Would like opinions on this plenum

szicree · #1 08-02-2007, 05:48 PM

I would love to get some input regarding this plenum design.

http://websites.expercraft.com/n51pw...ry&log_id=7264

I'm confident I could whip this together in a few days and think it looks like a much more elegant setup than the stock one. I just hate the idea of all that air swirling around over the case for no reason, and the rubber seals against the cowl seem downright primitive (please do not take offense

). I know that the stock system has worked well on thousands of planes and over jillions of flight hours, but...

RV8RIVETER · #2 08-02-2007, 06:27 PM

I can't agree more. After much thought and research I decided a while ago to build a 2 piece separate plenum. However, I will be glassing mine and putting a whole new front end on the cowl. I think it is the most elegant and efficient way to go. No air is wasted, all the air you bring onboard will be cooling something, and you don't need an access panel for the dipstick. It is more work, but nothing is free.

Check out this link, very interesting cooling design.
http://www.ez.org/feature/F0502-1/F0502-1.htm

DanH · #3 08-02-2007, 10:39 PM

Steve,
These might help. Mark did a nice job.

Shot at 2007-08-02

Rivethead · #4 08-03-2007, 12:45 AM

Does anyone have actual numbers on the temps. I'm moving rapidly toward plenum building and I really like that design. One change I'd make possibly would be to remove any sharp bends from the upper surface. Although maybe that's not practical and in real life can't happen. AHHH! 90% done 90% more to go.

DanH · #5 08-03-2007, 08:07 AM

The website in the first post should get you in contact with Mark Phillips.

AlexPeterson · #6 08-03-2007, 08:10 AM

I certainly do not know the actual performance of the setup shown in the pictures, but if there is not a large enough chamber for the air to slow down (i.e., recover pressure), it will not be as efficient. The single chamber (stock design or most plenums) balances out any differences in inlet flow between left and right.

Given the large number of variables affecting cht's within apparently similarly outfitted airplanes, the best way to really evaluate cooling systems might be to instrument the upper and lower chambers with a manometer to measure what the engine cares about - pressure differential top to bottom.

It is refreshing to see new creative approaches, but good instrumented data is the real proof of effectiveness.

Christopher Murphy · #7 08-03-2007, 09:47 AM

that set-up looks like it weighs a ton. All of those fasteners just add weight.

szicree · #8 08-03-2007, 09:54 AM

Quote:

Originally Posted by Christopher Murphy

that set-up looks like it weighs a ton. All of those fasteners just add weight.

C'mon now, a ton? I'd be willing to bet that the rubber seals and rivets that attach them on the stock setup weigh more than the fasteners on the dual plenum.