L'Avion

L'Avion

Well Known Member
Composite wing fuel tanks for RV-3

RV-3, SN 241, Type I Wing is going to require new fuel tanks.

Van's doesn't supply an RV-3 wing fuel tank kit, and Evan Johnson would prefer not to build from scratch, as we're going to have to do.

What about reverse-forming a wing fuel tank, and then creating a new one from either fiberglass, or carbon fiber?

donning flame-proof suit now,
Barney
 
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Not a good idea. I haav seen many fiberglass fuel tanks from Rans leak and had to be replaced with the new poly tanks.
 
If you build the tanks with vinelyester resin they will not leak. Vinelyester is made to withstand fuel etc. Glasairs are built with it . They dont leak!!
No need to seal the resin either like Lancair does with epoxy tanks.
 
Consider structural strength

In addition to carrying fuel, the fuel tank is structural...it provides torsional strength for the wing assembly. Can you achieve equivalent strength in a fiberglass tank, including the attachment points along the spar?
 
I actually think it's a good solution to your problem. I've built fiberglass fuel tanks before. I actually prefer them over aluminum and Pro-seal.

I was pretty far along in the design and contruction of a ferry tank for the back seat of the Rocket that I planned for a record cross-country run. It was fiberglass all the way.
 
Well

L'Avion said:
RV-3, SN 241, Type I Wing is going to require new fuel tanks.

Van's doesn't supply an RV-3 wing fuel tank kit, and Evan Johnson would prefer not to build from scratch, as we're going to have to do.

Sacrilege: What about reverse-forming a wing fuel tank, and then creating a new one from either fiberglass, or carbon fiber?

donning flame-proof suit now,
Barney
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Fiberglass is brittle and will bust like an egg in an accident and spray fuel on you. Even if a bird hit it. It will bend and deform and take the energy, it will punch a hole and blow fuel all over.

Second, the stock tanks are not hard to build. Piper to Boeing are all WET (metal) tanks. No thanks. Fiberglass is for hot tubs and boats, IMHO. Also they will not fit since the thickness of the skin will be greater. Good luck if you try it.
 
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Sacrilege: fiberglass fuel tanks

Use of the word "sacrilege" was metaphorical only, and not meant in any religious connotation; i.e. "a technical and not necessarily intrinsically outrageous violation of what is sacred." as in a comparison of a basically all aluminum aircraft to composite constructions. No offense was meant, I hope none has been taken.
 
I agree with the fitting being a problem. I strongly disagree with them bursting and being weaker. Being a Glasair builder, I can tell you there is no comparison to the impact resistance of a good Glass plane to a tin one.
I remember a instance where some fellows flying in loose formation flew into a flock of birds.The RV was trashed. The Glasair sustained no damage and it took a half dozen direct hits.

I have personally had 2 bird strikes at 200 knots plus in the Glasair and there was zero damage to my leading edges other than smudges.
Try that in your RV !!
Please bear in mind we are talking pure strength here not crumple resistance etc etc. Cant beat glass. I guess thats why all the best modern aerobatic planes are Glass.
Nuff said.
 
Thanks you are right

L'Avion said:
Use of the word "sacrilege" was metaphorical only, and not meant in any religious connotation; i.e. "a technical and not necessarily intrinsically outrageous violation of what is sacred." as in a comparison of a basically all aluminum aircraft to composite constructions. No offense was meant, I hope none has been taken.
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You are right my mistake, I got the dictionary out, thanks, deleted it.
 
Please excuse my lack of familiarity with the -3, but would it really be that big a deal to build some tanks using parts available from Vans? Are the -3 ribs different from the -4's? The skin could surely be adapted from a -4's. Fiberglass can be made about as strong as anything, but it just seems like fitting them to a metal wing would be a real challenge.
 
The RV-3 uses the same airfoil as the -4, but on a smaller scale. The chord is shorter on the -3.
 
Composite fuel tanks

Thanks to all for your suggestions.

Plans are in the works to construct composite wing tanks for the RV-3.

More as the plan progresses.

Barney
 
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