JN-4

JN "Jenny"
Curtiss JN-4 Jenny, 1918
Role	Trainer
Manufacturer	Curtiss
Designer	Benjamin D. Thomas
Introduction	1915
Primary users	U.S. Army Air Service Royal Flying Corps
Number built	6,813
Unit cost	$5,465
Variants	Curtiss N-9 Curtiss JN-6H

The Curtiss JN-4 "Jenny" was one of a series of "JN" biplanes built by the 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 U.S. Army, the "Jenny" (the common nickname derived from "JN-4", with an open-topped four appearing as a Y) continued after World War I as a civil aircraft, as it became 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 America to civil aviation through much of the 1920s.

Curtiss combined the best features of the model J and model N trainers, built for the Army and Navy, and began producing the JN or "Jenny" series of aircraft in 1915. 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.

The 1st Aero Squadron of the Aviation Section, U.S. Signal Corps received eight JN-2s at San Diego in July 1915. The squadron was transferred to Fort Sill, Oklahoma, in August to work with the Field Artillery School, during which one JN-2 crashed, resulting in a fatality. 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.

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