New to me Kitfox

[SkyPirate]

mike,..look into rolling your end seams instead of welding ,..if your putting a baffle in,.. there are a few ways you could attach it,,prior to forming your outer skin you could weld tabs that would hold the baffle in place and put a square hold where the tab could be folded thru the baffle to hold it in place and also limit expansion of the center section of the tank,..by doing this there is less chance of a leak because your flush welding the interior of the tank to a tab,,which will allow more flex on the baffle without stressing the baffle and weld joints,..ie from fuel sloshing back and forth putting side forces repeatedly,

get a good paste type sealer and put it on your end caps then roll a bead that forms the outer shell and end cap lip together,,this will allow the tank to twist but not leak and no welds to crack under stress,.. I'd use 3003 aluminum to make this,..if you have or know someone that has a French wheel it would make it allot easier to roll the seams,.. the skin I would overlap on the top in line with the filler port and do a folded seam with the same paste sealer in the joint the end caps and baffle would keep it from coming apart once installed..you could even solid rivet the over lap joint of the outer skin,.. and also solid rivet the tabs to hold the baffle,,with no welding at all

because of the area and weight of 13 gallons of fuel I'd use at least .020 thick aluminum or even .025

[t j]

Another question did any IVs come with a header tank only? If so what did the factory do to the wings to reinforce them? Drag, Anti drag bracing?

Yes and yes. Without the wing tank there is a drag, anti drag tube brace in those rib bays. There are drawings for all the wing with or with out tank combinations in your builder's manual.

[cap01]

my wings came with a 6 gal tank in each wing . the tanks fit between ribs . if there wasn't a tank installed , there would be drag/anti drag braces in that bay . the tanks will provide a part of the wing structure which a poly tank wouldn't do . I removed the 6 gal tanks and installed the large tanks that take up two bays . that required removing a rib and installing a shorter brace in the bay outboard of the tank .
I've seen pictures of a 9 gal poly tank mounted fwd of the instrument panel , I think with that the wing tanks were optional .

[SkyPirate]

something like this,..if I ever have a problem with my tanks this is what I will build

[avidflyer]

Hi Mike, I sent you a private message. Jim Chuk

[Xengineguy]

I have a couple sheets of 5052. I think it's .050. Was considering that, need to figure the weight . I have used it before with good results. I like to edge weld the ends,need the same "ribs" inside as a fiber tank. Maybe some sort of horizontal X also inside. To limit diagonal movement. Maybe just Stainless steel straps corner to corner inside the tank at mid height ? Still thinking about it. Thanks again for all the responses and ideas.
Mike

[Av8r3400]

This topic comes up every now and again. Aluminum tanks were tried on these planes in the early stages, then the idea was abandoned. They will crack and leak. This wing design is very flexible and this flexing will work harden the aluminum. Eventually leading to cracks and leaks.

Since you're still in the building stage, why not get the new updated tanks right from Kitfox. It is an easy instal at this point and they are designed to fit. No muss or fuss.

[SkyPirate]

I think it would work if no welding is involved, aluminum when it comes to welding is like any other multi component material, at the points of weld the heat burns off some of the properties which makes areas near the weld more brittle, steel you can add carbon even after its welded to replace what is burnt off in welding process, aluminum, although i have allot of experience welding it, im not sure there is a way to embed materials at welded joints after the fact, but no welding and rolled sealed seams with a seam sealer that retains its flex ,.. There is a good chance it would work

[Xengineguy]

Good points guys, I'm not committed to anything now. I might strip the inside of the original tanks and recoat with a better material, a product called "red coat" I use on a weekly basis and have for 20 years. (I build and repair/restore fuel tanks as part of my business).
As far as aluminum welding I too have some experience, it was my understanding that the rod alloy has a great deal of influence on the finished weld properties.
I also thought aluminum gets softer near the weld?? I would completely agree aluminum does fatigue when flexed and that's a problem!
Might just bite the bullet and get new tanks? Thanks for the input,not trying to be a pain. Mike.

[SkyPirate]

Your right Mike with the choice of wire/ rod used , almost all aluminum tanks I've welded were 3003 with exception to a few 6061 , if they cracked 99% of the time it was on a welded seam unless it was a puncture, not trying to be a pain either i was the road guy for Jones and Lamson, bryant grinder, and fellows gear shaper for awhile and also made Ravens dump body's and trailers for a while , most of the Ravens work was wire with exception to tanks, and built everything from nascar chassis to welding inkanel heat strips for asphalt heaters, not bragging, dont get me wrong i just think if the right process is used in building fuel tanks ,,it could be done and not have adverse effects