by Jamouneau, replaced the J-2. The changes integrated the vertical fin of the tail into the rear fuselage structure and covered it simultaneously with each of the fuselage's sides, changed the rearmost side window's shape to a smoothly curved half-oval outline and placed a steerable tailwheel at the rear end of the J-2's leaf spring-style tailskid, linked for its steering function to the lower end of the rudder with springs and lightweight chains to either end of a double-ended rudder control horn. Powered by a 40 hp (30 kW) engine, in 1938, it sold for just over $1,000. Several alternative air-cooled engines, typically flat-fours, powered the J-3 Cubs, designated J3C when using the Continental A series, J3F using the Franklin 4AC, and J3L with the Lycoming O-145. Very few examples, designated J3P, were equipped with Lenape Papoose 3-cylinder radial engines. The outbreak of hostilities in Europe in 1939, along with the growing realization that the United States might soon be drawn into World War II, resulted in the formation of the Civilian Pilot Training Program (CPTP). The Piper J-3 Cub became the primary trainer aircraft of the CPTP and played an integral role in its success, achieving legendary status. About 75% of all new pilots in the CPTP (from a total of 435,165 graduates) were trained in Cubs. By war's end, 80% of all United States military pilots had received their initial flight training in Piper Cubs. The need for new pilots created an insatiable appetite for the Cub. In 1940, the year before the United States entered the war, 3,016 Cubs had been built. Wartime demands soon increased that production rate to one Cub being built every 20 minutes. Flitfire Prior to the United States entering World War II, J-3s were part of a fund-raising program to support the United Kingdom. Billed as a Flitfire, a Piper Cub J3 bearing Royal Air Force insignia was donated by W. T. Piper and Franklin Motors to the RAF Benevolent Fund to be raffled off. Piper distributors nationwide were encouraged to do the same. On April 29, 1941, all 48 Flitfire aircraft, one for each of the 48 states that made up the country at that time, flew into La Guardia Field for a dedication and fundraising event which included Royal Navy officers from the battleship HMS Malaya, in New York for repairs, as honored guests. At least three of the original