Attitude based, like the new stuff ;)
AutoControl III/IIIB
Introduced around 1965, the Piper Autocontrol III is a attitude-based, single-axis autopilot with full roll control including nav, localizer and (today) GPS tracking. It also introduced heading hold with the addition of an autopilot directional gyro or HIS, and an optional radio coupler was available that allowed the pilot to chose between multiple nav sources or heading hold. The AutoControl III was a step up in capability and reliability; and, asside from most units being very “tired,” it’s still considered a viable autopilot today. Around 1973, Piper introduced the AutoControl IIIB with a redesigned controller and improved design and electronics, thus moving reliability up yet another notch.
One weakness in these systems is servo failure, which can sometimes lead to an electrical failure. Nonetheless, these autopilots are worth maintaining. Frankly, most need a complete rebuild, but you should be able to completely overhaul an AutoControl III or IIIB for 1/3 to 1/2 the cost of a new, comparable STEC autopilot—and some go so far as to suggest that the AutoControl III/IIIB, as an attitude-based autopilot, can actually fly the aircraft better! A completely overhauled and aligned AutoControl III/IIIB should provide you with a reliable and safe autopilot for many years.
Snoopy wrote:
some go so far as to suggest that the AutoControl III/IIIB, as an attitude-based autopilot, can actually fly the aircraft better!
Based on what I’ve experienced with my 55X I would agree to that 100%. I would certainly not get rid of one in favor of any STEC offering. Same goes for the Altimatics, even though they do lack GS tracking. Hence imho the upgrade with a 60PSS pitch channel makes the best sense for the legacy Piper single axis APs.
Snoopy wrote:
How can the Piper Autocontrol IIIb be interfaced with the G5? GPSS and HDG mode?
It is interfaced just like a regular HSI (except that you have to use isolation transformers) so you get all the usual modes of an Autocontrol IIIB with radio coupler. The G5 also works as a roll steering converter so you get GNSS as well.
That’s great. So
Autocontrol IIIB + Radio Coupler + G5 HSI = coupled HDG/NAV?
What happens with Altitude if you use Autocontrol IIIB? Nothing? You have to always correct it?
Snoopy wrote:
Autocontrol IIIB + Radio Coupler + G5 HSI = coupled HDG/NAV?
Yes. It’s actually all in the G5 Installation Manual.
(And GNSS roll steering using the roll steering converter function of the G5.)
Keeping the A3B might be a viable intermediary step then. Initially get two G5 wired up to the A3B and then sometimes in the future upgrade to GFC500.
How much is it to add some pitch hold solution?
arj1 wrote:
What happens with Altitude if you use Autocontrol IIIB? Nothing? You have to always correct it?
Autocontrol IIIB is single-axis. No pitch control. But according to the Installation Manual the G5 works with the Piper Altimatic III(B/C) two-axis A/P as well.
Snoopy wrote:
Keeping the A3B might be a viable intermediary step then. Initially get two G5 wired up to the A3B and then sometimes in the future upgrade to GFC500.
One additional restriction that is not obvious. You can’t have dual navigators connected to the G5 if you use a non-Garmin A/P such as the A3B. As best as I can make out, the reason is that the course deviation information goes directly from the navigator to the A/P and not through the G5, so you can’t switch the A/P navigator source. Only the heading deviation from the HDG and CRS settings come from the G5.
Airborne_Again wrote:
What happens with Altitude if you use Autocontrol IIIB? Nothing? You have to always correct it?Autocontrol IIIB is single-axis. No pitch control. But according to the Installation Manual the G5 works with the Piper Altimatic III(B/C) two-axis A/P as well.
But how does it look in reality? You just pull the controls back and forth? What is the point?
