Quad Oscillations.

[Dylansoup]

This is my first build, I have flown it before and it worked well, but the flight controller died, I have just put a new one in, it is now a Matek f722-std, i have a martian iv frame, hobby wing 20A esc's and T-motor f40 pro iii 1600kv motors.

I just got it working today, and took it out for a flight, firstly I noticed that in acro mode it oscillated badly and was un-flyable and secondly if i put it in angle mode, it was significantly worse.

i haven't touched my PID tuning as I have only just got it working.

I will link a short YouTube video of the oscillations, you can clearly hear it, and see it.

Any help would be greatly appreciated.

thankyou
Dylan.

 

[Launchpad]

My honest short answer is I think the problem all along is the ESC/motor combo.
The motors are meant for 4-6S batteries.
The ESC for 3-4S.
I looked back, but don't think I see mention the specs of your batteries.
Example: My 6" rig has 1900kv blasters, 30A 4-1 ESC. On a 4S, it hovers about 30% throttle.
Even if you're on a 4S, the props are smaller & the motors are slower.
Where was the throttle when you did have it flying the first time?

 

[Dylansoup]

Sorry yes, I’ve got a 4s battery, but I didn’t think this would be a problem, as when I flew it with my other flight controller it was perfect, no oscillations and I managed to get about 20 packs flown.
My throttle was only high enough to take off, if I went any higher I feared it would go out of control.

 

[wafflejock]

Yah 1600kv should be using 6S batteries for 4S you'd want about 2300-2600kv range. It will still fly with 4S but will be very under powered and so your throttle stick will need to be pretty high just to get it to take off, something like 50% throttle or less should typically be enough and I usually can hover with right around 40%-50% as well (maybe a little less like @Badfish said). With 2000+ kv motors you can run down to 3S and still take off but wouldn't have great control authority so likely to get wobbles too I started off with this since it was more tame but pretty sure I had 2300kv motors at the time, now I try to get 2450kv for running on 4S (1300-1550mAH) since it seems to be the sweet spot for power/control authority and flight time.

 

[Dylansoup]

Yes but I have used this setup before and it’s worked perfectly fine, the only difference is the flight controller? I don’t have enough money to get new motors or batteries, as I have just bought a new flight controller, surely it’s something to do with the flight controller? As it worked perfectly fine with my other flight controller, also I can take off with about 35% throttle