Sidestick pots instead of transducers.

Sidesticks use two sets of transducers, roll and pitch. Stick movement is mechanically transmitted to transducer units located below the sidestick frame. Transducer have multiple potentiometers inside, that convert stick movement to signals and send them to flight control computers.Genuine sidestick units in AR condition are not only hard to get, they are usually also without transducer units. I guess transducer are removed and sent to overhaul/repair and right back to “work”.

AMM chapter 27, Flight controls (27-92-00)

Without some sort of transducers sidesticks are just beautiful engineering sculpture and nothing else. I was eager to make my own transducers and try the sidesticks in simulator. I was deciding between two approaches, linear or circular? Original transducers use circular pots but looking at shafts going up and down sugested me to use linear pots. Using linear pots also seemed mechanically much simpler to make.

There are probably many ways to do it but I made a plastic brackets (reinforced L profiles) to attach 10K Bourns linear pots lengths 60 and 45 mm. I connected two vertical shafts together with screw and attached them to pot lever using nuts and washers. Potentiometer is attached at such height that neutral stick position brings pot lever in the middle of pot slider. I was in a hurry and use hot glue!
I connected all to Leo Bodnar BU0836A joystick controller and of to calibration.

I tested sidesticks with JeeHell and FSL A320. It’s a joy flying both, something completely different. Sidesticks allow precise input movements. Maybe they are a bit hard or sensitivity is not set properly? They are made in such a way that stick gets harder in pitch with larger deviations but I think in my case sensitivity is set too low around “normal” stick deviations. Question of stick response curve according to flight envelope… sounds like a lot of work!

Sidestick pots instead of transducers.
Tagged on:

2 thoughts on “Sidestick pots instead of transducers.

  • 01/04/2018 at 13:27
    Permalink

    Hi there!

    How happy are you with that construction. I’ve built something very similar (mostly inspired from what I’ve seen here – thank you by the way!), but I sometimes struggle with center position not being clean enough.
    In Prosim, that ends up with a sidestick fault ECAM message and I have to go through calibration again, setting new null-zones etc…

    Have you changed something to that setup so far? Or is your build so neat, that you never had such issues?

    Thanks!

    • 01/04/2018 at 21:39
      Permalink

      Hi,

      This was more of a test and a quick solution to fly. I knew that circular pot solution would probably be better than linear due to problem you described but I was quite happy with it initially. Circular approach would take much more time and design.
      I was also getting slightly wider center position area but not so serious. I just needed to adjust the null zone slightly and make it larger. Well eventually I got the genuine transducers solution that use circular pots inside. When you find the right pins they are spot on.

Comments are closed.