On Fri, 28 May 2021 04:12:38 +1000, Joey, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH the trolling senile asshole's latest troll**** unread

--
"Who or What is Rod Speed?

Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing "the big, hard
man" on the InterNet."
https://www.pcreview.co.uk/threads/r...d-faq.2973853/

On 26/05/2021 20:35, newshound wrote:
On 26/05/2021 20:12, The Natural Philosopher wrote:
On 26/05/2021 18:01, newshound wrote:
Actually I would not be surprised if washing machines had not done
that, and aero engine efficiency improvement is probably in double
digits over a decade.

Bless!

Quite the ArtStudent aren't you?

Gas turbine efficiency as such us where it was from the get-go - about
37%. Once you have made the transition to high bypass turbofans,
that's pretty much it.


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.

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.

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.

Andy

Vir Campestris wrote:
On 26/05/2021 20:35, newshound wrote:
On 26/05/2021 20:12, The Natural Philosopher wrote:
On 26/05/2021 18:01, newshound wrote:
Actually I would not be surprised if washing machines had not done
that, and aero engine efficiency improvement is probably in double
digits over a decade.

Bless!

Quite the ArtStudent aren't you?

Gas turbine efficiency as such us where it was from the get-go -
about 37%. Once you have made the transition to high bypass
turbofans, that's pretty much it.


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.

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.

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.

Andy

On BEV cars, the battery pack is pretty heavy, and the curb weight
is pretty high for the BEV. On the other hand, with regenerative
braking, some of the mass component is being neutralized a bit.
(The power used to accelerate the mass, comes back during
deceleration, with some losses in the process.)

Even if you made the mechanical framework out of pixey dust,
it's still going to be a heavy car. The longer the range (and
more expensive the battery pack), the more mass.

And this is used to alter the handling, because the mass of
the battery pack is down low.

Paul

Steve Walker wrote:
On 27/05/2021 08:05, Brian Gaff (Sofa) wrote:
I think what they need to look at is the number of cycles and their
ability
to still be as good ten years on, this is particularly the case for those
running vehicles.

It's going to be massive problem for the second-hand market. I was
reading up the other day on fast charging of EV batteries.

It appears that the manufacturers warrant the batteries for various
periods 5 years, 7 years or whatever. The more rapid charges someone
does, the shorter the battery life, so they have included software that
limits how many times a battery can be fast charged.

Don't do it often, no problem, do it often and the system will
eventually stop you fast charging, on at least some occasions, to
protect battery life and prevent in-warranty failures.

However, they are balancing convenience against warranty claims, so
allowing the maximum number of rapid charges for an acceptable number of
warranty claims, therefore a second-hand vehicle, that is just out of
warranty, could be very close to battery failure, depending upon how it
has been used. So you could buy a 5 year-old car and within months have
it written off as uneconomic to repair due to battery failure.


The offer a wide range for lifespan here, from ten to twenty years.

https://www.geotab.com/blog/ev-battery-health/

And the degradation is most noticeable towards the end...
which likely makes it easier in terms of warranty
claims.

Paul

On 27/05/2021 18:39, Joey wrote:


"Chris Hogg" wrote in message
...
On Thu, 27 May 2021 19:43:13 +1000, "Joey" wrote:



"The Natural Philosopher" wrote in message
...
On 27/05/2021 00:50, Joey wrote:


"The Natural Philosopher" wrote in message
...
On 26/05/2021 15:30, newshound wrote:


I am sure a fast motorway charge will not come at domestic rates

But what matters is how it compares with the cost of petrol.

That will be determined by politics

Not with the price of petrol and unlikely with the price of the
recharge.

I thought the price of petrol was mostly determined by politics,
specifically by how much tax is imposed by Govt.

But they aren't likely to change the way they do that once EVs are common.

They are absolutely likely to do that once EVs are common.

What are their options?

1/. To charge massive sales tax on all public (inc. fast charged)
electricity for cars. What that means is no one will use them - they
will all charge at home instead.

2/. Replace electricity tax with road tolls. - that will unfairly hit
fuel car drivers so they would reduce duty on fuel accordingly.

3/. Slap enormous road tax on electric vehicles. And see their sales vanish.

The only politically viable solution is road tolls, and if the income
comes from there it would be iniquitous to also get it from fuel duty.



--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

On 27/05/2021 20:59, Vir Campestris wrote:
On 26/05/2021 20:35, newshound wrote:
On 26/05/2021 20:12, The Natural Philosopher wrote:
On 26/05/2021 18:01, newshound wrote:
Actually I would not be surprised if washing machines had not done
that, and aero engine efficiency improvement is probably in double
digits over a decade.

Bless!

Quite the ArtStudent aren't you?

