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Pumpkin drop event

Motors are out of sync

NickH21

Junior Member
#1
Hey, just recently bought parts for my first quadcopter. I'm having issues with calibration on it, the problem is the flight controller that I'm using. Currently using the KK-Mini in conjunction with a Q Brain 4 in 1 20A ESC, What's happening is that when i spin up the motors, they all start at the same time although, they do not spin at the same speeds. Don't know how to fix this. it's not a problem with the speed control since I can plug all four motors into a throttle hub and then directly into a receiver and they all spin up at the same time, same speed, etc.

I've already switched the ground and positive leads on the PWN (Servo) Connections from Port 3 to Port 1 in order to have power distributed to the KK Mini FC since it requires power through M1 and not M3. All motors are going the right directions, self leveling is off, haven't mucked with the P Gains of anything or the Trims. ACC is properly calibrated, and when i tried swapping two ESC motor connections, the one that was spinning slower became the one spinning faster, and vice-versa.

I mean, I think it has something to do with the P Gains in the PI Editor that I have to change, but I want a second opinion on it and I have no idea what values I might have to change those to. Any advice would be much appreciated.

P.S. all ESC's were properly calibrated using 3 different methods, Direct to the receiver in throttle port for each motor, then using the throttle hub to link all 4 at the same time, and then tried again with the KKMini board's 1 and 4 fashion.

Here's all my specs:

X580mm frame glass fiber

Turnigy 2213 920 kV motor x 4

KK Mini Flight Controller with V1.25 Firmware

3S 5200mAh (11.1V) 10C discharge 20C Burst

Q Brain 20A 4 in 1 ESC

Random Tx and Rx 6ch that I found from one of my old F22 RC Planes

Thanks for your advice!

Nick Heanssgen
 

Snarls

Gravity Tester
Mentor
#2
Since you've done some pretty thorough troubleshooting, I suggest you just put some props on and see if the quad will take off. I fly a Flip 1.5 and usually at very low throttle on the ground at least one motor will appear to spin slower. Once I give it enough power and it starts hovering, the FC will adjust motor speeds accordingly.
 

NickH21

Junior Member
#4
Not in autolevel mode, and i tried putting props on it. Only one motor seems to be out of sync now. kinda weird because the thing is so far out of sync but its spinning like 2x faster than all the others. I tried adjusting trims to see if that worked but it didnt. Everything is back to being reset. Im going to try and upgrade my firmware on my kkmini and see if that helps at all. also, is there anyway i can put simonk or blheli firmware on my QBrain 4 in 1 20A ESC
 
#5
They can run BLHeli, but you're going to have to do some soldering.

If they're all running the same speed with the throttle hub that comes with the ESC, then that's unlikely to be your problem. As a few others have said, when you're on the ground they won't necessarily spin at the same speed. And the longer you're on the ground with them spinning, the farther apart they'll get, because the correction being applied by the flight controller isn't doing anything with the ground in the way. If your ESCs aren't plugged in to the correct motor outputs, it's going to flip over very quickly when you try to get it off the ground.
 

cranialrectosis

Faster than a speeding faceplant!
Mentor
#6
So does it fly?

It is common for this to happen while the copter is on the deck. If it happens in the air, you have a problem.