The B-50C was an advanced version of the B-50, designed to squeeze the maximum amount of performance that could possibly be gotten from the basic Superfortress design. The B-50C was to be powered by four new R-4360-43 turbo-compound engines, each rated at 4500 hp. The turbo-compound engines were sometimes referred to as Variable Discharge Turbine (VDT) engines, and had also been considered for the B-36. The change to turbocompound engines required a complete redesign of the airframe, with a wider wingspan and a longer fuselage to carry the additional loads imposed by the new wing. The wider wingspan required additional outrigger landing gear wheels to stabilize the aircraft on the ground.
The takeoff weight of the B-50C was estimated to be 230,000 pounds, almost 50,000 pounds greater than that of most other B-50s. A maximum speed of 430 mph was envisaged, plus a range of 9000 miles.
An early B-50A was set aside to serve as a prototype for the YB-50C. The mockup of the B-50C was completed by November of 1948. 43 production aircraft (14 B-50Cs and 29 RB-50Cs) were ordered. In late 1948, the Air Force concluded that the B-50C was sufficiently different from the B-50A and B which preceded it that a new bomber model number of B-54 was assigned.
However, fiscal year 1949 was a difficult time for the American defense budget, with large cuts being forced by financial exigencies. The B-54 offered little or no growth potential since it squeezed the maximum possible amount out of an already obsolescent design. In addition, it promised to be quite expensive to introduce into service. The outrigger landing gear fitted to the B-54 required wider taxiways than those which existed at operating bases, and its introduction into service would require a massive program of base reconstruction. In addition, it was discovered that jet engines could not be installed on the B-54 without completely redesigning the wings. The new K-1 bombing system could not be installed without sacrificing a belly turret or without a drastic alteration in the aircraft's fuselage.
Air Force Secretary W. Stuart Symington and General Vandenberg both supported the B-54 project, but General Curtis LeMay vigorously opposed it and argued for the cancellation of the B-54 in favor of more B-36s. The development of the B-36D with auxiliary jet pods fitted underneath the outer wings promised superior performance in speed, altitude and range, and, pending the availability of the B-52, General LeMay argued that the B-36 provided the best option for strategic deterrence. In addition, jet bombers then under development promised to achieve an even better performance.
However, Secretary Symington and General Vandenberg were reluctant to terminate the B-54 since the loss of the B-54 and the procurement of more B-36s would alter the medium/heavy bomber mix that had been recently approved by the Joint Chiefs of Staff. As an alternative, Secretary Symington proposed that some additional B-50s be substituted for the B-54. General LeMay was unhappy with this proposal as well, and countered with an argument that if it were not possible to replace all programmed B-54s by B-36s, the best alternative would be to secure additional B-47 medium bombers. After balancing all factors involved, the Board of Senior Officers agreed with General LeMay and recommended that the B-54 project be dropped in favor of the procurement of more B-36s and that the production of the B-47 Stratojet should be accelerated. The Board's recommendations were approved by Secretary Symington and General Vandenberg on April 5, 1949, and the B-54 project was formally cancelled. The partially-built YB-50C was also cancelled.
46-061 Boeing YB-50C Superfortress - Project cancelled 49-200/206 cancelled contract for Boeing B-54A - originally designated B-50C 49-207/229 cancelled contract for Boeing RB-54A - originally designated RB-50C 49-1757/177O Cancelled contract for Boeing B-54A originally designated B-50C 49-1771/1799 Cancelled contract for Boeing RB-54A originally designated RB-50C