what's the problem

[stark]

This is probably the fifth flight on my 425. Did 5 mins of sport flying in idle-up (95% throttle) and then while getting the bird to land in normal mode (75% throttle), the heli began to intermittently loose power and the tail was twitching.

What could be the problem? I'm using all stock parts.

cheers,

[Mikej]

It sounds as if you are hitting low voltage warning on the ESC - hat batteries and how much did you put back into them?

[stark]

Good point Mikej. But the low voltage alarm didn't set off on my aurora 9 transmitter radio. I have set low voltage warning to 20V.

My ESC (CC Phoenix ICE 75) is set to 3.2V/cell low voltage cutoff (i.e. 19.2V). And current limiting is insensitive (130A).

I've also captured my flight data log below. The first part is the 5 min sports flight with the twitching happening after 300s. The 2nd part is a few seconds hover with the twitching happening.

Any clues?

[stark]

I have replaced the 19T one way gear with 20T and haven't observed the issue since. Done with 80 mins of flying (10 flights) with no issues.

[minititinflyer]

i saw that the 19t one do not have one way grease in it when i got my own out the box so i put some on it and havent had problem so far 11 flights in but it sound you hit the low volt cut on it