Coupled approach?

In article . net,
Ryan Ferguson wrote:

Jeremy Lew wrote:

Is this true of the newer S-TEC autopilots as well? My club plane is
getting a 55X installed soon.

No, the 55X disregards the heading bug when the HDG mode is disengaged.
Overall, a much better, more modern autopilot compared to Century.

-Ryan

For sure, the Century is not a modern unit. Near as I can tell, the
design is about 20 years old. I gotta assume newer units are more
sophisticated.

Roy Smith wrote:


For sure, the Century is not a modern unit. Near as I can tell, the
design is about 20 years old. I gotta assume newer units are more
sophisticated.

Great thread, Roy. I fly coupled approaches with my Century 2K from time to
time, now I'll have to go experiment with setting the heading bug slightly off
course to see what happens.

I think the poster who explained that the heading deviation is summed with the
course deviation and that the A/P attempts to null the sum has it about right.
That's consistent with my observations.

The C2K is installed in lots of different airframes, so there must be some
provision to adjust the gain, which surely must be different from airframe to
airframe. I wonder whether the gain could be adjusted to optimize the damping,
giving the fastest possible convergence with the desired course without
overshooting and consequent oscillation. Unfortunately my intuition tells me
that the optimum gain setting might be dependent on how far out you are on the
localizer course.

Dave