Rolls-Royce considered the variable stator idea in the 1940s, but abandoned it until using it in the 1980s on the V2500 engine. They began development of two-spool designs, a concept that was also selected by Pratt & Whitney. The variable stator path was only selected by GE after a year-long design study competition comparing two spools and several stages of variable stators with objectives of efficient performance at cruise Mach 0.9 and at Mach 2, increased thrust, reduced fuel consumption and weight. The J79 emerged as a powerful, lightweight design 2,000 lb lighter than its 2-shaft competitor for the B-58, the J57 engine, and GE began considering it as the basis for a high-power engine for commercial use.