Curtiss JN Jenny

The Curtiss JN "Jenny" is a series of biplanes built by the Glenn Curtiss Aeroplane Company of Hammondsport, New York, later the Curtiss Aeroplane and Motor Company. Although the Curtiss JN series was originally produced as a training aircraft for the US Army, the "Jenny" (the common nickname derived from "JN") continued after World War I as a civilian aircraft, becoming the "backbone of American postwar [civil] aviation".

Thousands of surplus Jennys were sold at bargain prices to private owners in the years after the war, and became central to the barnstorming era that helped awaken the US to civil aviation through much of the 1920s.

Design and development

Curtiss began producing the JN or "Jenny" series of aircraft in 1915. While marketed to the US Army and US Navy as combining the best features of the model J and model N trainers, it was, in fact, a modified model J, with only the upper wing span adjusted. Curtiss built only a limited number of the JN-1 and JN-2 biplanes. The design was commissioned by Glenn Curtiss from Englishman Benjamin Douglas Thomas, formerly of the Sopwith Aviation Company.

The JN-2 was an equal-span biplane with ailerons controlled by a shoulder yoke in the aft cockpit. It was deficient in performance, particularly climbing, because of excessive weight. The improved JN-3 incorporated unequal spans with ailerons only on the upper wings, controlled by a wheel. In addition, a foot bar was added to control the rudder.

thumb|left|Curtiss JN-3, the progenitor of the JN-4, deployed to Mexico, around 1916 The pilots of the squadron met with its commander, Capt. [[Benjamin Foulois, to advise that the JN-2 was unsafe because of low power, shoddy construction, lack of stability, and overly sensitive rudder. Foulois and his executive officer Capt. Thomas D. Milling disagreed, and flights continued until a second JN-2 crashed in early September, resulting in the grounding of the six remaining JN-2s until mid-October. When two new JN-3s were delivered, the grounded aircraft were then upgraded in accordance with the new design. In March 1916, these eight JN-3s were deployed to Mexico for aerial observation during the Pancho Villa Expedition of 1916–1917.

After the successful deployment of the JN-3, Curtiss produced a development, known as the JN-4, with orders from both the US Army and an order in December 1916 from the Royal Flying Corps for a training aircraft to be based in Canada. by Western Electric Company (Bell Labs) design engineers Lewis M. Clement and Raymond Heising, the developers of the experimental wind generator-powered airborne wireless voice transmitter and receiver equipment.

In early 1919, a USMC JN-4 was also credited with what is believed to be the first successful dive-bombing attack during the United States occupation of Haiti. USMC pilot Lt Lawson H. Sanderson mounted a carbine barrel in front of the windshield of his JN-4 (previously, an unarmed trainer that had a machine gun mounted in the rear cockpit) as an improvised bomb sight that was lined up with the long axis of his aircraft, loaded a bomb in a canvas mail bag that was attached to the JN-4's belly, and launched a single-handed raid at treetop level, in support of a USMC unit that had been trapped by Haitian Cacos rebels. Although the JN-4 almost disintegrated in the pullout, the attack was effective and led to Sanderson in 1920 developing further dive-bombing techniques to provide Marine pilots with close aerial support to infantry comrades.

Variants

thumb|A JN-4 C227 "Canuck" (USAAS #39158) operated by the US Air Army Air Service in 1918, is now restored and on display at the Canada Aviation and Space Museum.

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"

thumb|The most radical development of the Curtiss JN-4 was the Twin JN (or "Twin Jenny") in limited production and service with the US military.

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. 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