Famed fighter and display pilot Gerhard Fieseler worked for Raab 1926 and masterminded that company's Fieseler F1 Tigerschwalbe. In 1930 purchased Segel-flugzeugbau Kassel, and 2 years later began building powered aircraft, changing name to Fieseler-Flugzeugbau. Factory at Kassel-Bettenhausen built Lippisch Delta IV as F3 Vespe, and tailed F4 and F5, latter leading to F5R with high-lift flaps. From 1935 company expanded, building 12 He 46, 200 He 51 and 30 He 72, while chief designer Reinhold Mewes produced Fi 97 STOL 4-seater, Fi 98 single-seat dive-bomber and, in early 1936, Fi 156 Storch STOL liaison/observation aircraft (at least 2,895 built by Fieseler, Benes Mraz and Morane-Saulnier). Several other designs remained prototypes, with singular exception of Fi 103 ('V-l') flying-bomb, though parent firm made only minor proportion of over 33,000 missiles produced (but all 175-odd piloted Fi 103R versions).