We just did this one with the Garmin unit a couple of months ago. The wing tip works well if you mount the unit halfway between the spar and the back of the main wing body. The only thing we found was for the strobes and other lights in that wing tip we needed to run a ground wire into the main center section of the cabin, for all the lights and strobe. If you don't use the wing as your ground conductor from the outboard end of the wing, there will not be an electrostatic field in parted to the wing structure close to the magnetometer. The only thing that you have then, close to the unit is the steel in the hinge bolts, counter balance weight, and wing tip screws ( use stainless ). We got 30-40% or there about.
Hope this helps. Yours as always. R.E.A. III #80888
Last edited by Robert Anglin : 08-12-2015 at 06:13 AM.