Beginners sometimes have a vague idea of the correct way to attach a collet style prop adapter, but aren't quite sure exactly when it's on right, or if it even fits correctly.

The following pics detail out the steps necessary to ensure a properly fitting and smooth operating adapter.

NOTE: Picture #3 below is very important. The first piece MUST be bottomed out, and not touching the motor base.

Chuck

Chuck:
As always, great info on topics that one would normally wonder about...
Rob

The first piece MUST be bottomed out, and not touching the motor base.

Just to clarify, for those who have not used a bullet-style collet adapter, bottoming out does not necessarily mean that the entire shaft is covered. On some collets, the shaft hole in the collet is not as deep as the motor shaft is long. Just make sure that shaft hole on the collet is competely "filled" with the motor shaft. Occasionally, due to machining issues, there are rough spots or burrs that keep the motor shaft from fully engaging the collet.

And make sure you are using the right size collet adapter for the appropriate size motor shaft. In other words, if your motor has a 3.17mm shaft, you would need a 3.17mm collet (and vice versa). If you use a small or larger collet...you might be able to get it to "fit"...but you run the unsafe risk of the prop/collet flying off and/or a wobbly/off-center mount.

Also, make sure that puppy is tight. I was doing a static amp test one time at the field, and guess what happened? At near full throttle, the thrust of the prop I was using took the collet with it...and left the plane behind.

Originally Posted by Bombay

Just to clarify, for those who have not used a bullet-style collet adapter, bottoming out does not necessarily mean that the entire shaft is covered.

Great clarification, Rob!

Chuck

A few questions here:

1. What prevents the adapter from not turning while the motor shaft is turning? Does it work somewhat like a Dremel attachment? Is it merely the circular tension created by the plastic propeller being pressed against the collet from the nose cone?

2. What prevents the propeller from not turning while the adapter is turning? Is it just the tension between the propeller and the adapter created from tightening on the nose cone?

3. How do you create all of this tension that seems to keep everything turning if you can't hold anything stationary while tightening the nose cone? In other words, how do you tighten the nose cone sufficiently to ensure you maximize the tension?

Originally Posted by jabetha

A few questions here:

1. What prevents the adapter from not turning while the motor shaft is turning? Does it work somewhat like a Dremel attachment? Is it merely the circular tension created by the plastic propeller being pressed against the collet from the nose cone?

Hi jabetha.

In the 3rd pic, you can see that part that slips onto the shaft has a slice in it, so to speak. There are actually four of these slices or slots cut into the piece.

You can imagine that if we were to squeeze really tightly on these areas, they would actually move down against the motor shaft and grip it very firmly.

The second piece that slips over the first actually is beveled on the inside, where it comes in contact with the first piece. So that if we were to push the second piece up against the first piece, it would squeeze down the slotted areas and cause it to grip the shaft.

Sooooooo, when we then put the prop on, we finally put the threaded spinner on last and start pushing that collar and prop further and further onto the first piece....causing the first piece to grip the motor shaft.

Originally Posted by jabetha

2. What prevents the propeller from not turning while the adapter is turning? Is it just the tension between the propeller and the adapter created from tightening on the nose cone?

The propeller doesn't turn, because at first, we are holding onto the propeller whilst we start the nut by hand and start the gripping process.

Originally Posted by jabetha

3. How do you create all of this tension that seems to keep everything turning if you can't hold anything stationary while tightening the nose cone? In other words, how do you tighten the nose cone sufficiently to ensure you maximize the tension?

We hold onto the propeller during the entire tightening procedure...

I hope this helps a little. If not, maybe I can try and explain it differently, which I will certainly do!

Take care,

Chuck

First, thank you very much for your responses. It would seem that everything stays in place and works as needed because of multiple 'compression' joints that keep everything squeezed together. All of this compression seems entirely dependent on the final nut which is tightened, squeezing the propeller against the collar. I would imagine that the any loosening or 'backing out' of this nut would be no less catastrophic than if the o-ring broke on a prop-saver. Which brings me to my final question:

What steps, if any, do people typically take to ensure that this nut does not loosen or 'back-out' at all?

Thanks again...

Originally Posted by jabetha

What steps, if any, do people typically take to ensure that this nut does not loosen or 'back-out' at all?

Hi jabetha,

I can't speak for what other people do to ensure the final nut (or spinner cone) stays put during use. What I can do, however, is tell you that in my opinion, the most important aspect is to keep the motor shaft free of all dirt, gummy deposits, and even the smallest of scratches or burrs. The same goes for the inside of the collett (the first piece that gets slipped onto the motor shaft).

Any dirt or burrs here will prevent the full contact surfaces here from engaging and giving us the necessary friction fit we are after. That's why I run a small piece of Emory paper over the shaft, then clean the surface afterwards.

