Junkers J 21

The Junkers J 21, sold as the T 21 and H 21, was a reconnaissance aircraft designed in Germany in the early 1920s and produced in the Soviet Union at the Junkers plant at Fili for the Soviet Air Force, where it was known as the Ju 21. It was an all-metal parasol-wing monoplane with a fixed tailskid undercarriage and a pilot and observer in tandem open cockpits. Two prototypes were built at Dessau, the second with a wing of reduced area, and although they missed the performance the Soviets had specified, series production began at Fili in August 1923. The production version had a BMW IV engine in place of the BMW III first fitted and carried machine guns for both crew, and a few examples tried L2 and L5 engines with little gain. Its performance was only marginally better than the First World War de Havilland DH-9A it was bought to replace, so it was itself soon replaced by licence-built DH-9As as the Polikarpov R-1. The Reichswehr evaluated it at Lipetsk and rejected it, and one went to Iran in 1924. Variants such as the single-seat J 22 fighter did not enter production.