Motor suddenly stop at mission

Hi everybody,
During a mission at minute 27min 54sec the engine stopped suddenly and I don’t know why.
This mission I have repeated several times before and I have not had any problems.
Thanks in advance. Log attached.

@Loren_DS I am sorry to hear of your crash. Unfortunately this was caused by the H_COL_MID parameter being set too high. This parameter is to be set for the PWM that corresponds to a collective blade pitch of zero degrees or a blade pitch angle that results in zero thrust. The autopilot uses this parameter to determine when the aircraft has landed. You can find the description on how to set this up in the wiki for swashplate setup.

Just to be sure please verify the collective blade pitch angle for H_COL_MID. I suspect it is more like 3-5 deg based on the range of collective min to collective max.

I’m sorry again but if you have any questions please don’t hesitate to ask


Hi @bnsgeyer,
I have rechecked the collective with the H_SV_MAN = 3 and the collective value was +1.5 degrees.
Do you think that this little mismatch could have caused the engine stop?
The funny thing is that I had no problems on the previous flights.

Now it is already set to 0 degrees and will test tomorrow.

What are the blade pitch angles for H_COL_MIN and H_COL_MAX?

-5 degrees and +11.5 degrees

@Loren_DS Based on your min and max and your PWM values, I determined your H_COL_MID blade pitch to be 4 deg. See below

H_COL_MIN 1500pwm -5 deg
H_COL_MAX 1725pwm 11.5 deg

H_COL_MID 1625
blade pitch (deg)= (11.5 - (-5)) * (1625 - 1500)/(1725-1500) - 5
blade pitch (deg) = 4 deg

That is interesting that you are reading 1.5. that is significantly different from what the calculation says it should be. You might want to set that a little lower. the calculations say H_COL_MID should be 1568. I’m not sure why it would be that far off. It doesn’t hurt anything to set it a little low, especially since you are not using collective to yaw mixing (H_COLYAW=0).

Hi @bnsgeyer,
now i have this value:
H_COL_MIN 1520pwm -5º
H_COL_MAX 1755pwm +11.5º
H_COL_MID 1592pwm 0.0º

blade pitch (deg)= (11.5 - (-5)) * (1592 - 1500)/(1755-1500) - 5
blade pitch (deg) = 0.95º

Do you think I should lower the value of H_COL_MID to 1580pwm?

Yes, set it to 1580. Like I said before, it isn’t that crucial since you aren’t using collective to yaw mixing. It will slightly affect the integrator handling if you enabled that option for the improved integrator handling thru the H_OPTIONS param. But it should still work fine.

ok @bnsgeyer I’m going to try what you advise me.

hello friends, I’m installing the fc apm pro to the heli align 450l, using the ac3.6 firmware, but having problems when I tested it, the motor suddenly stopped when the throttle was increased to 60%, it looks like the fc apm pro has restarted, and when I tested it again without blades, the motor seems normal until throttle is 100%… the fc apm pro doesn’t use the power module, do I need to buy a power module…?

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