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Louvre or not

rvdave

Well Known Member
I'm nearing final assembly but have not yet cut louvers into bottom cowl. Is there anyone who thought they would wait to see if they needed them and found out that they did help CHT's after installing them?
Some of the advice I received is wait to see if you actually have a problem but I don't know if there's anyone flying around without louvers that has acceptable temps?
 
Dave, I installed louvers as per plans and later regretted it...my CHT's were plenty low, so I had added that extra drag for little benefit. I went back (after paint, unfortunately), drilled out those louvers, and installed blanking plates.

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I've flown with the plates in place for a year, and found CHT's to be satisfactory. The one scenario that demands care is a short fuel stop in hot summer weather....the ensuing climb-out demands a higher climb speeds than usual to keep CHT's under 400F. This is not an inconvenience to me, and now I'm trying to figure out now how to patch those holes back up permanently without creating too much of a repaint job.

I did several other things on the cowl that I think have helped with cooling and minimize drag. For one, I removed that center support that is off-center, creating turbulence in the exit,

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and built a replacement with the center support centered and nicely faired into the nose gear in flight.

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I left the cowl full length, so it extends an inch or so behind the firewall, and I used baffle seal to seal the gaps around the nose gear. I think attention to details in this area pays off.

I would suggest to builders that they at least install the louvers with screws and nutplates, instead of rivets, so they could be more easily removed.
 

It's really not my habit to intrude,
And furthermore I hope my meaning won't be lost or misconstrued,
So I'll repeat myself...at the risk of being crude,
There must be fifty ways to leave your louver.

This is number 17.... :D

(Apologies to Paul Simon)
 
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