My question relates to using APC or APC style props with a prop saver. The APC props come with a set of plastic rings or spacers. I need to use one of these when I attach the prop to a motor using a prop saver. I found that the plastic rings can fall out when the prop is dislodged.

So my question is are we supposed to glue the spacer ring into the prop so it doesn't fall out? Seems like an obvious thing but I found in playing with the spacers, the fit is kind of sloppy. So if I glue the spacer in, it may not be dead center and the prop will be off balance.

The application is a flying wing so the prop usually gets knocked off the prop saver when I skid land.

I don't glue them in, in case I need to re-use them, but since every prop comes with the adapters I don't see a problem with gluing them in.

As far as sloppy fits go, I have only used APC brand props and the fit has always been tight. But if the prop comes on and off constantly, I could see it loosing up.

yeah you can run a drop of tiny spot of CA in to fix the ring in place. The rings should be a reasonably neat fit, if they are rattling about then something is wrong, but gluing it in wont make the issue any worse.

maybe the problem with the loose rings is because you are using cheap APC knock off props?.. Buy the real thing and you wont have a problem.

I never found it necessary to glue the spacer in. Once the prop is mounted on the motor shaft, it can't go anywhere. Also make sure your using the spacer on the backside of the prop which is the precision molded hole in the props center. The backside is the side with no lettering or numbers.

I use only genuine APC props, and I've once had a spacer loose enough that it could fall out. But the rest of the time, like others have said, the spacer is quite a snug, or tight, fit.

Not knowing what affect cyano will have on the plastic, I'd probably try some other kind of glue, such as white wood glue. I know it probably won't bond to the plastic, but it'll grip enough the stop the spacer falling out.

CA has no noticeable effect on the APC nylon, it doesnt actually stick to it very well but good enough to lock the ring in place. I'm only talking about a bit of CA the size on a pin head here.....
I've used it to fix in the rings on a few of my props just to prevent the ring being left behind on the shaft when I remove a prop, as can happen in the ring and shaft are a very snug fit.

thanks guys. This was with a Popwing kit from Nitroplanes so it was probably a knock-off prop. I have ordered a real APC prop. I also have some GWS props and they fit on the prop saver without adpater rings.

One other question. Having lost the spacer ring for the prop I have, does anyone sell spare rings? I didnt see anything on various wensites.

Originally Posted by stemo99

Once the prop is mounted on the motor shaft, it can't go anywhere.

It can fall out when using a prop saver because the prop is free to get knocked off the prop saver.

Originally Posted by stemo99

Also make sure your using the spacer on the backside of the prop which is the precision molded hole in the props center. The backside is the side with no lettering or numbers.

I have to use the front side. In a Popwing, the motor faces backwards and my understanding is that the numbered side has to face forward.

I always glue mine - tiny amount of thin CA and a touch of accelerator and done.

Mike

Originally Posted by pda4you

I always glue mine - tiny amount of thin CA and a touch of accelerator and done.

Mike

Same here.

mw

Me too. I glue 'em and then sit the prop hub on 240 grit and just revolve it a bit to remove any burrs. Most props I buy come with a selection of adaptors so I always have plenty of spares.

Originally Posted by rhodesengr

One other question. Having lost the spacer ring for the prop I have, does anyone sell spare rings? I didnt see anything on various wensites.

Hyperion makes various sized aluminum rings that fit the APC props. Pricy but, you get 4 - 5 in a pack for around $ 3.00. Thin electric and slo fly take different size rings, so you have to watch and make sure you are getting the proper rings for your type of prop, and come with either smooth or threaded internals so you can screw the prop onto a threaded shaft if you want or just have a slip fit.

Thought Max Products had them but couldn't find 'em with a quick search on their site.

I have a box... it has all the shaft spacers that come with either spinners or props. There must be 400 individual spacers in there.

Some fit well, some fit loosely.
Just keep 'em all when you buy stuff. You will find the one that fits the hub and shaft well the day you need one.

Originally Posted by rhodesengr

... I have to use the front side. In a Popwing, the motor faces backwards and my understanding is that the numbered side has to face forward.

You're right about the numbers having to face forward, wherever the motor's mounted.

But with APC props, the hole at the front is moulded and is not necessarily central, whereas the hole at the rear has been reamed to be central and to be a snug fit for the adapter. I've never used a prop saver, but I can see it might be a problem with a reverse-mounted APC prop. On my models with rear-mounted motors I've simply attached the prop on a regular prop adapter with a nut. I've knocked the motor off its mount once while landing, but never damaged a prop yet.

Originally Posted by rhodesengr

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I have ordered a real APC prop. I also have some GWS props and they fit on the prop saver without adpater rings.
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Go for the GWS props. they are usually very precise and efficent
(with correct RPM). APC SF props ... britle, heavy with production
deviations. I use "Haoye" (china version of APC) instead they are
less britle and cheaper (proper balancing is a must).