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glenn654

Well Known Member
has anyone tried to connect a plenum to baffling by using camlocs?...if it is possible. Would they be strong enough to hold the strain?

Glenn Wilkinson
 
I think that they might be strong enough to sustain the strain of air pressure inside the plenum. However, I doubt that they would be strong enough to prevent the fretting that would occur between the mating surfaces, when subjected to the vibration of the engine. This is just my own SWAG based on my own aluminum plenum experience.

It might work though. Go for it- that's why they call it "Experimental."
 
Why not hinges?

Van's uses hinges for the cowl because of even distribution of force, strength, and low cost. Why not consider using hinges instead of camlocks?
 
I used the hinge material to attach the "experimental" aluminum plenum top to the plenum sides.

I built the plenum as described in Van's instructions until it was time to add the rubber baffle material. Instead, I riveted on hinge segments around the inside edges of the sides, and used angle stock to form a support ledge on the inside of the rear baffle sections. Next came three supports front-to-back that divided the engine top into three sections; one over the left cylinder bank, one over the right cylinder bank, and the third over the engine case. Each of these uses ss hing pins for "easy" removal. The front ramp areas were the most difficult to fabricate.

I spent way to much time on this and would probably not do it again...
 
No, not yet. I am trying hard to finish the wiring behind the panel at this point. Everything else is completed.

There is an RV-8 in the area that also has installed a "doghouse" plenum. Turns out we are both engineers, worked independently of each other, and came up with very similar solutions. He has abt 400 hours on his...
 
Some more ideas....

Hi,

I have a very similar plenum - hinges down the side, screwed in the middle. The actual AL top was fairly easy to sort - the transition to the cowl and inlets on the other hand was a real PITA. Lots of time.

I still think it is the 'right' engineering solution, if I was doing it again I would spring for either the whole Sam James cowl, or at least the inlet rings as a minimum.

Lots of photos - http://www.rvproject.gen.nz/plenum.html

Yes it is flying, but only 70 hours - so difficult to say if it is a 'good design' from a fatigue perspective - but so far all good.

Regards,

Carl
 
Carl...impresive...well done. We have very similar solutions. The biggest difference is in the air inlet ramps. You fabricated nice glass portals, I matched the cowling openings with aluminum ramp inlets.
 
inlets

noelf said:
You fabricated nice glass portals, I matched the cowling openings with aluminum ramp inlets.
Click to expand...

I prefer your option! The round inlets were an on going challenge - photos not on the website yet - I'll try and dig some of them out given a bit of time.

Carl
 
I just used #5 nutplates and SS screws

A plenum is the greatest thing since fuel injection. I cut off the top of the side plenum and riveted on some 1/16" angle Then I fabricated on whole sheet of .032" aluminum to fit over the whole thing. I put another piece of angle down the middle, too, supported at the front and back. I glued a gasket to the angle and attach with the screws. Works perfectly! No leaks. I looked at using hinges, but found it would be hard to get the hinges to seal down as tightly as I wanted, so I opted for the screws. I don't take the top off very often, except at annual. I can see inside pretty good through the front. Oil temps and CHTs stay great on my 360. The best part is being able to run up the engine, adjust things, check for leaks, etc. without having to take the cowl on and off all of the time. The difficult part is getting a smooth transition from the front openings to the plenum. I may, someday make up a couple of FG transitions and redo the front for round holes with venturi intakes. Something for the future. Really isn't needed though, except to lower cooling drag. I have about 100 hrs. on this now and nothing has moved, cracked. etc. Just some food for thought. Roger.
 
I have seen it done

After I saw an RV-7 done this way, I wish I had done it myself, very fast to get the plenum on and off. Next time I will use camlocs on the plenum as well as the cowl.

Hans
 
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