In many ways, the Curtiss JN-4 Jenny could be considered the Model T of the skies. Roughly a contemporary of Ford’s famous car, the Jenny would eventually help to establish the practical reality of American aviation.
The Jenny was the first aircraft purchased in quantity by the American military, and consequently was one of the first mass-produced American aircraft. Used to train more than 90 percent of American pilots during WWI, it played a key role at the beginning of what would become the most powerful air force on Earth.
Before 1927, the Jenny would also be the first aircraft many Americans would ever see close up, let alone fly in. Post-war surplus Jennys, bought by enterprising barnstormers, flew across rural America to sell rides, thrill spectators, and inspire young pilots-to-be. It would have been rare indeed to find an American pilot that had not flown in the Jenny. Charles Lindbergh’s first aircraft was a Jenny bought in 1923 for $500, the equivalent of approximately $7,000 in 2016.
The Jenny began as a combination of two aircraft: the model J, designed by the British engineer, Douglas Thomas, formerly of the Sopwith Aviation Company and working under contract to Glenn Curtiss; and the model N, which was a similar design under parallel development. Both were developed as two-seat tractor aircraft, powered by the new Curtiss OX-5 engine.
With the best features of the J and N models combined, the American Army began ordering Jennys in December 1914, under the official designation JN-2. The “Jenny” nickname followed, derived from the JN designation prefix.
First used by the Army Signal Corps in 1916 for tactical operations in Mexico against Pancho Villa, the Jenny design was subsequently upgraded and given the designation JN-3.
The British Royal Navy ordered the upgraded Jenny for use as a primary trainer, and Curtiss opened another factory to meet the demand. Further design changes resulted in the JN-4 and JN-4A models, which were sold to the U.S. Army Air Service, the U.S. Navy, the British Royal Flying Corps and the British Navy.
Design changes continued, resulting in several JN designations: a Canadian licensed JN-4 known as the “Canuck,” a JN-4B, which had some success in the civilian market, and one experimental JN-4C. In 1917, one month after America entered WWI, the definitive version of the Jenny was introduced as the JN-4D.
Wartime demand totally overwhelmed Curtiss’ production capacity. Along with Canadian production, six other American companies were contracted to share the load: Fowler Airplane Corporation, Liberty Iron Works, Springfield Aircraft Corporation, St. Louis Aircraft Corporation, U.S. Aircraft Corporation, and Howell & Lesser.
During the Great War, Jennys were modified in numerous ways to perform various roles, some resulting in further designations such as: N-9, JN-4H, JN-4HT, and JN-4HB. The JN-4H models featured 150-hp Hispano-Suiza engines replacing the 90-hp OX-5, a welcome upgrade for the seriously under-powered Jenny. While designed and used primarily as a trainer, the Jenny also saw service as a reconnaissance, bomber, ground attack, seaplane, and fighter aircraft.
Flight instruction in the Jenny was completed in about 50 hours over the course of six to eight weeks. Training began in the front seat, with between four to 10 hours of dual seat instruction (with the instructor sitting in back screaming directions over the roar of the engine). Soloing moved the student into the back seat — the Jenny was always soloed from the back. After 24 hours of flying solo, followed by 16 hours of cross-country, training was complete.
In its intended role as a primary trainer, the JN-4D is said to have performed well, although it also has been said, “If you can fly the Jenny, you can fly anything!” It had a maximum speed of around 75 mph, and cruised about 10 mph less, with a landing speed of about 40 mph. It had relatively sluggish handling characteristics, with a modest rate of climb, all of 200 feet per minute. Stall recovery was tricky and used up a great deal of altitude, and its OX-5 engine was often rough-running and unreliable. Consequently, about 20 percent of all Jennys built were destroyed during flight training.
More than 6,000 Jennys were ultimately produced, but at war’s end, military orders were abruptly terminated. However, public demand for surplus aircraft was high. At 13 cents on the dollar, Curtiss bought $20 million worth of Jennys back from the U.S. government, refurbished, and resold them.
Jennys, along with a host of associated after-market parts and services, flooded a lucrative civil market. Along with the barnstormers roaming the countryside, Jennys found their way into several industries, including transportation, airmail, forest service, surveying, and many others. American civil aviation boomed.
Up through the early 1920s, Jennys became extremely popular and widely available, especially when air services began selling them as surplus. Private owners also sold Jennys among themselves, sometimes for as little as $50. However, around 1925 as improved aircraft designs became available, the popularity of the Jenny began to decline.
In 1926, the Air Commerce Act was passed, and the era of the Curtiss Jenny drew to a close. The Jenny in commercial use simply could not meet safety requirements. For a time, some continued to fly under grandfather clauses, but annual inspections eventually grounded the remaining aircraft.