Crash Assessment

I have been flying a large helicopter now for awhile with no issues thanks to Robert.

Today while flying only a few minutes in my ESC decided to shutoff. I was in a hover so to save it was very difficult. I don’t think it had to do with the Autopilot but if someone can double check my crash that would be great.

It’s a YGE 120amp ESC which has been working for a long time with no issues. In a hover my helicopter is pulling around 40 amps so I know I didn’t over amp the ESC.

All in all the helicopter came out okay from how far it fell soft grass helps. But it seems like maybe just maybe the Autopilot decided to cut throttle then ramp back up.

Thanks for taking a look.

ESC Failure…

Just out of interest did you have the ESC set to hard shut off on LVC? It would be easy to overlook or accidentally program it, and if the ESC detected a low voltage situation it would shut down hard vs the more desirable soft slow down protection.

Unfortunately though even the best brands like YGE or Kontronik can fail unexpectedly…

Hi Sean, sorry I didn’t see this earlier. So you were able to confirm it was the ESC? How?

I looked at the logs, yes, there’s no indication that the system shut down the ESC. Ch8 Output remains high the entire time.

Did you get into a blade-stall situation? Unfortunately it looks about like what we expect it would. The ESC failed while in Loiter, and the controller automatically increased collective to hold altitude, which would have drained all the rotor speed. You then switch to Stabilize, but it’s probably too late. I notice the Roll and Pitch control go sloppy.

I also see it appears you had the Current monitor hooked up? What are you using? It shows actually over 100A draw in hover, so maybe it’s not calibrated? The really strange part is that as it’s falling, the current draw increased to 350A. I wonder if this indicates a short in the ESC or something.

I never calibrated the current sensor so that might be an issue with what the current was showing. I was using an older YGE ESC because it can handle 14s. I am using the stock current sensor from the Pixhawk and the only draw is from the servos and gimbal. The ESC does however hook into a power distribution board because it needs 5v to turn on, so maybe that is what the issue was? As the heli was falling the ESC did start back up but the startup was not fast enough to recover.

Surprisingly the helicopter came out in pretty good shape. The landing gear took most of the damage.

I think the next ESC will be a kontroniks big boy.