Fuel drain valve flange countersinks

riseric · #1 02-13-2013, 10:01 AM

Hi all,

My fuel drain valve flange came with countersunk holes.

The plans calls for size AD 426-3-4 rivets but the countersinks are too big.

Size 4 rivets seem the perfect size for these countersinks.

I will then drill to 1/8" so the manufacture head sits tighly on the flange.

Anyone else have this issue???

ppilotmike · #2 02-13-2013, 01:58 PM

If Vans wanted them to be mounted inside the skin, it would make sense to have slightly oversized countersinks to allow room for the skin dimple. Are you sure it's to be mounted on the outside of the skin...? I was wondering about mine as well, but assumed that mounting inside might prevent water flow out the vent.

g zero · #3 02-13-2013, 02:12 PM

They mount on the Outside. Might want to check with Vans on getting new ones ( so they can get the vender to produce the proper counter sink ) . Vans might say put a 4 in it and be done , The Proseal is tuff stuff , but if if have to remove a stuck quick drain, inproper rivets may allow the bung to twist .
If you put 4's in there , disassemble your caged countersink and use it without the cage , woks well in tight spots like that .
Tom

Ron B. · #4 02-13-2013, 02:21 PM

On the RV-10 , they mount on the inside.

n82rb · #5 02-13-2013, 05:03 PM

i mounted mine on the inside. they look a whole lot better that way.

bob burns
RV-4 N82RB

longranger · #6 02-13-2013, 05:35 PM

Quote:

Originally Posted by n82rb

i mounted mine on the inside. they look a whole lot better that way.

bob burns
RV-4 N82RB

So the water in the tank has to be about 1/8" deep to flow out?

BigD · #7 02-13-2013, 05:38 PM

Plans currently show the the drain on the [i]outside[i] for the RV-10 (page 18-2); maybe that's a change...The rivets called out fit nicely on mine, my problem was misreading the length, which became clear after clinching a few. I agree with gzero about checking with Van's, but don't see any reason you couldn't do the substitution you asked about. Just my opinion.

==dave==

RV-10
Finishing tanks

riseric · #8 02-14-2013, 02:32 AM

As per the plans, they go outside the skin as seen on my photo.

I will contact Van's (don't know why I didn't think about that in the first place...)

Maybe they sent me the wrong ones...

I also don't see any issue with using a size 4 rivet.

I'll report back with Van's reply.

DaleB · #9 02-14-2013, 06:44 AM

Looks like a NAS1097AD4 rivet would be a good solution for that. Maybe I'm wrong.

ppilotmike · #10 02-14-2013, 08:04 AM

Quote:

Originally Posted by longranger

So the water in the tank has to be about 1/8" deep to flow out?

My concern exactly. Looking better doesn't always mean performing better. I'll have to check the parts I got with my kit to see if the countersinks are too deep. If they are, I'll return them for exchange BEFORE prosealing them on. Thanks for the heads up. Good thread.