Glow Engines Discuss RC glow engines

Spinner Balance ?

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Old 03-23-2014, 03:43 PM
  #1
Granpooba
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Default Spinner Balance ?

Have been balancing props it seems like forever. Was even just reading a posted thread on how folks balance their props and their favorite equipment to accomplish the balancing. But then an old question came to mind, which probably does not make much difference but wondering if it could.

Say that you have a perfectly balanced prop, but you have to trim the spinner for proper fit. Keep in mind that I am talking about a plastic spinner.
You trim the spinner as perfectly as you can, but does the trimming affect the balance in any way, shape or form, if you do not get a perfect trim ?

A spinner cut for your engine and prop, say from Tru Turn could be close to being in perfect balance. But when you trim a plastic spinner yourself, ever wonder about the balance ?

Mind you, I have never run into a balance problem. But would like to hear different opinions on this subject.

Thanks folks for your contribution on this subject.
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Old 03-23-2014, 03:48 PM
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Have had too many plastic spinners come apart after several hours of use. Now only use tru-turn spinners. Be safe. A plastic spinner comming apart will throw plastic bits a long way.
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Old 03-24-2014, 04:48 AM
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Trimming a plastic spinner will affect the balance but it's gonna take a reasonable size chunk to change the balance. Ideally you want to balance the prop and spinner once they fit together properly even if the amount of material is trivial.

Last edited by 1QwkSport2.5r; 03-24-2014 at 05:00 PM. Reason: Fixed typos, changed wording some.
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Old 03-24-2014, 04:20 PM
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Have to agree with both of your posts.

Presently wrapping up a Hangar 9 Christen Eagle II and not happy with balance on 16 x 8 Pro Zinger prop and Du-Bro spinner, thus considering switching over to a 15 x7 (3) blade Master Airscrew prop and a Tru Turn spinner. Saito 1.25 is powering this model.
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Old 03-24-2014, 04:46 PM
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I use the plastic spinners with aluminum bases without any problems on 2 and 4 strokes. I balance it all together as a unit. Once the prop, spinner, and base are balanced I etch a line to line everything up. I mostly use all APCs and etch an x on the side next to the other marks. This way it all assembles the same way every time. I've had an unbalanced prop do firewall/engine mount damage.
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Old 03-24-2014, 05:10 PM
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I have problems with fuel bubbling if my props aren't balanced well enough. I however do not use spinners, only spinner nuts which I trust to run true and be balanced well. I haven't bothered trying to balance my spinner nuts as my balancer doesn't fancy them. On engines I encounter vibration problems with I will run with and without the spinner nut to determine the culprit.

I exclusively use APC props and find they are often poorly balanced both at the blades and the hub. I always encourage balancing of the blades and hub, especially if using spinners/spinner nuts.
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Old 03-25-2014, 08:28 AM
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I had to carve out the openings in a Dubro spinner to accommodate APC props on my Big Stik 40. I balanced the prop on the Top Flite balancer, but this device cannot balance spinners unless there is a hold in the front of the spinner. The plan flew fine for a couple of flights, and I did not notice any excess vibration. Just to be safe, though, I wound up going with a Dubro Spinner Prop Nut. This little spinner bolts right onto the crankshaft, and can be used with the same starter cone used for larger props. This nut might not looked pretty with and engine cowl, but it looks good on the Big Stik.
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Old 03-25-2014, 01:18 PM
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Quote:
Originally Posted by N410DC View Post
I had to carve out the openings in a Dubro spinner to accommodate APC props on my Big Stik 40. I balanced the prop on the Top Flite balancer, but this device cannot balance spinners unless there is a hold in the front of the spinner. The plan flew fine for a couple of flights, and I did not notice any excess vibration. Just to be safe, though, I wound up going with a Dubro Spinner Prop Nut. This little spinner bolts right onto the crankshaft, and can be used with the same starter cone used for larger props. This nut might not looked pretty with and engine cowl, but it looks good on the Big Stik.
I also have used the same Dubro Spinner Prop Nut, mounted on a Saito .91 and have had no problems to date. Model and engine are now about 15 years old.
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Old 03-25-2014, 03:26 PM
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You can screw a spinner on with the Dubro balancer.

I had a 3 bladed prop that was very unbalanced, and it vibrated 3 engine mount screws out, and that chewed up the threads of the blind nuts. Most unbalanced props won't do that much harm though.

Last edited by blw; 03-25-2014 at 03:29 PM.
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Old 03-29-2014, 11:40 AM
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Quote:
Originally Posted by Granpooba View Post
Have to agree with both of your posts.

Presently wrapping up a Hangar 9 Christen Eagle II and not happy with balance on 16 x 8 Pro Zinger prop and Du-Bro spinner, thus considering switching over to a 15 x7 (3) blade Master Airscrew prop and a Tru Turn spinner. Saito 1.25 is powering this model.
Well, I chose to bite the bullet ! Just ordered a Tru Turn 3 blade spinner. To make sure that everything is correct I am having it cut for the Master Airscrew 3 blade prop and having the back plate drilled to fit my Saito 125 .
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