I was pretty sure it was down to weight althought wasn't sure how other factors were considered. It's been proven that the RB211 (with the IEN) on over 80% of the worlds 757s is more fuel efficient than the PW 2037.
I understand that the IEN gives increased thrust and better fuel efficiency as well as reduced noise but curiously this is not a feature of the Trent 800 while it is on the 700. Apparently a Rolls powered 777 is 7500lbs lighter than one powered by PW.
Thanks for input.
AL
Last edited by ALV2500; 28th Jul 2005 at 11:50.