Plug life is cut by about 1/2 on 100LL and O2 sensor response gets
slower
when poisoned with lead (which is not a problem for monitoring
mixture). I
get about 150 hours on plugs with mixed use of 100LL and auto fuel.
Straight auto gives about 250 hours plug life. Never tried a
constant diet
of 100LL so don't know what would happen.
Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com
Tracy, please tell us more about your experience with avgas versus
mogas. I'm very concerned about a turbocharged auto engine needing 93
octane unleaded, running avgas in a pinch. Others say that the O2
sensor will plate over in short order (1-2 hours?) and stop working,
leaving the engines to run in open loop mode. They also say the only
way to remove the lead from the O2 sensor is to replace it or run a
propane torch over it for 15 minutes or so. Neither of these has been
your experience? How many times have you had to use avgas when you
couldn't get mogas? I'm concerned that ANYtime I'm away from home or
relatives areas that I'll wind up having to use 100LL. I have a 25
gallon tank Mustang II. Good info about the plugs, too. They are a
pain to get to, but changing them is certainly easier than changing the
O2 sensor!
Thanks,
AI Nut
Not much to tell beyond what I said above. As far as the fear of going open
loop when the O2 sensor gets lead poisoning, my advice is DON'T use a closed
loop EFI system using an O2 sensor in an airplane. I use an O2 sensor only
to monitor mixture, not for feedback to the EC2 controller. I've used
100LL on one or more legs on virtually every long cross country trip. It is
not uncommon to find that mogas airports are out of that fuel.
Plugs hard to get to? Put a higher priority on maintainability when
designing your installation :-)
Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com
>From what I found out today, the O2 sensor will be mounted in the turbo
exit body, so it will be very easy to get to.
Don't use the O2 sensor to feed the computer? Won't mileage suffer, as
well as incomplete combustion causing potential engine harm? If you
don't use it, what value resistor do you use to feed the computer, if
anything? This is an idea that has not occurred to me. Seems like it
would shorten engine life and make plugs foul quite early.
AI Nut
Tracy is too modest to explain to you that he designed and builds the computer for
most of us putting rotary engines in airplanes. It does not use the O2 sensor. It is
open loop and uses only intake manifold pressure, RPM and intake manifold
temp to determine the correct mixture. It works very well indeed and is totally
redundant for reliability while being very reasonable in cost.
BTW shame on you Mr. Nut for not educating yourself by reading both
the ACRE NL web site and Tracy Crook's web site which the
address can be found on the ACRE NL web site.
Paul Lamar
The AirCraft Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site.
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