Supermarine Sea Lion

Supermarine Sea Lion

Supermarine Sea Lion

The Supermarine Sea Lion was a racing version of the Sea King scout plane. Three versions were produced and were entered in the Schneider Trophy Races of 1919, 1922 and 1923, winning in 1922.

The Sea King/ Sea Lion was a biplane flying boat, powered by a pusher engine mounted between the wings. The pilot sat in an open cockpit just in front of the wings.

The first racing version was the Supermarine Sea Lion I, G-EALP, a single-bay flying power with un-staggered wings and a pusher 450hp Napier Lion IA engine between the wings. This aircraft was probably a modified version of the Sea King I, although that isn't entirely certain. This was one of several British entries for the 1919 contest, which was held at Bournemouth. Unfortunately the weather turned against the competitors. Heavy fog forced all of the aircraft to land, and when the Sea lion attempted to take off later it was damaged in a collision with a floating object. The Sea Lion I survived this collision, but when it landed again sank. The aircraft was later raised, but didn't fly again. Eventually the contest was cancelled without a winner, although the Italians were asked to hold the next contest, as they had reached the highest speed before the fog stopped play.

The Sea Lion II was originally constructed as a amphibian scout aircraft, the Supermarine Sea King II. This made its maiden flight early in 1922, but despite a good performance didn’t sell. It was chose to be the basis of the British entry for the 1922 Schneider Trophy, a privately funded team led by Hubert Scott-Pine and Commander James Bird (one of the directors of Supermarine). The aircraft was redesigned by R.J. Mitchell. It was given smaller equal-span wings and became a single-span pusher flying boat. The amphibious landing gear was removed. The aircraft was powered by a 450hp Napier Lion engine, which was loaned to the team by Napier. In its new configuration it was renamed as the Sea Lion II.

The race was held on 10-12 August, and the Sea Lion II was flown by Captain Henri C. Biard. The only competition came from the Italians, who entered the Macchi M.7, Macchi M.7 Naval and S.I.A.I Savoia S.19, all pusher biplanes.

The Sea Lion II flew the 230 miles triangular course in 1hr 36min 22sec at an average speed of 145.7mph, giving Britain her second victory in the trophy. This performance was also awarded a series of world records – for duration, longest distance and fastest times to cover 100km and 200km, although as this was the first time these records had been set this isn't quite as impressive as it seems!

The aircraft was redesigned again for the 1923 Schneider Trophy. This time Mitchell gave it two-bay wings, a longer fuselage, wingtip floats and a 525hp Lion engine. In this configuration it became the Sea Lion III.

Britain also entered the Blackburn Pellet, but this aircraft suffered from two accidents before the race, sinking after the second one. The main competition came from the first military entry into the contest – two US Navy Curtiss C.R.3 floatplanes. These were dramatically different to the flying boats that had won in previous years, and won an overwhelming victory. The contest was won by Lt David Rittenhouse, USN, at an average speed of 177.38mph. Biard, in the Sea Lion III, could only manage third, at 151.16mph.

The Sea Lion III was lost in an accident in July 1924, when a pilot who was unfamiliar with it stalled at take off and was killed.

This defeat forced Mitchell to reconsider the design of his racing aircraft, and his next Schneider racer would be the Supermarine S.4, the first in a series of racing aircraft that gave Mitchell valuable experience of designing advanced monoplane aircraft, and thus played a part in the design of the Supermarine Spitfire.

Sea Lion I
Engine: Napier Lion IA
Power: 450hp
Crew: 1
Span: 35ft
Length: 26ft 4in
Height: 12ft 3in
Empty weight: 2,000lb
All up weight: 2,900lb
Max speed: 147mph
Endurance: 2hr 30min
Armament: None

Sea Lion II
Engine: Napier Lion II
Power: 450hp
Crew: 1
Span: 32ft
Length: 24ft 9in
Height: 12ft 0in
Empty weight: 2,115lb
Loaded weight: 2,850lb
Max speed: 160mph
Endurance: 3 hours

Sea Lion III
Engine: Napier Lion III
Power: 525hp
Crew: 1
Span: 28ft
Length: 28ft
Height: 12ft
Empty weight: 2,400lb
Maximum take-off weight: 3,275lb
Max speed: 175mph
Endurance: 3 hours


Sea Lion

It's flippers allow it to walk on the land

“One of the Largest Animals in New Zealand”

They can dive to deep depths, they can walk on all fours, and they love to frolic and play! They’re sea lions, an amphibious species of marine mammals. Sea lions can survive in disparate climates and have well-developed social structures that often mimic that of humans. In some locations, like New Zealand, sea lions make the list of largest regional animals.


