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Io 540 plenum

glenn72pc

Active Member
Looking for a Plenum for my RV 10 io540 not a Sam James plenum possibly one that was built for the stock cowling or if somebody has a mold and is willing to rent or produce a plenum for me also I remember seeing somebody from South Africa producing these plenums but I have been unable to find that source
 
Why not just make the plenum. Its not hard at all and would be a great learning tool in fiberglass.. You can find lots on help and guidance online too..
 
I’d be curious to know what the advantage is if any to a plenum vs standard cowling rubber? Could there be a less drag/ speed advantage? I have standard with no cooling issues but would always be interested in less drag/ more speed :)
 
Plenum

I have no issues with cooling speed extra speed would be nice but my main goal is to take the load off of the cowling my Engine cowling half’s used piano hinges to keep them together and I can see how they’re being affected by the pressure within the cowling
 
How are the cowling hinges being affected by the pressure within the cowling? There are 10's of thousands of airplanes with piano hinges holding the cowl together.

Heck, I have a plennum and the whole top lid is held on with piano hinges.
 
I’d be curious to know what the advantage is if any to a plenum vs standard cowling rubber? Could there be a less drag/ speed advantage? I have standard with no cooling issues but would always be interested in less drag/ more speed :)


Personally, the plenum allowed me to control the air over the cylinders. My #6 was always hotter than the rest, by putting deflectors and other attached to the plenum I was able to move it off of #4, cooler than most, and get the temps down on 6 now it’s all within 10f. Not something I could do with baffling and the top cowling. There are, of course numerous ways to resolve the same issue using baffles but not nearly as controlled as a plenum.
As for the easy way to do it yourself? Use the top cowling as a mold, put about 3-4 ply over it and you have the start of a plenum now you need to create a nice way to attach it. Instead of rubber use a thin L bracket - match drill and you have a nice plenum without shipping costs.
Best of success!
 
A plenum does not need to be complicated.

I used the "stock" baffle sides as a basis for my plenum and simply added a flat wrap "lid" made of .016 2024. As mentioned, held in place by piano hinge on all sides. Takes 30 seconds to remove and 2 minutes to install (no tools).
 

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Mike, are those Rutan Boomerang style inlet?

As others have noted, a plenum is just a lid. Details like attachment are important, but there a lots of ways to do it. The most critical factor is probably the inlet and ducting into the plenum, in particular as the inlet velocity ratio moves closer to freestream velocity.
 
A plenum does not need to be complicated.

I used the "stock" baffle sides as a basis for my plenum and simply added a flat wrap "lid" made of .016 2024. As mentioned, held in place by piano hinge on all sides. Takes 30 seconds to remove and 2 minutes to install (no tools).

Looks good, but how do you access the dipstick?
 
Mike, are those Rutan Boomerang style inlet?

As others have noted, a plenum is just a lid. Details like attachment are important, but there a lots of ways to do it. The most critical factor is probably the inlet and ducting into the plenum, in particular as the inlet velocity ratio moves closer to freestream velocity.

looking at the Rutan Boomerang plenums, it looks as if they are one piece units that provide cooling air only to the cylinder heads. interesting design.
 
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