composite airplane grounding
Peter Ashwood-Smith
>now about how (and whether you need) to ground a composite
>airplane to avoid sparks during refueling. Even though the
>Velocity is fiberglass, the fuel caps are metal, as are the
>mounting rings glassed into the top of the strake.
>
>What are the chances that a spark could occur when we put
>the fuel nozzle up to the cap? Has a fire/explosion ever
>occurred from this? And lastly, what do other
>manufacturers, especially Beech and the Starship gang
>(sounds like a rock group), do for their airplanes?
>
>Thanks for your help in advance,
>
>Bob
>bg...@nando.net
>Velocity 173BG (95% done, 95% to go)
I believe they lay a copper mesh into the composite as
it is being layed up. These meshes are all connected and form
a ground plane for the aircraft. I believe this is required
for lightning protection. I suspect they then connect the
mesh to the sharp static charge "bleeders" (word?) at the
wing tips to help keep the charge down in flight.
Non metalic objects can build up static charges too, the
only difference is that they cannot easily bleed all of the
charge off through a single point since the object itself
is non conductive. You can still get a spark off the object
though, but I suspect not as strong. But, it only takes
a little spark. (i.e just think of your pile of laundry
when it comes out of the dryer, any one of those little
sparks could set of an explosion.
If it were me I'd ground the plane near the gas tank
or at the ring. But if you have two tanks you'd have to
ground them both...independently.
--
Cheers,
-------------------------------------------------
Peter Ashwood-Smith | email: pet...@bnr.ca
Bell Northern Research | work : (613)763-4534
Ottawa, Ontario, Canada | home : (819)595-9032
Mike Thompson
>for lightning protection. I suspect they then connect the
>mesh to the sharp static charge "bleeders" (word?) at the
--------
>wing tips to help keep the charge down in flight.
Static Discharge Wicks - not only on tips but on trailing edges as well.
SITYS Dittos! - Mike
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Kevin Hansen
>
> Our Velocity builders group is having a discussion right
>
> now about how (and whether you need) to ground a composite
>
> airplane to avoid sparks during refueling. Even though the
Rub a piece of fibreglass with some wool or fur and check out the
huge static charge that you pick up. Most kinds of plasic will hold
a large static charge just waiting to fry fuel or electronics.
That notwithstanding, it is still a regulation to ground an aircraft
during refueling. Why take chances with the FAA and explosives?
Dirk Rackley
wrote:
>From: bg...@nando.net
>Mime-Version: 1.0
>Content-Type: TEXT/PLAIN; charset=US-ASCII
>
>
>Our Velocity builders group is having a discussion right
>now about how (and whether you need) to ground a composite
>airplane to avoid sparks during refueling. Even though the
>mounting rings glassed into the top of the strake.
>What are the chances that a spark could occur when we put
>the fuel nozzle up to the cap? Has a fire/explosion ever
>occurred from this? And lastly, what do other
>manufacturers, especially Beech and the Starship gang
>(sounds like a rock group), do for their airplanes?
>Thanks for your help in advance,
>Bob
>bg...@nando.net
>Velocity 173BG (95% done, 95% to go)
Something I suggested over on CI$ was to use copper tape (sort of like that
used in laminated in antenas for composite planes) in the upper skin.
Ground the one end to the cap, and run it out past the fuel bay with a
terminal on the other end.
The stuff is thin enough that it would pass over the ribs. In this manner
you could ground as many things as you wanted, and just run wires from the
terminal end up to the engine mount. You could also include the gear.
Then on fueling the standard aligator clip could be used on the exhaust
stack or whatever.
Dirk
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