KK2.0 Tricopter Yaw Issues

[AshBreeze]

Hi FliteTest forums.

I've built and have been flying a tricopter (RCExplorer 2.6HV style) for some time, and I've been working on getting the KK2.0 board better tuned in. I've started flying it via FPV and I am noticing a lot of tenancies the tricopter has that I want to try to get rid of with tuning.

The roll and pitch P and I gains are rock solid. The yaw is what has been giving me trouble. Initially it flew fine, except when yawing the tricopter would lose / gain altitude a lot. I modified the gains from stock 50P / 50I down to 50P / 25I and that helped get rid of the altitude issues, but now whenever I yaw, the tricopter also rolls and pitches, making turning while in FPV a nightmare. Yawing to the left = roll to the right and pitch fowards. Yawing to the right = roll to the left and pitch backwards

Does anyone have any ideas what could be causing this, or is it just the way it normally flies?

Thanks.


Tricopter setup info:

Motors: DT750 (All counterclockwise)
ESC: SimonK flashed F20A
Props: 9x4.7
Battery: 4s3000
Flight Controller: KK2.0 flashed to 1.6

Roll / Pitch
P Gain: 66
P Limit: 100
I Gain: 44
I Limit: 20

Yaw
P Gain: 50
P Limit: 20
I Gain: 25
I Limit: 10

 

[crlock]

well the kk does not have a barometer so you'll have to compensate the altitude loss by hand. and i would say those props are a little small for your motors maybe you should go with 11x4.7 props, you'll get more thrust and maybe compensate for the extra weight of the fpv gear.

 

[Cyberdactyl]

crlock is right, those props are on the very small for DT750's. You're losing a lot of capacity. Sort of like driving on the interstate in second gear. The props all the same is also probably slightly aggravating the control. Last, I would say that you may be stressing the 750's a bit as well with the 4S. They aren't spec'd for 4S. Probably not a big deal, just be aware.

Your numbers look ok, well within "norms" for a DW size tri.

 

[AshBreeze]

Thanks for the input. From some the testing I've done since, I think the problem is more in the CG.

Also, I am using the motor/prop/battery setup recommended by David for his tricopter so I'm not too sure that is the problem, but I may try larger props / smaller battery if I cannot find the problem anywhere else.

 

[crlock]

i don't think david would recommend using a 750kv motor with 9x4.7 props, and 4s battery maybe you missread it? go with bigger props, balance your copter and you'll be up in the air in no time

Cyber, are we calling it DW tricopter? that guy is like a rockstar now xD i want my name on a tricopter model "The Crlock" sounds awesome =D