Heinkel (He-70) / Blitz: This fast German mail-plane and passenger aircraft was produced in 1932. The Luftwaffe operated He-70's from 1935 as auxiliary bombers and reconnaissance aircraft. Its main weakness was that elements of the air-frame were made out of "Elektron", a light and strong alloy of magnesium, which burns readily when ignited and is difficult to extinguish. However, most of the monocoque fuselage was made out of Duralumin. Only 15 were built.