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Sam James Cowl

I'm still building, but I've got the plenum and will be getting the cowl. Conventional wisdom here that I've read is that it saves you the boatloads of time otherwise spent sanding, filling, and finishing the Vans cowl. The plenum helps with cooling. There also seems to be quite a bit less baffling work that needs to be fabricated. All in all it's one of those areas I'm more than willing to spend the money to save time, and most likely gain efficiency, on something I otherwise would be pulling my hair out on.
 
I have the James cowl and the plenum. The cowl is a work of art....the plenum not so much. If you read my blog at www.darinanderson.com you can see what I ended up doing to make the plenum fit nicely. Making the James cowl fit without a plenum might be a challenge but I'm sure it can be done.

Darin
 
I'm fitting the James cowl and plenum now - the cowl looks great, the plenum will have to be carved up and pieced back together to make it fit. I knew that before I bought it, and went that route anyway because I wanted the plenum and figured it would be faster to start with the James plenum that to start from scratch, even knowing I would have to carve it up.
 
I have a 7 and in the middle of making my own plenum cover. I really did not like the SJ cover, poorly shaped to cowl, rough on the outside, smooth on the inside, required a modification to allow a high mounted oil cooler, and the inlets did not align. So - - I decided to make my own. Lot (^3) of work.

Having said all that, many, have made it work. I decided to take the risk with a new cover rather than other things of remaking the SJ.

Here is a picture of the piece cut,shrunk, stretched, and finished for a buck and the mold for the real thing. I am waiting on fiberglass supplies to move forward.
IMG_1330.jpg


Early stage inlets:
Air%252520Inlets%252520progress%25252001.JPG
 
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I have a 7 and in the middle of making my own plenum cover. I really did not like the SJ cover, poorly shaped to cowl, rough on the outside, smooth on the inside, required a modification to allow a high mounted oil cooler, and the inlets did not align. So - - I decided to make my own. Lot (^3) of work.

Having said all that, many, have made it work. I decided to take the risk with a new cover rather than other things of remaking the SJ.

Here is a picture of the piece cut,shrunk, stretched, and finished for a buck and the mold for the real thing. I am waiting on fiberglass supplies to move forward.
IMG_1330.jpg


Early stage inlets:
Air%252520Inlets%252520progress%25252001.JPG


Looks like a project Bill! Did you use one of the Smooth-on rubbers to make your mold?
 
Plenum isn't needed.....but...building the transition from round inlet to baffles will consume more than just a few hours.

Any time you deviate from the plans it adds time and money. My plenum fit badly. I hacked it up and still want to redo it. My cowl was ok, but I still needed to cut the intake scoop out and add material for air cleaner clearance.
 
I agree with the others.

I installed the short cowl on my O-360 and had to modify the FAB substantially, including fabricating a different carb heat flapper valve.

The plenum was modified by building a ramp by the oil cooler and cutting the front off and laying fiberglass directly on the engine (which was covered in Vaseline). This produced a snug fit.

For the oil door, I covered the top cowl with som stretch wrap after laying out where it should go and laid the fiberglass right on the cowl. I then trimmed my door and cut the hole in the cowl.
 
I'm still building, but I've got the plenum and will be getting the cowl. Conventional wisdom here that I've read is that it saves you the boatloads of time otherwise spent sanding, filling, and finishing the Vans cowl......All in all it's one of those areas I'm more than willing to spend the money to save time, and most likely gain efficiency, on something I otherwise would be pulling my hair out on.

Bwaaaaahahahahaaha!

Oh grasshopper, you have indeed drank deeply of the holey Koolaid ;)
 
I'm still building, but I've got the plenum and will be getting the cowl. Conventional wisdom here that I've read is that it saves you the boatloads of time otherwise spent sanding, filling, and finishing the Vans cowl. The plenum helps with cooling. There also seems to be quite a bit less baffling work that needs to be fabricated. All in all it's one of those areas I'm more than willing to spend the money to save time, and most likely gain efficiency, on something I otherwise would be pulling my hair out on.



