The J57 was a development of the XT45 (PT4) turboprop engine intended for the XB-52. As the B-52 power requirements grew, the design evolved into a turbojet, the JT3. The prestigious Collier Trophy for 1952 was awarded to Leonard S. Hobbs, Chief Engineer of United Aircraft Corporation, for "designing and producing the P&W J57 turbojet engine".[3] On May 25, 1953, a J57-powered YF-100A exceeded Mach 1 on its maiden flight.