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From: Lancair Mailing
List [mailto:lml@lancaironline.net] On Behalf Of John
Hafen
Sent: Sunday, October 01, 2006 11:34 PM
To: Lancair
Mailing List
Subject: [LML] DuPont Corlar, BASF R-M Undercoat DP25,
and SP-008A-PT Silver Plate Coper Coating
The highly conductive ground plane is of marginal use in
some applications and critical in others. Both the L3 Stormscope and the
Avidyne/Ryan TCAD require very good ground planes. Tests at Ryan on the
silver plated copper paints showed degredation after a year and in some cases
complete failure in 2 years. They suggest that as the skin flexes that
microfissures occur in the conductive layer causing islands of conductivity
between which there are non-effective areas. Rather than investigating
further they just suggest that builders install a more effective ground
plane like sheet metal or metal mesh.
I used a Ni plated graphite non-woven fabric epoxied
to the fuselage in the manner of another layer of BID. The non-woven
materials are not as easy to apply as they tend to stick to the roller as much
as to themselves. However they conform beautifully to complex
curves. I had flat plaques tested at an open field site and they came back
with data about the same as solid metal. As for longevity - ask me in a
couple years after a few hundred pressure cycles. For now the TACD works
fine and the Stormscope - well it is having a few internal problems so I do not
know yet.
Robert M. Simon
ES-P N301ES
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