M

mlwynn

Well Known Member
Hi all,

I have been working (in my usual fits and starts) for several weeks on the tanks. I am working on the plumbing now and a few questions have come up.
1. The tank support brackets are plain aluminum and will need to be primed. Should I avoid priming the side that gets prosealed to the inboard tank rib?
2. The anti-rotation bracket is also plain. Primer is a no-no in the tank. SHould I conversion coat it or just not worry about it?
3. I have this giant roll of 1/4" aluminum tubing from which I make the tank vents. Any tips on how to straighten it out? I suppose it is not really important that it be perfectly straight, but it would be more esthetically pleasing.
4. I am still confused about the service bulletin, specifically where I drill the hole and where the safety wire goes.
5. Do any of the hard-core primer-types prime the outside of the end ribs on the tank?
6. I am using a standard fuel pickup. Should it be touching the skin, specifically not touching the skin or what? The closer it is to the skin, the less "unuseable" fuel the tank will keep.

The instructions are pretty sketchy about all this. I wish we had the step by step check the boxes off that we had for the empennage.

Anyway, thanks in advance.

Michael Wynn
RV 8 Wings (tanks)
San Ramon, CA
 
My plan

Hi Michael,

Since I didn't build my tanks, I cannot answer some of your questions directly. But here goes...

1. Mine were not primed, and of course are already attached to the tank. Once I have complied with the service bulletin I will be priming them. Not sure how I'll do the 'back' of the flange but we'll see...

2. Mine wasn't primed, no conversion or anything inside the tank itself.

3. No idea!

4. Once I get around to drilling that sucker I'll grab some photos. One night during the week I hope. Keep an eye on my builders log. I also intend to go the proseal route as well, like "Captain John" did with his (see the original service bulletin thread; the one with hundreds of posts!!).

5. I will be, just as soon as I've done the SB.

6. No idea. I didn't do mine and I'm using the flop tubes.

Not sure this reply really helps that much, but there ya go! :D
 
Michael

1. It does not matter if you prime the attach bracket or not. Remember you are going to be wiping down any parts that get pro-sealed with MEK , so if you used a good primer and did a good job, the primer will still be there. If you didn't or didn't prime the proseal will act as a primer and protect it.

2. You don't have to worry about the roation bracket. If I remember correctly, the bracket is made out of the same alloy as the longerons and that has a low susceptability to corrosion. If it worries you, coat it with proseal.

3. I don't know of any ways to perfectly straighten out the tubing. You can slowly unroll it by hand and work/roll it on a long flat table.

4. Drill hole in AN nut and probably the easiest thing is to drill a hole in the anti-rotation bracket to safety wire to. But, I have not complied and probably will not since I completely prosealed over all my tank connections 3 yrs ago when I completed them.

5. I can't speak for the hard core guys, but I did prime them after my tank was complete and tested OK.

6. I don't remember what the plans said, so you might want to recheck. I nestled mine in a "dab" of proseal (no proseal in screen of course) , so it would be secure in the "optimum" position and against the skin. But not "really" against the skin, but against the proseal, which was against the skin. If you know what I mean.

Hope that helps.
 
I posted a couple of pictures of the completed SB on a previous post, so you can search for that.
I have my pick up tube/screen against the bottom of the tank. You can visually inspect through the drain hole if you remove the fitting.
I, personally, wouldn't prime anything that goes inside the tanks themselves. If you keep the tanks full, you should never have a problem with anything corroding.
Good luck on straightening out that tubing, but be careful not to mess with it too much. Once it's in the tank, no one is ever going to be looking at it! (Well, at least we hope not!)
 
Briand,
Well, go ahead if you must. I'm presently flying a 1985 RV-4 while building my "8". Looking in the tank is just like looking in my brand new RV-8 tank. Pristine! There is no reason to get corrosion in your tank unless you fill it with water, and leave it in there.

Don't sweat the small stuff.

I have a friend starting his 9th RV. He doesn't prime, does very little deburring, and builds an RV every year. He keeps telling me, "We won't see any corrosion in our lifetimes", and I agree.

Cheers, pete
 
For straightening tube material like the the vent line, pick up a set of spring benders from Avery -- I think they're something like $12. Slip the proper size over the tube. Bend straight. Done. Move to next task.
 
Just to throw out an idea...

Have you chosen an engine yet or more specifically, a fuel system yet?

If not, consider installing a vapor return line (for fuel injection) NOW. Much easier at this point and if it isn't used in the end, it can be simply capped off.

Rat
 
vapor return

I am planning a fuel injected engine. Having flow with both carbs and injected, the injection just makes more sense. This is the first I have heard about a vapor return line. Where does it go? I will search the archives for information. If you can direct me, might save a bunch of time.

Regards,

Michael Wynn
 
Installing a 1/4 inch vapor return line at this point is a very good idea especially if you are planing to use a fuel injected engine.
Return lines can be plumbed into other parts of the fuel system but ideally they should return to your tanks.
As for corrosion in the tanks,that is why we keep the tanks full when your plane is parked.
 
Fuel Vent Line Question

I am busy sorting out the vent line. Question one: which way should the right angle face? I asked Van's and they were pretty vague. Also, should I proseal the various spots the vent line goes through the ribs? I'm not sure if it is better to do that so they don't vibrate or better to give them some room to move.

Are most people putting proseal in the threads of the fittings or just prosealing over the top? On that subject, I am a little unclear how tight those fittings go. Is there a torque specification, or just pretty tight?

Thanks as usual for everyone's input.

Michael Wynn
RV 8 Wings (tanks)
San Ramon, CA
 
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