I was almost done with my initial tuning flights, and had been having pretty good success progressing through each tune session.
Doing small ovals in PosHold mode, it abruptly lost power and fell from the sky. To my eyes, it appeared to get “shot down” by some sort of anti-drone tech. I know that isn’t it, but it sure looked like that.
I suspected a solder joint somewhere, but I have gone through every solder joint and connector in the entire system and all appears solid and tight. It’s a real mystery and I’m hoping someone here can interpret my log better than me. Any help would be great.
BTW, this is a test platform for a scale helicopter I am building. I test the mechanics thoroughly before installing them in the fuselage - thank goodness.
A pic of the test platform as flown is attached. 600 size, 12S, Castle Edge HV 80 ESC, separate 20amp BEC, Pixhawk 6C Mini FC. Edit: Governor is controlled by ESC.
Thanks for the reply. I downloaded the castle log and had my AI agent look it over. This was her opinion:
Key moment near the end:
Throttle input stayed high: about 1.675 ms
Power-Out suddenly dropped from about 70% to 0.8%
Current dropped to 0 A
Voltage rose from about 43.5 V to 44.0 V
Motor speed began decaying
That means:
Pixhawk was still asking the ESC for power, but the ESC stopped driving the motor.
It does not look like:
low voltage cutoff
over-current cutoff
over-temperature cutoff
normal throttle reduction
radio failsafe
Your limits were:
voltage cutoff: 38.67 V
current cutoff: 140 A
temperature cutoff: 289.7°F
At the event you were nowhere near those.
The heli test platform and skids I had the mechanics bolted to took most of the damage, so I was able to clamp the mechanics to the bench and spin the motor up. While it was running, I tugged on motor leads, jiggled connectors, wiggled all electrical connections. Nothing shorted, or glitched, or anything. It’s a complete mystery. There is no reason a Castle ESC would just randomly fail under completely normal conditions. I’m perplexed.
I think you left the battery get too low. The ESC may have just cut power because it hit the low voltage cutoff. The flight controller definitely lost power as the log abruptly stops unless that occurred because of the aircraft hitting the ground. There is nothing else that I can see that makes me think it was something with the flight control logic. looks like it was the ESC.
The battery ejected on impact. I had 43.5 volts when power quit. LVC is set at ~38 volts, so that’s not it.
Everything points to the ESC, but it just doesn’t make sense. Ive been using Castle ESCs since they only catered to brushed gliders. Ive never seen one just quit for no reason. But I cant risk continuing to use it….
Anybody want to buy a used Edge HV 80? Works fine until it doesn’t.
It could be linked to harmonic frequency between motor and ESC.
I have just recently lost a rather special, large drone due to sudden ESC failure. Nothing else was found to be a problem, but motor suddenly started surging for no apparent reason, following complete ESC and motor burnout.
On long cable runs a capacitor in the power line is vital to prevent such issues. I had some installed, yet it still happened.
Yours has a rather short distance (from what I can see in the photo), between battery, ESC and motor. So should not occur, but also depends on wire thickness.
Consider voltage spikes due to poor quality capacitor leads with too high resistance. Check ESC temp if available. Chris Rosser has a video that stresses ESC’s until they burn. The IR view of the boards reveal very high temp in poor-quailty capacitor leads that sometimes result in the capacitor leads melting their solder joints. Capacitor leads are coated in lower resistance metal (copper?), but poor quality ones have too-thin coats for our demanding aplication. I have a plan to replace capacitors annually.
