[Sven]

Originally Posted by AndyJWest

Yes and no. Each 'engine' is in fact two mounted side-by-side, geared to a common propshaft. Not a very good idea, as it turned out. (see http://en.wikipedia.org/wiki/He_177#Engines)

It was a good idea really, it could use already existing engines and it saved drag and other disadvantages of a 4 propeller setup. The engines in the prototypes caught fire due to overheating, this was fixed in the later production variants though with different engines and various other fixes. But just as they had successes the fuel was cut, and the bombers were to be grounded for the rest of the war in favour of the fighters.