Fuel Tank Fabrication Questions

[Brian Jackson]

Greetings All.

I am in the beginning stages of fleshing out the design for a pair of fuel tanks of my gyro and was hoping those in the know might point me in the right direction regarding ports, venting, material, etc. I don't recall building them being discussed here in great detail, and I don't want to assume they're simple.

I would like to make them from aluminum sheet of a generous but reasonable thickness, formed and welded. There is an early rendering in post #1 of the Crescendo Build thread that shows them. Fabricating the exact shape is not a problem, but things like internal lining (if any is needed), and other practical considerations would be very welcome. Thanks in advance for any feedback.

Regards,
Brian

[JPAnderson]

I built the integrated fuel tanks on my VariEze. The internal baffles are to keep the fuel form gaining too much inertia when it sloshes around. Vents and line are pretty simple but improper routing does causes a lot of engine outs on homebuilt aircraft. Either all uphill for vents and all downhill for fuel lines. No low and high points/bends in the routing to avoid a vapor lock.

The Tony Bingeles books from EAA cover building basic fuel tanks. If your a member the magazine archives should have some very good articles. The Brits make really cool motorcycle gas tanks out of welded aluminum and videos showing that are on youtube. The capacity and shape will dictate design considerations.

Welded tanks probably have a better chance of developing stress cracks versus riveted. Vans Aircraft like the RV-6 uses some nasty stuff to work with called Proseal to seal riveted seams.

I'm not real turned on about sitting on a plastic tank of 5-8 gallons of fuel in a gyro crash. A friend died in Gyro crash, probably at impact, but there was a nasty post crash fire that assured no open casket. Any thoughts on the issue appreciated. I had a hard landing with my kasperwing that broke off the nosewheel resulting a real short stop. The Kasperwing fuel tank was in it's rack behind my head and held down with two bungees and it kept going and landed 20' away intact. I liked that.

More later, lunch time.

John

[JPAnderson]

Brian,

I found the post on Crescendo build and saw what you proposed for tanks. Nice looking design. I'd try and weld them and keep a close eye on leaks. Rubber mounted for vibration isolation? What would you use for fuel cap(s)? They use a mild weldable aluminum for tanks, maybe the 3030H-14 at aircraft Spruce? I don't have a good reference in front of me but I'll do some digging.

The Brits use Oxy/Acetylene mostly. No fancy tig or anything. Maico and CZ race bikes didn't even dress the welds out with a file and the tanks had flat bends, no compound curves and a coffin shape.. The Brits dress out the welds and polish the compound curved tanks.

John

[scottessex]

Just search the web for weld in aluminum fuel tank necks, you should be able to find something, Find a good welder that knows how to TIG aluminum.
Plus there are plenty of places that make custom fuel tanks.

[scottessex]

https://www.google.com/search?client...30.TnfBbMu-qQw