stan_tew(at)yahoo.com
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 Posted: Tue Aug 27, 2013 7:27 am Post subject: RotaxEngines-List Digest: 2 Msgs - 08/26/13 |
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Bob,
2 strokes run on a very fine line between "just right" and "too lean". When the mixture gets too lean the cylinder is subject to pre-ignition. This is disastrous. If you need proof I can post a photo of a 582 piston with a .5 in hole in the center of the piston crown.
STAN 2
N29TD
From: RotaxEngines-List Digest Server <rotaxengines-list(at)matronics.com>
To: RotaxEngines-List Digest List <rotaxengines-list-digest(at)matronics.com>
Sent: Tuesday, August 27, 2013 2:00 AM
Subject: RotaxEngines-List Digest: 2 Msgs - 08/26/13
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RotaxEngines-List Digest Archive
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Total Messages Posted Mon 08/26/13: 2
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Today's Message Index:
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1. 04:39 AM - Running 582 Engines LOP (BobP)
2. 07:52 AM - Re: Running 582 Engines LOP (Guy Buchanan)
________________________________ Message 1 _____________________________________
Time: 04:39:04 AM PST US
Subject: Running 582 Engines LOP
From: "BobP" <matronics(at)panth.co.uk (matronics(at)panth.co.uk)>
I have a Rotax 582 with a warp comp prop in a Pulsar. The engine has the oil injection
system fitted.
Because of the slippery Pulsar profile (5000rpm and 90 knots at 12 litres/hour)
EGTs tend to nudge the maximum limit when in fast cruise descent - because
of the low load on the fast revving engine. I prefer the keep the engine away
from red line limits, and can reduce EGTs by either throttling back even further
so the engine is developing minimal power, or by slowing the plane down and
applying flaps to make the plane more draggy.
Neither of these options is ideal, and I wondered if it is possible to safely reduce
EGTs (at cruise power) by running the 582 engine lean of peak (LOP) eg
by using a hacman type device to weaken the mixture. The normal cruise mix seems
fine (plugs noses mid to deep brown) so I don't want to raise the carb needle
and richen this setting.
Any thoughts/experience on running a 582 injected engine LOP appreciated - good
and bad.
Thanks
Bob P
--------
BobP
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=407485#407485
________________________________ Message 2 _____________________________________
Time: 07:52:41 AM PST US
From: Guy Buchanan <gebuchanan(at)cox.net (gebuchanan(at)cox.net)>
Subject: Re: Running 582 Engines LOP
On 8/26/2013 4:37 AM, BobP wrote:
| Quote: | Neither of these options is ideal, and I wondered if it is possible to safely
reduce EGTs (at cruise power) by running the 582 engine lean of peak (LOP) eg
|
by using a hacman type device to weaken the mixture. The normal cruise mix seems
fine (plugs noses mid to deep brown) so I don't want to raise the carb needle
and richen this setting.
| Quote: |
Well. As far as I know there's no such thing as LOP for a 582. Or
|
if there is, the peak is well beyond what the engine will handle. So you
always live rich of peak, but constantly bump up against it, since the
EGT limit gives you best power and fuel economy. (That said, I have run
too lean by long descent with a lean mixture through "peak" until the
engine quit. The engine was at idle, however, so I never noticed an EGT
"peak".)
Your idea of using a Hacman for EGT control is a good one, though.
I used one all the time I had my 582 (4 years, 500 hours) and loved it.
I only had to change mains a couple of times, in Utah and Idaho, when I
was spending a lot of time at altitude and wanted to "re-center" my
mixture control. (My home port was at 1500'.) The Hacman gave me about
80F EGT range, which seems small, but is quite useful. What Hacman will
/not /do is give you enough control to go downhill any way you want. If
your mains are set correctly you'll /always /be able to redline the EGT
going down hill. You just have to get used to either very long or very
short or stepped descents. (There was another system on the market which
screwed the mid-range needles in and out that might have given more
control. Don't know what happened to it.) I highly recommend the Hacman.
(Easy to install, too.)
Guy Buchanan
Ramona, CA
Kitfox IV-1200 / 912-S / Warp 3cs / 500 hrs. and grounded
Now a glider pilot,= Use the Matronics List Features href="http://www.matronics.com/Navigator?RotaxEngines-List" target="_bl-========================tp://forums.matronics.com/" target="_blank">http://forums.matronics.com</ t; http
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