Hello Everyone,

Ok the only crashed I get now are when a prop falls off the quad will in flight.  It has cost me two cameras and a good amount of embarrassment.  It only happens once every 15 flights but I hate it.  So has anyone ever super glued the collet prop ad pater to there motor?  It seems even if the motor goes bad at some point a new motor comes with a new collet adapter.


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"I certainly wouldn't want the Federal Government to get involved."

It won't happen until someone not involved in the flight activity is injured.

I've had the bolt in type adapter in my MK for like 2 years without a failure, and those blades have been subject to some fairly harsh usage with sudden direction changes.

Ok folks, for what it is worth I have posted my cross-sectional sketch of a collet-type adapter.

Pros will probably <yawn>...

It is for the newbies and others that may not quite understand what the device is supposed to do. I hope we can use it to  illustrate proper installations of these gadgets and perhaps standardize the phrases used to discuss them.


Nice drawing Doug. Thanks for sharing.

You are welcome. :)

I had considered another sketch with a washer and nut rather than part 5, but that seemed a trivial effort.

Another consideration for this issue might be the use of a safety wiring system as used on many full-szied aircraft and racing vehicles (motorcycles in particular).

Some parts would be too small for drilling the locking wires. This scheme would not prevent a loose collet from slipping/leaving a shaft but it might see use in keeping the assembly on the motor and not becoming a hazard.


I have often wondered about the absence of any safety wires on our craft.  

Some parts would be too small for drilling the locking wires.

I've seen some pretty small hardware on my Cessna that was safety wired.  A 1mm hole in the 4mm motor shaft would accommodate a 55 gauge safety wire.  

I think I could drill in the aluminum parts easy enough. Not sure about the smallest shafts like the purple motors.

There might be a solution if an adapter could bolt to the turning housing and then feed through the wrench bar hole and then to the other side - somewhat balancing the assembly. This way if the collet lets loose, for what ever reason, the assembly stays on the shaft - even if the aircraft comes down.



The older purple motors have tapped holes on the housing which could be used for this purpose.

Also, rather than a wire through the wrench bar hole, you could just use one of the rubber prop retainers used on some slower electrics. Dave Skinner from Bask Aerospace uses these on quads he flies and sells ... saw one fly recently and it had no problems.

This would also give you some force holding the prop down even if the spinner comes off, so you could probably still land safely. I'll try and find time to rough up a sketch this weekend... would be very easy to adapt existing parts to make this.

Maybe the simplest approach is to use ESC feedback like this:


The first thing that would happen if a collet started to slip is the prop would free spin and the motor should speed up instantly or cause some recognizable change. If it's a hex or octo then the esc could shut down before sending the prop flying off and maybe into other props.

If you're airborne when this happens, a prop flying off and striking your craft is the least of your worries... the sudden stop when vehicle meets Earth is going to cause way more damage.

The 'prop saver' idea is a good start.

My suggestion of through the wrench bar hole would not work if the retaining nut were actually only a nut and washer. For that arrangement, the 'over the hub' method is the only solution.

With a spinner nut, a 'thru-hole' solution would also retain the nut in the event of a rotational force failure- a situation that counter-turn threads would resolve.

Now is a good time to reveal a previously edited photo of the thru-hole idea...

Clipping off the motor shaft would be a good start and reduce the amount of retaining wire/strap/material.

I am willing to bet that somewhere, someone has a bolt on adapter (previously shown) that fits this magnet housing. We would then just cut off the shaft, bolt it on and remove one failure point from our machine.

All we need then to worry about is the loose nut behind the wheel sticks.  ;)


So it seems that even loctite, a 2.5mm wrench and praying just isn't enough to keep my props on.  Two came off today whilst flying in the middle of the F1 Grand Prix track in Melbourne NEAR WATER.  No damage, just two useless arms.

And to make matters worse, the store that I ordered my Tiger Motors from can't get them in, so I need to find another place. 

There are times where this does really just test you.


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