Vertical Card Compass?

On Sat, 31 Mar 2007 12:12:41 GMT, Mike Spera wrote:




I have pretty much decided that when the one I have breaks, I'll probably
replace it with a SIRS compass: http://www.sirs.co.uk/aircraft%20light.htm


O.K., but the gent asked about a vertical card compass repair, SIRS only
appears to produce conventional wet compasses.

As another poster suggested, the obvious "repair" may be to replace the
Hamilton with a Precision PAI700 vertical card compass (Chief Aircraft
and others). Around $300 with mount. One piece, no electronics except
for the light.

Be aware though that some have had difficulty in keeping these units
accurate. One web site suggests that an installation using a magnetized
screwdriver knocks these things permanently off their gimbals. I have
had one go toes up.

Even if they do die every couple of years, I will still replace them
given the useless (whiskey compass) alternatives.

Good Luck,
Mike

The Hamilton compass which the OP asked about has a remote sensor, which
can be mounted in the tail or a wing. In my case, I used it because the
standard compass could not cope with the magnetism in the frame of my
Mooney, and, if that is the reason the OP installed a Hamilton vertical
card compass, he will have the same problem with the PAI700.

I have been told that magnetism issues are the usual reason to use the
Hamilton, as it was considerably more expensive than the non-remote sensing
vertical card compasses.

The SIRS compass, which has four instead of the usual two fixed magnet
adjustments, and also has a more viscous damping fluid than the usual
airpath, may provide a more stable instrument than the PAI700.
--ron