mitchell autopilot

[dave]

Hello, I have a 59 Bellanca Cruisemaster that has a Mitchell Executive
autopilot in it. To engage the autopilot, you push in a knob on the
left side of the panel just left of the vsi and below the ai. When
engaged it would roll left at about a 20 degree bank, so I adjusted
the autopilot trim knob to the right of the dg and that seems to
almost get it to fly the plane straight & level. The heading bug
doesn't seem to be working at all, does anyone know of a shop that
will work on something this old, or should I just consider myself
lucky that it even works this well? The plane is @ 4A0 just SE of ATL.

Thanks,
David

[James M. Knox]

(dave) wrote in news:1d1076cb.0405041401.2b05e923
@posting.google.com:

> Hello, I have a 59 Bellanca Cruisemaster that has a Mitchell Executive
> autopilot in it. To engage the autopilot, you push in a knob on the
> left side of the panel just left of the vsi and below the ai. When
> engaged it would roll left at about a 20 degree bank, so I adjusted
> the autopilot trim knob to the right of the dg and that seems to
> almost get it to fly the plane straight & level. The heading bug
> doesn't seem to be working at all,

I'm not familiar with the "Mitchell Executive" but it sounds very
similar to one they marketed as the Autocontrol II (and several other
names). It has TWO pushbuttons, with the trim (ROLL) control in
between. If the right button is NOT pushed, then the DG heading bug
will have no effect. If it *is* pushed then the ROLL control will have
no effect.

Common failures are the electrolytic caps in the "computer", and the
dumb little AMP connectors between the computer and the AI and DG. If
the one from the DG has fallen off, then the heading bug will have no
effect, but then neither would the ROLL control (in HDG mode).