Sea Lion I var Supermarines första flygplan som byggdes för att delta i tävlingen om Schneidertrofén. [ 1 ] Flygplanet som konstruerades av F. J. Hargreaves var baserat på spaningsflygplanet Supermarine Baby men utrustad med den mer än dubbelt så starka motorn Napier Lion. [ 1 ] [ 2 ] Flygplanet som fick registreringsbokstäverna G-EALP [ 3 ] och flögs av Basil Hobbs kolliderade med ett flytande föremål (troligen en stock) vid starten från Swanage och flygplanet sjönk efter att det landat i Bournemouth. [ 3 ] På grund av dimma bröt de flesta maskiner loppet. Endast en italiensk Savoia S.13 fullföljde de tio varven men diskvalificerades eftersom den missat ett rundningsmärke. [ 3 ]

Det dröjde till 1922 innan Supermarine åter ställde upp med en maskin för att tävla om Schneidertrofén. Den något mindre men betydligt framgångsrikare Supermarine Sea Lion II liknade sin föregångare, men var baserad på Supermarine Sea King och designad av Reginald Joseph Mitchell.


See also

The Supermarine Southampton was a 1920s British flying boat, one of the most successful flying boats of the interwar period. It was a development of the Supermarine Swan, which was used for a ten-passenger service between England and France.

The Supermarine Seagull was a British amphibian biplane flying boat developed from the Supermarine Seal by the Supermarine company. The Seagull was constructed of wood. The lower wing was set in the shoulder position and had two bays. The engine was mounted in a nacelle slung from the upper wing and powered a four-blade propeller in tractor configuration. The fuselage had an oval cross-section and had a planing bottom with two steps.

The Supermarine S.6 is a 1920s British single-engined single-seat racing seaplane built by Supermarine. The S.6 continued the line of Supermarine seaplane racers that were designed for Schneider Trophy contests of the late 1920 and 1930s.

The Supermarine S.4 was a 1920s British single-engined single-seat monoplane racing seaplane built by Supermarine to compete in the 1925 Schneider Trophy. It crashed and was destroyed before the competition started.

The Supermarine Swan was a 1920s British experimental amphibian aircraft built by Supermarine at Woolston. Only one was built and it was used for a passenger service between England and France.

The Supermarine S.5 was a 1920s British single-engined single-seat racing seaplane built by Supermarine. Designed specifically for the Schneider Trophy competition, the S.5 was the progenitor of a line of racing aircraft that ultimately led to the Supermarine Spitfire.

The Supermarine Sea Lion II was a British racing flying boat designed and built by the Supermarine Aviation Works for the 1922 Schneider Trophy at Naples, Italy which it went on to win. The earlier racing flying boat for the 1919 Schneider Trophy the Sea Lion I was a different design.

The Supermarine Sea King was a British amphibious biplane fighter designed and built by the Supermarine Aviation Works in 1920.

The Supermarine Baby was a British flying boat fighter aircraft of the First World War designed and built by the Supermarine Aviation Works. Although only one was built, it formed the basis for the later Sea King fighter and Sea Lion I racer.

The Supermarine Nanok was a British three-engined biplane flying boat built by Supermarine. Built to meet a Royal Danish Navy requirement, the single prototype was rebuilt as a private air yacht and renamed the Supermarine Solent.

The Supermarine Seal was a British amphibian biplane flying boat developed by the Supermarine company. The Seal was further developed into the Supermarine Seagull.

The Avro 539 was a British single-seat racing biplane built by Avro for the 1919 Schneider Trophy.

