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Fuel tank after ELSA certified

KALEWIS

KALEWIS

Well Known Member
Just taking a poll of rv-12 builders who would be interested in a solid aluminum welded fuel tank with a float type sight gauge. Also, the tank may or may not have foam "anti-slosh" inside...maybe. The tank would be the same size as the original, just solid aluminum...it would be built to fit exactly as the original as well. A local machine shop is interested in fabricating, so a prototype may be in the works soon.

---Could only be used after ELSA certification---

Thoughts??
 
A good idea IMHO. Maybe even offer a model that holds 30 gallons?

I'm not familiar with the "foam anti-slosh". The only thing I like in my gas tanks is gas.
 
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Anti Slosh ...

Building fuel tanks for racing moto's and buggies taught us to follow the
age old regimen of installing baffles in the tank designed to allow full flow
without the normal sloshing experienced when racing off-road.
If that is not what he referred to - then back to the drawing board.
 
Don't know about anti slosh If it's a good idea or Van's likely would be using it. Tank must have the baffle to control lo gas flow as in Van's tank.
Dick Seiders
 
I just don't like all that fuel, in a light weight tank just behind my head. I have seen what's left after a post crash fire. If you showed up at any sports car event with the Vans tank they wouldn't even let you take it off the trailer.I would like to explore welded tanks, especially if it has safety foam. I know their is a weight penalty, just more incentive to lose a few pounds.
 
I am interested in the idea, BUT, the purpose of the two baffles in Van's tank is NOT really there for anti-sloshing although it does help in this regard.

Scott McDaniels has indicated more than once that the baffle in Van's tank is there to ensure fuel flow at high angles of attack (takeoff & landing).

This would suggest that the two baffles within the tank are IMPORTANT. The baffle size and the size of the holes from one side of the baffle to the other (governing the fuel flow rate from one side to the other) has to be engineered in any design to ensure this design consideration has been covered.
 
I would sure be interested in something safer. I think if they make one there will be a good market for it. I am willing to pay the weight penalty.


Brad Stiefvater
 
I visited a builder that suggested a round tank in the wings made out of 5 " irrigation pipe. It would fit through the lightening holes in the ribs. The additional capacity would be around 7-8 gallons per wing. It is an interesting idea for those needing extra fuel capacity.
 
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You won't find many homebuilders that build resin fuel tanks willing to put ethanol in their tanks. AVgas yes, but not ethanol. Boat people don't like it either. In fact, the only non-ethanol gas you can find around here is at boat docks.
 
Polyethylene

Seth is correct- the issue with boat tanks and ethanol that I see mentioned relates to boats with fiberglass tanks and incompatibility with the sealant used in those tanks. My boat has a polyethylene tank and I have had no problems and most of our gas has ethanol. And as mentioned, many small engines use polyethylene tanks. I have had fuel lines go bad but never seen a polyethylene tank go bad due to long term exposure.

In fact- polyethylene is considered to have very good chemical resistance to even 100% ethanol. Hence, there is really no incompatibility.

Seth- there have been several previous threads addressing the possibility of polyethylene tanks. I did not go back and search those but if I recall correctly, the primary challenge was around getting the appropriate baffles in place within the tank. As Marty mentions, these baffles are apparently very important for assuring appropriate fuel flow across various flight configurations. Certainly not impossible but I think the opinion was that trying to incorporate baffles might make them very expensive and not as practical as an aluminum tank.

Jeff
 
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...and besides...

virtually every newer car on the road today has a polyethelene fuel tank. Including my 2007 which is a flex fuel vehicle and capable of running on E85. Oh by the way it also has baffles inside the tank, molded in during it's construction.
 
Seth

My mistake, I thought this was your original question:

has anybody looked into a poly tank?

There is lots of polycarbonate in the RV12. As well as much homebrewed resin. The previous threads Jeff mentions are correct: such a tank would require numerous interior baffles to accomodate three axis flight...apparently that exceeds a reasonable cost. There is really nothing wrong with the aluminum tank and proseal...its the sight gauge that caused problems.

People who fly 12's care about ethanol because the Rotax engine prefers unleaded car gas and in fact recommends more frequent oil changes if you use AVgas.
 
Don Jones said:
virtually every newer car on the road today has a polyethelene fuel tank. Including my 2007 which is a flex fuel vehicle and capable of running on E85. Oh by the way it also has baffles inside the tank, molded in during it's construction.
Click to expand...

Investing in a mold (or molds) that will be used to make many thousands of tanks is cost effective.

Investing in a mold to make a couple of hundred is not.

Molding the part is cheap. Producing the mold is Veeeeeery expensive.
 
It's an Opportunity

You guys are missing the mark. This is a great excuse, reason, whatever, to go to the TIG welding school in Georiga, research and then buy a TIG welder (you can never have too many tools), butcher up many expensive aluminum sheets until you have exactly the tank you want. All for only a couple of thousand $$ and a whole lot of fun!
 
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