Autopilot planning

[Mruffatto]

So I've read the prior topics on putting an autopilot in the 4 place and I'm still undecided. I was wondering if there was any updated experiences. It sure doesn't look like it is as simple as I had hoped. Jared's experience with his Dynon autiopilot documentation was disheartening to hear. I have a Dynon setup in my RV7 and have used my autopilot on virtually every cross country. I typically only use the track and altitude function but I would think in the future it would be nice to have access to the more advanced options. I installed mine prior to Dynon's autotrim feature and than had it in a later update. At this point I'm planning on electric pitch trim like Battson.
To back up a bit I'm only in the planning stages of my build. The QB kit will be arriving shortly. I initially thought I'd install Dynon again because that is what I currently have but I'm not opposed to Garmin. Actually there's a few things swaying more towards Garmin.
Any thoughts or advice?

[flashf16]

What's swaying you towards Garmin? I was thinking Dynon for my build but was unaware of the autopilot issues...

[Mruffatto]

I have not done much research yet but I don't believe the dynon intercom can accommodate 4 headsets. I got the suspicion from the forums that the autopilot system may more robust. And just watching some of the videos on features impressed me. I have tried the skyview hdx though. I have the older one.

[AZBearhawk272]

The Dynon autopilot works well and is quite adaptable.
I doubt that the Garmin will handle the Bearhawk any better.

A big part of the equation is getting the Bearhawk setup and rigged properly before attempting to train the autopilot to do its thing. Adverse yaw is the challenge
to overcome.

Auto pilots have a quirky sense of humor. They do not understand bank right, heading change left.........
Ailerons need to be rigged so small inputs around neutral do not create adverse yaw.......

[Mruffatto]

Do you use it often? Did you put in a yaw dampner?

[jaredyates]

It very well could be that someone could figure out how get the autopilot working well enough for them. Much of my frustration was in Dynon's unwillingness/inability to even tell me what the settings did, after more than a year of asking. Since then, perhaps they have made a manual, hired more support people, or otherwise sorted it out. I think the servos are capable of moving the controls, but without adequate software and without any guidance, I just ran out of patience waiting. Also, my standards for the system's performance were high. If the system couldn't fly the airplane without my attention, then it wasn't worth carting around.

[robcaldwell]

I purchased my AP Servos (SV-42) through Aerotronics when I had them build my panel. jaredyates, I mentioned your frustration when working with Dynon and Jason Smith at Aerotronics told me that if I have problem at all with the AP servos to let him know as he has a direct relationship with Dynon. In fact, Jason said he would walk me through the set up and calibration when that times comes. I would be happy to document the process and share with others.

[jaredyates]

Yes please! You are just the right person for this task, having more persuasive abilities etc.

[Rollie]

I have the Garmin autopilot servos run by the G3X in my Patrol. It does everything it is supposed to. I don't have a yaw damper so I do keep my feet on the rudder pedals and I have to keep it in trim when it makes course corrections or turns, but I got used to that pretty quickly.

[500AGL]

I don’t have experience in the Bearhawk but I do have a little with the G3X and A/P in taildraggers. As Rollie mentioned, most use a 2 axis A/P, which works great, understanding that it’s a 2 Axis A/P.
For example in a Carbon Cub SS or EX (not the xcub) you will find in light to moderate chop if your feet on flat on the floor the aircraft will develop a sashay, and “swim” like a fish wagging its tail. This is caused by the A/P reacting to the attitude upset, which levels the aircraft but isn’t counteracting the yaw effect. In turbulence of course this is a continuous reaction, and the fishtail/sashay will develop quickly, much like a Pilot Induced Oscillation, but on the horizontal plane.

The fix for this is simple. Rest your feet back on the pedals to keep the rudder from vacillating back and forth, and the fishtail is gone. Just the pressure of your feet on the petals will keep it in line, and the 2 axis A/P works well.

If you want a true hands off and still use a 2 Axis you could always rig up a spring interconnect between stick (ailerons) and pedals like Beech did in their Musketeer/Sundowner/etc.

pb

[svyolo]

With the stick assembly right next to the rudder cable, that might be remarkable easy to set up, although getting it "tuned" will take a lot longer.

[500AGL]

Yep, pick a dozen springs and test them...

[N942VT]

The first (I think) LSA with a Garmin 2 axis A/P will be flying in the next couple weeks. GSA28 servos and GFC500 controler. Garmin is good with lot's of adjustability on position and gain, adverse yaw can be controled with slow roll rate and A/P gain. Peter has quite a few hours on an A/P equipped Carbon Cub so his opinion is from experience.

[Russellmn]

I've been looking pretty closely at running the Garmin setup, 3 axis, coupled with a G3x in my Patrol, but that may change in the several years it will take me to build it...

[auburntsts]

Another option to a yaw damper is a spring bias manual rudder trim. That’s what I use in my RV-10 and it works like a charm. This is the one I have and I think it could be adapted to a Bearhawk. https://www.aerosportproducts.com/product/rudder-trim/