 The N-9 was initially powered by a 100 hp (75 kW) Curtiss OXX-6 engine.Curtiss was awarded an initial contract for 30 aircraft in August 1916, and an additional 14 were ordered by the United States Army, which maintained a small seaplane operation.It quickly became apparent that the aircraft was underpowered, so Curtiss replaced the engine with a 150 hp (112 kW) Hispano-Suiza, manufactured in the United States under license by Wright-Martin's Simplex division (later Wright Aeronautical).