Although the first series of JN-4s was virtually identical to the JN-3, the JN-4 series was based on production orders from 1915 to 1919. •
JN-1 — possibly unofficial designation of the second
Model J, which served as the prototype for the Model JN. •
JN-1W — Two aircraft that appear in US Navy records, which may have been confused with the
Models S-4 and S-5. •
JN-2 — first production version, 8 built •
JN-3 — variant with new unequal-span wings and improved flight controls, 97 built for the
RNAS (some sources indicate 91, but serial numbers total 97; 12 built in Canada) plus 2 for the US Army. The six surviving JN-2s were modified to this standard. •
JN-4A — production version of the JN-4, 781 built •
JN-4B — This version was powered by an OX-2 piston engine; 76 were built for the US Army, and nine for the US Navy. •
JN-4C — experimental version, only two were built •
JN-4 (Canadian) Canuck — Canadian-built version, 1,260 built by
Canadian Aeroplanes Ltd. for the RFC in Canada/RAF in Canada and USAAC: Independently derived from the JN-3, it had a lighter airframe, ailerons on both wings, a bigger and more rounded rudder, and differently shaped wings, stabilizer, and elevators. Its use by the USAAC was curtailed as the lighter structure was claimed to cause more accidents than the US-built aircraft, although no air fatalities were attributed to the structural integrity of the type. •
JN-4D — improved version, adopting the control stick from the JN-4 (Canadian) 2,812 built •
JN-4D-2 — One prototype only, the engine mount was revised to eliminate the down thrust position. •
JN-4H — two-seat advanced trainer biplane with ailerons on both wings, 929 built for the US Army, notable for introducing the use of the
Wright Aeronautical license-built
Hispano-Suiza 8 V-8 engine for greater power and reliability •
JN-4HT — two-seat, dual-control trainer version •
JN-4HB — bombing trainer 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-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 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==