|Jungmann CASA 1.131
|Jungmeister CASA 1.133
Sturdy and agile, the Bü 131A was first delivered to the Deutscher Luftsportverband (DLV). The Bü 131B was selected as the primary basic trainer for the German Luftwaffe, and it served with "virtually all" the Luftwaffe's primary flying schools during the war, as well as with night harassment units such as Nachtschlacht Gruppen (NSGr) 2, 11, and 12. Yugoslavia was the main prewar export customer; "as many as 400 may have found their way" there. She was joined by Bulgaria with 15 and Romania with 40.
Production licenses were granted to Switzerland (using 94, 88 built under licence to Dornier), Spain (building about 530), Hungary (which operated 315), Czechoslovakia (10, as the Tatra T 131, before war began), and Japan, the last of which built 1,037 for Army with Hatsukaze power as the Kokusai Ki-86 and 339 for the Imperial Japanese Navy Air Service (IJNAS) as the Kyushu K9W. In Spain, production continued at CASA until the early 1960s. The Jungmann was retained as the Spanish Air Force's primary basic trainer until 1968.
The Bü 133 was a development of the Bücker Bü 131 Jungmann two-seat basic trainer. First flown in 1935 (by Luise Hoffmann, the first female works pilot in Germany), it was slightly smaller than the Bü 131. The prototype, D-EVEO, was powered by a 140 hp (104 kW) Hirth HM506 inverted, air-cooled inline-6 engine.
The aircraft showed "astonishing agility" at its first public appearance, the 1936 International Aerobatic Championship at Rangsdorf, but the Bü 133A garnered no orders; only two Bü 133Bs, with 160 hp (119 kW) version of that same Hirth HM506 inline-6 engine, were built.
The main production type was the 160 hp (119 kW) Siemens-Bramo Sh 14A radial powered Bü 133C, which had a distinctive cowling and a 13 cm (5.1 in)-shorter fuselage, and the same fine aerobatic performance as the Bü 133A.
Fifty-two were manufactured under licence by Dornier for the Swiss Air Force (which kept it in service until 1968),. A similar number were built for the Spanish air force by CASA, and were designated the CASA 1-133.
The Taylor E-2 Cub first appeared in 1930, built by Taylor Aircraft in Bradford, Pennsylvania. Sponsored by William T. Piper, a Bradford industrialist and investor, the affordable E-2 was meant to encourage greater interest in aviation. Later in 1930, the company went bankrupt, with Piper buying the assets but keeping founder C. Gilbert Taylor on as president. In 1936, an earlier Cub was altered by employee Walter Jamouneau to become the J-2 while Taylor was on sick leave. (The coincidence led some to believe that the "J" stood for Jamouneau, while aviation historian Peter Bowers concluded that the letter simply followed the E, F, G, and H models, with the I omitted because it could be mistaken for the numeral one). When he saw the redesign, Taylor was so incensed that he fired Jamouneau. Piper, however, had encouraged Jamouneau's changes, and hired him back. Piper then bought Taylor's share in the company, paying him US$250 per month for three years.
Although sales were initially slow, about 1,200 J-2s were produced before a fire in the Piper factory ended its production in 1938. After Piper moved his company from Bradford to Lock Haven, the J-3, which featured further changes by Jamouneau, replaced the J-2. The changes mostly amounted to integrating the vertical fin of the tail into the rear fuselage structure and covering it simultaneously with each of the fuselage's sides, changing the rearmost side window's shape to a smoothly curved half-oval outline, and placing a true 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.
A number of different air-cooled engines, most of flat-four configuration, were used to power J-3 Cubs, resulting in differing model designations for each type: the J3C models used the Continental A series, the J3F used the Franklin 4AC, and the J3L used the Lycoming O-145. A 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. 75 percent of all new pilots in the CPTP (from a total of 435,165 graduates) were trained in Cubs. By war's end, 80 percent 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' entry into the war, 3,016 Cubs had been built; wartime demands soon increased that production rate to one Cub being built every 20 minutes.