GEnxPower From United States of America, joined Apr 2005, 121 posts, RR: 0 Reply 11, posted (7 years 2 months 2 weeks 5 days 2 hours ago) and read 2671 times:
I'm thinking US's HUGE trade defecit with China must have influenced the decision a bit. It might have been a significant factor, IMHO, with both countries trying to balance surplus-defecit numbers.
Quoting KSUpilot (Reply 7): What are the major differences between the GENx and the Trent 1000?
Just as any GE engine vs RR engine in the past 2 decades, GEnx is 2 spool engine while Trent 1000 has 3 spools. Trent once again has shrouded HPT blades, compared to GEnx non-shrouded HPT blade design (cantilevered).
GEnx features next generation of composite fan blade technology from GE90's. We are extending that technology to even the fan case, with GEnx becoming the world's first engine with fully composite fan blades and fan case.
I'm not sure on this point, but I believe Trent 1000 has titanium alloy fan blades and fan case.
These are just some points on top of my head. There are so much more.
Every design feature mentioned here could be argued over for its pro's and con's and engineering trade-offs.
BOE773 From , joined Dec 1969, posts, RR: Reply 14, posted (7 years 2 months 2 weeks 5 days 1 hour ago) and read 2622 times:
The GEnx series will also be more fuel efficient in all flt regimes than the Trent series.
RR engines are more prone to airflow instability towards the rear stages of the HPC, (Hi Pressure Compressor) as the design requires a longer HPC spool resulting in a more complex airflow which increases the probability of airflow stall. In twin spool designs such as GE and Pratt engines, the stall margin is wider.
Jben From Australia, joined Aug 2006, 77 posts, RR: 4 Reply 16, posted (7 years 2 months 2 weeks 5 days ago) and read 2588 times:
Excuse me, you *know* that the GeNX will be superior to the Trent 1000, how precisely? You have access to the engineering data at GE and Rolls Royce? Also, both engines are still in testing... the developmental engine is not necessarily representative of the final production article anyways.
Really? RR engines are more prone to it? You know this, how exactly? You're wrong and the three spool design is an excellent design that reduces weight dramatically. The difference between GE90's and Trents on the 777 shows that even at similar thrust production, the two trent turbines weigh substaintially less than the GE90. It's not an accident that on the 772, the Trent 877/895 are actually the best selling engines... Maybe you'd like to comment on the PW4080? How's that selling?
Jben From Australia, joined Aug 2006, 77 posts, RR: 4 Reply 18, posted (7 years 2 months 2 weeks 4 days 22 hours ago) and read 2545 times:
Yes, we get that it's the best selling thus far.
I'm also a little concerned that you seem to be plagiarising without giving credit to the source. With phrases like "complex airflow which increases the probability of airflow stall" that seem to originate from this article at wikipedia http://en.wikipedia.org/wiki/Rolls-Royce_Trent . Conveniently, however, you skip the last part of the line "making the engine's airflow very stable over a wide range of spool speeds".
PM From India, joined Feb 2005, 6812 posts, RR: 65 Reply 19, posted (7 years 2 months 2 weeks 4 days 22 hours ago) and read 2536 times:
Quoting BOE773 (Reply 17): The GEnx is the best-selling engine for the Boeing 787.
Yes, it is for now but it's still very early days. At this stage of the 777 programme the PW4000 was in the lead and the GE90 trailed in third place... I wouldn't draw too many conclusions this early. (And, yes, I'd say the same thing even if RR were in the lead right now.)
Quoting BOE773 (Reply 17): Selected for three new wide-body aircraftunder development,
True enough but things are never quite that simple. Was it ever really likely that Boeing would offer the next generation of 747 with only a non-US engine? Once they had opted for a single-source and a 787 engine, the GEnx was always likely to win that race. And as for the A350, the RR Trent has also been chosen and may now be in the stronger position following the launch of the XWB. None of this is to deny that the GEnx is a fine engine and has won lots of orders on merit but that's not the whole story.