The Junkers EF 61 was an aircraft used by Germany for high altitude flight research before World War 2.
Probably Junkers was world leader in high—flying aircraft until the Hs 128/130 programme. The Ju 49 of 1931 was the first aircraft in the world with a pressure cabin, and in the two EF 61 research aircraft of 1936 work went much further. Odd in that much of their outer skin was fabric, these aircraft had a crew of two in a pressure cabin forming the nose. V1 had a large pilot porthole in the nose, a sandwich of special plastics called Reilit. V2 had a raised metal cupola offset to the left, with small ports. At the rear of this cupola was provision for an MG 15, while four 551lb (25Okg) bombs could be carried in an external bav. Both aircraft crashed, V1 due to control flutter In December 1937 the official view was that much more research would be needed before bombers could fly high enough to be immune to interception.