Century 41 Autopilot

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  • #84970

    Anyone have any experience with a Century 41 autopilot? I’m comparing different types for a 414, and am not sold on a S-TEC 55x, which was the front runner until recently.

    #104965

    flew over 700 hrs with a Century 41 back during my M20J days without a hiccup. I had my old 400B replaced on my 340 with a S-Tec 55X. This is a very moody AP at best. It tends to have an intermitent porpoising issue that makes my wife not want to fly with me. The problem is that it does have a mind of its own and it only does it every 10 hrs or so. Often while flying in the clouds.

    #104966

    Why did you replace the 400B?

    #104969
    quote RPettineo1:

    Anyone have any experience with a Century 41 autopilot? I’m comparing different types for a 414, and am not sold on a S-TEC 55x, which was the front runner until recently.

    What is in the plane now? A properly repaired 400A/B autopilot is a pretty good autopilot. If I were going to put an Stec in I would put a 65 first choice and a 60-2 second.

    #104976
    quote RENRIQUEZ:

    Why did you replace the 400B?

    400B died during approach. Sent for $2,000 worth repair and did the same thing after a few months.

    #104980
    kkushner1
    Participant

      Curious, which shop did the $2000 repair?

      #104982
      rwelsh
      Participant
        quote :

        flew over 700 hrs with a Century 41 back during my M20J days without a hiccup. I had my old 400B replaced on my 340 with a S-Tec 55X. This is a very moody AP at best. It tends to have an intermitent porpoising issue that makes my wife not want to fly with me. The problem is that it does have a mind of its own and it only does it every 10 hrs or so. Often while flying in the clouds.

        There is nothing wrong with the STec 55X AP, if and a big if, it was installed correctly which obviously it wasn’t installed correctly on you plane. Your elevator and or trim bridal cables are probably way too loose. The cable tension absolutely has to be on the very high end of the tension limitation for your aircraft. Also the tension gauge needs to be calibrated to zero tolerance. Most shops today do not have accurate tensionimeters if they have any at all. Because of the way the 55X sends out a signal for elevator or trim control, creates the problem if the cable tension is too loose. The computer senses a need for trim input and sends out about 1.5 volts DC to the servo. If the cables are loose, then the voltage will jump up to 3 or 4 volts , but by the time the extra voltage gets to the servo, the trim will be wanting to go the other way. Very confusing for the AP. This is also the problem when the servo armature gets dirty as the armature only moves about 1/10 the circumfrance of the armature so the armature wears and gets dirty in a very small part of the armature. If that is your problem, then you will need to do a servo “burn in” per the STec manual. This entails removing the bridal cable and running the servo at 28 volts for 10 minutes in each direction.

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