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Posted for "Mark Ravinski" <mjrav@comcast.net>:
Message
----- Original Message -----
From: Larry Henney
You might ask the currently Fasted LNC2 Driver in the Western Hemisphere to
chime in here as he does I believe have a dual chambered system.
Here are a couple of shots of my dual chambered system while under
development.
I used regular Jefco epoxy/ glass and some G 10 circuit board material for
the structure.
A foam core was first fitted and then glassed over.
My intent was to smooth up the airflow and reduce cooling drag.
There is really no great load on these parts so they were made very light -
2 bid in most areas.
I believe a plenum does take much of the load off the cowling however.
Quite a few higher time planes show spider cracks in the top cowel.
There have been no heat or distortion problems in about 200 hours. (and 3
Airventure Cup races)
The problems of uneven cht are worse from front to back and climb speed to
cruise than from left to right.
However, generally never more than 30 Degrees of variation between cylinders
and usually better.
I try to tune them for cruise (or racing) and live with more variation in
climb.
My oil cooler is in back and gets air from the back of the plenum on both
sides. Oil temps stay at 180-190 except that one race where OAT went over
100F.
The worst part of the deal (other than all the close fitting) is the limited
maintenance access.
Mark Ravinski
N360KB 1300 hrs (Only fastest this year)
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