Of equal importance is the fact that there must not be anything looser than a nice "slip fit" between the motor shaft and the collett. A few thousandths of an inch of clearance is all that is necessary.

A good, firm "hand tightening" then, with a suitably sized nail is all that becomes necessary to keep that nut from backing off.

Most of the forces that are keeping the assembly together come from the friction between the shaft and collett; and not the tightness of the final nut.

Chuck

I have found that my Eflite prop adapters don't seem to fit properly on Eflite brushless motors. Has anyone else noticed this?

Hangar 9 Piper Cub Power 46
6 mm shaft
I used the appropriate Eflite prop adapter and tightened the nut down as much as possible. Unfortunately, I can easily pull it off the shaft of the motor.

Power 10
5 mm shaft
Same thing...tightened it down as much as possible, however I get the same result.

And yes, I am putting it on correctly

This doesn't happen with Tru Turn Prop Adapters and spinners which I've used. My prop flew off the Cub at the flying field while we did a flight check. Luckily it didn't hit anyone

Thanks,

Bob I.

Hi Bob,

Did both of these planes come with the motor and prop adapter? Or did you have to buy the motors and prop adapters separate?

Something doesn't seem right here.

Chuck

Cub came with the power 46 mounted and 6 mm prop adapter in the kit. The Power 10 included a 5 mm prop adapter as well. I'll bring them to my LHS tomorrow and hope they can shed some light...I've probably done something wrong...but when we flight checked it...it was set up correctly (on the Cub). I have seen other posts which have mentioned that their prop adapters just weren't made quite right. I'm really hoping this is the case.

Thanks again,

Bob I.

Originally Posted by NUMB-LOCK

Cub came with the power 46 mounted and 6 mm prop adapter in the kit. The Power 10 included a 5 mm prop adapter as well. I'll bring them to my LHS tomorrow and hope they can shed some light...I've probably done something wrong...but when we flight checked it...it was set up correctly (on the Cub). I have seen other posts which have mentioned that their prop adapters just weren't made quite right. I'm really hoping this is the case.

Thanks again,

Bob I.

Hi Bob,

Both the E-Flite Mini Ultra Stick, and the E-Flite Mini Ultra Pulse come with E-Flite Park 450 motors.

Now here's the thing, they aren't really E-Flite Park 450 motors at all. The stand alone 450's have a 4mm motor shaft, and the "kit" version of the 450 comes with a 3.2mm motor shaft. In other words, in addition to the kit version not being of the same high quality as the stand alone 450, it doesn't even share the same parts.

Back in the old days, we would call this deceptive business practices. In todays world, it's just business as usual.

Chuck

Good to know...I honestly thought I had done something wrong.
I'm lucky that prop didn't hit anyone that day.

Thanks again,

Bob I.

Originally Posted by NUMB-LOCK

Good to know...I honestly thought I had done something wrong.
I'm lucky that prop didn't hit anyone that day.

Thanks again,

Bob I.

Hi Bob,

I'm not saying that's the same problem you're having. I was just alerting you to a particular case involving two E-Flite planes. It could very well be that either you installed it wrong, or they just included the wrong adapter with your plane. I use E-Flite motors and adapters exclusively, and have not had any problems so far (knock on wood... )

Chuck

This is not a reply but a question.

I note that this is a very old thread and find it very useful. However, my issue is how to tighten the cone after the cowl has been installed because the shaft also turns after tightening. Or is the adopter is the adapter squeezing the shaft well enough not to come loose when spinning. Thanks.

Originally Posted by AshleyP

This is not a reply but a question.

I note that this is a very old thread and find it very useful. However, my issue is how to tighten the cone after the cowl has been installed because the shaft also turns after tightening. Or is the adopter is the adapter squeezing the shaft well enough not to come loose when spinning. Thanks.

Hi Ashley,

Don't worry about the thread being old; it's here for beginners, so it'll be here a long time...

Now the thing about these collet adapters is that they work by friction, and yep, sometimes our application will make it rather difficult in letting us hang onto the motor while turning the spinner nut. This is easy to overcome when the motor is hanging out in the air, but rather a pain when it's recessed or behind a cowl.

However, 9 times out of 10, if the adapter is actually the right size, simply hanging onto the prop while tightening the spinner is all that it takes. The problem comes when we try to use cheap spinners, or have a motor that the shaft size is not exactly what it's supposed to be. It only takes a few thousandths of an inch undersize on a motor shaft to make it darn near impossible to get the spinner to tighten securely around the shaft.

I don't know of any 'tricks' to remedy this situation. Some guys use metal shim stock to make the shaft a little bigger in diameter. I don't trust remedies like this, however. But that's just me and my way of thinking.

If I ever do run into a fix for sloppy adapters on undersized shafts, I'll be sure to post it here on my Blog page, though!

Take care,

Chuck