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There's gotta be a better way: fuel tanks.

AeroDog

Well Known Member
Friend
With all the stories I've read about leaking fuel tanks, I have to think there's a better way to do this. I've seen some talk about welding the seams, but has anyone actually tried it? (Yes, I used the search function.) Is there some compelling reason that it can't be done? Has anyone tried some sort of composite? This is a fairly mature technology in the world of race cars.

Jerre
 
Jerre,

I shuddered when I put my tank together. There are fairly large gaps at the corners only filled with Pro-seal. But if you follow the directions carefully it works fine. I've got 5 years and 570 hrs on my 12 with no leaks.

Rich
 
I've seen some talk about welding the seams, but has anyone actually tried it? (Yes, I used the search function.) Is there some compelling reason that it can't be done?

Jerre ... As I understand it apparently the 2024 aluminum alloy that the tanks are built from does not lend itself well to welding. A welded tank could be made but would need to be made from a more weldable alloy such as 5000 series aluminum.
 
Jerre ... As I understand it apparently the 2024 aluminum alloy that the tanks are built from does not lend itself well to welding. A welded tank could be made but would need to be made from a more weldable alloy such as 5000 series aluminum.

Having just finished my tank, I would agree that it's a rather crude way to build a tank. However, it's cheap which is probably the reason they're done that way.

If you're building ELSA I'm not sure if using an alternate method of tank construction would cause issues or not.

Jim
 
Agree

My fuel tank is done and proofed for one week using the balloon method. Hopefully, it will be ok with gasoline in it.

I think that a plastic tank (don't know which plastic) would be best and I'd like to be able to put 25 gallons into it. I haven't searched this out but a race car mechanic friend told me that they use some kind of plastic and that they usually don't have problems during collisions, spin outs into walls, etc.

I believe that Van's design is adequate, but I'd pay a lot to have a plastic purpose built fuel tank to mount behind my passenger - my wife. Just sayin - not criticizing Van's. I love this kit!
 
Crude construction method?
Of the almost 10,000 RV's that people have built and flown, I haven't heard them described that way very many times (the RV-12 tank is assembled with blind rivets, but overall is not much different from the other RV's, and the other RV's are not much different from many certificated airplanes).

Everything in airplane design is a compromise.

I am confident that no one is likely to find a different construction method that will be as light or for anywhere close to the same cost.......
 
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If you're building ELSA I'm not sure if using an alternate method of tank construction would cause issues or not.

If you are building E-LSA, using an alternate method for anything (unless specifically documented in the plans) is not allowed.
 
Crude construction method?
Of the almost 10,000 RV's that people have built and flown, I haven't heard them described that way very many times (the RV-12 tank is assembled with blind rivets, but overall is not much different from the other RV's, and the other RV's are not much different from many certificated airplanes).

Everything in airplane design is a compromise.

I am confident that no one is likely to find a different construction method that will be as light or for anywhere close to the same cost.......

Sorry Scott..........didn't mean to push your button.

I totally get why it's done the way it is. It's light, effective, a good compromise, and inexpensive (which I mentioned). I also understand that if Vans did everything as it could be done, nobody could afford the kits. All that said..........I'll still stand by my statement that it's a crude way to build an EXERNAL fuel tank. :) No big deal..........it certainly gets the job done.

Best Regards, Jim
 
Sorry Scott..........didn't mean to push your button.

You didn't "push my button" at all Jim.
I am just talking facts rather than opinion (the reason the last line says "I am confident that no one is likely to find a different construction method that will be as light or for anywhere close to the same cost.......")

It is a viable and likely optimal way to do it if weight and cost are important engineering goals.

If those aren't goals (in an airplane like the RV-12 the first one is a very high priority), there are a lot of other ways a tank could be produced.
 
Just a data point to add to this discussion...

Glasair supplies welded tanks for the Sportsman. There is a service bulletin from the early days when some of the welds were porous. Since that small batch of tanks which contained what amounts to a manufacturer's defect, there have been no significant issues with fuel tanks.

By the same token, Stoddard-Hamilton also shipped some plastic moulded tanks for the Glastar. They quickly became pretty famous for leaks which were resolved only by replacing the tanks with the welded aluminum ones.

Zenith also provides welded tanks for aircraft like the CH750.

While the Vans standard method is a good method of fabricating tanks, a search on this forum will reveal multiple threads talking about leaking tanks. As was mentioned earlier, every design/build decision is an exercise in balancing compromises. One needs to be happy with the compromises Van and team have chosen.
 
You didn't "push my button" at all Jim.
I am just talking facts rather than opinion (the reason the last line says "I am confident that no one is likely to find a different construction method that will be as light or for anywhere close to the same cost.......")

It is a viable and likely optimal way to do it if weight and cost are important engineering goals.

If those aren't goals (in an airplane like the RV-12 the first one is a very high priority), there are a lot of other ways a tank could be produced.

We're definitely on the same page Scott. I can't believe how light my tank is and as expensive as a welded tank would be, I'd rather build mine like I did. Plus, if I built it, I can also fix it if needed. My neighbor is building a Rans S-20 and both of his plastic tanks have had leaks.

"Crude" probably wasn't the best way to describe the tank construction :confused: ..........I just couldn't think of another word to use at the time.

Jim
 
Any body coated tanks with clear epoxy ? It was suggested by tech counseled with -6 ? Seriously ?onsidering , as it would be paintable, and not affected by fuel !
 
Derakane vinyl-ester epoxy (used in Glasair fuselages) has excellent characteristics for fuel tanks. In fact it is used to fabricate fuel storage tanks in the petroleum industry. It obviously has decent structural characteristics as well, since it has successfully been used in the construction of quite a few aircraft. It responds best to vacuum bagging as air-cured Derakane never really cures and remains slightly "gummy" to the touch.
 
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