Originally Posted by Booglebox
Hmm.
With the G500/G600, have they activated all the fuel tanks? Or, are they going to pull another -ER stunt and install a fuel pump to a tank that is already there for $1m, a year after EIS?...
Well regardless, even if the G600 only has its advertised fuel capacity of 38,760 lbs, that means that that it consumes 2% more fuel per mile than the 20 year old G550 even though the G600 has a clean sheet fuselage, clean sheet wings, clean sheet engines, upgraded systems, and about the same MTOW. It only achieves 1% less fuel burn than the G650 despite have a newer and smaller fuselage, newer and smaller wing, much newer clean sheet engines, the same speed performance, and 9% lower MTOW.
When I read articles about commercial airframers upgrading their models, like the A320 to the A320NEO, or the B737 Next Generation to the 737MAX, they talk about efficiency improvements and which improvements are attributable to aeordynamic improvements, weight loss, engine improvements, etc. In these examples it seems like when airframers re-engine an existing plane, they do it because the new clean sheet engines will deliver several percent overall efficiency improvement to the plane.
For example see this article
here, where Boeing admits that it is the new clean sheet engines, not their own aerodynamic and design improvements, that will deliver the
majority of a 14% efficiency improvement over the 737NG. This means that they expect the new engines alone to deliver more than 7% efficiency improvement to the overall plane.
Compare this to our case of the G600 vs the G650. The G650 has engines nearing 20 years from entry into service. The G600 has brand new engines. It has a newer and smaller wing, a newer and smaller fuselage, 9,000 lbs lower MTOW, and yet the G600 only saves 1% on fuel burn? That's ludicrous. It should be saving at least 5%-10% on fuel burn.
The comparison with the G550 is the same in my opinion, completely not believable, although its less clear cut because the G550 is so much older and slower. I still think the G600 should fare better in comparison, it will be a 20 year newer plane. Yes the G600 is a little bigger and faster, but a lot of technological improvements in aerodynamics, aerostructures, and engine technology happen in 20 years. The 737MAX is scheduled to come out 20 years after the 737NG, and its advertised as delivering a 20% efficiency improvement over the first NGs, and its not even a clean sheet design! The G600 is a clean sheet plane! And it gets 2% less efficiency than than the G550?!