The Curtiss N-9 was a seaplane variant of the Curtiss JN-4 "Jenny" military trainer used during the First World War. As a seaplane, the N-9 was equipped with a single central pontoon mounted under the fuselage. A small float was fitted under each wingtip. With the additional weight of the pontoon, a number of structural and aerodynamic changes were required, the design of which made use of wind tunnel data developed at the Massachusetts Institute of Technology, meaning the N-9 was the first US Naval aircraft to incorporate wind tunnel data directly into its design. The wingspan was stretched an additional 10 feet, the fuselage was lengthened, the tail surfaces were enlarged, and stabilizing fins were added to the top of the top wing. The N-9 was initially powered by a 100 hp Curtiss OX-6 engine.
Curtiss was awarded an initial contract for 30 aircraft in August, 1916, and an additional 14 were ordered by the US Army, which maintained a small seaplane operation. It became quickly apparent that the aircraft was underpowered, so Curtiss replaces the engine with a 150 hp Hispano-Suiza, manufactured in the US under license by Wright-Martin's Simplex division (later Wright Aeronautical). The aircraft was redesignated N-9H.
A total of 560 N-9s were built during the war, most of which were "H" models. Only 100 were actually built by Curtiss. Most were built under license by the Burgess Company of Marblehead, Massachusetts. Fifty others were assembled after the war by the Navy at the Pensacola Naval Air Station from spare components and engines.
Over 2,500 US Navy pilots received their seaplane training in the N-9s. Besides this primary role, though, the aircraft was also used to help develop ship-borne aircraft operations during the war, especially the development of ship-mounted launch catapults. In 1917, several N-9s were provided to the Sperry Gyroscope Company for conversion to the Hewitt-Sperry Automatic Airplane configuration, flight testing the new autopilot components intended to be used in pilotless "aerial torpedoes".
The N-9s were retired by the Navy in 1927, as more modern trainers became available. Only one example of the type has survived, and is now a part of the National Air and Space Museum collection. Originally on display at Chicago's Museum of Science and Industry, it was transferred back to the Navy pending transport to NASM. It was fully restored in 1966 by the Naval Air Engineering Laboratory in Philadelphia, Pennsylvania.
- Length: 30 ft 10 in (9.4 m)
- Wingspan: 53 ft 4 in (16.2 m)
- Height: 10 ft 9 in (3.3 m)
- Empty weight: 2,140 lb (973 kg)
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