"If I remember correctly about 3 to 1," That seemed strange to me given multistage compressors. Maybe 3:1 is true for a micro turbines, but for larger jets wik

"If I remember correctly about 3 to 1," That seemed strange to me given multistage compressors. Maybe 3:1 is true for a micro turbines, but for larger jets wikipedia says the pressure ratio is 30:1 to 40:1 citing the Trent 900 at 39:1 and the GE90 at 42:1. Which according to the same article says that a 40:1 PR is equivalent to a 15:1 compression ratio. http://en.wikipedia.org/wiki/Overall_pressure_ratio http://en.wikipedia.org/wiki/Overall_pressure_ratio