My first Wookong-M - problems with throttle flat spot

[Jake]

HI Guys,

I'm really hoping somebody can help me. I've just finished building my Hexacopter with DJI Wookong-M. Got everything set up and calibrated, but when I spin up the motors there is a dead band/flat spot from about 10% throttle up to about 60%. Within this band absolutely no increase in RPM from any of the motors - they just keep ticking over at a low rpm. Once i get past the 60% ish, they spin up really fast as if they're catching up.

I've calibrated the ESCs more than once. When i plug the ESCs directly into my receiver, they are fine - a nice smooth throttle response as i increase throttle. So it must be Wookong related. I'm using a Spektrum DX8 and AR8000 Rx.

This is not my first multi-rotor, but it is my first Wookong.

Anybody got any ideas on this??

Thanks

 

[fj_montilla]

Sounds about normal to me. Once you start up the motors the copter will not take off until you're above 50% throttle. From there you should have a smooth gradual rise. This is a DJI thing. Some love it, some hate it. There seems to be nothing wrong with your Hex.

 

[fj_montilla]

By the way I use a DX8 as well

 

[Jake]

Thanks for the reply. However, its the same on the way back down i.e. smooth above 50% but as you drop below, the motors spin down really quickly. This would almost certainly lead to a crash. I've used the Naza previously and didn't encounter this. I don't dare even attempt a flight with it like it is.

 

[fj_montilla]

The Naza V2 has the same takeoff deal. The reasoning behind it, I think is that 50% should be your hover. So you take off, and bring back throttle to 50% you should be in hover. Anything below 50% your craft should be descending. And yes, watch out you don't bring that throttle below 10% while in flight, cause gravity takes over. If your craft is rapidly slowing down at say 40%, then I would calibrate my radio again with WKM assistant. Your descents should be gradual.

Is there a way you can show us some video of a short hover?

 

[Jake]

I'll have to take the plunge and test fly it. It's a new build and hasn't been in the air yet, i've just noticed this from ground tests and got scared! However, i've just noticed if I put it in manual mode, all is normal. So it would seem that you're right (not that i didn't believe you of course) and it is just the Wookong doing it's thing for whatever reason (safety perhaps). Can't say as my old Naza used to do that though, but perhaps i was running old firmware.

 

[fj_montilla]

I strongly recommend Attitude mode to test fly. Yes manual mode is quite a different animal, and a lot of s800/WKM owners would vouch for this and actually recomment to stay away from manual. Attitude is stable and you'll get a feel for the controls. If you are proficient in manual mode using the Naza, then you could experiment, but get a feel in attitude mode first. Good luck

 

[Jake]

Thanks for your help. Appreciated.

 

[eyeball]

Yep...pretty standard throttle response from the wkm and Naza nowadays. Don't panic,
simply takeoff in atti and everything should be good.
Happy landings!

 

[Carapau]

The reason you throttle is doing this is due to the way GPS mode works. In short, your throttle is not a throttle, it is a rate of climb lever (GPS mode only). So, on the bench, below 50% you wont see much change in the throttle as you are effectively asking it to descend. Once you go over 50% you are now asking it to climb and it will very quickly ramp up the revs until it sees a change in altitude. As you reduce your throttle on the bench ie your rate of descent, the revs will very quickly drop off below 50% because no descent is being detected. What you are experiencing is very normal. The older firmwares had a much smoother way of doing this but once you get used to it, it is fine.