Gas turbine efficiency as such us where it was from the get-go -
about 37%. Once you have made the transition to high bypass
turbofans, that's pretty much it.


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?

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

Andy


--
The urge to save humanity is almost always a false front for the urge to
rule.
€“ H. L. Mencken, American journalist, 1880-1956

"The Natural Philosopher" wrote in message
...
On 27/05/2021 18:39, Joey wrote:


"Chris Hogg" wrote in message
...
On Thu, 27 May 2021 19:43:13 +1000, "Joey" wrote:



"The Natural Philosopher" wrote in message
...
On 27/05/2021 00:50, Joey wrote:


"The Natural Philosopher" wrote in message
...
On 26/05/2021 15:30, newshound wrote:


I am sure a fast motorway charge will not come at domestic rates

But what matters is how it compares with the cost of petrol.

That will be determined by politics

Not with the price of petrol and unlikely with the price of the
recharge.

I thought the price of petrol was mostly determined by politics,
specifically by how much tax is imposed by Govt.

But they aren't likely to change the way they do that once EVs are
common.

They are absolutely likely to do that once EVs are common.

Not with the TAX ON PETROL they arent.

What are their options?

1/. To charge massive sales tax on all public (inc. fast charged)
electricity for cars. What that means is no one will use them - they will
all charge at home instead.

2/. Replace electricity tax with road tolls. - that will unfairly hit fuel
car drivers so they would reduce duty on fuel accordingly.

3/. Slap enormous road tax on electric vehicles. And see their sales
vanish.

None of that is the TAX ON PETROL.

The only politically viable solution is road tolls,

The other politically viable solution is to pay for roads
out of general taxation and avoid the need for the
much more expensive collection of road usage data
and charging that when you actually do the miles.

and if the income comes from there it would be iniquitous to also get it
from fuel duty.

Not a problem if roads are paid for out of general taxation revenue.

"The Natural Philosopher" wrote in message
...
On 27/05/2021 20:59, Vir Campestris wrote:
On 26/05/2021 20:35, newshound wrote:
On 26/05/2021 20:12, The Natural Philosopher wrote:
On 26/05/2021 18:01, newshound wrote:
Actually I would not be surprised if washing machines had not done
that, and aero engine efficiency improvement is probably in double
digits over a decade.

Bless!

Quite the ArtStudent aren't you?

Gas turbine efficiency as such us where it was from the get-go - about
37%. Once you have made the transition to high bypass turbofans, that's
pretty much it.


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?

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

A long way above stall speed actually.

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

In article , The Natural Philosopher
writes
On 26/05/2021 15:30, newshound wrote:
On 26/05/2021 10:14, John Rumm wrote:
On 25/05/2021 21:22, newshound wrote:
On 25/05/2021 19:56, Chris Hogg wrote:
On 25 May 2021 17:52:19 +0100 (BST), Theo
wrote:

I came across this article:

https://arstechnica.com/science/2021...e-years-away-n
o-batteries-are-improving-under-your-nose/

It's a good roundup of all the different lithium ion chemistries
and how
things have been improving of late, and how that impacts
applications such
as phones and EVs.

Theo
" That means that the capacity of your current batteries is over 1.5
times what they would have held a decade ago."

Am I supposed to be impressed?

Not exactly Moore's Law, is it. Of course it is still worth having.
In the absence of real physics/material breakthroughs (like, for
example, a single layer atomic structure like graphene, but an
insulator) it's getting close to physical limits, although cost will
continue to come down.

Funny you should mention that, but:


https://www.forbes.com/sites/michael...-range-breakth
rough-as-new-aluminum-ion-battery-charges-60-times-faster-than-lithium-ion



Interesting.
I forget the numbers, but doesn't a motorway petrol station
effectively deliver tens of megawatts of power when its fuel pumps
are all going. So, to achieve equivalent performance in terms of
"refuelling" times recharging stations are going to need fairly
substantial grid connections as we reduce the present battery
charging rate restrictions. Or else be connected to a hydrogen grid
with some big fuel cells. Either way, there are significant
infrastructure questions on top of any basic technology solution.

yes, but they are really not show stoppers.

Also, most of the demand for charge will be during the working day.
Petrol stations have very efficient storage so although the capital
(the pumps) is under utilised, it doesn't screw the economics because
these are cheap.

I am sure a fast motorway charge will not come at domestic rates

Just as motorway petrol doesn't come at supermarket price.
--
bert

On Sat, 29 May 2021 05:00:10 +1000, Joey, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH the trolling senile asshole's latest troll**** unread

--
Sqwertz to Rodent Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On Sat, 29 May 2021 05:02:34 +1000, Joey, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


FLUSH yet more of the trolling senile asshole's latest troll**** unread

--
Xeno to senile Rodent:
"You're a sad old man Rod, truly sad."
MID:

On 26/05/2021 20:08, The Natural Philosopher wrote:

Stop. No one sane is suggesting batteries for grid long term energy
store. The most they would be used for on the grid is very short term
smoothing.

