[Thermos]

I'm installing the fuel tanks on my RV-7 wings in preparation for taking them out of the jigs. Vans' instructions say to only install some of the AN3 bolts and machine screws holding the tanks on, hinting that there may be some reason to remove them later on in the construction process. I'd rather go ahead and install all the bolts and screws if there isn't much chance that I'll need to take the tanks off again.

So...how many of you who've finished your airplanes actually needed to take the tanks off once your wings were un-jigged?

Thanks,

Dave

 

[zilik]

I voted before I read the post!

I have never removed my tanks once they were installed for the last time. I found that after installing the wings it was easier to work on wiring and stuff if the tanks were not in the way. So the wings were installed, sans tanks and then the tanks installed as late as possible in the build process.

 

[174Bob&Nancy]

tank removal

its easier to fit the wing without the tanks in the way when sliding the front spar into the fuselage.

 

[rv8guy]

I did not take them off during construction, but I have since then. I'd put all the bolts in any way, just to be on the safe side. Or maybe I am the only one who forgets things--mostly where did I put those AN3 bolts?? Can't lose em if they are in.

 

[mjmulia]

tanks

I had my wings painted with the tanks on and then had problems with fuel leaking from the cover plate. I had to remove the tanks to repair and when I did the painted screws "poped" some paint off as they were unscrewd. I guess I could have taken an xacto knife around each screw but I did not. Next airplane I will paint the wing with the tanks off. Mike

 

[Mel]

I had my wings painted with the tanks on and then had problems with fuel leaking from the cover plate. I had to remove the tanks to repair and when I did the painted screws "poped" some paint off as they were unscrewd. I guess I could have taken an xacto knife around each screw but I did not. Next airplane I will paint the wing with the tanks off. Mike

Avery has a paint cutter that will cut the paint around the screw heads. I've done several tank removals with great success.

 

[L.Adamson]

I had my wings painted with the tanks on and then had problems with fuel leaking from the cover plate. I had to remove the tanks to repair and when I did the painted screws "poped" some paint off as they were unscrewd. I guess I could have taken an xacto knife around each screw but I did not. Next airplane I will paint the wing with the tanks off. Mike

I painted the wings with tanks on. I've also removed some access panels under the wing, and they came off easily, including the screws.

Perhaps it's the paint, but I've already decided that I prefer to paint as an assembly, rather than two pieces; because, as I screwed on the wingtips, I then had some paint strip out as I tightened the screws. Yet no paint strip problem with the fairing between the wing and fuselage.

So either way, you might screw up the screw holes by taking them out, or putting them in.
With the tank on, it's done, and all the screws and seams look great. With the SB done before paint, hopefully they won't be removed again.

L.Adamson

 

[n5lp]

I did it today

My airplane has been flying for about 9 years and I have had individual tanks off three times, the last time being this afternoon. It's only about a 15 minute job if the tank and/or screws are not painted in place. Against my instructions, my painter did paint everything in place, but that was only a problem for the first tank removal. My advice is to plan on removing them, although I am sure there are people that haven't had to.

I originally installed the access plates with the supplied cork gasket and Fuel Lube, which was being highly touted at the time. I'm not a big Fuel Lube fan, having had to replace that whole mess at around a year and a half. The Fuel Lube turned into a crispy, ineffective, white substance.

The second attempt was with Aircraft Spruce's version of a Pro-seal type sealer. I installed the plates with the sealer and no gasket and squirted a little of the sealer into the screw holes and tightened the screws. I have read recently on this forum that that is not a good way to seal the screw holes.

For the last 7 or 8 years I haven't had any more problems, until this weekend. I hadn't flown for about three weeks, because of ear problems, and when I went to the airport on Saturday the right tank, which I left full to the top, didn't have enough fuel in it for any to come out the quick drain.

I took the tank off this afternoon and surprisingly, since I lost 19 gallons in three weeks, there is no obvious source for the leak, although there are lots of blue stains. The tanks have never had anything in them except av-gas until today, when I put in a couple of gallons of high octane car gas to try to see the leak. No leak apparent. I left for a couple of hours and came back. Not a single drop has leaked onto the floor. I'll go out again tomorrow.

If I can't get anything to happen I think I'll install some o-ring screws on the plate. The most likely place or at least where the biggest mess is, is the two lower mounting screws. I know they are under the greatest pressure, but jeez, it's not by much.

Looks like it has been leaking for a while. I probably should have noticed before, but between black paint and black asphalt hangar floor, I didn't.

An odd thing. Pretty much everywhere there is a blue stain, the original sealer (Philippine Quick Build) is very gooey, just a little more viscous than peanut butter. I had to keep wiping it off my fingers after trying to clean up a little with alcohol. It doesn't seem like fuel should soften this sealer!

Oh, and whatever I do to this tank I'll be ready to do to the other. I find they aren't in perfect synchronization but it will happen over there to sooner or later.