Rolls-Royce RB401

The Rolls-Royce RB.401 was a British two-spool business jet engine that Rolls-Royce began developing in the mid-1970s as a replacement for the Viper. Prototype RB.401-06 engines were already being built when the higher-thrust RB.401-07 was approved. Both used a single-stage fan driven by a two-stage low-pressure turbine, an eight-stage high-pressure compressor, an annular combustor and a single-stage transonic high-pressure turbine, and the -07 had a larger fan. The -07 was rated at 5,540 lbf (24.7 kN) take-off thrust with a bypass ratio of 4.2 to 1. Ground testing of both versions continued into the early 1980s, but a lack of funds led to the project being cancelled.