Why are you changing the subject?
I am talking about hydrogen for vehicles b ecause batteries wont work

Hydrogen is a possible candidate for long term (seasonal) energy
store. It is ballpark economic (i.e. within an order of magnitude).

When that doesn't work either, some bushy-tailed ArtStudent„¢ will
have a lightbulb moment and say 'why don't we make renewable diesel
fuel?'


Biodiesel? It doesn't scale, but we do do it.

No. Not biodiesel


Which is precisely what I reckon will happen.

Burn that with *pure* oxygen and hey presto - no NOx!, just CO2 and
water. Collect the CO2 and water and feed it back to your syndiesel
plant...


A field of rapeseed? Or one of those fusion plants, that are on the
verge of being on the verge of... being very expensive.
Bog standard nuclear power or sur[plus wind power


Ah, I've just listened to an "Inside Science" podcast where F1 engineer
Paddy Lowe and friend are discussing manufacturing synthetic petrol from
CO2 and hydrogen. I guess this is what you are referring to.

https://www.bbc.co.uk/programmes/m000w5j9

I wasn't entirely convinced that this was better than rapeseed oil, or
bioethanol, but it is good someone is looking at it. Like hydrogen,
synthetic fuel does offer a long term energy store for variable
generation capacity. Time will tell how economic and scalable it is.

On 27/05/2021 07:38, The Natural Philosopher wrote:

So I have no problem with charging electric cars. If it needs to be done
it can be done.Â* What can't be done in my opinion is to make batteries
sufficiently good to fully replace fuel, and indeed there are severe
limitations on the supply of lithium to do it.

There are other more pressing problems with automotive battery supply
than lithium. Here is quite a good deep dive:

https://www.youtube.com/watch?v=1Xwxe0wU4b8


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

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

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.

Andy.

"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.

On Mon, 31 May 2021 08:56:06 +1000, Joey, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

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.

You ARE an auto-contradicting pest! FAR too spaced out, senile nutter!

--
Sqwertz to Rodent Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On 30/05/2021 21:37, Vir Campestris wrote:
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.

Andy.
In general an aircraft without flaps has around 2:1 ratio of top speed
to stall speed. Extra power in military aircraft pushes that towards 3:1
as does heavy implementation of flats and slats etc.

Its hard to get one single figure for stall speed from e.g. an airliner
as it depends on altitude, temperature, and aircraft weight as well as
what flaps etc are deployed, nevertheless a 747 lands at around 160mph
typically with all the gear out.
One may conjecture therefore that without the flappy bits out it would
be bear to its stall sped which gives a top speed of around 480 mph..at
a 3:1 ratio

(Whether or not you could fly a 747 at 480mph at ground level I do not know)

Now http://www.hochwarth.com/misc/AviationCalculator.html

tells me that at 45000 ft and Mach 0.8 the IAS is 215 knots or about
250mph, although TAS - true airspeed is over 500mph

That is not a huge amount above the IAS stall speed without flaps of say
180mph..a tight turn that increases the effective 'weight' of the
aircraft would be something to avoid

It's not the on the edge coffin corner that say a U2 used to fly at with
the difference between speed of sound and stall speed not much over
5mph! but it is a significantly smaller envelope than operation at lower
altitudes

In practice the designers do a lot of optimisation with one aim in mind
- minimising fuel and maximising income in terms of passenger miles and
high operational utility. I,e, mist passenger miles per day, since
interest on the capital cost of the aircraft accrues on a daily basis,
not on how many miles it flies!


--
In theory, there is no difference between theory and practice.
In practice, there is.
-- Yogi Berra

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.

its not hard to make a 2g turn and stall the thing.


--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

"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.

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

On Mon, 31 May 2021 19:58:43 +1000, Joey, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH the trolling senile asshole's latest troll**** unread

--
Kerr-Mudd,John addressing the auto-contradicting senile cretin:
"Auto-contradictor Rod is back! (in the KF)"
MID:

"The Natural Philosopher" wrote in message
...
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.

On Tue, 1 Jun 2021 06:20:38 +1000, Joey, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH the two senile assholes latest off topic senile ****

--
"Anonymous" to trolling senile Rodent Speed:
"You can **** off as you know less than pig **** you sad
little ignorant ****."
MID:

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


"The Natural Philosopher" wrote in message
...
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


--
"Women actually are capable of being far more than the feminists will
let them."