this has been bugging me for a while and im at the point where im just going to post and see if anyone has run into this. one of my motors ? front right ? keeps losing prop tension mid flight. not totally loose but like, i land and the prop has noticeable play on the shaft when it shouldnt. the other three are fine every single time.

ive tried two different prop nuts, tried a new prop, checked the shaft and it looks straight to me. motor is a T-Motor F40 if that matters. frame is a stretched X so the motor positions are a bit different than a standard build but i dont think thats relevant. it runs clockwise direction so its a reverse thread nut, and yeah im tightening it the right way, before anyone asks.

only thing i can think of is maybe the shaft threads are stripped slightly? but it feels snug when i tighten it i just dont get how it keeps walking loose. anybody dealt with this or am i missing something dumb

the threads on the shaft are probably just worn even if they feel okay when you tighten down. T-Motor shafts are hardened but if you've crashed on that corner a few times the threads go subtly and you won't necessarily see it or feel it until the prop walks off under load. easiest test is swap the whole motor to a different position and see if the problem follows it. if it does, thats your answer and honestly just replace the motor, repairing shaft threads is more trouble than its worth on something that cheap relatively speaking.

loctite. not the permanent stuff, the blue medium strength. tiny bit on the threads. i know some people have opinions about this on props but ive been doing it for years on problem motors and never had an issue getting props off. the vibration from just normal flying is enough to back a nut off slowly if everythigns not perfect and loctite just eliminates that whole variable