Peter Duniho wrote:

Very few light general aviation airplanes have "self-correcting"
gyros
(known as "slaved" gyros, because they are slaved to some sort of
actual
magnetic compass, usually solid state), but it's true that they
exist.

Actual drift in an actual airplane varies wildly. A brand-new gyro
with

Pete

Regarding solid-state:

I thought this too until a RAS'er (the other one: rec.aviation.student)
set me straight; and I have one :-)

The King KCS 55a, in a typical installation uses the KMT 112 remote
Flux Valve (a liquid filled magnetic compass) - Not solid state.

http://www.seaerospace.com/king/kcs55a.htm

a.