Kitfox Static discharge Fire

[Av8r3400]

The resistance will be very high. For sure.

My point is the resistance from the filler neck of a plastic gas can to its base will also be very high. But that will ground static just fine. Why won't this also apply to grounding the exhaust of the plane?

[bholland]

I don't know if this helps but I have attached a few links discussing this subject. It seems like grounding the aircraft would help just as setting the can on the ground would but what happened to Amer is concerning especially since our tanks are fiberglass. I would like to know if they remembered to ground it before filling. There are many more articles discussing this phenomenon if your interested you can google and many pop up.

cdc.gov/niosh/docs/98-111/pdfs/98-111.pdf

alabamacounties.org/wp-content/uploads/2012/.../2008-05-Truck-Bed-Liners.pd

Brett

[airlina]

As an added measure I made up a 10' wire lead with alligator clips on each end. If fueling at a fuel farm I always clip one end to the metal tank filler while the other goes to my exhaust stack. Then the fuel farm ground cable goes to the exhaust stack as well . On occasion I have to fuel from a jug , so I then clip one alligator clip to the tank filler and this time the other goes to a 2 foot ground "T" stake that I drive in the ground by the hangar. the T allows an easy pull out of the ground. Bruce N199CL

[HighWing]

...doesn't the fiberglass fuel tank in the plane ground to the wing spars and the rest of the airframe the same way...? Isn't all of this extra grounding to fix an extremely rare occurrence a little over blown?

Through the silicone? I don't think so. But as suggested, an Ohm meter will tell the tale. What motivated me - printed circuit boards are typically fiberglass and with the voltages used, the slightest conductivity would seriously impact all the gadgets we use for navigation, communication and forum chat.

[ken nougaret]

I'm going with the 10' wire and alligator clips as Bruce suggests. At least during the winter months when the air is dry.

[Av8r3400]

Through the silicone? I don't think so. But as suggested, an Ohm meter will tell the tale. What motivated me - printed circuit boards are typically fiberglass and with the voltages used, the slightest conductivity would seriously impact all the gadgets we use for navigation, communication and forum chat.

I will agree fiberglass is insulating in nature. So is polycarbonate plastic. Why does sitting a polycarbonate gas can on the ground considered a safe practice, then? Is silicone calk more insulating than a polycarbonate gas can? What about the carbon-black fuel line attaching the tank to the airframe? What about the silver coating in the fabric covering the tank, will that conduct the static charge away?

Static charges are an odd thing. They don't behave like normal electric potiential.

[David47]

..... What about the carbon-black fuel line attaching the tank to the airframe? ....

The fuel line is ok. In order for there to be an explosion, you need fuel vapour together with a spark from a static charge, brought about by a potential difference between two objects. Liquid fuel is too rich a mixture.

[LSaupe]

I would have to do some digging but I think it is more of a static type charge and discharge. Like the experiment of generating a charge using a glass rod and rabbit fur. Stripping off the valence electrons. Surface effect. Just needs a path to displace itself (or come back into equilibrium) with its surroundings.

Similar to static wicks on the trailing edge of wings etc to dissipate any stored voltage.

Very interesting topic.

I will agree fiberglass is insulating in nature. So is polycarbonate plastic. Why does sitting a polycarbonate gas can on the ground considered a safe practice, then? Is silicone calk more insulating than a polycarbonate gas can? What about the carbon-black fuel line attaching the tank to the airframe? What about the silver coating in the fabric covering the tank, will that conduct the static charge away?

Static charges are an odd thing. They don't behave like normal electric potiential.

[Av8r3400]

The fuel line is ok. In order for there to be an explosion, you need fuel vapour together with a spark from a static charge, brought about by a potential difference between two objects. Liquid fuel is too rich a mixture.

I referenced the fuel hose not as a source of fire or explosion, but as a source of static conductivity to the airframe, in order to discharge it through the "normal" grounding procedure of grounding the exhaust pipe.

[Wheels]

I'm not very smart either, but ... I operate a hydro electric generation company.
Static electricity is unforgiving of fuel vapor. The less distance from a source of fuel to a ground, the better for me. I"m grounding twice, once at the aircraft to discharge the airframe from its potential, then the filler neck to make dang sure.
(unless someone who IS smart can educate me as to my error)