SJ Cowl Plenum/Baffling pics?

[cjensen]

For those that have the SJ cowls...can I get some pics of how you made your baffling to go along with the plenum?

Is there any difference in the baffling system between Van's and the SJ cowl?

[Radomir]

It's very similar.. sides are same (just not as tall) and main difference is front inlet ramps.. I don't have any pics handy now (sorry).. but it wasn't that big of a deal to do.. I used Van's baffle kit..

[frankh]

A little group I started to help those of us with SJ cowls and plenums.


http://groups.yahoo.com/group/JamesAircraft/


You can either modify a Van's baffle kit or save yourself $200 and make your own from the templates that James supplies...I made my own, simple enough.

Frank

[hevansrv7a]

Sam provides drawings and if you have a band saw and a good size brake you can do it. Next best is to use Van's, which I did. You end up leaving out some parts such as at the center of the back and center of the front and you have to cut them down a lot vertically. There was some serious re-bending needed to get the ramps to merge with Sam's plenum at the front. I ended up making some laid-up-in-place fiberglass parts to help seal the front at the bottom of the plenum. There's a difference between Sam and Van on the gaps between lower baffles below the cylinders and Sam says if you follow his guidance your CHT's will be extremely close. I didn't, yet. Mine are maybe 25-30 degrees from hottest to coldest. In general I'm very pleased with the cooling, including oil temps. Fitting the oil cooler is tighter than with Van's. You have to ensure clearance from the fins of the cylinder. I'm sending some pics via email.

[Deems Davis]

I installed the cowl and plenum on my RV-10 here's a link to a photo album of the cowl install:
http://deemsrv10.com/album/Sec%2047%...ing/index.html
construction log w/ write up's for cowl:
http://deemsrv10.com/cowlinglogindex.html

Here's a link to an album of the plenum w/Van's baffling:
http://deemsrv10.com/album/Sec%20FF2...num/index.html
Link to construction log w/ write ups for Plenum and baffels:
http://deemsrv10.com/FF2logindex.html

[TGRV7]

Deems, I am checking out your foto's of your SJ Cowl install.
I see some complex shapes on the baffles. Did you fabricate all the baffles from sheet stock?
I am considering the SJ cowl/plenum/Horz Induction
Does not look like an easy task.
Thx

[Deems Davis]

There are some complex shapes even though Sam sends some paper templates along with the plenum. They aren't super accurate (hand drawn). Most folks I've talked to have opted to use Van's baffle kit and to make the modifications (both to plenum and baffles) necessary to adapt it, rather than cutting the baffles from the templates. I believe that this approach is less work and effort and yeilds a cleaner/more accurate installation. The Baffles and the modifications are really not all that big of an effort relative to the rest of the cowl/plenum work.
Sam warns that the exit area at the bottom of the cyl's is different with Van's and that you need his size area to ensure equal cooling across cyls. I checked and there is a difference in the size of the exit area. However, given all of the other variables, I don't think it's as major an issue as Sam maintains.

[cjensen]

Thanks for all the replies, pics, and emails everyone! That helps!

[lostpilot28]

Hey guys, I'm going to buy the Sam James Cowl and was thinking of going with the Plenum. I thought the Plenum didn't need baffeling to work. Am I correct in reading your posts that baffeling is required? Is it used only to attach the plenum to the engine?

Alternately, what if you don't go with the plenum? Is the Van's baffeling sufficient for cooling? What is the benefit to the SJ Plenum? Thanks.

[frankh]

I would go with the plenum...or even make a plenum by taking a 2 layer mold of the underside of you cowl and cutting to size.

less leakage=more speed...It also means more hassle to get to the top of the ngine as well but cst La vie!

Frank