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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How tight are you screwing the collet on the adaptor? I use small nail and tighten it till the nail bends.

Everyone should be using reverse threaded prop mounts for the reverse rotating props.

Such as these

With one hand twist the motor in it's direction of rotation, with your other hold the leading edge of the prop to represent the drag imposed on it by the air. If this action loosens the prop mount nut then you need to put reverse threaded mounts on that motor. 

I have used "Lock-Tite"  BLUE.  It works.

I think reverse thread is a MUCH BETTER idea.  

That's the way ALL saw blades are mounted !

That helps but a properly attached prop adapter should work fine regardless of direction. I had issues with props coming loose until using a little bit of Loctite on the nut (the blue kind).

I didn't mean to sound so bossy with that first sentence, sorry.

What I meant was-

Everybody should think about trying reverse threaded prop mounts on half of your motors. It will make your life much easier. Just tighten them a reasonable mount, no need to risk over tightening aluminum threads.

Threadlock works, but I like to remove my props all the time.

A correctly sized collet-based propellor mount, properly installed, should not come off under normal operation (or even a crash).

I think part of the burst in 'loose prop' posts may be due to:

  • A bad fit of the adapter and motor shaft (This includes the wrong adapter for the shaft size)
  • A poor installation of the adapter to the shaft (Challenge: Find good instructions that help you understand the device)
  • A poor quality adapter even if sized properly (Cheap don't mean good all the time)

Using reverse threaded collets will mitigate the rotational forces on the nut BUT will not fix a badly sized (or fabricated) adapter or installation. When installing the device, you are doing two things; compressing the propellor hub and compressing the collet on the motor shaft.

In a few days I will have a cross-sectional graphic of a typical prop adapter finished. I could not find one to reference to so...in true DIY spirit, I am making one to share. I have been tempted to machine one to a cross-section for the show-and-tell as I could not find a picture of one done that way either.

I hope to illustrate where these devices can go wrong and try to raise the understanding of how they are supposed to work.

The basic machine part has been around since before WW2 so... it was around before Rocket Science became a term.


Agreed R.D. IMHO the only issue here is whether the collet adapter is the correct size for the motor shaft.

If it isn't correct no amount of screwing down, whether reverse threaded or not, will secure the adapter onto the motor shaft. It could even be that using loctite might, in some instances, glue an incorrectly sized adapter onto the shaft without the splined collet actually biting mechanically onto the shaft, hence causing a potential failure.

Just my two pennies worth.

There are a number of options available there for the standard 3dr motors collets, but I wouldn't use super glue.  Nail varnish works a treat for most applications, or use the blue loctite.

However, I have upgraded all my collets/prop adapters and the problems pretty much disappeared.

I'm looking at changing my motors (for a number of reasons) to Tiger - who have CW and CCW nuts.  Check out: http://www.rctigermotor.com/list.php?catid=55


I use blue locktite and the types of prop adapters that screw onto the motor with a few screws. Impossible to come off.



These clamp style prop adapters seem to me an an unnecessary point of failure. Although I haven't had one come off myself in flight yet, they make me incredibly nervous.

I don't disagree that from an engineering perspective it is *possible* to fit and tighten these to a degree where they are mechanically sound, using loctite and CW/CCW threads to help, but your average user is going to have a pretty high likelihood of getting it wrong over time, as it is not self-evident whether you've done it correctly.

One of the reasons I'm looking to move to T-motors is that they feature prop adapters that screw directly on to the outrunner case, which seems like a much more direct and foolproof solution than hoping that two pieces of cheaply manufactured metal (shaft + adapter) are being pushed together with just the right amount of pressure to stop them sliding apart, yet not too much that you strip the thread or bend something when applying the opposing force.
I agree completely. As for the thought of super glue vs locktite how do they differ? When I go to the store they seem to be the same. At this point I am stuck with what I have but it does make it stressful.

Super glue (cyanoacrylate) is not designed to be removed, ever. Thread locking compound like Loctite is designed to hold against vibration and light stress but will still break free under extreme stress like a wrench. If you use super glue you might not ever be able to take the adapter off again. Note the Loctite goes on the nut, not on the shaft and collet. Also use the blue which can be removed at room temperature, the red is for high temperature and extremely high stress use like combustion engine heads and requires very high temperatures to remove (likely to damage something like an electric motor during removal).

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