I posted before how concerned I am over the quality of Van's quick build tanks due to all the reports I have read over the years of leaks developing, along with fuel vent lines dripping, some puking large amounts of fuel after fueling, so I decided right off the bat that I was going to do a preemptive strike by opening up all the bays on mine and resealing them. I also decided that since I am in the process, I may as well extend the tanks by 12" for about 3.5 more gallons per side. I would not fill them completely on a regular basis, only for XC trips where I want the extended range for longer legs or longer reserves for weather diverting or other reasons. Looked into the extended range tanks but they are pricey and more complicated due to additional plumbing and transfer pumps. I originally wanted to extend the inboard end of the tanks, and then shifting the tank outboard. Once I got the tanks off I realized that would not be possible without drilling all new Z bracket holes in the spar, along with the fact that the tank skin screw holes are spaced closer together on the inboard end. Nothing would line up! I decided to remove the filler, use a couple small pieces of skin aluminum and plug up the hole flush and relocate the filler in the new bay.
The wings are unpainted and still in the rack, so it only took an hour to remove the tanks. Ready for surgery.
[/url]DSC02024 by David C, on Flickr[/IMG]
Parts needed arrived from Van's. Unfortunately the packers missed packing several items in the wood crate, including the tank skin! Something to do with the flu going around at Van's and everyone pitching in to fill the voids. Oh well, the missing stuff is on its way.
[/url]DSC02025 by David C, on Flickr[/IMG]
I centered a 1/4" pilot hole in the outboard bay baffle and used a 5" hole saw to open it up. The tank is upside down in this photo and I measure the distance from the top tank skin to the bottom of the vent line. No wonder people complain about dripping fuel vents. Any fuel above the lowest part of the vent line opening is going to come out. That's about 5/8" on this tank. Over fill the tank and its going to come out!
[/url]DSC02029 by David C, on Flickr[/IMG]
Just an example of a possible leak source in the first bay. You can see an air bubble that formed in the sealant next to the rib flange.
[/url]DSC02030 by David C, on Flickr[/IMG]
No filet of sealant extending over the rib flange onto the tank skin. You can also see the shine of the rivet shop head the sealant is so thin.
[/url]DSC02031 by David C, on Flickr[/IMG]
The outboard end rib and filler flange. Again,,, air bubbles/pin holes in the sealant, the fillet is pretty much wiped away, and you can see the rivet shine right through the sealant on the filler flange rivet.
[/url]DSC02032 by David C, on Flickr[/IMG]
Continued,,,,,,,,
The wings are unpainted and still in the rack, so it only took an hour to remove the tanks. Ready for surgery.
Parts needed arrived from Van's. Unfortunately the packers missed packing several items in the wood crate, including the tank skin! Something to do with the flu going around at Van's and everyone pitching in to fill the voids. Oh well, the missing stuff is on its way.
I centered a 1/4" pilot hole in the outboard bay baffle and used a 5" hole saw to open it up. The tank is upside down in this photo and I measure the distance from the top tank skin to the bottom of the vent line. No wonder people complain about dripping fuel vents. Any fuel above the lowest part of the vent line opening is going to come out. That's about 5/8" on this tank. Over fill the tank and its going to come out!
Just an example of a possible leak source in the first bay. You can see an air bubble that formed in the sealant next to the rib flange.
No filet of sealant extending over the rib flange onto the tank skin. You can also see the shine of the rivet shop head the sealant is so thin.
The outboard end rib and filler flange. Again,,, air bubbles/pin holes in the sealant, the fillet is pretty much wiped away, and you can see the rivet shine right through the sealant on the filler flange rivet.
Continued,,,,,,,,