On 31/05/2021 21:20, Joey wrote:


"The Natural Philosopher" wrote in message
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On 31/05/2021 10:58, Joey wrote:


"The Natural Philosopher" wrote in message
...
On 30/05/2021 23:56, Joey wrote:


"Vir Campestris" wrote in message
...
On 28/05/2021 20:02, Joey wrote:


"The Natural Philosopher" wrote in message
...
On 27/05/2021 20:59, Vir Campestris wrote:
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

A long way above stall speed actually.

and slightly below mach 1 at as high an
altitude as they can because that reduces drag.
snip

I tried and failed to find a reference for that.

Given that an airliner's stall speed clean is over 150kt (easily
found) and the air pressure at cruising height is under a quarter
that at sea level (also easily found) I would expect them to be
fairly close.

They arent, for a reason, FAR too dangerous.

Well they are : from 150kt to 450kt at ground level, you are up to
250kt at say 40,000ft, and the speed of sound has come down.

2:1 ratio as you say in another isnt anything like fairly close.


It is if you need to pull a tight turn

But you dont with the commercial airline flights we are discussing.

WWII aircraft were in high speed stalls on tight dogfights at full
throttle

Doesnt happen very often at all with the commercial
airline flights we are discussing for some reason.

It is not uncommon for an aircraft to pull 2g in clear air turbulence

But they dont in fact stall in that situation with commercial airline
flights.


Indeed they have done


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