Hi Bob,
I built a plenum for my TSIO550. Unfortunately I don’t have before/after data on it but Charlie Kohler told me that my heads are running very very cool even having the tight lower old cowl that became obsolete because of cooling issues. My oil temp is running a little above average (approx 190F at an OAT 20…25F at FL200)
The actual plenum was a piece of cake – I just taped down cardboard sheets on the engine, waxed it and laid 3 layers of carbon on top. After it was dry I removed it and cut it to size.
Making the baffling and modifying the cowl to reduce the leaks turned into a real project. Fred Moreno has a lot of helpful tips in the archive for the baffling. I also copied the design of the sliding oil door from Brent Regan. The air-inlet is copied from 320/360 pictures ( when it comes to plenums there is a lot more know how than on the IV side – obviously the 320/360 group is more fanatic about speed J)
I don’t remember how many hundred hours I have in this – but it was a lot. You need a lot of passion to go there especially since you have a flying airplane already.
If you look for the most economical and quick solution I probably would go to Aerochia – I think they have a complete cowl-plenum- design that they sell.
If you really want to do this by yourself you are welcome to stop at 5G7 any time and look at my design to collect further ideas.
Ralf
From: Bob Rickard [mailto:r.rickard@rcginc-us.com]
Sent: Monday, June 03, 2013 5:11 PM
To: lml@lancaironline.net
Subject: IV-P TSIO550 Plenum
Gents - a couple of questions regarding plenum design (IV-P/TSIO 550 specific)
1. What do you do about the oil door on top of the cowl?
2. Is it better to have absolute min volume around the engine, or is it ok to mold to the cowl for the upper sides?
3. What do you do for airflow on the pilots side where the 3rd intercooler is?
I'm definitely sold on the plenum idea and have a great carbon man here in STL. Just need to figure out those specifics to get designing…..
Tom, I looked at your plenum page
where you place the poster board over the engine for a mold shape. I was thinking how easy that could be on the IO550 even if it didn't do all the fancy work up front with diffusers and so forth. Such a simple piece might seal the back, two sides for perhaps 75% positive seal. It would get rid of a lot of silicone strips with (what appears to be) reasonable effort. Great idea.
Legacy
A lot is possible. Could be gear actuator, could be a door actuator, could be the dump valve, etc.
President, Rickard Consulting Group, Inc.