Re: Both engines?
LEAP works differently to the PW geared TF. The PW uses a planetary gear box to reduce the rotational speed for the fan compared to the low-pressure turbine that drives it (and the LP compressor right behind it for the core).
RR did the right thing when they developed the RB211 (from which all modern Trent engines are derived). That was the first commercial three-spool design (and three shafts within each other), so that the HP turbine drives HP compressor, IP turbine drives the LP compressor and LP turbine drives the fan with *no* gearing needed. They patented that if I remember correctly.
PW is trying to do the same thing with two spools... it's a design that's been described as too complex and too heavy, and now too problematic, but hey...
Biting the hand that feeds IT
