The Supermarine Southampton established the British Empire’s expectation of a long-range, independent flying boat capability. It was the first major success in what became a series of large, multi-engine flying boat designs from Supermarine, all designed by Reginald J. Mitchell and each an iterative development, building on the success of the previous example.
The family started with the Supermarine Swan, a 1924 one off built to specification 21/22 for a “twin-engined amphibian flying boat for civil operations”. The Swan had unusual forward-folding wings, and a ‘landing carriage’ that could be brought up below the wings. Its retraction was powered by a small, horizontally rotatable propeller and gear system, but the equipment was later removed, making it a pure flying boat, along with the wing folding.
Initially powered by two 360hp Rolls-Royce Eagle IXs, these were replaced by 450hp Napier Lion IIBs in the conventional biplane layout. It had a very deep Linton Hope wood-structure fuselage and planing hull. The pilot’s cockpit was in something like a submarine’s conning tower set above the fuselage, leaving the hull interior clear for passengers. First flown on 25 March 1924 by Capt Henri C. Biard, i…
