question on durability of plenums

[scsmith]

Pete Howell and Vlad have recently posted some good threads on making a cooling plenum. I've been toying with the idea on and off. I have an idea of a way to make composite rings that lock into the stock cowl inlets.

But an additional consideration came to mind. The plenum makes a nice structural connection to the baffles, adding a lot of support, and damping. My guess is that there would be much less problem with baffles cracking over time ( especially for the folks that mounted their oil cooler on the baffle).

On the other hand, the plenum shell itself may tend to flex and crack at the connections to the baffles.

So, my question:

For those that have plenums made with a fiberglass or carbon layup attached to aluminum baffles, what has your experience been on durability over time? Better than normal baffles with seals? about the same? worse?

Since I'm only about a month from flying, this would be a follow-on project for me.....so I'm just thinking.

[petehowell]

300hrs with baffle seals, 150hr with plenum - no cracks with either. O-320, carb, CS prop.

The O-360 has bigger pulses, that might be a better test.

[db1yg]

270 hrs with fg James plenum. No cracks or indications of stress of any kind from my Eci 0360.

Cheers,

db