F5J motor misbehaving

[GuyB]

Hi

fully charged 850mah 4S lipo. Two short motor runs of no more than 6 seconds each. 10 mins flying if that. Next run and the motor runs at less than 10% power even at full throttle. 
 

battery has enough charge in it. End point adjustment on transmitter at max. 
 

Can anyone let me know what / why this is happening. See video for how the motor is running now 

https://youtube.com/shorts/b7HAtWWxohE?feature=share

Thank you 

Guy 

 

[EssexBOF]

Could be a cell down under load.

[cirrusRC]

Have you got programming card for the ESC?  Check what low voltage cut off is set to.  

[John Minchell]

I had an ESC which heated up slowly on the first flight which was ok and then the second flight, if soon after, it went into thermal slow down mode and wouldn't give full throttle.  Might be worth a check.

[Jef Ott]

To me it sounds like a stripped gear. 

Do you allow a slow start on the motor either in the ESC or from the Tx output?

If not, that can damage the gearbox in that way.

[FrankS]

What type of motor is it? I had an outrunner once that did something similar, the rotating case was slipping on the propeller shaft, spent ages trying to reset the ESC etc until we found the problem.

[Graham Lorimer]

I would be removing the motor from the model, unscrew the gearbox from the motor and check the pinion is not partially stripped or slipping on the shaft.

[GuyB]

Thank you again for all the replies. Will work through the different scenarios and hopefully sort it. 

[Jef Ott]

On 01/06/2021 at 15:44, Graham Lorimer said:

I would be removing the motor from the model, unscrew the gearbox from the motor and check the pinion is not partially stripped or slipping on the shaft.

I thought the pinion could be slipping too, and is the more likely (and cheaper to fix) option!

Fingers crossed.