Cost of gas is beginning to hurt

In article . com,
wrote:

On Apr 27, 6:34 pm, "Morgans" wrote:
"JGalban via AviationKB.com" wrote

That's what I figured. Turbocharged engines are a different kettle of
fish.
The main reason is the higher temperatures in the induction system lowers
the
detonation margin considerably.

Not just the temp, but the pressures involved.

In a turbo, not producing boost, a low compression ratio is fine with low
octane gas. When the boost is putting all of that extra air and gas into
the combustion chamber, it is still compressing at the same ratio. You end
up with the normal internal pressure, plus the extra pressure the turbo
boost shoved in there. Then detonation becomes a big problem, without the
extra octane.

But you knew all of that, already. g
--
Jim in NC

If the engine is turbo "normalized", it never increases the boost
above what the engine would see at sea level power, right? That's why
turbo aircarft engines are rated at the same max power as non turbo
engines. If the engine doesn't need high octane gas at sea level, why
would it need it at altitude where the cylinder pressures are no
higher (merely boosted back to sea level MP). Am I confused?

Regards,
Bud

Even turbo normalizing increases the temperature of the fuel/air mix
entering the cylinders, due to compression of the air to achieve
"normal" pressures. The increased temperature increases the octane
requirements, all by itself.

On Apr 28, 9:09 am, Orval Fairbairn wrote:
In article . com,





wrote:
On Apr 27, 6:34 pm, "Morgans" wrote:
"JGalban via AviationKB.com" wrote

That's what I figured. Turbocharged engines are a different kettle of
fish.
The main reason is the higher temperatures in the induction system lowers
the
detonation margin considerably.

Not just the temp, but the pressures involved.

In a turbo, not producing boost, a low compression ratio is fine with low
octane gas. When the boost is putting all of that extra air and gas into
the combustion chamber, it is still compressing at the same ratio. You end
up with the normal internal pressure, plus the extra pressure the turbo
boost shoved in there. Then detonation becomes a big problem, without the
extra octane.

But you knew all of that, already. g
--
Jim in NC

If the engine is turbo "normalized", it never increases the boost
above what the engine would see at sea level power, right? That's why
turbo aircarft engines are rated at the same max power as non turbo
engines. If the engine doesn't need high octane gas at sea level, why
would it need it at altitude where the cylinder pressures are no
higher (merely boosted back to sea level MP). Am I confused?

Regards,
Bud

Even turbo normalizing increases the temperature of the fuel/air mix
entering the cylinders, due to compression of the air to achieve
"normal" pressures. The increased temperature increases the octane
requirements, all by itself.- Hide quoted text -

- Show quoted text -

Never disagreed with this. It is the assertion that the turbo "is
putting all of that extra air and gas into
the combustion chamber" that is of contention. The total mass of fuel
(air + gas) the cylinder injests is the same as a normally aspirated
engine at sea level. That is why having a good fuel flow guage is such
an important factor in running lean of peak, and is a major part of
TAT turbo installations. Heck, when doing the lean test they
recommend, monitoring fuel flow is the primary issue. The poster said
it is "not just the temp". It is. It is also why intercoolers are so
nice. They reduce the work the turbo has to do, and increase the
detonation margin without lowering power output.

Regards,
Bud

On 2007-04-27 11:52:18 -0700, "Matt Barrow"
said:


"C J Campbell" wrote in message
news:2007042709185616807-christophercampbell@hotmailcom...
On 2007-04-26 05:36:04 -0700, ktbr said:

C J Campbell wrote:

Okay, doing some further checking, Democrats controlled both houses in
2005. The Dems had a 26-23 majority in the Senate and a 55-43 majority
in the House.

Well in the eyes of Democrats thats a landslide.

It certainly is when you consider that Al was saying that the Republicans
controlled both houses.

It was the Democrats who passed the gas tax increase that takes effect on
July 1 in Washington, not the Republicans.

Algore, Kerry and Hillary have all said (when addressing the appropriate
audiences) that we should be paying $5.00 a gallon and taxes should be
raised accordingly.

Wow! More money to **** away.

They do. And when a loaf of bread costs $10 because that is what it
costs to farm and transport the wheat, grind it into flour and
transport that to the baker, bake it and transport the finished loaves
to the store, they will blame the greedy farmers. But it won't matter
because no on will be able to drive to the store to buy the bread
anyway.

After the food riots then, no doubt, they will have even better
programs to save us.
--
Waddling Eagle
World Famous Flight Instructor

"C J Campbell" wrote in message
news:2007042815125816807-christophercampbell@hotmailcom...
On 2007-04-27 11:52:18 -0700, "Matt Barrow"
said:


"C J Campbell" wrote in message
news:2007042709185616807-christophercampbell@hotmailcom...
On 2007-04-26 05:36:04 -0700, ktbr said:

C J Campbell wrote:

Okay, doing some further checking, Democrats controlled both houses in
2005. The Dems had a 26-23 majority in the Senate and a 55-43 majority
in the House.

