Fiberglass fuel tanks

[SC Patrol 253]

I'm just back from Sun n Fun. What a great week! I had a good conversation with another builder regarding techniques for making fiberglass fuel tanks.

Has anyone out there given it a try on a Bearhawk? I'm seriously thinking of giving it a try. Seems much easier than learning to weld aluminum.

Thanks,

Todd
Patrol 253 (scratch build)

[DRLPatrol]

Good idea, keep us informed. How would they compare weight wise?

Doug

[Chris In Milwaukee]

The only thing that worries about glass tanks is if you plan to use auto gas with ethanol. We know we shouldn't, but it's possible

[S Lathrop]

I would be very cautious about fiberglass tanks given the shape and size of the tanks in the Bearhawk.

As an example, .050 x 5052 aluminum and 5 layers of Kevlar, vacuum bagged, with the appropriate epoxy resin, are about equivalent structural materials. This is the standard I would use if I were to build a composite tank. The composite is a lot more work and cost to build. And you have the issue of some kind of mold to form the composite as it cures. The Kevlar gives a better weight ratio than glass fiber in a composite.

Fiberglass / composite tanks might work very well with a smaller tank or for sure a tank that has a lot smaller surface are relative to volume.

When I first learned to weld, I taught myself how to weld by welding aluminum because it was hard to do. The trick is to get the right lenses for the goggles, proper flux and rod. Once you master Aluminum, steel will be easy by comparison. When I started using heli-arc welding, the similarities to gas and aluminum made heli-arc easy to do. It also helped that there were a lot of people gas welding aluminum in the Indy area to learn form.

[marcusofcotton]

The only thing that worries about glass tanks is if you plan to use auto gas with ethanol. We know we shouldn't, but it's possible

That's just a matter of which resin to use. Off hand I don't recall which would be the desirable one without a little research.

[SC Patrol 253]

The gentleman that suggested fiberglass for the tanks builds fuel tanks for the US military. He said the main issue is to use Vinyl Ester as the resin, which is fuel resistant. It is also the resin used on the Glastar and Glasair. Don't know if I will try it or not, but thinking about it.

[Chris In Milwaukee]

I'd be interested to learn more about his process. The BH fuel tank provides strength to the wing structure, so I'm curious how the two would compare of similar strength. Modern composites are amazing things.

[Bdflies]

Fiberglass is an incredibly flexible medium to work with. By that, I don't suggest that it bends easily, but rather, it becomes easy to create things, not easily done in other ways. In the 4 years I spent, building a Glasair, I got pretty good at 'glass. There are techniques and tricks to learn and nobody likes the smell and mess. You could easily build foam core sheets, mold them to shape and join them, into a fuel tank. You could do this "easily" if you're pretty good at 'glass work. It will weigh more than the aluminum tank. It won't hold quite as much fuel. I would not suggest this as a 'first time' project.
I'm competent at glass and spent more than 40 years around welding. I'm a competent welder, as well. Personally, I'd buy an aluminum tank, from someone who builds fuel tanks all day long.

Bill

[SC Patrol 253]

Bill,

That is likely what I will do. I'd love to have time to learn another skill but I need to start reeling it in and making faster progress on my Patrol

TR

[geraldmorrissey]

Why not take that enthusiasm and apply it to something a little less comprehensive. How about a composite door/window frame, wing tips, misc fairings, instrument panel etc. Lots of places for application, maybe even a little weight savings. A composite project I'm thinking about is a set of very thin light weight air ducts for distributing heated air to the right spots in the cabin.
Cheers
Gerry
Patrol #30 Wings.

[jaredyates]

If one choice is learning to weld aluminum to make the tanks, and the other choice is learning to make tanks out of fiberglass, there is a third choice, which is to buy the pre-made and leak tested tanks ready to install, and spend those few months on some other sort of progress.

[SC Patrol 253]

Perfect idea. I tend to dive down too many rabbit holes! Made my tailwheel unit and burned many weeks. I love the details bit my build could go on forever.


Sent from my iPhone using Tapatalk

[jaredyates]

There's nothing wrong with wanting to learn how to do it all, but in a case where you're wanting to make a design change due to reluctance to learn a skill that Bob specifies, then buying parts may be a better choice.

[SC Patrol 253]

Have you found a source for Patrol tanks? I could find a local welder to do it but would rather find someone who has done a number of sets.
Thanks,
Todd

[jaredyates]

There's always Mark Goldberg :

http://bearhawkaircraft.com/estore/estore_patrol.html