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Keith, I'd be focused on egt's not cht's as the
main indicator of how far LOP you are. Make sure you get past peak, other
than that, cht's below 400.
Sounds like you have a very good
installation.
On my c172rg with an O-360 I can run just slightly
lean of peak before the vibration gets unreasonable. ...so I have
the MP back to 21 or less before going there.
If I can get the cht's to < 390 I'm
happy.
Colyn
----- Original Message -----
Sent: Saturday, October 31, 2009 4:17
PM
Subject: [LML] LOP operations with
O-360
So, after reading John Deakin's articles upwards of 5 times,
I'd been itching to try lean of peak operations, but figured it was out of the
question without fuel injection, and quite possibly balanced injectors at
that.
I then came across an update saying that someone had quite a bit
of luck with non-injected engine using carb heat, which supposedly helped
vaporize the fuel prior to entering the cylinders.
So, up I went today.
Being cautious of the rough transition zone, I pulled through it pretty
aggressively once it started happening, a little too far, evidently, because
the engine gave up. I figured that might happen, but also figured the
restart would be uneventful, consisting of no more than gently pushing the
mixture in until it fired again).
My EGT's were around 1450 and
the engine smooth as silk. Hmmm...had I pushed too far, back over to
ROP? It didn't feel like that was possible, I'd barely inched the
mixture forward. Fuel flow was around 9.5. That would be normal
for being up at 9/10k, but not down here at 4k, with wide open throttle.
Then I saw the CHT's. Oh baby. 320!
Just to confirm, I edged the
mixture in a tiny bit more, and sure enough, the EGT's crept up 20degs. That
confirmed, I was on the lean side ever since the restart.
Later on, I
killed the carb heat, and while I could feel a TINY different in vibration, it
was not significant.
Holy cow, it seems to run perfectly happily on the
lean side, with an O-360! Who knew??
With that VERY informal test out
of the way, I will now become well-versed with the lean finder mode on the
engine monitor...today's flight was just to find out if I should bother
digging deeper. For a 60-80deg drop in CHT's, and 9.5gph instead of
12gph (down low, least), I'll take it!
I'm posting this for
those that are interested in LOP, but haven't tried it with non-injected power
plants.
Keith
N360JH
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