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

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

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


--
€œThose who can make you believe absurdities, can make you commit
atrocities.€�

€• Voltaire, Questions sur les Miracles Ã* M. Claparede, Professeur de
Théologie Ã* Genève, par un Proposant: Ou Extrait de Diverses Lettres de
M. de Voltaire