Hi Craig,
This is my answer to your questions below. I'm Jim Hergert with 400 hrs on
my Sexy N6XE L4P. I don't have the same results that you have and I have
flown that same trip from CA. to Sedona, AZ. about 40 times, some in IMC for
short periods. However, when I was getting ready to fly my airplane for the
first time, and worried with my Super paint job, another 4P with white wings was
into it's flight test period and we noticed several Burn spots on the
leading edges looking more like spiders out from burn points. This airplane had
flown into some heavy IMC. I was very concerned at that point and rechecked all
grounding. Both airplanes were wired by the same guy and had the same Strobe
system. We all felt that the Strobe wiring was closer to the leading edge than
on mine or that the wires were twisted different. Other comments below;
Craig's posting;
Recently out of fresh paint, my wife and I flew our
IV-P to Sedona, AZ. Some IMC leaving California but otherwise a a VFR
uneventful flight. Upon landing in Sedona, I noticed deep pitting (to
the depth of carbon) every 10-12" on the leading edge of both wings.
Running my hand near each pit released a significant static discharge. No
damage was noted to the fuselage. No rocks or debris were noted at the
departure or arrival airport.
Wings were bonded to the fuselage by a braided
grounding strap attached to the top skin near the speed brake opening and
terminated at the gear box near the rear spar attachment. The run was
approximately 4-5 feet. The ailerons and elevators also were grounded to
the wing using braided grounding straps. Multimeter testing revealed that
there was connectivity between all wing components and the
fuselage.
Unfortunately, I did not install static
wicks from Napa to Sedona. I installed the wicks in Sedona and have
not noticed any additional pitting since installing them.
My question to the listers:
1) Have any of you
experienced similar pitting problems?
See above.
2) Is the 4-5 foot
grounding strap too long?
No.
3) Should the bottom
skin be grounded as well?
All pieces should have a ground even if it is just to each other. This
is more important than running a long common ground cable.
4) Have I adequately
dealt with this issue by installing the wicks?
My wicks are on the trailing edge of the Winglet just next to the aileron,
which is grounded, and I have never heard a static noise. However, I have been
in other 4P's that snap all the time when in IMC conditions. This maybe the
radios also. I have also flown without the wicks installed and not noticed
a problem.
If I were you I would make sure you have the wire bundle in the leading
edge of the wing covered or at least a ground wire running with the bundle so it
is the least resistance to ground rather than the carbon fiber, shielded
even.
I am heading back to the paint shop on Friday and
want to make sure I have resolved this issue. Any comments are greatly
appreciated!
Don't forget that the Paint Preparation could also be the problem. Painting
Carbon takes different steps than painting cars. Sorry I don't know who painted
your airplane. But that is another subject.
See you at Oshkosh!
After the repaint maybe fly to OSH without using the Strobes, I know about
the traffic. Then if OK after inspection, use the Strobes on your way
back.
Your always welcome to stop at Sedona and call me.
Jim Hergert
928-284-0800
Craig Gainza
IVP TSIOF 550
Napa, CA