Prop Nut mystery

[Tsenkbeil]

Hey y’all, this maybe a really simple thing but I’m struggling to wrap my mind around it. Just got done building an FT Duster, I have an emax 2213 on it and I can’t for the life of me figure out why it throws the prop nut off? Nut tightens to the left and the motor turns to the left (ccw for you more rc educated folks) I’ve not had this problem with my cub (same motor combo just don’t like swapping power pods). I’ve tighten the heck out of it and even put blue loctite on it, and somehow that joker still came off???? Any help or ideas would be greatly appreciated!

 

[CarolineTyler]

Hey y’all, this maybe a really simple thing but I’m struggling to wrap my mind around it. Just got done building an FT Duster, I have an emax 2213 on it and I can’t for the life of me figure out why it throws the prop nut off? Nut tightens to the left and the motor turns to the left (ccw for you more rc educated folks) I’ve not had this problem with my cub (same motor combo just don’t like swapping power pods). I’ve tighten the heck out of it and even put blue loctite on it, and somehow that joker still came off???? Any help or ideas would be greatly appreciated!

Why not get a nylock nut, they seem to work well.

 

[Hai-Lee]

In answer to your problem I will answer as if I was suffering the same issue and therefore the things I mention to try are what I would do. My responses may be different to the responses of others but HECK what works, Works!

Firstly I would check the motor shaft for a wobble or slight bend and the prop balance as there must be something that is causing the prop nut to rotate. Secondly I would note that the prop nut if not secured will not self tighten with the motor rotation direction.
Now to secure the prop with everything against me, (bent shaft, out of balance prop, and a standard nut), I would look around for a locking washer.. I would fit the locking washer between the prop and the prop adapter to lock the prop to the shaft and remove the prop as being the cause of the nut loosening. Now I would tighten the prop nut severely and add a drop of locktite or similar.

If it still was a problem I would remove the prop nut and replace it with a locknut or fit a second locking washer between the prop and the nut. After tightening I would again add the locktite. If you have no locktite then a very small smear of epoxy in the exposed thread will stop the prop nut from undoing. It can be removed to replace the prop if needed but it will take a bit of effort to remove the epoxy first.

Just my thoughts!

have fun!

 

[Tsenkbeil]

In answer to your problem I will answer as if I was suffering the same issue and therefore the things I mention to try are what I would do. My responses may be different to the responses of others but HECK what works, Works!

Firstly I would check the motor shaft for a wobble or slight bend and the prop balance as there must be something that is causing the prop nut to rotate. Secondly I would note that the prop nut if not secured will not self tighten with the motor rotation direction.
Now to secure the prop with everything against me, (bent shaft, out of balance prop, and a standard nut), I would look around for a locking washer.. I would fit the locking washer between the prop and the prop adapter to lock the prop to the shaft and remove the prop as being the cause of the nut loosening. Now I would tighten the prop nut severely and add a drop of locktite or similar.

If it still was a problem I would remove the prop nut and replace it with a locknut or fit a second locking washer between the prop and the nut. After tightening I would again add the locktite. If you have no locktite then a very small smear of epoxy in the exposed thread will stop the prop nut from undoing. It can be removed to replace the prop if needed but it will take a bit of effort to remove the epoxy first.

Just my thoughts!

have fun!

Thanks for the ideas! I’ve tried the loctite method but no luck, I will give my props another balance just to be sure they are spot on. Haven’t tried the lock nut yet simply because nobody here cares left hand threaded nuts that’s open on the weekends, however I’m going to give Fastenal a try Monday and see what they have. Thank y’all again!

 

[Bricks]

If your prop shaft is long enough lock another nut against the one holding the prop on.

 

[PsyBorg]

I had that same problem on the Versa copter before I / they started using nylocs. Every time I would hit the ground the prop would stop abruptly and that cone nut would spin right off. Sometimes you would find it sometimes not. hi lee is correct though. If there is any imbalance that will vibrate loose unless some method of locking is used.

 

[Namactual]

One more thing to consider:
I have had the ESC's with auto timing do some odd things when blipping the throttle really fast. The motor will stop and start really fast during fast stick movements. This has jettisoned a few props for me as well. I switch the ESC timing to the appropriate setting rather than auto and all is well.

I am not sure if the ESC you have is using auto timings, but it's just one more thing to check.

 

[Tsenkbeil]

One more thing to consider:
I have had the ESC's with auto timing do some odd things when blipping the throttle really fast. The motor will stop and start really fast during fast stick movements. This has jettisoned a few props for me as well. I switch the ESC timing to the appropriate setting rather than auto and all is well.

I am not sure if the ESC you have is using auto timings, but it's just one more thing to check.

Please excuse my ignorance, how do I see if my ESC is in auto timing? I’m using an Emax BL Heli 30amp. If it is in auto timing how would I go about changing that? I apologize fo the questions, still very new to this wonderful hobby.

 

[Namactual]

It looks like you do not have an auto timing with that particular ESC...
Emax BL Heli Manual PDF

I can not find the number of poles for that particular motor, but I would guess middle timing would be best. That should be the default?

The thing to test would be while on the ground, move the throttle stick up and down real fast and see if you can hear the motor stumble or stutter. You don't have to use the full range either, you could stay under half throttle most of the time. It will be during the initial start when it will stutter while it is already spinning. It's almost like hitting the brake. Speaking of which, that's another thing to check. If you go from full throttle to zero, does the motor instantly stop, or does it keep spinning for a second or two?

Both of those issues are a sure fire way to loosen a prop nut.

I am not saying this is your issue, but this happened to me before.

 

[Tsenkbeil]

It looks like you do not have an auto timing with that particular ESC...
Emax BL Heli Manual PDF

I can not find the number of poles for that particular motor, but I would guess middle timing would be best. That should be the default?

The thing to test would be while on the ground, move the throttle stick up and down real fast and see if you can hear the motor stumble or stutter. You don't have to use the full range either, you could stay under half throttle most of the time. It will be during the initial start when it will stutter while it is already spinning. It's almost like hitting the brake. Speaking of which, that's another thing to check. If you go from full throttle to zero, does the motor instantly stop, or does it keep spinning for a second or two?

Both of those issues are a sure fire way to loosen a prop nut.

I am not saying this is your issue, but this happened to me before.

I’ll do some testing this afternoon and check on both of those, thank you for the help and knowledge!

 

[Namactual]

No problem bud.

Just keep safe while spinning that motor up with the prop on. Safety first as they say. Prop strikes are not fun.

 

[kilroy07]

Prop strikes are not fun.

AMEN!