Bwaaaaahahahahaaha!

Oh grasshopper, you have indeed drank deeply of the holey Koolaid ;)

Scott - I've got to agree with Dan here - you might have spent a little more money but you didn't save yourself any time on those prep items. I've got the James cowl and plenum in hand, and they are far from a finished item.
 
James Cowl and Plenum

Used to belong to a builders club that was responsible for the construction of several RVs. My 9a was the only one that we built with a James cowl and plenum (this was in 2005-06) although my brothers 7a does have a non-James plenum with a Vans smooth cowl.

My opinion is that the cowl prep/install for the James vs Vans cowl is no more difficult. The James plenum, on the other hand, added many hours and frustrations to the build in order to get a good fit. My James plenum (circa 2005) was "racked" diagonally----appeared that it was taken out of the mold too soon. Like others, I had to cut off the back flange and part of one side, as well as reworking the area in front of the oil cooler pick up. I also had to lay up the front flange on the engine to make it fit properly. It was far easier on my brothers 7a to simply use the Vans baffle kit and a carbon fiber top which was available commercially back in 2007. The most challenging part of this was matching the baffle openings to the oval Vans cowl openings--on which he did a great job.

Cheers,

db
 
Looks like a project Bill! Did you use one of the Smooth-on rubbers to make your mold?

Andy, I used an isophthalic resin and a tooling gel coat. It is a polyester resin and was recommended for making multiple pieces. I looked at the smooth-on site and it had many interesting methods. I still have not decided between resin infusion or hand layup with a vacuum bag afterwards. Supplies will arrive on Tuesday. It will fit the Vans baffles nicely on three sides. The front was set back from standard and other mods were made for the lack of flow on the #2 and #3 heads around the shallow fins. I think the design is easily replicated. The inlets are being made separate so the cover can be removed alone.
 
one way or another you are going to have to seal the air flow around the engine to provide for adequate cooling. If you want to build full baffles and fit to the cowl I imagine that would work. The idea behind the cowl and plenum is to reduce the cooling drag and make the air that is let in more efficient. I have the Sam James system on my RV-9 and it works great. As another post in this series notes the plenum does require a lot of slicing and splicing to get it to fit properly. I would do it again knowing the amount of work involved.
 
I built my plenum by hand using Vans baffles as the sides. A buddy used the Sam James system. I don't believe he saved any time. James should be a little embarrassed by the plenum fit and finish in my mind. A professional with a mold should be much closer to actually fitting out of the box.
 
I built my plenum by hand using Vans baffles as the sides. A buddy used the Sam James system. I don't believe he saved any time. James should be a little embarrassed by the plenum fit and finish in my mind. A professional with a mold should be much closer to actually fitting out of the box.

Yeah, you are right. Sad, with a nicely fitting cover, it actually could be faster than the standard cowl baffles. I know that Will and Sam have divided up the work, but if Will took it on, it would be a real gem!
 
James Cowl Adds Time

You have it backwards, the James cowl will need more fitment and time than the Vans Cowl.
 
cool aid?

No,
I finished the plane a couple of months ago and have both the cowl and the plenum. The cowl is a work of art that Will James does and I only had to make minor mods. He has been very helpful answering questions during my build.

The plenum need some help all around the edges - basically cut and fill, but that was on the edges only. The front needs some creative shaping. All said and done, It was much easier to use the plenum as a starting point.
I am happy with the results. Engine cooling is excellent and the cylinder temperatures are uniform and cool. With the air temp at about 65F and the engine running at 2600/26" (IO360M1B) - which is about 80% power, the CHT were about 325 - 350F. They get a little hotter when in full power climb at 110kts.
I like the conical intake filter (fuel injected with front servo). There is provision for alternate air which works quite well.
I have the oil cooler on the firewall so it does not interfere with the plenum. I had to reduce the flow to the cooler to get the oil temperature up to 180F - the plenum is providing plenty of cooling air to the oil cooler.
 
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