Well in the eyes of Democrats thats a landslide.

It certainly is when you consider that Al was saying that the
Republicans
controlled both houses.

It was the Democrats who passed the gas tax increase that takes effect
on
July 1 in Washington, not the Republicans.

Algore, Kerry and Hillary have all said (when addressing the appropriate
audiences) that we should be paying $5.00 a gallon and taxes should be
raised accordingly.

Wow! More money to **** away.

They do. And when a loaf of bread costs $10 because that is what it costs
to farm and transport the wheat, grind it into flour and transport that to
the baker, bake it and transport the finished loaves to the store, they
will blame the greedy farmers. But it won't matter because no on will be
able to drive to the store to buy the bread anyway.

After the food riots then, no doubt, they will have even better programs
to save us.

It becomes a vicious circle. http://preview.tinyurl.com/22yeyo

On Apr 27, 6:40 pm, "Matt Barrow"
wrote:


I have seen this 30%/70% number repeatedly, but I don't remember it
ever came from a scientific survey, or just someones rough estimate.

FAA figures.


Care to provide the source (URL of the original data)?


That has contributed to the big decline of
overall 100LL consumption in U.S.

Do you have a cite for that last one?

What's the GA activity level over the past few years?

Year US Avgas production and import (thousand barrels)
1999 7485
2000 6648
2001 7121
2002 6584
2003 6255
2004 6295

source:
http://www.indexmundi.com/en/commodi...ly_monthly.htm

On Apr 27, 6:40 pm, "Matt Barrow"
wrote:


That has contributed to the big decline of
overall 100LL consumption in U.S.

Do you have a cite for that last one?


This is an even better source showing the decline of 100LL
consumption:

http://tonto.eia.doe.gov/dnav/pet/hist/a403600001m.htm

"M" wrote in message
ups.com...
On Apr 27, 6:40 pm, "Matt Barrow"
wrote:


I have seen this 30%/70% number repeatedly, but I don't remember it
ever came from a scientific survey, or just someones rough estimate.

FAA figures.


Care to provide the source (URL of the original data)?


That has contributed to the big decline of
overall 100LL consumption in U.S.

Do you have a cite for that last one?

What's the GA activity level over the past few years?

Year US Avgas production and import (thousand barrels)
1999 7485
2000 6648
2001 7121
2002 6584
2003 6255
2004 6295

source:
http://www.indexmundi.com/en/commodi...ly_monthly.htm

Try "Operating Hours".

It's only in the past year or so that hours flown is recovering to pre-2001
levels.

Hell, just look at your 2003-2004 numbers.

"M" wrote in message
oups.com...
On Apr 27, 6:40 pm, "Matt Barrow"
wrote:


That has contributed to the big decline of
overall 100LL consumption in U.S.

Do you have a cite for that last one?


This is an even better source showing the decline of 100LL
consumption:

http://tonto.eia.doe.gov/dnav/pet/hist/a403600001m.htm


Do you understand correlation vs causation?

On Apr 29, 1:46 pm, "Matt Barrow"
wrote:

This is an even better source showing the decline of 100LL
consumption:

http://tonto.eia.doe.gov/dnav/pet/hist/a403600001m.htm

Do you understand correlation vs causation?

You're simply arguing without any solid number. Just because you
believe 100LL still has a bright future doesn't mean it's true.

"M" wrote in message
oups.com...
On Apr 29, 1:46 pm, "Matt Barrow"
wrote:

This is an even better source showing the decline of 100LL
consumption:

http://tonto.eia.doe.gov/dnav/pet/hist/a403600001m.htm

Do you understand correlation vs causation?

You're simply arguing without any solid number. Just because you
believe 100LL still has a bright future doesn't mean it's true.

I never said 100LL had a bright future. I figure inside ten years and it'll
be banned. , for one, would love to invest in TAT and their PRISM system.
MOF, even if 100LL enjoys a long and fruitful life, I'd put a PRISM system
on my airplane the moment the STC is signed.

NTL, You're about oh-for-five in comprehension, on just about every aspect.

One last time: show me flight hours, not any irrelevant numbers you can pull
out of your ass without a context and you might make a small point.

You say the 70-30 ration has been falling for ten years. You've come up with
several unrelated numbers to substantiate your point, such as number of
gallons sold, which does not take into effect the effect of the fall off in
economic activity.

If you can't avoid going off on tangents, or putting round pegs in square
holes, there's no point in me following up.

In sum: you can ext
--
Matt Barrow
Performace Homes, LLC.
Colorado Springs, COract your foot from your mouth and get off your agenda
anytime.