Float Plane Yaw

[CraigO]

Thanks for the forum access and info! I’m curious if someone with a floatplane and/or a RANS S7 have had successful use of the autopilot. The new-to-me S7 amphib will not hold heading unless I am doing the rudder dance. It has roll and pitch servos, and elevator trim. I have adjusted rudder cables so the ball stays near center with feet on the floor, and gone through the configuration, test, and in flight tuning. I’ve probably been spoiled by the same setup working great in a C172!
I’m guessing I’ll need yaw damper or roll trim or both. I know it’s a low slow plane that needs input, but I would rather reduce the fatigue factor for a planned PA to AK trip!
Thanks.
Craig

 

[jnmeade]

My S7-S has Dynon AP pitch and roll and it flies fine. Mine hunts a bit on altitude, but I have never recalibrated that, and a friend with a similarly equipped S20 has minimized hunting in his, so it's probably possible if I'd only do it.

 

[GKC Aviation]

I would be checking the shear pin in the roll servo.
It will still have enough friction to feel ok on the ground, but won't have enough to drive the ailerons in flight.
Worth a try...

 

[CraigO]

Thanks, I will check that. I assumed the shear pin was intact because it controls 90 or 180 degree turns well IF I keep the ball centered with rudders. And in smooth air with my feet on the floor, the AP will maintain the steep slip in pic, so it is holding altitude and TRK with the heading off by 30 degrees!

 

[GKC Aviation]

Ah, ok so it is trying.
I am guessing that if you roll the aircraft without the AP (a normal turn), it takes some rudder to prevent the slip.
I have no experience flying the S7 or any floatplane, however I expect the floats have a fair bit of say in wanting to go straight, and a banked turn will result in a fair amount of slip if not coordinated with the rudder to pull it around in the turn. More than a conventional gear aircraft.
If you want to have a feet on the floor AP, then maybe the yaw damper will be required in this instance.
Others that have experience with this may chime in hopefully.