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RV-6 plenum revisited

whittfic

whittfic

Well Known Member
Patron
Some time ago I submitted some photos of an engine plenum project I was working on http://www.vansairforce.com/community/showthread.php?t=48209&highlight=rv6+plenum . At that time I made the rather bold statement that I would have an update and more photos of the finished product within a couple of weeks. Well, as always life and other priorities tend to get in the way of ones pleasure, so only now some eighteen months or so later can I offer an update of some very slow progress.

The attached photos show a mostly completed system apart from minor fibreglass finishing and painting. The question was asked about how I proposed sealing the gap between the plenum and cowl. After some head scratching I made up flexible ducts using Dan Horton's nicely timed articles he wrote for the forum (Thanks Dan, your idea worked a treat!). A simple screwed down clamping system should provide an adequate seal around the edges of the ducts and keep everything in place. The removable plenum 'lid' allows for easy spark plug servicing etc.

http://i456.photobucket.com/albums/qq282/whittfic/DSC03338.jpg
http://i456.photobucket.com/albums/qq282/whittfic/DSC03337.jpg
http://i456.photobucket.com/albums/qq282/whittfic/DSC03342.jpg
http://i456.photobucket.com/albums/qq282/whittfic/DSC03340.jpg
http://i456.photobucket.com/albums/qq282/whittfic/DSC03339.jpg
http://i456.photobucket.com/albums/qq282/whittfic/DSC03335.jpg
http://i456.photobucket.com/albums/qq282/whittfic/DSC03333.jpg

Enjoy.

Clive Whittfield
Auckland
New Zealand
RV6 Saving up for Skyview!!
 
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Must be something in the water.....everybody from New Zealand seems to do high quality, creative fabrication!

That's nice Clive.
 
Plenum

Clive
That is very nice. You have just inspired me to install spark plug access doors in my james plenum.
Matt
 
If you feel like skiing Lake Tahoe, I'll give you a free place to stay in exchange for building me one of these!!!:D
 
Build me one also

Sig600 said:
If you feel like skiing Lake Tahoe, I'll give you a free place to stay in exchange for building me one of these!!!:D
Click to expand...

If you prefer the ups and downs with football coaching changes and like Texas Tech Football I will put you up for 2-3 games of your choice to re-build my RV-10 plenum so it looks as pretty as yours.
 
Don't Know if it is true but ...

I installed a brace made of aluminum angle from a crankcase bolt to the rear baffle over where the oil cooler is hung. The baffle kit said to do this to prevent baffle cracking back in this area. Mine hasn't cracked in ~7 years of operation with the brace, it may not have cracked without it either and you do have the top cover glass for support so your situation is different. Please take this as an observation comment with no pretense of real knowledge.

Bob Axsom
 
Wow!

Wow! :eek: I cannot even imagine this type craftsmanship, truly impressive. I am constantly amazed at what builders are able to envision and create. Nice work. - Steve
 
The Best!

Yes Vlive, that is the best one I have ever seen and I have looked at lots!
Any performance numbers or temps you can share?
Thanks
 
The coolest thing is that you have modified the cowling so that the front air inlets are no longer split between the top and bottom cowling - They go with the bottom only (see last photo). Nice dude.

Erich
 
erich weaver said:
The coolest thing is that you have modified the cowling so that the front air inlets are no longer split between the top and bottom cowling - They go with the bottom only (see last photo). Nice dude.

Erich
Click to expand...

Check out "From The Ground Up" (episode 10 I believe) to see another way to do this. He also used a plenum and modified the front of the cowling. Any one know the pros/cons of doing this?
 
Geez thanks people, I am getting a little swell headed here with all the nice comments!:)

How was it done? Unfortunately I didn't document the process or take any progress photos, so I will try to explain what I did as best I can. It might seem a little lengthy tho', so if you feel your eyes starting to glaze over I wont be offended if you hit delete and move on.

I started by taking a quick mould off a section of the Vans supplied top cowl to get the basic shape. I cut and bonded this to flat pieces of wood that were clamped to the inside surfaces of the fitted baffles (I'm starting to form a pattern or replica here of the finished product). I then removed this semi-formed pattern from the baffles/engine assembly, braced it and cleaned it up sufficiently to take another mould (remember, I haven't started forming the inlet shapes yet). I formed the corner radii in this mould using nothing more than auto filler and a suitably sized socket from my tool collection.

More sanding and cleaning up, then I made a rough 'plenum' from this mould still without inlets. This was trimmed and fitted to the engine, ensuring there would be enough clearance under the upper cowl. Rigid urethane foam was then used to form the shape of the inlets. The trick here was to fit and size the blocks of foam so that when the cowls were in place, the inside edges of the cowl inlets were just touching the foam. The inside shapes of the inlets were then traced onto the foam with a sharpie. Final shaping of the foam could then be done using the traced shapes as a reference.

Fibreglass cloth was layed over the foam shapes followed by lots of filling and sanding to blend them into the plenum shape, resulting in the finished pattern. The final two-part mould was then taken from this pattern using tooling resin and chopped strand fibreglass mat.

The plenum itself was made using fibreglass twill cloth, core mat and fire retardant vinylester resin.

Those of you who are familiar with fibreglass work will know this is very much the 'Readers Digest' version. There is a lot more detail to the process than described here. I have the advantage of being general manager of a composite manufacturing company, (Composites International Ltd) mostly doing aviation related work, so have the advantage of resources and plenty of experienced help to call on for ideas if I need it.

Tahoe...? Lubbock...? I have to confess I had to google these places to find out where they were:eek:. Yep, they look really nice,....and quite a contrast to the temperatures we are currently experiencing in the middle of one of our hottest summers on record here in NZ!

If anyone wants more info I will do my best to help.

Clive
 
Flaude said:
Absolutly beautiful but does it worth the hours!!
Click to expand...

Depends on your perspective I guess. If your primary interest is to get flying quickly then probably not. However I am one of those people who 'gets' to build the plane rather than 'has' to build, so for me it's not an issue. Besides it's taking me a while to save for a Skyview so I have time:)

Anyway, given my occupation, fibreglass work is not the scary beast that it can be for some, so it's each to their own I guess. Have a look at this website www.compositesinternational.co.nz in about two weeks time when we have it up and running and you will see what I mean.

In answer to an earlier question, won't have any temps or any other flight info for a while, I am still at that 90% done, 90% to go stage of construction.

Clive
 
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