Sorry to revive this topic, but I did some tests on my S550 before go to fly again (last fly was last summer…) and I think that something is wrong with motors sync…
I tested all motors in sequence, and they clearly don’t run at the same speed at 1% throttle : https://youtu.be/1HYUdYhEpUE
The difference seems to be less important at 5% (but I think that I hear a different song…) : https://youtu.be/4i4KCUjBjfY
Blheli throttle calibration problem ? Arducopter minThrottle problem ?
I don’t think that blheli or arducopter parameters have change since last summer (last succesful flight).
I will try to do autotune for the first time on this hexacopter, and I’m trying to avoid a desync crash…
First those motors are a very poor choice for a multirotor. You must have bought the cheapest you could find. Motors that use collet prop adapter are not well suited for multirotor use.
How they run at 1% or 5% throttle has little meaning. As was said multiple times in this thread just fly it.
2nd flight, I solve gimbal vibration problem by improving gimbal mounting on frame and optimizing gimbal PID…
But the copter seems to rapidely go down at the end of the test, until ground touch…
When the copter gone down I was increasing throttle, at the end I decreasing throttle because the copter was not responding to RC…
I don’t think that it was auto land or RTL (10,6V pixhawk, 11,6 real cold state, failsafe set to 10,3V) and too fast alt failing.
Excepted ESC cut off voltage (may be to high) I have no idea…
Two new flights : same problem at 10,5V for one battery and 10,6V for the other.
If I try to takeoff immediately after “emergency landing”, the copter take off normally and then lose altitude after few seconds…
Battery hasn’t enough amps at 10,6V in load ?
3S 8aH 60C, lipo voltage drop seems to be linear during flight (without high failing voltage rate excepted at takeoff)
I see on multiple topics thar ACCEL_Z_P rate can be the problem, should I try autotune to calibrate PIDs… (I known’t if autotune set ACCEL_Z_P but may be than others parameters tuned by autotune can solve the problem…)
7 minutes flight time is enough for autotune ?
I can unmount the gimbal to reduce weight and remove gimbal motors power consumption but it may be not enough…
Yes do auto tune with no weight is best. You may need over 15 minutes of flight time. Mine took 18 minutes but it’s always windy here so that made it take longer.
