World's biggest jet engine about to get bigger, quieter .......and make more contrails


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This engine is going to have a fan diameter of 11 feet - that is 3.35m for most folk!!

And more efficient - which means even more contrails!!
But the testing isn't just about making things quieter; it's about making the engine more fuel efficient, producing fewer emissions.
"Economics to airlines is all about fuel burn," said Chuck Johnson, GE Aviation's program lead for the 9X. "We're committing to a 10 percent fuel burn improvement on the GE9X."

And GE's own page on the GE9X is here -

Delivering bigger fuel-burn advantages
The GE9X will be the most fuel-efficient engine GE has ever produced on a per-pounds-of-thrust basis, designed to achieve significant fuel burn savings over its predecessor, including:
10% better SFC than the GE90-115B-powered 777-300ER.
5% better SFC than any other twin-aisle engine in 2020.

these days about 50% of the operating cost of a passenger aircraft is fuel - up from about 1/3rd in 2000 (from a course I did in 2003). The increase is largely driven by increasing fuel costs (duh) but also lower costs for maintenance and crew - the total cost per seat/mile is dropping - which means the fixed-or-slightly-increasing-fuel-cost-per-seat-mile is a larger portion of the total.

However this of course means more contrails - since higher efficiency engines tend to produce more contrails as this study measured - so it will be a bumper time chemtrail believers to be worried![/ex]

Mick West

Staff member
And the reason why higher efficiency engines make more contrails is interesting - it's not, as is sometimes though, that they produce more water (they actually produce less, a lower quantity of equally moist air, all things being equal, and there are other factors there, like the size of the plane), it's because more of the energy of combustion (heat) gets translated into thrust, so the exhaust is cooler.

i.e. it moved the starting condition of the exhaust gases from point X towards point B.
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