RE: REFLECTOR: Thermion

["Chuck Caldarale" <n828cl@ix.netcom.com>]

The Thermion article in LPM also got me thinking about static protection. I
don't personally know of any static-induced refueling fires in composite
aircraft, although I am aware of a couple in metal ones. (I doubt that these
situations will show up in any database other than an insurance company's,
since I don't think they're considered in-flight accidents or incidents.)

In any event, since the fuel is more or less conductive, and the only real
spark point is the fuel cap area, I'm considering grounding the cap to the
fuel, and then the fuel to the tie-down lugs.

I was going to just drop a chain from the cap housing to the floor of the
tank, but the screen idea Bill Wade mentioned seems to be a better way to
skin the cat. [Hope none of my three cats are reading this.] To ground the
tank, I'm attaching a wire to the fuel line right as it comes out of each
tank, and running it out to fit under one of the bolts on the tie-down lug
at the end of the center spar. I'm also running a third wire between the two
tanks.

This provides a grip (and spark) point for the refueling rig ground clamp
that is well away from the flash area at the fuel cap, yet should allow any
charge that accumulated around the cap to drain off. If you run a tank dry,
though, this won't work, but then you probably have other things to worry
about...

 - Chuck

P.S. Might not get much static build up in Florida, but up here in Minnesota
it's pretty easy to generate a spark, especially in the winter. Just ask the
aforementioned cats.