Roger,

 

Who made the plenum/duct for you ??

 

I made the duct for me. 

 

I lined the upper cowl and engine with painters plastic and shot in a can of X30 expanding foam to get a mold.  This allowed me to put up a single bid (after aerodynamic contour whittling down the foam).  This flash bid was them built up with roughly 4 bid all around and 6 bid at attach points.  Some people use high temp epoxy.  I used regular jeffco and have had minimal repairs

 

Larry

 

 

Roger Iverin

On Mon, 03 Sep 2007 13:00:00 -0400, LHenney wrote
> Peter,
>  
> I believe about ½” would be adequate for 90% of your baffling gaps. However, during engine start and shut down you will still get an occasional contact of metal to glass. This has spider cracked the gel coat on numerous cowls (over the years). Perhaps ¾” would have been adequate. However, around the top of number 1 & 2 cylinders I did not have that much clearance. ). I built my baffles twice before shifting to a cooling plenum (duct) out of frustration with that contact damage. In addition to better cooling ( big factor!) , the plenum allowed rounded edges, smoother contact surfaces, and overall less maintenance.
>  
> Larry
> N360LH


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