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Tinyhawk S...Roll of Death (kinda) on hard roll+yaw?

#1
Hope this hasn't already been asked. Searched everywhere (on these forums and elsewhere) for a solution. No joy...

If I am going at speed (say >15mph) and hard roll AND yaw at the same time (like you'd do to turn sharply), the quad just rolls out of control. Kinda like the flip of death, but it sometimes recovers.

Using JESC 48. Stock 2s pids. Max roll rate approx 800 deg/sec. 2s 450mah tattu batts.

I tried reversing motor direction to prevent air 'bunching' in front of the quad but that didn't help. Also tried all kinds of PID adjustments-no effect.

Any ideas?
 
#2
might be browning out, might need a capacitor. Have you looked at the black box log? look for a motor dropping out (might be a dysnc, bad connection, bad motor) check if one motor is hotter than the others (as soon as you land)....take the props off...spin up motors in betaflight and see if one dysncs (itll get kind of jerky/twitchy)....or take props off...power up quad (with radio on) switch into air mode, arm it and and try and duplicate problem on the ground. calibrating the ESC's might be needed.
 
#3
@MorningViewFPV thanks, I'll give blackbox a go if I can get it to work.

None of the motors feel particularly warm after flight and the lack of abnormal OSD behaviour suggests to me it's not a brownout issue (though I could be wrong, of course).

Will also give the 'no props' test a go, assuming I can get over my fear that doing this will overload the motors! :D

Thanks for the help-will report back.
 
#5
Sorry, I meant underload :) Surely that's bad (for prolonged periods, at least)? Same as flooring it in neutral could damage your engine, since the excess energy's gotta go somewhere (ie heat)?
 

FDS

Well-known member
#6
Nope, the motor is better with no load on it. Brushless motors love revs, that’s why they are good for quads! Heat in motors happens because of load, like too much prop pitch, or poor tune.
What does happen if you run props off on the bench is that if you just use the radio and throttle then the PID loop runs out of control and the motors don’t return to idle, as there’s no load on the gyro. Use the sliders to test individual ESC’s.
 
#7
yes use the sliders, not your radio. check each motor slowly spinning up...if there is a problem you shouldn't have to give it much gas to see if it dysncs.