Supermarine Sea Lion II

Sea Lion II
Role	Racing flying-boatTemplate:Short description
National origin	UK
Manufacturer	Supermarine Aviation Works
Designer	R.J. Mitchell
First flight	1922
Number built	1
Variants	Supermarine Sea Lion III

The Supermarine Sea Lion II was a British racing flying boat built by the Supermarine Aviation Works. Designed by Reginald Mitchell, the Sea Lion II was a modification of Supermarine's Sea King II. It was powered by a Napier Lion engine.

Entered for the 1922 Schneider Trophy contest at Naples, Sea Lion II was planned to be able to attain a speed of . It competed against two Italian aircraft. Supermarine's test pilot Henry Biard flew the aircraft to victory at an average speed of —the first post-World War I success by a British aeroplane in an international competition.

The Sea Lion II was renamed the Sea Lion III for the 1923 contest, after Mitchell modified the design, and it was re-engined. .

Development

The Schneider Trophy race for seaplanes and flying boats had been won by Italy in 1920 (by a Savoia S.19 flying boat, the only aircraft to take part in the meeting) and again in 1921 by a Macchi M.7, in another uncontested race. A third consecutive Italian victory would result in the trophy being permanently retained by Italy. The British aircraft company Supermarine Aviation Works competed in the 1922 contest with a self-funded entry, in contrast to the Italian and French entries, which were sponsored by their respective governments.Template:Sfn The British entry was financed privately by Supermarine's managing director, Hubert Scott-Paine, with the assistance of Napier (who provided the aircraft's engine), Shell (who donated the fuel free of charge), and the Castrol (who gave Supermarine the required lubricants).Template:Sfn

File:Sea Lion II hull and Napier Lion engine on display.jpg

The hull and the Napier Lion engine of the Sea Lion II during its construction

Supermarine developed a racing flying boat as a modification of their Sea King II fighter,Template:Sfn a single-seat biplane amphibian powered by a Hispano Suiza engine in pusher configuration that had first flown in 1921.Template:Sfn The Sea King II was of similar layout to the Supermarine Sea Lion I that had competed in the 1919 Schneider Trophy race, with the Sea Lion I a modified version of the earlier Supermarine Baby, a flying boat fighter aircraft of the First World War.Template:Sfn Compared with the Sea Lion I, the new aircraft had a more refined hull shape, a differently-designed tail, and a propeller that had four blades, instead of two.Template:Sfn

The Sea King II was modified at the company's works at Woolston, Southampton by Supermarine's chief designer and chief engineer, Reginald Mitchell,Template:Sfn who incorporated a Napier Lion engine loaned by Napier.Template:SfnTemplate:Sfn The new engine resulted in an increase in power of 50 per cent;Template:Sfn Mitchell hoped the new aircraft would be able to reach a speed of , which if attained would make it the fastest Britain aircraft to date.Template:Sfn His modifications to the rudder and the fin caused the hull to have to be strengthened by adding an extra layer of varnished fabric stretched around the structure.Template:Sfn The Sea Lion II was registered as G-EBAH.Template:Sfn

1922 Schneider Trophy contest

The Sea Lion II was entered into the 1922 Schneider Trophy race,Template:Sfn which took place at Naples on 12 August 1922 after the Italians brought the initial date for the race forward by two weeks.Template:SfnTemplate:Sfn High winds restricted the time available for the plane to be flight tested in England.Template:Sfn The aircraft was dismantled before being put into crates and transported to Naples on board SS Philomel, free of charge.Template:SfnTemplate:Sfn The Sea Lion II competed against two Italian aircraft, a Macchi S.7 and a Savioa S.19, with two French entrants failing to start the race.Template:SfnTemplate:Sfn The course consisted of 13 laps, each of length ;Template:Sfn during practice runs, none of the teams showed their true capabilities.Template:Sfn The race, which took place on an unusually hot day, was uneventful.Template:SfnTemplate:Sfn Sea Lion II was flown by Henry Biard, who won the race at an average speed of ,Template:Sfn and took over one and a half minutes less time to complete the course than the second-placed aircraft, flown by Alessandro Passaleva.Template:Sfn The victory was the first post-World War I success by a British aircraft in an international competition—it generated publicity for Supermarine, and demonstrated Mitchell's "magic touch" when modifying the airframe to improve the performance of an aircraft that originated from an old design.Template:SfnTemplate:Sfn

For the 1923 Schneider Race, which was held at Cowes on the Isle of Wight, the Sea Lion II was redesigned and re-engined with a Napier Lion engine. It was renamed as the Supermarine Sea Lion III.Template:SfnTemplate:Sfn

Operators

• Royal Air Force
• Supermarine Aviation Works

See also

Related lists

• List of flying boats and floatplanes