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Plenum with stock cowl

N733JJ

Well Known Member
I know this has been asked many times but a search does not show any current info. Is anyone making a plenum that will match up with the stock RV-8 cowl?

Scott A Jordan
80331
 
I?ve been looking as well - no joy.

I used the James Cowl and plenum on the RV-10 and got great results. I would have done the same for the new RV-8 project but the James RV-8 cowl requires a prop extender that I did not want to use. I did see one RV-8 that used the James plenum with a stock cowl, but he had to do a lot of glass work to install the round inlet rings (the James plenum is designed for the round, alumni inlets). Also complicating the install is I?ll have the IO-360-M1B engine with horizontal injection.

I?m still debating if I?ll go that way or not (engine mount next week so my time is running out).

Carl
 
I made my own using the stock cowl for my -7A. I secured the lid to Van?s baffles by adding a strip along the back and bending the sides in slightly. The hardest part was getting a nice seal around the top of the inlets. I used Van?s baffle material secured to the top cowl that lays up nicely inside the plenum. It?s really not too hard to make and I would do it again verses the baffles.
 
I know this has been asked many times but a search does not show any current info. Is anyone making a plenum that will match up with the stock RV-8 cowl?

Scott A Jordan
80331

You don't have to have one, but is there a technical reason you desire a plenum (cover)?
 
You don't have to have one, but is there a technical reason you desire a plenum (cover)?

I flew without the plenum for many years but looking out at the cowling bulging from the internal pressure. Couldn?t stop thinking about the pressure on the sky bolt fasteners, couldn?t take my eyes off the ?scalloping? between the fasteners. I have never heard of a cowl failure but the sight bothered me. So, I build myself a plenum, it was crude, not pretty but got the pressure off the cowl. Surprisingly, it did not improve cooling (which had always been fine) at all.

Now, I am going through my plane and fixing/improving all the little things I am not 100% happy with before I retire and don?t want to put money into it. New panel, repairing/replacing all the fiberglass parts...

Interestingly, after converting from steam gauges and a VM-1000 engine monitor to a G3X, my CHTs have all gone up 30-40degrees with no other changes! Can?t fingure this out, Garmin doesn?t want to hear about it even though I have heard the same from a couple others. So, a better plenum, cleanup under the cowl and see what I get.

Scott
 
Still available.

NJ33JJ - FYI, I reached out to RVBits, and while they don't list the plenum on their website anymore, they will still make them. But the shipping from South Africa is expensive (about $300). They are doing a Carbon Fibre one for me now.

I also have a nearby neighbor that has one he was going to put on a different type of aircraft, but that plan didn't work out, so he might be interested in selling it. Let me know if you are interested.
 
NJ33JJ - FYI, I reached out to RVBits, and while they don't list the plenum on their website anymore, they will still make them. But the shipping from South Africa is expensive (about $300). They are doing a Carbon Fibre one for me now.

I also have a nearby neighbor that has one he was going to put on a different type of aircraft, but that plan didn't work out, so he might be interested in selling it. Let me know if you are interested.

Chuck,
I would be interested in your buddies plenum if it would fit without a lot of work. Another option might be to get a carbon fiber like you, have them shipped to the U.S. together, might save some on shipping. What is the price of the CF one? I assume this is Johansson?

Scott
 
Scott - I am in San Diego, and you are New York, so I don't know if the "split shipping" idea would work. Bummer, because it sounded like a great idea.

Chris said he is sending me the full quote, so I will let you know what that comes back at. I am getting a full set of Intersection Fairings as well.

My buddies plenum was for an RV-8 originally, and it came from RVBits, so if yours is an 8, that is what it was made for.
 
Plenum

Chuck: I am in Northern Ca. And would be interested in a plenum for my RV6 and would like to explore the split shipping. Please let me know what you find out. Thanks, Bruce Estes
 
Chuck: I am in Northern Ca. And would be interested in a plenum for my RV6 and would like to explore the split shipping. Please let me know what you find out. Thanks, Bruce Estes

Bruce,

I was told by RV Bits that to add an additional plenum would increase the shipping price by $80. Then you would need to add on the price for me to ship it to you. So you would save some, but I'm guessing not a lot. Maybe $100 in total. I will be ordering soon, so let me know if you want to pursue this.

I was just going to buy the non-CF plenum (which was made by RV Bits for an 8) from my buddy, but since I have to pay the shipping for the gear transition fairings anyway, that wouldn't really save me any money. So I am going to get both the plenum and fairings in one shipment.
 
Chuck: thanks for the info. I emailed RV Bits, inquiring about a plenum for my RV6 but have not heard back. What is the cost for your new plenum and is it glass or c/f? I am still thinking of making my own but need more info. Thanks, Bruce
 
You might check out this link - Very nice work, the best inlet connection to the cowl I have seen posted.

http://www.vansairforce.com/community/showpost.php?p=578167&postcount=1

I made my plenum cover based on a layup of the inside of the cowl. It has to be finished first or it is a tremendous amount of work to finish it smooth. I like the way Pete Howell did his. He cut some foam insulation blocks and filled within the baffle area and did a lay up on top. This way you could make the 90 perimeter flange too. Aluminum would work fine. The center hump matching the trailing shape of the spinner is not necessary, unless you have something to clear.

Personally, I would make the inlets one piece to the rings with urethane flexible ducts like DanH made his, if I were to do it again. My neoprene works great, very flexible, but having enough straight length is a design problem for the ideal inlet diffuser shape. There is not enough length on the vans cowl to waste any.

I think the most difficult area is that inlet ring to mate with the cowl. At least it would be for me.

Good luck in this project, and be sure to measure your upper and lower cowl pressures before and after to know what you have. Otherwise, it is literally shooting in the dark.
 
I flew without the plenum for many years but looking out at the cowling bulging from the internal pressure. Couldn?t stop thinking about the pressure on the sky bolt fasteners, couldn?t take my eyes off the ?scalloping? between the fasteners...

Scott

Is that from the internal pressure or the airflow over the top of the cowl lifting on the cowl?
 
Chuck: thanks for the info. I emailed RV Bits, inquiring about a plenum for my RV6 but have not heard back. What is the cost for your new plenum and is it glass or c/f? I am still thinking of making my own but need more info. Thanks, Bruce

Did you email Chris or me? I did not receive anything yet.
 
Plenum quote price?

I email you as listed on your website. I want pricing for a plenum for my RV6 with a IO360. Thanks, Bruce Estes. [email protected]

Bruce did you ever get that quote from Jan? I wanted one from him a while back and he said they weren?t fabricating them at that time but would let me know in a few months when they were and let me know so I could place my order. Never heard from him and then noticed they were removed from his site. :confused: They looked like a pretty nice product. I purchased their gear leg fairings and there top quality. :)
 
I did not get a response. Nothing. Not even a polite ?We are not building that plenum?. Bruce Estes

Thanks Bruce.
I wonder why more folks aren?t producing these. Once the first mold is constructed ( the hard part) it should be pretty easy to knock these out.
They must get sick of the mess and smell.
 
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