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Multicopter => Multi Copter => Topic started by: markvanhaze on February 02, 2014, 10:00:50 AM

Title: Tricopter with kk2 weird behaviour question
Post by: markvanhaze on February 02, 2014, 10:00:50 AM
I am using the HK X900 frame for my tricopter, kk2 and dt750s with 3 identical props (no counter prop).

The tri flies perfectly, can pretty much hover without any stick input BUT its tilted about 5 degrees to one side.

The booms are all straight, nothing is bent and yet its always tilted. Now thats not a problem flying line of sight but when on FPV it is very annoying and just counter tilting the FPV cam does straighten the picture but makes the tri awkward to fly since then left and right banking inputs are different to what you actually see on your goggles.

So whats wrong here?
Title: Re: Tricopter with kk2 weird behaviour question
Post by: Loopdreams on February 02, 2014, 10:42:06 AM
Have you set it level on the ground and done the ACC calibration?
Title: Re: Tricopter with kk2 weird behaviour question
Post by: markvanhaze on February 02, 2014, 10:44:12 AM
I did the acc calibration and had it on the ground but maybe it wasnt perfectly level.  will check that now, thanks for the tip.
Title: Re: Tricopter with kk2 weird behaviour question
Post by: iwan_canobi on February 02, 2014, 02:37:12 PM
Quote from: markvanhaze on February 02, 2014, 10:00:50 AM
....with 3 identical props (no counter prop).

Thats why. With no counter rotating prop the tricopter would naturally yaw, so the yaw mechanism will be countering this in the opposite direction, which gives it a slight tilt when hovering. If you get a counter rotating prop on the front right (looking forwards) then it will sit perfectly level.

Good video here showing the difference:

Tricopter Counter Rotating vs. Non-Counter Rotating Propeller Demo on Vimeo (http://vimeo.com/22778782)
Title: Re: Tricopter with kk2 weird behaviour question
Post by: markvanhaze on February 02, 2014, 04:43:03 PM
Makes perfect sense now - thanks for the excellent video link.
Title: Re: Tricopter with kk2 weird behaviour question
Post by: Pr][nCe on February 06, 2014, 09:53:44 PM
i am running rcexplorer.se style tricopter with kk2.1 and all level flight here and all the same props, but i did make sure board was dead level on all axis and then calibrated it
Title: Re: Tricopter with kk2 weird behaviour question
Post by: MatZeRO on February 06, 2014, 10:56:52 PM
I had the same issue when I had the props all spinning the same way, add one spinning the other way and it will be perfect.