Mailing List flyrotary@lancaironline.net Message #45153
From: Mark Steitle <msteitle@gmail.com>
Subject: Re: [FlyRotary] Re: hauling gas
Date: Tue, 10 Feb 2009 07:20:44 -0600
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Good points Al.  When building my wings, I installed ground leads from the fuel cap rings to A/C ground.  And the capacitive fuel probes, which are metal and run the length of the fuel tanks are also tied to a/c ground.  So, prior to fueling, I ground the fuel trailer to the a/c via the exhaust pipe and also ground the fuel tank vents to the metal hangar.  My fuel trailer has regular gas pump hose with an integrated ground.   
 
Before I purchased my fuel trailer I used plastic gas cans and I always got a very uneasy feeling when refueling. 
 
Mark S.

On Mon, Feb 9, 2009 at 5:39 PM, Al Gietzen <ALVentures@cox.net> wrote:

Whatever you decide to do, be sure to ground everything properly before removing the fuel cap.  One spark could ruin your whole day. 

 Mark S.

Yes; but 'grounding' in the case of a plastic airplane has a little different meaning. Grounding the airplane to the vehicle is meaningless unless you are grounding metal that is in contact with the fuel in the tank. 

 

You need to ground (connect) the fuel in the tank to the hose (nozzle; whatever).  The static potential can build up between the hose and the fuel in the tank because of the friction in the hose dragging off some electrons.  Since the fiberglass tank in non-conducting, you need to ground the hose to some metal that is in contact with the fuel in the tank.

 

My simple approach is to use a metal chain, which serves as cap retainer, which hangs from the metal cap flange into the fuel, back to the cap.  Contacting the end of the hose to cap/cap flange prior to removal takes car of any residual.  Maintaining contact between the hose and the flange (keeping the cap chain, or cable, hanging into the fuel) keeps fuel and hose at the same potential.

 

One other lesser concern is if you are re-fueling immediately after landing, particularly in low humidity.  There may be residual static charge on the surface due to friction with the air.  This is easily dissipated by wiping with a damp cloth.  It will dissipate on its own if the plane has been parked for a while.

 

I mention this because there seems to always be a lot of confusion among the Velocity folks about 'grounding'.

 

Al G

 

 

 

 


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