On 28/05/2021 11:20, The Natural Philosopher wrote:
On 27/05/2021 20:59, Vir Campestris wrote:

Missing the point. We were not discussing GT thermal efficiency,
we're talking about fuel per passenger mile. Which goes down with
each new Trent (composites and aerodynamics helps too).

There are some number here.

Where?

Oops here...

Don't forget that a lot of the things aircraft do don't apply to cars
- such as choosing the ideal cruise height and speed for the weight of
the aircraft, and changing it as the aircraft gets lighter.

but those are not really affected by any changes in engine 'efficiency'
In reality long haul airliners fly quite close to 'coffin corner'
slightly above stall speed and slightly below mach 1 at as high an
altitude as they can because that reduces drag.

The engines are tuned for best overall efficiency in terms of jet
exhaust velocity and bypass ratios in that regime.

I'm not convinced that composites are all that much of a good thing in
the long term either. Aluminium is a lot easier to recycle than
carbon-epoxy composite.

not, its harder. you can turn carbon epoxy into plant food and water in
any high temperature incinerator

That's not what is generally meant by recycling.

Andy