The Curtiss Twin JN was a twin engined aircraft based on the famous JN-4 Jenny, produced in small numbers as an observation type.
The Twin JN was briefly designated as the JN-5, but that name was soon passed to a prototype of a true advanced trainer that never entered production, and the twin engined JN became known as the Twin JN.
The prototype Twin JN was produced in April 1916. Its wing span was increased by adding an 11ft 4in centre section on the upper wing, and panels between the lower wings and the fuselage. It was a three bay biplane, with the two Curtiss OX engines mounted on the first set of inter-wing struts. The prototype had one degree of dihedral on the wings outside the flat centre section (making it barely noticeable in photographs), and a Curtiss R-4 rudder with enlarged fin. It carried a crew of two, with the pilot behind the wings and the observer in the nose. This meant that they were too far apart to easily communicate, and reduced the usefulness of the aircraft
On production aircraft the dihedral on the wings was increased to a rather more visible 3.5 degrees, and the fin was modified. The starboard engine was modified so that the propeller rotated in the opposite direction to the port engine, to improve the rather marginal directional controls. The production aircraft were given a third wheel, under the nose, to prevent it from tipping up on landings. The extra power gave the Twin JN a small but useful performance boost, with its top speed increased from the 75mph of the JN-4D to 80mph, and the service ceiling rising from 6,500ft to a rather more useful 11,000ft.
The Twin JN was produced in small numbers. The Army bought seven in 1916 and early 1917 and was given eighth as a donation to the Militia (serials 102-107, 428 and possibly 470).
The Army aircraft were used on the Mexican border in 1916, at the time of Pershing’s Punitive Expedition into Mexico.
One of the eight Army aircraft, serial no.428, was delivered to the army as a Twin JN, but photographs suggest that it was a different design – a two bay biplane, with a different observer’s cockpit a scarff ring, and lacking the nose wheel. This may have been a twin engined version of the Model R.
The US Navy received two Twin JNs (A93 and A198), which were used as twin-float seaplanes. This second aircraft has caused some confusion, and is sometimes reported as a JN-1 used as a gunnery trainer. There wasn’t actually a JN-1, and this appears to be an error.
Engine: Two Curtiss OXX-2
Power: 90hp each
Crew: 2 (pilot and observer)
Span: 52ft 9 3/8in (upper), 43ft 1 3/4in (lower)
Height: 10ft 8 11/33in
Empty weight: 2,030lb
Gross weight: 3,110lb
Max speed: 80mph
Climb Rate: 3,500ft in 10min
Service ceiling: 11,100ft