"Matt Barrow" wrote in message
...

"M" wrote in message
oups.com...

What's really strange is all those new 4 seaters are designed with
engine requiring 100LL, instead of 91/96.

It part of a big bore engine.

True, but IO-470J/K can run on 80/87.

80/87 is leaded fuel. That's even a worse problem than 100LL.

I'm sure they'll do fine on
SR-20 airframe. It also won't be very hard for TCM engineers to
reduce the compression ratio a bit and make IO-550 run on 91/96.

My point is the aircraft manufacturers are short sighted. Relying on
a fuel that's going to be increasingly more expensive than automotive
fuel doesn't do GA much good.

You better dig into things before making such a statement. You're speaking
from a vacuum.


Don't tell the government that 80/87 is a leaded fuel. They have made such
a big deal out of it being unleaded so it won't poison your platinum
catalytic converter that afterburns your exhaust to clean up the combustion
partial products! :-)

There has been a move afoot for some time to eliminate 100 octane "Low Lead"
aviation fuel, because it is the only leaded fuel still being made in the
US. Then all aircraft would have to use the available unleaded fuel.

My experience with the big modern engines is somewhat limited since my
newest airplane left the factory in the spring of 1955, about the time I
started college. However, I can say with the authority of experience that
the IO-520's that I have flown not only demand 100LL but are finicky about
that. I have gotten brands of 100LL that the 520 definately didn't like,
and brands that caused her to hum along just fine.

My poor old main ride also has a three hundred horsepower engine and burns
exactly the same amount of fuel per horsepower per hour as the IO-520. It
actually get a bit MORE efficiency because an airplane runs on thrust, not
horsepower. My 1800rpm cruise allows considerably more pounds of thrust
per horsepower than the higher cruise rpms of the more modern engines. Of
course I squeeze my 300 horsepower out of a measly 680 cubic inches instead
of 520. That does add a few pounds of weight and a bit of frontal area. I
also have half again as many cylinders hanging in the breeze as the little
520! :-)

Plan now. The 10th or 11th ( I lost count several years ago ) annual
rec.aviation annual EVENT at Pinckneyville is coming up soon. It is planned
this year for May 18, 19, and 20. It is an unparalleled opportunity to
actually see some of the people you have exchanged various views with on the
internet. If you have never heard of the Pinckneyville Flyin see the
unofficial FAQ at http://www.ousterhout.net/pjy-faq.html

If you still have any questions you will have to come to the flyin to get
them answered. Or, perhaps, merely rendered irrelevant. :-)

We would appreciate any folks planning to attend drop an email to Mary at
and let her know how many folks are coming and what days.
It is a long way to the nearest grocery store and even farthur to a good
liquor store from the airport and we don't want to run out of essential
supplies! :-)

Highflyer
Highflight Aviation Services
Pinckneyville Airport ( PJY )