I don't think people understand why the 777LR planes have such powerful engines and it is leading them to make mistakes regarding the 350 engines.
The 772A can fly with 77k engines and take it over 5000nm.
The 773A can fly with 90-98k engines (depending on brand) and fly 6000nm.
The 772ER uses those same 90-98k engines to fly 7700nm.
The 773ER uses 115k engines to fly those 7700nm.
The 772LR uses those 115k engines (derated to 110k) to fly 9400nm.
What's my point? In a large twin, all the power is needed to carry the FUEL, not the weight of the plane, on a single engine take-off.
So, you can decrease the weight of the 359 to 20% below a 772 (the 787-10 will be lighter than the 772 as well), but that only takes you so far, because unless you have a great leap in engine efficiency, you still need to carry a lot of fuel to get you FURTHER than the 772ER/773ER (in order to "kill" them).
95k might suit a 772 sized "killer" and take it 9000nm with a heavy payload. But with only 80k, you aren't going to get there. Which is why the 787-10, using the currently defined GEnx or Trent families for the 787, can only make it 7500nm or so. Those extra 1500nm cost ALOT (see above).
Maybe, maybe Airbus can get a 95k engine to serve the 350-1000 well if they only want to match the 773ER range at a slightly lower payload if the airfram and engines are truly more efficient, but I would imagine they need at least 105k to carry enough fuel to fly 8500nm+.
Since so much of the 350 performance will be based on engines and using lighter materials, there is absolutely nothing preventing Boeing from having GE
build the GEnx2 to replace the GE90 for use on the 787-10 and a lightened version of the 773ER. Since the GEnx uses GE90 technologies and applies more efficient pieces to it, while making more extensive use of composites, this technology can be reapplied to the larger GE90 sized engine, with a larger fan.
|Quoting Stitch (Reply 25):|
It could, however, possibly be used on the 772 and the 787-10, both of which will compete with the new A350-900.
Correct. If Airbus is getting it's efficiency from the engine (which was their claim about the 787 at first), then you can "350ize" the 777 family in response. Unless Airbus is truly ready to change the way they think about building airframes, they can only gain a temporary advantage. It won't be a "leap-frog" move for very long.
Of all the things to worry about... the Wookie has no pants.