drain in FAB?

prkaye · #1 04-14-2009, 08:46 AM

It occurrs to me as I work on the FAB that there is no palce for water to escape. If water gets in there, how can it get out, without getting sucked up into the engine?
I'm wondering why the plans don't call for us to drill a small water-drain hole in the bottom of the FAB (at least I haven't seen an instruction to do this). I suppose one drawback is that it would reduce the air pressure in the FAB...

scard · #2 04-14-2009, 08:52 AM

Yeah, drain required. one inside the filter space, one outside the filter in my opinion. This is even more useful to let raw fuel out if someone pumps the throttle too much without the engine running.

prkaye · #3 04-14-2009, 08:57 AM

Is this in the plans? I'll have to check-again. If not, what size drain-holes would you recommend?

647jc · #4 04-14-2009, 09:08 AM

The instructions (page 2 para. 6) say to drill two 1/8" holes at the lowest point of the bottom of the box, one inside and one outside the filter.

Ron B. · #5 04-14-2009, 02:44 PM

Yes, isn't it great that they mention the drains at the beginning of fabrication and later when it's time to position the holes they only discribe the inside hole with the optional drain tube. Got me in trouble as my partner said two were required and I said he was mistaken. Luckily he knew they mentioned at the beginning of the instructions. At least this is what was supplied with the RV-10.
Ron

RV3 Pilot · #6 04-14-2009, 03:29 PM

Here's a little hint for finding the low spot. On my 3 (taildragger)

I waited till I had mouned the fab with the a/c sitting on its gear, put an ounce or so of red dye in and let it settle and leave a stain mark or sight from underneath with a flashlight. Drill away
Tom
RV3 x 2.

osxuser · #7 04-15-2009, 09:47 AM

Put the whole thing together, find where the filter sits, and put one on each side of the filter... done. There are a LOT of RV's out there flying without this, and only two out of three I know of lit on fire

.

N941WR · #8 04-15-2009, 03:31 PM

Quote:

Originally Posted by osxuser

Put the whole thing together, find where the filter sits, and put one on each side of the filter... done. There are a LOT of RV's out there flying without this, and only two out of three I know of lit on fire

.

Close but not exact.

Put one small hole (#30) in the aluminum plate that covers the bottom of the K&N air filter. Then put another #30 hole in the low point on the FAB.

This will allow any fuel to drain out of the carb, past the filter plate, into the FAB, and then drain out of the FAB.

frankh · #9 04-15-2009, 03:33 PM

Quote:

Originally Posted by osxuser

Put the whole thing together, find where the filter sits, and put one on each side of the filter... done. There are a LOT of RV's out there flying without this, and only two out of three I know of lit on fire

.

I feel warm and fuzzy all over..NOT!

Pmerems · #10 04-15-2009, 08:45 PM

I have been debating about installing the filter bypass on my FAB. I am just completing it and need to decide.

I called a local RV-6A driver and asked if he had installed his. He originally did, but gas dripped from the throttle body down onto the plate and through the door gap onto the bottom of the cowl. During a engine start he had a FAB box fire. Fortunately as the engine started it extinguished the fire. He didn't know this until he inspected the FAB and found it damaged. He promptly removed the filter bypass valve and glassed in the bottom.

His recommendation was to glass in a piece of 1/4 aluminum tubing to the outside bottom of the FAB, drill the drain holes into the tube and run a hose to the lower firewall/cowl exit. Similar to the fuel pump overflow/pressure relieve vent tube run per the plans.

Food for thought...............

Paul