The Curtiss N-9H was a seaplane version of the famous Curtiss JN-4D trainer used by the U.S. Air Service during the First World War. To make the conversion, a single large central pontoon was mounted below the fuselage, with a small float fitted under each wingtip. These changes required a 10-foot increase in wingspan to compensate for the additional weight.

During the war, 2,500 Navy pilots were trained on the N-9H. In addition to training a generation of Navy pilots, the N-9H was used to develop tactics for ship-borne aircraft operations in 1916 and 1917, using catapults mounted on armored cruisers. After the war, the airplane was again employed to successfully demonstrate a compressed air turntable catapult. In July 1917, several N-9Hs were acquired by the Sperry Gyroscope Company and were used as test vehicles for aerial torpedo experiments conducted for the Navy's Bureau of Ordnance. The N-9H was withdrawn from the U.S. Navy inventory in 1927 after ten years of exemplary service.

The Curtiss N-9 was a seaplane version of the famous Curtiss JN-4 trainer used by the U.S. Air Service during the First World War. To make the conversion, a single large central pontoon was mounted below the fuselage, with a small float fitted under each wingtip. These changes required a 10-foot increase in wingspan to compensate for the additional weight. Further modifications to the standard Curtiss JN-4 design were required to cope with stability problems that emerged in the N-9. They included lengthening the fuselage, increasing the area of the tail surfaces, and installing stabilizing fins on the top of the upper wing. The N-9 was initially powered by a 100-horsepower Curtiss OXX-6 engine. The U.S. Navy made use of wind tunnel data developed at the Massachusetts Institute of Technology in its redesign the JN-4. The N-9 was the first U.S. Naval aircraft to incorporate wind tunnel data directly into its design.

The Curtiss Aeroplane and Motor Company of Garden City, N.Y., received a Navy contract for thirty N-9s in August 1916. Another fourteen were ordered by the U.S. Army, as it was also conducting seaplane operations at that time. The 100-horsepower N-9 was satisfactory for pilot training, but it lacked the performance needed for bombing operations and gunnery training. To meet these requirements, Curtiss replaced the OXX-6 with a 150-horsepower Hispano-Suiza, then being manufactured under license in the United States by the Simplex Division of the Wright-Martin Company, and later by Wright Aeronautical Corporation. This improved model was designated N-9H.

A total of 560 N-9s were manufactured for the Navy during the First World War. Most of them were the Hispano-Suiza-powered N-9H model. Of these, only 100 were built by Curtiss. The majority were produced under license by the Burgess Company of Marblehead, Massachusetts. An additional 50 were assembled after the war by the Navy at the Pensacola Naval Air Station from spare components and engines.

During the war, 2,500 Navy pilots were trained on the N-9. In addition to training a generation of Navy pilots, the N-9 was used to develop tactics for ship-borne aircraft operations in 1916 and 1917, using catapults mounted on armored cruisers. After the war, the N-9 was again employed to successfully demonstrate a compressed air turntable catapult. This type of catapult was later installed on battleships, replacing turret-mounted platforms for launching aircraft. In July 1917, several N-9s were acquired by the Sperry Gyroscope Company and were used as test vehicles for aerial torpedo experiments conducted for the Navy's Bureau of Ordnance. The N-9 was withdrawn from the U.S. Navy inventory in 1927 after ten years of exemplary service.

The example in the NASM collection is the sole surviving Curitss N-9 seaplane trainer. The U.S. Navy re-acquired it from the Museum of Science and Industry in Chicago in 1957, agreeing to take temporary custody of the airplane for the Smithsonian Institution until such time as it was able to accept it. It was officially transferred to the Smithsonian by the Navy in 1963. It was then restored for the Smithsonian at the Naval Air Engineering Laboratory in Philadelphia, which completed the project in 1966.