I know that a few years ago (about 10 or so) that Stoddard-Hamilton the
previous makes of the Glasairs had a lighting strike test aircraft under a
NASA contract. With a N-number something like NxxxLP, the LP for Lighting
Protected. Possibly Bruce Grey from the Glasair website can give you, or
direct you to more information on this aircraft. My very limited
understanding is that they built a wire mess into the composite with
dissipators at the trailing edge surfaces.
Wayne Cahoon
Aircraft Engravers
(860) 653-2780
(860) 653-7324 Fax
http://www.engravers.net
----- Original Message -----
From: "Fred Fillinger" <n3eu@comcast.net>
Subject: Re: Europa-List: Lightning strike
>
> David Joyce wrote:
> > ...
> > Paul's experience strongly suggests that the fitting of a
> > ground wire from wing tip to wing tip gives a significant
> > degree of protection.
> > I had been thinking of retro-fitting nav lights when/if UK
> > Permit privileges are extended, but this makes me feel that
> > it would be worth getting on with it soonest.
>
> I think we need to be careful with words like "significant." I have
> relevant tech documents by the experts, plus reports of other
> incidents to composite aircraft with lighting systems, and it seems
> lightning enters/exits/or doesn't as it wishes.
>
> It is true that the tips of the 4 aircraft extremities are involved in
> almost all incidents for known reasons. What I cannot find is
> anything suggesting that adding wire out to the tips (into the
> relevant "Zone 1A" as they call it) will makes things safer. If
> lightning sees nowhere to travel from a tip in the pre-events
> preceding the actual electrical discharge, it may just do nothing.
>
> Seems to me that if the answer were as simple as heavy gauge wire
> sufficient for many kiloamperes -- from the 4 extremities and easily
> calculated to be a safe arcing distance from other metal -- were a
> solution, it would be an attractive one. But the only approved
> solution after all the research and testing done is metal mesh in the
> skins.
>
> The other thing about a ground and hot wire doing such double duty is
> that it's connected to many other wires. In my case, this includes
> the sender in the fuel tank. Paul has sent me add'l "forensic"
> tidbits concerning his strike, and it seems these pathways may have
> whacked an avionics box and the battery contactor.
>
> In the famous UK glider incident, it involved a metal aileron control
> tube extending out to within Zone 1A. On an unlighted Europa, the
> metal extends only out to about 60% of semispan, electrically miles
> away from this zone.
>
> I also have a doc which suggests one incident, and Paul's, was only a
> little "streamer," not the full bolt. Likely also the one I
> encountered years ago. Hence, minimal physical damage.
>
> Reg,
> Fred F.
>
>
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