I plan also on putting a metal braid down the filler opening into the
tank and connecting to Graham's aluminum tank outlet fitting. I plan on
Alum pipe runs which will ultimately be grounded to the engine ground. A
ground clip on the exhaust pipe when filling at the local FBO during
refueling should then be quite effective.
Cheers,
Pete
A239
-----Original Message-----
From: Graham Singleton [mailto:graham@gflight.f9.co.uk]
Subject: Europa-List: Static when refueling?
<graham@gflight.f9.co.uk>
>Static when refueling?
> As long as both are at
>the same potiential (voltage wise) then there will be no current
flowing
>between them. The obvious way is to ground the truck to earth and
ground
>the aircraft fuel system to earth ground. That keeps all partys in
this
>equation equal.
I think that the problem may well be static charge generated when fuel
flows through a non conducting pipe. First it flows down the PE filler
moulding, then the moulded rubber section, (that may? conduct a little)
then into the insulated tank. At the same time it starts to flow up the
breather tube, usually also non conducting, first as vapour, then
splashing, often onto the fuselage top of Classics, air flow through the
1/4" tube has to be fast, finally as liquid. In the standard
installation
the breather is not very far away from the filler, particularly in the
Classic. One Classic I know of caught fire from a static spark, right at
the end of the refuelling from a metal can. It was a hot dry day.
I would recommend that the breather pipe should be solid aluminium, 3/8"
dia. not 1/4 and that it, the filler cap assembly and the funnel or
other
apparatus used to refuel should be kept grounded together. Paul
McAllister
has a picture of the breather we developed on his web site I believe.
This
diverts splashes back into the tank filler.
Graham
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