lml@lancaironline.net Mailing List Archive

Ralf,

I'm not clear exactly what you did. ...but the question of interest is what's the resistance from the leading edge to the end of the wick? You could have good continuity from the wick to the engine without having good continuity from the leading edge to the wick.

Issues along the way:

- paint on leading edge leads to carbon very nearby. Could be a problem if there is a lot of filler there.

- bonding cable from trailing edge to aileron and another one to flaps should be buried in conductive epoxy both ends. Different products have variable performance. Ask Brad Simmons what he uses.

- attach point of wick socket needs to be buried in conductive epoxy

- non carbon surfaces should be coated with anti-static paint to lead the charge over to the carbon part. (wing tips?)

Colyn

On Jan 7, 2013, at 1:26 PM, <bronnenmeier@GROBSYSTEMS.COM> wrote:

Dear subscribers,

In 2011 I saw some static discharge with missing paint nicks on the leading edge of my wings when flying in the clouds. I added the Lancair static wicks (2 on each aileron and 2 on each side of the horizontal stab). When I installed them I used the metal bands to connect everything together and get a good electrical connection back to the engine/ground. I thought the problem was resolved.

On Dec 25^th I flew the plane from cold Ohio to Orlando. There was a lot of weather coming up from the south-west and I had to go out to the east coast to get around the worst part. The usual under 3 hrs flight took me 3.5 hrs on this day. At least 2.5 hrs during the flight I was IMC (in the clouds, somewhat between unidentified layers, light rain etc.) I started out at 17.000 and had to decent half way into the flight to 11.000 because of too much ice on the wings. There were airplanes at FL250 this day still IMC.

Below the freezing level in IMC I saw again some sparks off my leading edge. Down in Orlando the wing did not feel charged when I touched it. I had some minor paint damage on the leading edges again. On the way home I was again for about 45 min IMC below the freezing level – I did not see any sparks but the wing felt charged after landing. I found some more paint damage.

When I checked the electrical connection first I did not get a signal from the wicks to the engine. After I cleaned up the aluminum of the wick on the outside I had the signal back to the engine. On one little paint damage hole where I was able to see the carbon I tried to get a signal back to the engine and I did not get a signal ( I did not want to dig deeper or grind of paint so I left it alone).

I have some safety wire corkscrewed around my wicks and they are covered with heat shrink tubing (to keep them from vibrating in flight)

I got silver metallic paint with clear coat on top. I did not use conductive primer. To fix the little holes I put clear coat in the little holes and wet sanded the leading edge again (I can still see the little holes but at least I cannot feel them any more – assuming the air flowing over it is blind anyway….)

Question: did I miss something? Is there maintenance required on the wicks? Or are there just situations where you can’t help it and you get static discharge?

Thanks for your help

Ralf