version JN-4HG — gunnery trainer version JN-4HM — communications conversion of JN-4HT, powered by Wright-Hisso E 150-hp (112-kW), six converted, used to fly the first US Air Mail (May–August, 1918) JN-5H — advanced trainer biplane, only one built JN-6 — improved version of JN-5 trainer biplane series, notably used four ailerons, 1,035 built for the US Army and five for the US Navy JN-6H — improved version of the JN-6 JN-6BH — bomber trainer version JN-6HG-1 — two-seat, dual-control trainer version, 560 built from JN-6 production, 34 for US Navy JN-6HG-2 — single-control gunnery trainer. 90 delivered JN-6HO — single-control observer trainer version, 106 delivered JN-6HP — single-control pursuit fighter trainer version JNS ("standardized") — During the postwar years of the early 1920s, between 200 and 300 US Army aircraft were upgraded to a common standard of equipment and modernized. "Specials" Allison Monoplane — conversion of JN-4 (Can) G-CAJL by the Allison Company, Kansas, that mounted a parasol wing in place of the biplane configuration, only one conversion made Curtiss Stinson Special (1918) — a custom-built, single-seat aircraft for Katherine Stinson, constructed from the fuselage of a Curtiss Model S plus new biplane wings and JN-4 tail surfaces, powered by a 100-hp (74.5-kW) OXX-6 Ericson Special Three — Some reconditioned aircraft built by Canadian Aeroplanes Ltd. were fitted with a third cockpit. Hennessey Monoplane — a 1926 monoplane conversion by James R. Hennessey, three-place transport, 90-hp Curtiss OX-5, span: 36 ft (11 m) length: 25 ft (7.6 m) Severski 1926 biplane — a JN-4 modified with a roller/ski undercarriage, one experimental aircraft converted by the Seversky company Sperry Monoplane — conversion offered by the Sperry Company that mounted a parasol wing in place of the biplane configuration Twin JN — An enlarged twin-engined version of the JN-4, they were powered by two OXX-2 V-8 engines, built in 1916 as the JN-5 for an observation role; among the many other modifications was an enlarged wingspan and new rudder adapted from the Curtiss Model R-4. Two of the series saw action with the US Army on the Mexican border in 1916–1917. A total of eight Twin JNs were built, with two in US Navy service. Operators Military operators Argentine Naval Aviation Australian Flying Corps No. 3 Squadron AFC - Used for training. Central Flying School AFC at Point Cook, Victoria. Brazilian Naval Aviation (JN-4D variant) Royal Flying Corps Canada (primarily JN-4 (Can)