The Gloster VI was a racing seaplane developed as a contestant for the 1929 Schneider Trophy by the Gloster Aircraft Company.

The Gloster III was a British racing floatplane of the 1920s intended to compete for the Schneider Trophy air race. A single-engined, single-seat biplane, two were built, with one finishing second in the 1925 race.

The Gloster II was a British racing floatplane of the 1920s. A single-engined biplane, two were built to compete in the 1924 Schneider Trophy air race. However the crash of the first prototype during testing meant that it could not be made ready for the race, which was postponed. The second aircraft was also lost in a crash.

The Gloster IV was a British racing floatplane of the 1920s. A single-engined biplane, the Gloster IV was a development of the earlier Gloster III intended to compete in the 1927 Schneider Trophy race. One aircraft competed in the race, but retired part way through. The three aircraft built continued to be used as trainers by the High Speed Flight for several years.

The Blackburn Pellet was a single-engined, single-seater biplane flying boat designed as a contender for the 1923 Schneider Trophy competition. It was destroyed while taking off for the trials of the contest.

The Sopwith Schneider of 1919 was a British racing seaplane. It was a single seat biplane intended to compete in the 1919 Schneider Trophy. After this race was abandoned due to fog, the Schneider was rebuilt into a landplane racer as the Sopwith Rainbow, being destroyed in a crash in 1923.

The SIAI S.51, Savoia Marchetti S.51 or Savoia S.51 was an Italian racing flying boat built by SIAI for the 1922 Schneider Trophy race.

The Supermarine Sheldrake was a British amphibian biplane flying boat developed by Supermarine from the Supermarine Seagull with a revised hull. It was powered by a Napier Lion engine mounted between the wings driving a four-bladed propeller. Only one Sheldrake, serial number N180, was built.


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In need for a contender for the 1922 Schneider Trophy race, Supermarine developed a racing flying boat as a modification of their Sea King II fighter. The Sea King was a single-seat biplane amphibian powered by a 300 hp (224 kW) Hispano Suiza engine in pusher configuration that had first flown in 1921. Modified as a flying boat with a 450 hp (336 kW) Napier Lion engine, G-EBAH was entered into the 1922 race. Flown by Henri Biard, it won the race at an average speed of 145.7 mph (234.48 km/h).

For the 1923 Schneider Race to be held at Cowes, England, the aircraft was re-engined with a 550 hp (410 kW) Napier Lion and redesignated Supermarine Sea Lion III. The aircraft only managed third place behind the American Curtiss CR-3 seaplanes. The aircraft was transferred to the Royal Air Force in 1923.


In need for a contender for the 1919 Schneider Trophy race Supermarine developed a racing flying boat as a modification of their Baby. The Baby was a single-seat biplane fighter flying boat powered by a 450 hp (336 kW) Napier Lion engine in pusher configuration that had first flown in 1917.

Re-built as racing flying boat G-EALP was entered into the 1919 race flown by Basil Hobbs. On 10 September 1919, the aircraft struck flotsam when Hobbs took off from Swanage Bay, having landed in thick fog in order to get his bearings, and the fuselage was holed. When he alighted near Bournemouth Pier for his compulsory first lap landing the aircraft sank. The race ended in chaos due to the fog and the results were annulled.


Sea Lion II var till det yttre lik sin föregångare, men var i själva verket ett helt annat flygplan designat av Reginald Joseph Mitchell. Den var mer strömlinjeformad och något mindre vilket gjorde att den kunde uppnå högre hastighet trots att den hade samma motor. [ 1 ] Flygplanet som fick registreringsbokstäverna G-EBAH och flögs av Henri Biard vann tävlingen om Schneidertrofén 1922 med en medelhastighet av 234,5 km/h. [ 2 ]

Inför nästa års tävling 1923 utrustades flygplanet med en starkare motor, kortade vingar och andra förbättringar och kallades efter det Sea Lion III. Trots förbättringarna fick den se sig slagen av den amerikanska Curtis CR-3. Efter tävlingen lämnades flygplanet över till Royal Air Force, men den starka motorn gjorde flygplanet svårfluget och det totalhavererade i juni 1924. Därmed upphörde också Supermarines satsning på flygbåtar och Mitchell inriktade sig i stället på att konstruera vad som skulle bli Supermarine S.4. [ 1 ]


Supermarine Sea Lion I G-EALP

I understand that, after sinking off Bournemouth during the 1919 Schneider Trophy Race, Sea Lion I G-EALP was salvaged and its hull was put on display at the Science Museum, South Kensington, in 1921. Does anyone know for how long it was on display and what became of it subsequently?

