Both use the same "rate based" technology, very low tech. Which means that
the autopilot cannot tell the difference between roll, skid, and slip.

If you have an S-Tec, (or is it Meggitt now?), you need to be careful in
turbulence. One should be active on the rudder with this system.

What the S-Tec gives up in performance, it gains in safety. Since it depends
solely on the electric turn coordinator, a vacuum failure does not affect
it's operation.

Karl
"curator" N185KG
"Marco Leon" mmleon(at)yahoo.com wrote in message
...
Of course I checked the S-Tec site as well (and I didn't even need Google
for it!). Not surprisingly, the S-Tec literature will not say that one
is
"better" at certain functions than the other but will only highlight
differences. The only two differences that it states are 1) that the
System
Twenty/Thirty has "Low and high gain" VOR/LOC/GPS tracking and the System
40/50 replaces the variable gain with the ability to track reverse courses
and 2) the System 20/30 includes a "roll computer" with its turn
coordinator.

Can anyone explain why one is better than the other (if at all)?

Marco


"Schmoe" wrote in message
. net...
Marco Leon wrote:
A pilot friend insists that there is a fundamental difference in the
way these two systems operate. I am thinking about installing an
autpoilot and since I have the extra panel space, I would like to get
the System 40 or 50 for (what looks like) a more user-friendly
interface. However, he claims that the newer System 20/30 is better
at handling its duties in a number of different aspects.

Can anyone point me to an article or maybe share their experiences?
Google turns up nothing.
\

I don't know, Google worked pretty well for me:
http://www.s-tec.com/prodbrochures.html The differences should be pretty
clear after perusing their product brochures.