Problem with maintaining hover and bucking up and down

[LeeT]

I just finished changing motors and batteries on my hex. I went from T-motor 2216-900 on 3S to KDE 2814-515 on 4S. The hex lifts off around 70% stick throttle and after a few second it then accelerates upward. When I give it any stick it will rock back and forth violently. It is also listing to the left. The hex is well balanced and COG is as close to center as I can get it. I did reduce the gains from 140, 140, 100, 140, 110, 110 to 120, 120, 100, 120, 100,100 which helped a little with bucking. I have a hard time holding it in a hover as it either wants to accelerate and go up or slow down and come down. Throttle response is very slow. I have the throttle start set to recommend.

It flew fine the last week before I changed out the motors.

The props are 12 X 4.5.

My guess is one or more of the ESCs are on the fritz. As I solder the motor wire directly to ESC it is possible I could have damaged one of them. Four of the ESCs were warm to the touch after a very short flight of less than 2 minutes.

The motors spin up as expected without the propellers on.

Thoughts?

Thanks.

 

[haha49]

try lowering your gain settings by 10 or 20 percent then try a flight and see if it improves or gets worse. I find with 10 inch props and 8 inch the gains can be the same bump up to a 12 inch prop or 13 you have to lower them allot or you have a bad day.

 

[38super]

It does sound like one or more ESCs may be giving you trouble ....power lag as you power up. If you had soldered leads on you could have moved them around (ESCs) to see if it changed flight
characteristics

 

[DucktileMedia]

Sun light can affect the barometric sensor in the FC. Either cover it with tape or foam depending on which FC you are using. Also, you should be lifting off lower than 70% throttle. What's your AUW? What props are you using? I dont fly DJI stuff and cant remember if softening the throttle curve helps or not. You need Kloner.

 

[Scott Drysdale]

Don't know enough about your history or your equipment so bare with me......
IMHO - The sudden acceleration upward could be a symptom of a motor and/or prop balancing issue.
At least that was my experience with a Naza on a modified F550 some time ago.....
And that is a common occurrence when upgrading to more powerful motors that accentuate vibration magnitude.
And if you need 70% throttle to get to a hovering mode, eCalc seems to suggest the payload is too heavy.

 

[LeeT]

When I did ecalc, I used 3300 as AUW. Actual came in at 2918. and told me I would run about 62% at hover. I am using 12X4.5 Gemfan carbon filled props. They are balanced (checked twice). I am assuming the motors are balanced or close to it as they are KDE. They run very smooth without the props on. The V2 Naza supposedly does not need black tape, and I did not have these issues before I changed out my motors / props. To clarify, the issue is that the motors are surging, either acceleration or deceleration.

The motors are rated at 24+ amps, 535 watts. I am using DJI 30 amp ESCs. What I don't know is the 30amps burst or continuos? I suspect it might be burst hence my issue with the motors surging.

Anyways I sucked it up and just purchased 6 new 35amp ESCs. I'll update this thread after I mount the new ESCs. Thanks, for all of the responses.

 

[Scott Drysdale]

Interesting..... I had a similar issue just last week but with the MR tied down for ground testing. The motors surged up and down with no change to the RC xmitter throttle input.
The next day I tried the manual calibration of the ESC throttle range as per the ESC manufacturer's instructions......using the RC Transmitter.
This required that I bypass the MR FC and connect the ESCs directly to the RC Receiver throttle output channel...... used a 6 Y harness so I could configure the range of all 6 ESCs at the same time.

In short, the issues disappeared and the MR throttle speed was subsequently, exactly in line with the RC Xmitter throttle position......no more surging etc.
But in my case I was using Turnigy Plush 45A ESCs and the Xaircraft SuperX FC.

While the DJI products are all supposed to handle the throttle range configuration from within the NAZA or equiv Assistant software instructions, the above might be worth considering.

When I did ecalc, I used 3300 as AUW. Actual came in at 2918. and told me I would run about 62% at hover. I am using 12X4.5 Gemfan carbon filled props. They are balanced (checked twice). I am assuming the motors are balanced or close to it as they are KDE. They run very smooth without the props on. The V2 Naza supposedly does not need black tape, and I did not have these issues before I changed out my motors / props. To clarify, the issue is that the motors are surging, either acceleration or deceleration.

The motors are rated at 24+ amps, 535 watts. I am using DJI 30 amp ESCs. What I don't know is the 30amps burst or continuos? I suspect it might be burst hence my issue with the motors surging.

Anyways I sucked it up and just purchased 6 new 35amp ESCs. I'll update this thread after I mount the new ESCs. Thanks, for all of the responses.

 

[LeeT]

The DJI ESCs do not have the ability to calibrate, sync or upgrade the firmware. The new ones I am getting (Castle Creations) I'll be able to change the settings using my PC via Castle Link.