Cinestar 6 WKM sudden wobbles

[Michael64]

Hey Ken what firmware version are you using currently, and is the firmware without bugs.

Michael64

 

[Kari]

Interesting method to find CoG Z point Ken, i'll try that way also. I also had an idea fix couple of alu posts vertically to center plates with zip ties so i can hang cs with my fingers or with wire from them. Now my Z CoG is couple of cm under lower center plate so it's a bit difficult to see it precisely. But will try that next when i replace new esc:s. I'm next going to try FlyFun 40A:s and 30A rapid esc:s from abusemark, i hope to get both sets in couple of days.

Ken, you are using 30A esc:s without problems? I'm little worried at the moment if 30A:s are enough for qc3328:s. Like Gunter wrote in earlier post he had some problems with 30A esc:s and 30A motors and problems were gone after going to 40A:s. I had 30A maytech v1:s when this wobble came up so don't know if it has anything to do with it has same amp rating as my motors or did one esc failed anyway (if esc even is the problem, can't be sure).

Wbrown i personally would not recommend using 30A V1 or any V2 for now with our setup, even i know there is a lot successful flying with V1:s. Also i didn't yet get 12X6 thin e props flying as good as graupner 11X5, but i will try them again later and give more time to find gains.

Kari

Could be one or all of the following, gain settings, prop size, ESC firmware. My CS6 flies nicely in both ATTI and GPS mode, I'm using AXI 2814-22 motors, Graupner 11 x5 props, DYS 30A ESCs with FastPWM firmware, and gain settings of 220 on basic pitch and roll with ATTI pitch and roll TX adjustable from 40% to 110%. With this setup I can get video smooth enough to not need any post process stabilization while flying in ATTI mode.

I've seen the wobble you're referring to and it took a lot of trial end error to eliminate it, the end result being the setup I'm currently using. I just thought of one other thing that can contribute to the wobble, the Z axis measurement used in the Assistant software has to be within a CM +/- of the actual CoG for the axis. The method I've found most effective to measure the CoG on Z axis, take a piece of wire or heavy twine and loop it through one of the outer openings on the lower frame plate. With the CS setup as though you were about to fly it, battery(s) and camera in place, lift it by the wire and note if the center plates are vertical or angled to the right or left. If they're perfectly vertical the CoG for the Z axis is where the wire is, if it's angled so that the lowest part of the centerplate is to the left of vertical it means the CoG is also towards the left. Move the wire to the left and see if the centerplates are vertical there, if it now has the bottom of the centerplate right of vertical then the CoG would be somewhere in between the two points the wire was attached at. If you have the patience and can find appropriate places to hang the frame from you can find the exact Z axis CoG by moving the wire the frame is hanging from until you find the point where the centerplates are perfectly vertical, measure from that point to the center of the side of the IMU and enter the number in the Assistant software.

In your case it would help to know what gain settings you currently have as well as the takeoff weight and what the rest of your setup is. The WKM like to have heavy disk loading on the props, it seems to fly best with the smallest props that will get the job done, a lot of stability problems people have had were solved by swapping to a smaller prop and doing some gain adjustments.

Ken

 

[wbrown]

Thanks for your help guys. Hopefully will get to the bottom of this soon. I have just been putting up with it lately, flying in manual mode. But after some more testing today it is soooo much easier to fly in atti mode.

Flying weight is 5.7kg using torxpower 3536 pro motors with apc 12x6 thin electrics. I measured the Z setting for imu as you suggested Ken and it appears to be pretty spot on with these settings:

GPS
X: -22
Z:- 20
Y: 0

IMU
X: 0
Y:0
Z: -11

Here is a picture of the mounting set up:

View attachment 3448

The basic gains are adjustable from my transmitter, I have found these settings to work the best in flight


P: 260 R: 260 Y: 260 and vertical at max: 250

Atti gains are both at 80 percent

I have noticed that the motors tend to make a very high frequency squeal during flight, if that means anything or not!
But aside from that flies great in manual mode then powers up a bit on flicking to atti mode, holds very well just wobbles and vibrates too much to actually do anything with the footage.

Thanks,

Will

 

[redridinghood]

Will, is your imu solidly mounted? Try to tie it down in some way. Plus if the shield you have over the esc's vibrates with airflow that would mess up the imu.

 

[wbrown]

The IMU is attached with foam double sided tape - as you woud a gyro on heli's. It seems to be firm enough. The plate it sits on is quite thin but dosnt have a lot of movemt in it.

If I'am to swap esc's what is the best for multirotors? Ken, you are now using dys esc's instead of the maytech's, Any particular reason?