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<< Lancair Builders' Mail List >>
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Marv et al
Greetings from Angola, West Africa where our communications lines are often
down for weeks on end and I am just catching up on a couple of weeks worth
of LML posts since returning to work from UK I have a new IO 320 D1B with a 3 blade MT attached to G-PJMT which currently
has about 32 hours total time. I see CHT's of between 400 and 420 F on climb
out and have been taught to bring back the revs to 2400 and manifold
pressure to 24 inches at about 1000 feet AGL after take off. This sees the
CHT's slowly start to reduce and when I'm in the cruise at levels between
3000 feet and 7,500 feet at the same power settings they run between 340 and
365 F. My fuel flow at take off power is approx. 14.6 USG per hour and I've
been told that there is a way to increase that up to around 16.0 USG per
hour for take off by adjusting a setting on the fuel servo. This apparently
allows for better cooling at the higher power settings. Because the
temperatures seem to come down to reasonable figures in the cruise is it
right to assume that the higher temperatures are due to the lack of fuel
flow at take off power as opposed to poor baffling or restricted exit air
flow ? For reference at 7500 feet recently I was seeing 8.5 USG/hr at
approx. 75 F rich of peak at 24 x 24 and CHT's of about 350 F but I can't
remember the OAT at the time.
Can anyone help me out here ? When I'm home in a few weeks time I'll try
Rick Argente's tip of maintaining the higher settings and see if the CHT's
come down quicker. Am I over concerned at seeing 420 F or could I let it get
up around the 450 F without too much concern ?
I also find that I need to lean out on the ground for taxiing when operating
out of an airport only 80 feet above sea level. If I don't the engine tends
to run rough and there is a larger mag drop. One passenger I took for a
flight who has over 1500 hours PIC couldn't understand me leaning at this
level but maybe that's because he is used to carburetted engines ? I'm glad
to see I'm not the only one with this problem. Once the power is applied the
engine really does run smoothly.
My oil temperature is running at about 175 - 180 F. and I have not seen it
get above 196 F even when sitting on the tarmac waiting in line for 20 mins
with an OAT of 80 F. which for UK is pretty hot ! I feel that although a
little low, the oil temp is within limits. Does anyone feel I should try and
restrict the air flow a little to raise it closer to the 190 - 200 F.mark ?
I'm still running straight 80 oil, will it likely differ when I change over
to Ashless dispersant oil after 50 hours ?
Appreciate any feedback on these questions. Unfortunately I will miss
Oshkosh this year due to work as I would have liked to have been there for
Don Goetz's roasting. Don really helped me get more familiar with flying
G-MT I hope you do him proud. I will be in Redmond for the Lancair Fly-In
though so hope to get to meet some of you there. Fly safe Michael Holland G-MT
LML homepage: http://www.olsusa.com/Users/Mkaye/maillist.html
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