Good morning All! My CH750 STOL has a "heavy" left wing. When flying straight and level with elevator trimmed (both gas tanks equal, pilot and passenger on board) I still get a left wing drop when letting go of the stick. I installed Dynon AP this past winter and need to fix this heavy wing issue before I can properly tune  the AP.

Anyone out there correct a heavy wing issue? What steps did you take to correct it?



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Thanks Jonathan, I did see this and was wondering if there was anything I should be doing before going straight to this fix. 



This was a big problem for me and following just part of the video fixed the issue and it flies mostly hands-off now. The trim is the only issue in that one click less or more is still too much up or down and getting elevator trim perfect is hard, but the AP does a great job once activated now.

The trim is the only issue in that one click less or more is still too much up or down and getting elevator trim perfect is hard ...

My STOL 750 flew straight and level but I found the elevator trim was much too sensitive.  I had to make brief "jabs" at the trim to attempt to fine-tune it and it was very annoying!  I found that Ray Allen makes a Servo Speed Control that allows you to adjust the trim speed and it works great!  As I recall, I reduced the trim speed about 50% and it seemed "just right" at that speed.



David, have you done the bungee and adjustment for the elevator control cables?  Relatively easy fix that I would consider as part of proper rigging (assuming you haven't "divorced "the elevator and flaperon controls)

Hi David, not sure what you are referring to re: "bungee and adjustment to elevator controls". Can you elaborate please :)



The bellcrank to which the elevator cables are attached is attached to the flaperon control torque tube. Tension on the lower elevator cable tends to pull the bellcrank and roll the torque tube as a result.  The Zenith plans call for a small bungee hooked to the upper elevator cable and attached to a fuselage stiffener (vertical "L") to apply a bit of force opposite to what is present due to the bellcrank offset on the torque tube as wellas separate the cables a bit to preent chafing. Clear as mud, eh?  A picture is worth a lot of words, but I don't have the plans in front of me.  A search on the forum should give you a good idea on what I am trying to explain. But what I have said above is the general idea...and will most likely get rid of the heavy wing.

Good luck

p.s.  did you get the float pics?

Thanks David. I will check the tension on the bungee which was installed by the initial builder. I suspect it needs some adjustment for sure.

Yes, got the float pics..thanks! I will get back to you soon over the next few weeks. Been crazy busy lately :)



Dave, I was in the "hell-hole" today and took this pic of the bungee which is attached to the cable coming from the top of the elevator bellcrank and pulls it to the aircraft right side.


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