by Roger » Fri Nov 20, 2009 2:02 am
Hi Phil and all:
Phil, I used a vertical card compass in my Highlander. When I initially set the panel with the compass up temporarly in place, the compass was off by some 30-40 degrees. I talked to a rather inventive friend of mine at our local EAA chapter, about this, and he reminded me of a story I'd read about years ago in a magizine about the problem on navel ships, that have a problem with magnitisim caused by the ship plowing through the ocean, and they install an electric generator whth a 'degauser". Don't ask me exactly how that works, but this friend of mine had made a simple one, and brought it down and degaused my Highlander. It had some kind of an DC converter and amplifier, and he plugged it into my wall socket and ran this probe over all the steel tubing in the front of the airplane, and bingo, all the magnatisim was gone in that part of the steel airframe. He said that the welding process is what causes the magnitisim in the first place. My compass is well within the +- 2 degrees deviation error.
Our guy Wes, here on the forum is an electric guru, and I'll bet he or Jak, can tell you about de-gausing. Not sure of that spelling, but you should be able to look it up on google.
Roger