The Supermarine N.1B was a single-seat scout designed to escort the RNAS's patrol flying boats.
In April 1917 the Admiralty Department of the Air Board issued Specification N.1(b), which called for a small boat to act as an escort to the RNAS's larger flying boats, and to replace the Sopwith Baby seaplane. The aircraft could be a tractor or a pusher, and a flying boat or a floatplane. It was to be armed with one Lewis gun and the mountings for a second above the top wing, have a top speed of 85 knots, a service ceiling of 10,000ft and an endurance of 3 hours. It was to have folding wings so it could be stored onboard ship.
Supermarine produced a pusher biplane, with a two-step hull based on the AD Flying Boat (the Admiralty Department two seat patrol boat first designed in 1915). It had an open cockpit close to the nose. The pusher engine was mounted just below the upper wing. The tailplane was carried just above the vertical tail fin, in order to keep it well above the water. A small fin was added on top of the tailplane after early trials.
The N1.B made its maiden flight in February 1918, with Flight Lieutenant Goodwin at the control The aircraft was originally powered by a 200hp Hispano-Suiza engine, with which it reached 116mph at sea level in April 1918. It was later given a 200hp Sunbeam Arab engine, with which it reached 10,700ft.
Three were ordered (N59, N60 and N61). Of these only N59 was completed and assembled. The parts for N60 were completed, but it was used as a source of spare parts. N.61 wasn't completed. The type wasn't ordered into production.
The N.1B was the start of a long family of Supermarine pusher flying boats,. The Supermarine Sea Lion I may have been built using the hull of N61 and the Sea King I was also based on the N.1B design. The basic design was also used on the Supermarine Seal, the start of a family of aircraft that ended with the Supermarine Walrus, a spotter plane that saw service during the Second World War.
Engine: Hispano-Suiza or Sunbeam Arab
Power: 200hp (either)
Span: 30ft 6in
Length: 26ft 3.5in
Height: 10ft 7in
Empty weight: 1,699lb (Hispano-Suiza) or 1,902lb (Sunbeam Arab)
All-up weight: 1,902lb (Hispano-Suiza) or 2,508lb (Sunbeam Arab)
Max speed: 116mph at sea level (Hispano-Suiza)
Climb Rate: 430ft/ min (Sunbeam Arab)
Service ceiling: 10,700ft (Sunbeam Arab)
Endurance: 3 hours
Armament: One or two .303in Lewis guns