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I'm a pretty new CTLSi owner and experienced something today I've not seen before:  While on an XC from Tucson to Sedona under close to ideal weather conditions, the autopilot would "hunt" 6 or seven degrees around the HSI or TRK.  Altitude hold was spot on and the "average" heading was fine.;  Just a gentle roll left and right along the intended path.  Same indications on the way home.  No change shifting from the  Garmin 796 to Skyview.  In the Skyview touch (ver 15.3.3) autopilot setup screen, the torque was set at 100 - I varied it down to 80, no effect.  Sensitivity was set to 20 and I tried it at 15 and 25 (it would only go as high as 24).  The higher setting seemed a little better, but that could have been me getting used to it - ha!  Used the autopilot a couple months ago with similar load and conditions with no problems (but, it was ver 15.1 something).

 

Any thoughts or suggestions?  The plane is a delight to fly and seems in excellent condition in all other respects.  Thanks in advance for your help!

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On 5/8/2018 at 7:32 PM, Slowpilot said:

Any thoughts or suggestions?  The plane is a delight to fly and seems in excellent condition in all other respects.  Thanks in advance for your help!

Maybe Duane can chime in here, since he flies a CTLSi. Perhaps you can compare your autopilot settings with him. At least that would give you a fair comparison of where you are at.

Have you sourced the Dynon Autopilot Tuning Guide? It is a flowchart routine, on setting the autopilot sensitivity, gain and torque.

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My Dynon has a tendency to go searching if I get lazy and am flying uncoordinated.  Try centering the ball before futzing with the settings.

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26 minutes ago, S3flyer said:

My Dynon has a tendency to go searching if I get lazy and am flying uncoordinated.  Try centering the ball before futzing with the settings.

Maybe it’s a Dynon quirk, but you should not have to center the ball to keep the AP tracking stable.  My TruTrak AP is rock solid tracking even when the ball is way out.  I fly with the ball out to balance fuel tanks while on AP frequently.

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39 minutes ago, FlyingMonkey said:

Maybe it’s a Dynon quirk, but you should not have to center the ball to keep the AP tracking stable.  My TruTrak AP is rock solid tracking even when the ball is way out.  I fly with the ball out to balance fuel tanks while on AP frequently.

Wouldn't that make for quite inefficient cruise as far as fuel consumption is concerned ? 

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23 minutes ago, Warmi said:

Wouldn't that make for quite inefficient cruise as far as fuel consumption is concerned ? 

Our blunt nosed, shaped CTs seem to pay little penalty. 

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I've had my Dynon AP since they were first released around 8 years ago and that has always been the behavior when driven by my D100.  The AP servos are the same for the Skyview but the software is much more configurable so there could be tweaks that fix the behavior.  Also, the ball being out only one unit is no big deal.  It's when it is a ball and half out that I've noticed occasional wandering.

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1 hour ago, Ed Cesnalis said:

Our blunt nosed, shaped CTs seem to pay little penalty. 

I think you are correct.

There seems to be "an art" to balancing the fuel in a CT.

That is something you taught us well, Ed.:)

 

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52 minutes ago, WmInce said:

I think you are correct.

There seems to be "an art" to balancing the fuel in a CT.

That is something you taught us well, Ed.:)

 

I remember the phrase 'present the fuselage to the relative wind' to describe slipping.  Our CTs have a big hole, making slipping less draggy I think.

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15 hours ago, WmInce said:

Maybe Duane can chime in here, since he flies a CTLSi. Perhaps you can compare your autopilot settings with him. At least that would give you a fair comparison of where you are at.

Have you sourced the Dynon Autopilot Tuning Guide? It is a flowchart routine, on setting the autopilot sensitivity, gain and torque.

Bill, right after Walt put the topic on the forum, I called him and gave him my history with the same problem.  I fixed it in flight by adjusting the sensitivity on the autopilot servo's.  Walt has all my input.  Have not heard back so maybe it is a non issue with him now.

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Andy, Bill, Dave and Ed - and you Duane!

MANY THANKS!!  Between family commitments and local winds, I haven't been up again to try out further adjustments to the torque, gain and sensitivity.  Bill, at your suggestion, I did find the AP tuning guide and I think it will go a long way toward solving my issue.  I also wandered over to the Dynon forum and there was not much on this topic, suggesting that if properly set up, not many folks seem to share this issue - hope that is the case.  One good suggestion was to inspect the servos & linkage before getting too deep in the software weeds.  I have an annual coming up the end of this month with Roger and I'm sure we will give it a good look.

Billie and I continue to be very pleased at our decision to buy the Flight Design.  The community support is fantastic!!!

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I suspect that adjusting sensitivity and torque settings will solve your problem.  If not, you might have a "sticky" aileron bearing.  I recently found my TruTrak A/P wandering all of a sudden.  I happened to look at my aileron bearings and found one bearing was tight and not allowing the aileron to freely move.  Once the bearing was freed up, the A/P wandering stopped.

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Thanks Dick.  That makes sense.  I've had a chance to read through the Dynon Autopilot Tuning Guide that Bill put me on to and I think I can pick a calm morning and go through that myself.  Your aileron binding experience also makes sense, and as mentioned above, we will look at all the linkage during the annual in a couple weeks.  The plane has just over 60 hours on it now so I'm not expecting "wear" issues per se, but there could be something that has worked lose, etc.

 

Thanks!

 

Walt

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Walt,

I recommend, before you use the Tuning Guide, check the following:

1)  Dick's recommendations above.

2)  Integrity of autopilot servo shear screws, at autopilot servo swing arms. (SkyView System Installation Guide - Revision AD, Pg.10-8, Feb-2018)

3)  Perform an autopilot servo calibration test. (SkyView System Installation Guide - Revision AD, Pg.10-16, Feb-2018)

Those mechanical things need to be verified okay, before going to the tuning guide.

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On 5/11/2018 at 2:56 PM, Duane Jefts said:

Bill, right after Walt put the topic on the forum, I called him and gave him my history with the same problem.  I fixed it in flight by adjusting the sensitivity on the autopilot servo's.  Walt has all my input.  Have not heard back so maybe it is a non issue with him now.

Excellent Duane, thanks for reaching out to Walt.

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Duane - THANKS!  I had mentioned your help earlier, but there were several folks I tried to acknowledge so I hope you don't feel overlooked.  I flew today for an hour doing touch & go's.  My annual with Roger os less than two weeks off and we will inspect all the mechanical stuff and will go through to Dynon check list and will follow your good advice.

 

Have fun in St. Louis!!!

Walt

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