The He 177 used two Daimler-Benz DB 606 "power system" engines, each of which consisted of two combined Daimler-Benz DB 601 engines, each DB 606 weighed 1.5 tons. The He 177A-3 and its successors used two DB 610 "power system" engines, each of which consisted of two combined Daimler-Benz DB 605 engines, each DB 610 weighed 1.5 tons. Due to problems with both the DB 606 and the DB 610, the He 277 was intended to use four unitized BMW 801E 14-cylinder radial engines, each mounted in an individual nacelle and each turning a three-blade, four-meter diameter propeller.