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Old Jun 01, 2007, 10:06 PM
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How to "balance" a prop when it's unbalanced?

Okay, so it's pretty clear how you determine whether a propeller is balanced or not. But after you've made that determination, then what? I believe the insert tells you not to alter the prop in any way, but after you've spent $4 on something that's a little unbalanced, what's the next step? Do you trim a little off the heavier side? Add a little paint? What?
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Old Jun 01, 2007, 10:19 PM
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Bergen, NJ
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I think I read someone about using nail polish. Paint will probably work also. I have no tried either of these because I have never balanced a prop. Sanding a little of of the propeller might work too but is probably one of the harder techniques.
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Old Jun 01, 2007, 11:20 PM
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Start with a prop balancer.
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Old Jun 01, 2007, 11:38 PM
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Quote:
Originally Posted by fly_boy99
Start with a prop balancer.
Did you read my entire post?
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Old Jun 01, 2007, 11:57 PM
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If you don't know where its unbalanced then you cannot rectify the situation.

I have a TopFlight magnetic prop balancer. I have on occasion sanded down the heavier side of a prop, I have added small pieces of tape to the lighter side, then you can also add some light CA with microfillers to the lighter side to accomplish the task.
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Old Jun 02, 2007, 01:14 AM
CSI
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Del Rio Intl, Texas, United States
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I have tried many different methods to balance my props over the years...some worked well, others not so well. Since going to an all electric fleet I have found the perfect method for me. I keep a can of Krylon Clear spray paint on hand. I hold the prop by the heavy side and spray a very light mist towards the outer 3rd of the light blade. I recheck the balance, then repeat until it balances. Some props take 2-3 sprays, some just one. No tape to come off, doesn't show, doesn't alter the prop dimensions.
On a few props it is mostly the hub causing the balance problems. This shows up pretty quick after a spray or two. In these cases I either spray some clear on the light side of the hub, or I use some thin CA and accelerator directly on the hub.
Hope this helps give you some ideas.
Ken
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Old Jun 02, 2007, 10:07 AM
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United States, TX, Rockwall
Joined Jun 2001
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My method cannot be more simple, but I cannot take credit for it. I use the Great Planes finger tip prop balancer. Turn off the ceiling fans and check the prop. I flip it over and make sure the same side is still heavy and that I did not breath on it while checking.

Now, depending on how bad it is, I will use the shiny, scotch mulitpurpose tape (or packing tape) and put it on the back side. After a while you get a feel for where to put it, how far out on the blade depending on how off the prop is.
Just make sure you have no wrinkles. I have done this on up to 22" props with no problems and it does not affect the efficieny.

DONT file, or do anything that will change the shape of the prop tips where most of the thrust comes from. And as long as the tape is not over hanging the edges you are not going to affect the prop.

Simple, fast, and it works...

Kirby
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Old Jun 02, 2007, 03:57 PM
Balsa to the Wall
Deep in the East Texas Piney Woods
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I agree with CSI, only I use a spray can of clear polyurethane for the blades. If the hole is off center enough to keep from balancing, take it back to the store.


Chuck
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Old Oct 30, 2010, 04:27 PM
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Quote:
Originally Posted by CSI View Post
I have tried many different methods to balance my props over the years...some worked well, others not so well. Since going to an all electric fleet I have found the perfect method for me. I keep a can of Krylon Clear spray paint on hand. I hold the prop by the heavy side and spray a very light mist towards the outer 3rd of the light blade. I recheck the balance, then repeat until it balances. Some props take 2-3 sprays, some just one. No tape to come off, doesn't show, doesn't alter the prop dimensions.
On a few props it is mostly the hub causing the balance problems. This shows up pretty quick after a spray or two. In these cases I either spray some clear on the light side of the hub, or I use some thin CA and accelerator directly on
the hub.
Hope this helps give you some ideas.
Ken
How can you tell when the hub is the out of balance area?
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Old Oct 30, 2010, 05:20 PM
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Hastings, New Zealand
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When one blade is heavier it will hang down on the prop balancer. After balancing the blades, the prop should stop at a random position. If it always stops in the same position but with the blades horizontal, then the hub may be heavier on one side (perhaps due to the hole being off-center).

It takes a lot more weight to make a significant difference at the hub. If the imbalance is slight then I wouldn't worry about it.
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Old Oct 30, 2010, 05:33 PM
Gamma
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Newbury Park, CA
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Check out the DuBro video on prop balancing.

Gamma
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Old Oct 30, 2010, 06:04 PM
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If you use solvent based spray varnish you will need to re-balance one the varnish has dried and all the solvent has evaporated!
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Old Oct 31, 2010, 05:36 PM
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I am having to use 3 layers of scotch tape on the end of these black props to get them even close to balancing. I use a Dubro balancer and I have verified the balancer with some APC props I have previously balanced, so it is not the balancer. I don't notice anything obvious in looking at the props. I wonder if there is a point where you toss them in the trash for fear that something major is out of whack?
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Old Mar 31, 2011, 07:43 PM
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Quote:
Originally Posted by Gamma View Post
Check out the DuBro video on prop balancing.

Gamma
DuBro video on prop balancing.
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Old Jul 10, 2011, 05:40 PM
Learning is worth the effort
United States, MI, Grand Rapids
Joined Jan 2009
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Here is a good link on balancing props and hubs.

http://www.horizonhobby.com/Articles...ArticleID=2256
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