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The smallest aircraft I know of that has a yaw damper is the Pilatus PC-12.

From an engineering standpoint, how hard is it to make a light-weight solution for a light single engine plane?

The system in mind would also automate the corrections for all left turn tendencies, and coordinate the turns.

The reasoning for it is a no-hands-and-feet autopilot flying, plus the other benefits in takeoff rolls, etc.

The components I'd imagine would be needed:

  1. Slip indicator digital output;
  2. IAS digital output;
  3. Logic board;
  4. Rudder control-tab powered by an electric actuator.
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  • $\begingroup$ How does a yaw dampener apply to a "no-hands-and-feet" autopilot? Many of the GA autopilots I know (even the one in my 1977 Cardinal) can fly turns hands (and feet)-off, and even coupled GPS approaches. Because smaller aircraft don't suffer from dutch roll like larger ones do, I'm not sure this is even an issue for light aircraft... $\endgroup$ – Ron Beyer Sep 8 '16 at 0:59
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    $\begingroup$ Not in my experience with 172's, 177's, and PA-28's. Pitch and power are pretty coupled (if you want to maintain altitude and speed), but unless you are doing high AoA maneuvers I haven't found the need to retrim the rudder. Maybe I'm making small changes subconciously, but the auto-pilot doesn't have any problem with dutch roll in the aircraft I've flown. I'm not sure yaw dampeners are even active on the ground for aircraft that have them... It sounds to me like you are confusing rudder trim for yaw dampers. Most light aircraft don't have much of a dutch roll problem. $\endgroup$ – Ron Beyer Sep 8 '16 at 1:10
  • $\begingroup$ Related: What is the “yaw damper”? $\endgroup$ – mins Sep 8 '16 at 6:19
  • $\begingroup$ Can't resist pointing out that what you are talking about is not yaw damper but autorudder. Any damper, by definition, dampens oscillations and has rates (yaw rate in this case) as the main input. It is a Stability Augmentation System but not a control system (autopilot) per se. Some manufacturers incorrectly use the term. In practice, it is often possible to combine both functions, although on some aircraft the damper actuates its own independent rudder-like surfaces (e.g. SF-50 or Sukhoi-25). $\endgroup$ – Zeus Sep 9 '16 at 3:47
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Yes. The Garmin Perspective avionics suite for the Cirrus SR-22 is equipped with a yaw damper in its GFC-700 AFCS.

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The King KAP140 autopilot also offers a yaw damper function for aircraft with a servo controlled rudder trim.

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    $\begingroup$ I never know the King autopilot has yaw damper! $\endgroup$ – kevin Sep 8 '16 at 5:59
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The short-coupled Beech Bonanza line (33s and 35s) are known to do the "Bonanza boogie" and it's not uncommon to see examples fitted with aftermarket yaw dampers. Late model 33s/35s are 3,400lb airplanes which is pretty light. These are the smallest planes that I can recall seeing equipped with a Y/D. There is probably a Supplemental Type Certificate (STC) to equip a 172 with a Y/D but I can't imagine anyone actually spending the money to install a system like that in a Cessna 100 series.

Many piston twins, like the Cessna 300/400 series and Piper twins like the Seneca and Navajo, are commonly equipped with Y/Ds. This class of airplane can range from about 4,500lb to over 6,000lb.

The PC12 weighs in at roughly 10,000lbs.

Genesys Aerosystems, formerly S-TEC, makes a Y/D add-on for most of their autopilots. Century also offered the feature and the old Cessna/ARC Nav-o-Matic 400/400A/400B autopilots from the 1970s had the option. It's actually a common feature on mid-to-high end autopilots and, if shopping for a light twin, would be on my list of things to have.

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