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prkaye

Well Known Member
does anybody know of a builder site with a really good documentation of the installation of Vans FAB?
 
specific question

OK, well how about a specific question about something these FAB instructions I'm not understanding...

The stage for compressing filter between the mount and airbox. I don't udnerstnd their technique for doing this. They start by saying "mount the top plate 1/16 inch below the top of the filter". Huh? Mount the top plate to what? The filter sits under the top plate once it is screwed into place beneath the mount plate. Besides which, the filter doesn't seem very compressible.

Also, the filter they gave me is only about 2.5 inches deep. My Fiberglass Airbox is about 4 inches deep. This means if I push the top/mount plates down on top of the filter so the bottom of the filter is pushed agains the bottom of the airbox, the plate sits about 1.25" below the upper edge of the airbox. Am I supposed to trim away all this fiberglass overhang?
 
Do a Google search...

...on "Why does it always have to be Fiberglass"

The link will take you to a builder 'fabing the FAB.
 
Thanks, I had actually found that, but it's mostly about how to do fiberglass work (which I already learned when I did my aft skirt). It does't really answer my questions about how this FAB goes together (such as the two questions above).
 
Did you receive...

...the several pages of instructions, drawings, and figures?? There is not a lot of step-by-step help in there; it is left up to the builder work through the steps.

Also, a look ahead should be performed on the "FAB BYPASS VERTICAL" kit. This kit can be installed after the FAB is finished, but it would have been easier without the air box top plate already riveted to the fiberglass box.

The position of the top plate (1/16..or whatever) below the filter height allows the fiberglass box and top plate to compress the filter which forces a seal between the top and bottom of the filter. Thus, all the air goes through the filter and not squeak through any gaps.
 
Phil,

Take a look at this builder's RV-9A site. Lots of detailed photos. Start at bottom of page 91... Does not answer all your questions, but should give you a head start.

http://www.n2prise.org/index.htm

You should keep a repertoire of favorite builder sites, they came in real handy for us, especially for the baffles (among other things).
 
On my 7A the filter Is captured between the three al angles surrounding the left, right, and aft sides of the FAB and the floor of the inlet ramp. The fwd side has no al angle so the rubber lip on the filter is only captured between the fwd edge of the fiberglass and the fwd inlet ramp floor. Call if you want. 702 area code two seven 8 zero 273.
 
I know exactly what you mean.

I am working on my FAB now and just drilled the top plate to the FAB. I'll post some pictures today.
 
thanks!

Set the filter in the fiberglass, put the top plate on top of the filter, mark and trim. Leave a little extra and take apart. Reinstall without filter. Push top plate past your mark by 1/16th and drill. That will compress the filter when you reinstall. That's it in a nutshell
Click to expand...

AHhhhh.... now I guess if I were smarter I could have deduce that from Vans' instructions, but it would have been a lot easier if they had just said it clearly like that! Thanks!
 
Polyester resin?

Starting to make sense to me now, seeing the parts on the plane.
In one of the steps, where you make cuts in the air box to get the forward end at the right height, they say "Use polyester resin and glass cloth to close the cut". Why Polyester? Can't I use west systems epoxy here?
 
prkaye said:
does anybody know of a builder site with a really good documentation of the installation of Vans FAB?
Click to expand...

Does this help?
http://nerv10.com/wcurtis/10FFwd/indexFF4.html

http://nerv10.com/wcurtis/10FFwd/FF4a.html

FF3e.jpg
 
In progress

I'm using a fuel injected with vertical induction on my RV-8. The FAB was offset pretty far to the left and I had to make spacers since the injector servo is shorter than a carb. I made a new mounting plate and had a friend with a CNC milling machine cut out the big hole on his machine. He did the same thing for the spacers I made out of delrin. The hole on the new mounting plate was offset 1/2" to the side so I could center my FAB better in the scoop.

As others have explained, the filter gets pushed into an oval shape and held in place by the brackets you make and rivet to the top plate. Once that is done, you can put the top plate in the FAB, make sure it is about 1/16" below the top of the filter, and then drill and cleco the top plate to the fiberglass. Here are some photos of my work in progress. Hope they help.

gal.php
 
Thanks guys, made good progress on it today. Tomorrow I'm going to work on the door part of it.

Another question, just out of curiosity, why is the carb offset to the side of the sump (requiring the FAB to be angled to meet the airscoop)? I presume there must be a good reason the engine is designed this way...
 
Mixture operation??

William, isn't your mixture operation reversed, the way you installed it?

Regards, Tonny.
 
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