Coupled approach?

"James M. Knox" wrote:
The AI provides the "wing leveler" primary input, while the DG and NAV
signals are summed to provide a heading. Amazingly effective, for such
a trivial analog approach, it will (if carefully adjusted) intercept and
track a NAV signal. However, in a strong crosswind, it will do so "off"
the actual courseline (parallel to it).

Not quite parallel, but rather with a constant CDI offset, which for VOR
and LOC signals means a constant angular displacement.

2. Like all such systems, there is no turn anticipation.

I've never let the Century AP's fly anything but the most shallow turns.
I generally disengage the AP approaching the fix, hand-fly the turn,
then give the stick back to Otto for the next straight segment. In
fact, most of the time I just leave it in heading mode.

a) too little, and it will fly S-turns about the desired
course line, and b) too much, and it will wing rock itself until you
toss your cookies. Getting it set "just right" is an inflight specific
adjustment unique to each individual autopilot unit and N# combo.

I once flew a plane that had a *way* underdamped roll-rate. If you
reset the heading bug, it would slam you into a turn, hold that until it
was right up to the desired heading, then slam the wings back level.
IIRC, it didn't use excessive bank angles, just excessive roll rates in
and out of the turns. Not fun.

Roy Smith wrote in
:

"James M. Knox" wrote:
The AI provides the "wing leveler" primary input, while the DG and
NAV signals are summed to provide a heading. Amazingly effective,
for such a trivial analog approach, it will (if carefully adjusted)
intercept and track a NAV signal. However, in a strong crosswind, it
will do so "off" the actual courseline (parallel to it).

Not quite parallel, but rather with a constant CDI offset, which for
VOR and LOC signals means a constant angular displacement.

Good point... It's a constant voltage offset. I beleive one of the Century
(or old Mitchell) manuals actually uses the word parallel, but you are
right - it's a constant degree offset, only parallel for following
something like a GPS courseline.

In article , Roy Smith
writes:

2. Like all such systems, there is no turn anticipation.

I've never let the Century AP's fly anything but the most shallow turns.
I generally disengage the AP approaching the fix, hand-fly the turn,
then give the stick back to Otto for the next straight segment. In
fact, most of the time I just leave it in heading mode.


Not so. My Garmin 430 when coupled to the Century will anticipate, tho with
the Archer speed,that is not much. I generally let the autopilot do the turn.
At the turn I turn the heading but to the new course and let the 430 trim it
out. If the heading change is large, I sometimes do this in two steps of half
value each.

Chuck