Fuel Tank Filler Neck

[Mehul Botadra]

I looked a lot for this but couldnt really come up with anything. I saw a lot of teams using a plastic filler neck which eliminates a lot of issues with the solid filler neck. My questions are,

1. Is it allowed? Dont tell me if a lot of teams are using it, it is. I know that. But is it preferable?

2. How do you sort the leakage issues, if any?

3. Is it any special kind of plastic, or the one that does not react with fuel will do wonders?

[Sameh]

I can just reply on the first question.

1- Yes it's allowed, but it's subject to approval in the event. I saw lots of teams passed scrutineering with it.
B9.6.5 A clear filler tube may be used as a sight tube, subject to approval by the Rules Committee or technical inspectors at the event.

[Ockham]

If you're wondering about a certain plastic reacting with fuel, the best way to find out it to mass a sample, leave it in a container full of fuel for a week or so, then mass it again and look for a delta. You need a pretty precise scale, but if the fuel's eating the material, that'll tell you. Just make sure the test sample is fully dried before massing it the second time.

Outside of a fuel cell specialist's recommendation, the only plastic I trust in contact with fuel is Teflon (polytetrafluoroethylene, or PTFE), but it's only available as semi-rigid tubes.

Fuel Safe sells several types of fuel hose, as well.

http://w w w.fuelsafe.com/store/parts-accessories/fill-accessories/hose.html

Sealing this stuff is actually elementary. A hose clamp and beaded (DO NOT skip the bead) tube create a fine seal.

[Pico]

Question 2 and 3: That's engineering

[E-Rolla]

At Curtin Uni we have used a clear plastic tube.

All I know is it has to take a certain heat rating I think and for fuel you can't use a tube that is silicone based product because it will be soluable with the fuel.

I think the bonus from using it is that it's easy to mock up on the fly, just cut to length with a hack saw once in the car, easy to curve around things and doubles as a sight tube.

We haven't had to much issue with it in FSAE-A.

We do have to be careful with how close it gets to the exhaust, the heat makes it very very soft so we have had to wrap it with fibreglass heat tape in the past.

At the to for the filler we just use an alluminium fitting as perwhat most other teams would usually run and we just ron a rules complient house clamp around it.

We picked our tube up from Pirtek or Enzed, any hydraulic hose or industrial oil fitting store should stock it.

If you want I could post up pics of ours later, we'll probably run the same thing this year in December at FSAE-A 2010.

We mainly started to use it for ease of getting the bends and trying to stick to no more than 45 degrees from verticle