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By: avion ancien - 18th March 2019 at 15:30 Permalink - Edited 18th March 2019 at 15:31

Having contacted the Science Museum, it tells me that its archives contain no reference to G-EALP having been on display at South Kensington and, in consequence, it doesn't know what might have become of the hull (if it had been displayed in the museum). So it looks as if it's another of A.J.Jackson's uncorroborated assertions, for which we don't, and won't, know the basis.

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By: farnboroughrob - 18th March 2019 at 17:30 Permalink

I have seen other references to this going on display, maybe in a magazine of the time? I got the feeling it was a temporary exhibition, probably resulting in a bonfire? I am guessing that they had little interest in such a 'new item' long term. Indeed I remember reading that the famous editor of The Aeroplane CG Grey castigated the museum for preserving Amy Johnson's Moth less the place ended up full of old, worthless aircraft! Sadly the Science Museum has never really promoted its collection and the website is very poor with no history of each air frame unlike the RAFM website.

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By: avion ancien - 18th March 2019 at 18:21 Permalink - Edited 18th March 2019 at 18:22

Thank you, FR. Searching Flight magazine for 1919-22, using the words 'Science Museum', produces nothing relating to the Schneider Trophy Sea Lion. I can't undertake the exercise for The Aeroplane, but if when next you're visiting The Hub . ! Also, they may have there a copy of 'Aeronautics : Catalogue of the Collection in the Science Museum, South Kensington' (HMSO, 1922), although if that does contain any reference to the hull of G-EALP I would have thought that my enquiry of the Science Museum would have thrown this up.

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By: Schneiderman - 18th March 2019 at 19:02 Permalink

I wouldn't worry too much about the museum having no record of it having been put on display as a lot of early stuff is poorly documented. I asked about the preservation of the S6B some time back and they had hardly anything reliable pre-war.

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By: Lazy8 - 18th March 2019 at 20:43 Permalink

"Schneider Trophy Racers" (Robert Hirsch, Motorbooks) says "After the contest the aircraft was dismantled and the hull was loaned to the Science Museum for a 1921 exhibition." That suggests that the reason the museum have no record is that it was never theirs. The ultimate fate will rest with Supermarine. As to what the exhibition was, and when, I don't have an answer.

A note re: searching in old magazines. I've noticed that it was often called simply "the South Kensington Museum" at that time. The 'Science' part comes later.


Some Karaya silliness - Sea Lion and Pellet

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You can see how I have sorted the struts into small zip-lock bags - each strut has a tiny number embossed on the plug - very thoughtful of Karaya

Here are the completed wheels with PE spokes and the lovely little engine made up of ten parts , some of them microscopic!

and the underside showing the tiny bits of filling I had to do.
And here she is with the main struts added and I am working on the engine struts at the moment, following a great build by chap on the Unofficial Airfix website. To put you in the picture , there are six seperate struts for the engine and another four to support the wing in the middle - aarrgghh! All have to be aligned and the correct length

Now the Blackburn Pellet

Not as advanced as the Sea Lion but a start has been made

A Humbrol tin for scale - tiny aren't they! Beautifully crafted resin. The brown thing is the beaching trolley - only used a couple of times!!
Wing and cabane struts added and the empennage and its struts attached to the tail.

Both models in their present state - you can see the upper wing for the Pellet which is upside-down with the odd little Lamblin radiator hanging underneath.

Anyhoo, more later. Stay healthy all you Hyperscale critters!!

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Watch the video: 水上機シーライオン Supermarine Sea Lion II