft, assembled using the fuselage and engine originating from Walrus L2301. Constructed in 1939, L2301 was delivered to the Irish Air Corps and bore the Irish designation N.18. During its delivery flight on 3 March 1939, it experienced engine failure followed by hull damage after ditching into the sea. It was subsequently towed to the former launch area used by Curtiss H-16 aircraft at the old U.S. Naval Air Station Wexford Ireland.[12] In March 1939, L2301 was among three Walruses (alongside N.19 (L2302) and N.20 (L2303)) supplied to the Irish Air Corps for maritime patrol duties during the period known as the Irish Emergency.[4][2]

On 9 January 1942, four Irish nationals hijacked N.18, intending to fly it to France to join the Luftwaffe. Their attempt was thwarted when RAF Spitfires intercepted and escorted the aircraft to RAF St Eval; both the plane and its occupants were returned to Ireland.[4][12]

Following World War II, N.18 was transferred to Aer Lingus and assigned the Irish civil registration EI-ACC. The airline never operated it, however, and sold it in 1946 to Wing Commander Ronald Gustave Kellett for £150.[4] Subsequently registered as G-AIZG in Britain, it was flown recreationally until 1949 by members of No. 615 Squadron RAF.[12] In 1963, FAA personnel from HMS Heron recovered it from a dump at Haddenham airfield, previously home to RAF Thame,[13] and donated it to the Fleet Air Arm Museum, where restoration took place between 1964 and 1966.[4][12]

Walrus W2718

Walrus W2718 at Duxford in 2021

After serving with the RAF during wartime, Walrus W2718 was operated by Somerton Airways on the Isle of Wight until its retirement in 1947. It was later repurposed as a caravan.[14] The aircraft eventually became part of the collection at Solent Sky, an aviation museum based in Southampton, UK,[15] where initial restoration efforts aimed at returning it to flight status were undertaken.

Restoration resumed in 2011 after being sold again, this time at Vintage Fabrics in Audley End, Essex. In 2018, following another sale to a private owner, the aircraft was relocated to the Aircraft Restoration Company facility at Duxford Aerodrome.[14]

Specifications (Supermarine Walrus I)

Walrus arrangement drawings
Layout diagrams of the Supermarine Walrus

Template:Aircraft specs

See also

Template:Aircontent

Notes

  1. ↑ The Spitfire obtained (TE384) was eventually restored to airworthiness.

References

  1. ↑ London 2003, p. 182.
  2. ↑ 2.0 2.1 London 2003, p. 183.
  3. ↑ Nicholl 1966, p. 116.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 Cite error: Invalid <ref> tag; no text was provided for refs named Smith
  5. ↑ Brown 1971, p. 34.
  6. ↑ Kulikov, Viktor P. (2004). "British aircraft in Russia" (PDF). Air Power History. No. 1. Air Force Historical Foundation.
  7. ↑ 7.0 7.1 7.2 London 2003, p. 213.
  8. ↑ "Whaling Ship 'Balaena' Departs for Antarctic". British Pathé. 1946. Retrieved 20 April 2023.
  9. ↑ Grierson, John (June 1947). "Air-Whaling" (PDF). Flight. Vol. 52, no. 2011. ISSN 0015-3710.
  10. ↑ Brown 1971, p. 47.
  11. ↑ Simpson 2007, p. 8.
  12. ↑ 12.0 12.1 12.2 12.3 Cite error: Invalid <ref> tag; no text was provided for refs named FAAM
  13. ↑ Peter Chamberlain. "1945–1963". Haddenham Airfield: A history of a small Buckinghamshire airfield. Retrieved 29 September 2010.
  14. ↑ 14.0 14.1 Cite error: Invalid <ref> tag; no text was provided for refs named Fid
  15. ↑ "Over 20 aircraft to discover and explore". Solent Sky Museum. Retrieved 9 August 2020.

Sources

Further reading

  • Franks, Norman. The RAF Air-Sea Rescue Service in the Second World War. Barnsley, UK: Pen & Sword Books Limited, 2017. ISBN 978-14738-6-130-5. Available at: https://books.google.com/books?id=Ub-wDQAAQBAJ
  • Lezon, Ricardo Martin, and Robert M. Stitt. "Eyes of the Fleet: Seaplanes in Argentine Navy Service, Part 2." Air Enthusiast, no. 109, January–February 2004, pp. 46–59.

External links

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