18-05: VA-112 Fuel Drain Flange Error

It is my habit to check each part during the prep process and final drill and deburr everything before going on to prime (not in the case of the tanks) and rivet it all together. It was during this process i noticed the following with the VA-112 fuel drain fitting flange:

As you can see, the countersinks are a lot deeper than they should be. 

I emailed Van's on the 24th September to see what the go was with the part and got the following reply:

Excellent question and thankyou for the supporting photo.  Always way more helpful for Tech Support.

 Remember a rivet doesn’t go there, a dimpled skin does!  And a machine countersink for a dimple is set to a slightly different depth than for a rivet.  In other words a dimple need to nest in the countersink, not a rivet.

 Now having had that said, it does look like the machine countersinks might be slightly on the deeper side for that VA-112 but not enough to matter (all the same in the parts bin here at the mothership).  With all the ProSeal (Tank Sealant) that will be utilized and proper tank construction, you will still have a beautiful and fantastic fuel drain installation.  A “Lindy” award at Oshkosh for sure.

 Use the rivet callouts per the plans.

 On another note, I’ve attached a pdf diagram for nesting dimples FYI.

 Best regards and happy building,

That is all well and good, however the part sits on the OUTSIDE of the skin, so there are no dimples involved. (unless the rivets were installed from the inside out), so i had to go back and question the sage advice from the mother ship, then got this reply the next day:

You are correct.  The flange goes on the outside.

 You have several options:

 1. Install as is with AN3 rivets.

 2. Install with upsized AN4 rivets.

 3. Enlarge the drain hole in the skin and mount the flange inside with AN3 rivets.

 4. I can send you new VA-112’s when we receive them from the supplier.  We are currently investigating quality control discussion with them.

I elected to get some new ones, as i didn't want to have larger than necessary rivets in that drain area, which could potentially reduce the pathways for water to get out of the tank. I requested new ones on the 25th September - they finally arrived on the 9th December! 

Here you can see the old versus the new:

The incorrect flange on the left and the correct one on the right.

AAAAAAAAAAANYWAY....

Today i installed them. It was a fairly simply process - i used the hand squeezer with a ground down flat set to fit up against the flange shoulder. I taped off the water pathway to make sure that water could get to the drain.

I used Scott McDaniels trick from this fantastic video, to apply a very small dollop of sealant. The only thing i did differently, was to use a flared piece of tubing. 

The water pathways were masked off.

These were all set with the hand squeezer - a couple were not perfect rivets but i didn't think it mattered on this part.

I used the trick from the video above, but used a flared piece of tube left over from the vent line fabrication.

It works great - you just place on top and give it a little twirl. I wish i had used this trick on all the rivets! 

These are very neat due to the fuel tube trick

I'm glad i waited for the new flanges with the correct depth countersinks - these came out nicely. I know they are on the bottom of the tank and are simply drain flanges but...