Junkers Ju 49

The Junkers Ju 49 was a German research aircraft built to investigate high-altitude flight and the techniques of cabin pressurization. It was the world's second working pressurized aircraft, after the American Engineering Division USD-9A of 1921, and carried the first pressurized cabin in a German aircraft, which held its two crew. A cantilever all-metal monoplane with stressed duralumin skin, corrugated on the flying surfaces, it was powered by the Junkers L88a, an upright V-12 made by combining two six-cylinder inline motors, with a two-stage supercharger and intercooler. Its first flight on 19 October used the unsupercharged L88 version, and the supercharged engine was installed by summer 1932. Intended for about 6,000 m, it was flying at 10,000 m by 1933 and routinely at 12,500 m by 1935, setting no absolute records but feeding experience into later pressurized aircraft such as the Ju 86P. Only one was built, and it crashed in October 1937 while with the German research centre Deutsche Versuchsanstalt fur Luftfahrt.