Autopilot Debate

[md11flyer]

Agreed Charles, I would not throw big money into the Old autopilot. There are too many places that can suck money from your pockets.
I would only keep it if you could get it operating with minimum investment. Like I said before alot of times the problem is in the cabling
and connectors, so overhauling units such as servos and computers will not fix the problem.
You could get a good idea of the money that is required by taking it to a shop that has all the century test equipment. They could test each unit individually
and if all passes, then they can test your cabling for problems. Not sure what they will charge for that, but if you are confident that most of the components are good,
it might be worth saving the old autopilot.
Regarding the level off within 100 feet, I must admit it isn,t that accurrate, I have to nurse it to the level....but it does work. Also with long flights and altimeter changes
you have to adjust the altitude on the controller as well.


Gary

[Charles Schefer]

Thanks Gary that's sort of what I assumed regarding the precision of the altitude pre-select. Maybe I need to find a good AP shop in my area that will work on these. So far I've only found Autopilots Central and as I previously mentioned their "estimate" was "you could quickly spend 8-10K". I don't know of any shops with the test equipment you reference, the local avionics shop here at HEF does not have it and says they really only do S-Tec these days. I am fairly technically inclined but I honestly don't have the time to get into researching and troubleshooting it myself (as you seem to have done on yours which I admire). I've already spent too many hours troubleshooting and diagnosing oil temp and pressure issues and building test circuits to troubleshoot oil temp calibration. The Autopilot would be a whole new level.... ugh!

- Charles

[md11flyer]

Charles, I forgot to mention that your autotrim on the altimatic 3 is sensitive to cable tension. Apparently the tension changes with temperature
because of the expansion differences between the aluminum hull and the steel cables. Anyway that would be an easy check to elliminate your autotrim
problem if its because of the cables being to tight or to loose.

Gary

[Charles Schefer]

[md11flyer]

Charles, To save you looking up the specs, The Stabilizer tension for the PA-30 with altimatic 3 installed is 18 lbs with a generous +- 20%
The stab Trim cable is 12 lbs +- 20 %. These specs are taken from the revised Piper Pitch Trim Manual dated 2/25/77.
I haven't checked to see if this is the latest manual, so use at your discretion.

Gary

[Charles Schefer]

Thanks Gary I think I may have all the cable tensions checked. It would be pretty awesome if I could get the Altimatic 3 working with minimal expense... I wouldn't mind putting a few K into it... my worry would be that after 2K it might still not be fixed and then drip-drip-drip... I'm at 10K.

- Charles

[SLIMDREDGER]

If you need parts for the Altimatic III, John Rabourn and I have all of them salvaged from a geared up landing PA30. Autopilots Central had done a complete overhaul of the system 4 years ago per the records. Previous owner said 10K had been spent on it at the time.

A. H. Powers ICS 2978

[Charles Schefer]

Thanks Albert. I actually have 2 Altimatic IIIs though I am not sure how complete the 2nd one is (the one not in the plane). The one that is not currently in the plane was the original. The previous owner obtained a second one (which is now installed) from another PA-30 owner who was upgrading to an S-TEC 55x. So when I bought the plane I received both (one in the plane and one out). I think I'm OK on parts but your post confirms what I suspected.... doing an overhaul of the Altimatic could result in a 10K bill. I'd rather put that sort of money into a new Century 2000 or S-Tec of some variety.

Thanks,

- Charles

[bernard nowlen]

For everyones info, Bob Ferguson retired from autopilots central about a week ago. The new point of contact is Randy and he has been with them over 20 years.

[Charles Schefer]

[Steven Lefferts]

Charles -

One important thing to mention to you.... Whether it's for this autopilot issue or anything else avionics related, Mark Granger at Pro-Jet at JYO is outstanding. We have had a lot of work done by his shop, and are thrilled with his knowledge and ability. We had various autopilot / avionics issues and he has been able to zero in on each of them and get them fixed right away.

We were using Capital Aviation at HEF, and they were always decent folks with some good techs but Mark's crew got to the botom of our problems with much more precision.

-Steve

[Charles Schefer]

Steve thank you so much for this post... It's funny you mention this because just the other day I asked someone I trust for the name of the best avionics guy in the area and Mark Granger's name came up. I was told that Pro Jet acquired Landmark fairly recently and Mark was with Landmark. I was also told that Mark used to be with Capital. I know Pat Colgan over at Capital fairly well and think well of them but I know they don't deal with old autopilots. Frankly I will probably do nothing until I can put in an Aspen and then perhaps upgrade to a newer AP of some type.

- Charles

[Charles Schefer]

[md11flyer]

Charles, I know what you are saying about the small amount of play incorporated in the yoke. Just wondering what the figures were on your control cable and bridal tensions.

Gary

[Charles Schefer]