This aircraft was being developed as a true Heavy Bomber. However, problems with the engine arrangement caused considerable delay and many crashes due to engine fires. Despite many problems it went on to be mass produced. Seventy five percent of the prototypes crashed and a good percentage of pre-production airframes were written off in crashed or in-flight fires. A significant number were used in tank busting using 50 and 75mm guns. This aircraft was such a big problem that the manufacturer was forbidden to develop a four engine version, but done so anyway with the result being a different model. Name this aircraft. Answer by PM only. Do not answer " Was It " or with a question mark. Name of the aircraft is sufficient. Answer will post at 1100 hrs on Friday, 12 / 15. Welcome aboard new players: Chopperfan, Smoffo and Bofuf.