Thread Tools
Old Jun 01, 2007, 11:06 PM
DaveInLA is online now
Find More Posts by DaveInLA
Registered User
Discussion

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?
Sign up now
to remove ads between posts
Old Jun 01, 2007, 11:19 PM
WhatHappened is offline
Find More Posts by WhatHappened
Registered User
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.
Old Jun 02, 2007, 12:20 AM
fly_boy99 is offline
Find More Posts by fly_boy99
Flying motor mount master
fly_boy99's Avatar
Start with a prop balancer.
Old Jun 02, 2007, 12:38 AM
DaveInLA is online now
Find More Posts by DaveInLA
Registered User
Quote:
Originally Posted by fly_boy99
Start with a prop balancer.
Did you read my entire post?
Old Jun 02, 2007, 12:57 AM
fly_boy99 is offline
Find More Posts by fly_boy99
Flying motor mount master
fly_boy99's Avatar
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.
Old Jun 02, 2007, 02:14 AM
CSI is offline
CSI
Find More Posts by CSI
CSI
I promise, just ONE more order
CSI's Avatar
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
RCG Plus Member
Old Jun 02, 2007, 11:07 AM
kepople is offline
Find More Posts by kepople
Real Men Fly Pink Planes...
kepople's Avatar
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
Old Jun 02, 2007, 04:57 PM
Chuck is offline
Find More Posts by Chuck
Balsa to the Wall
Chuck's Avatar
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
Old Oct 30, 2010, 05:27 PM
crobar is offline
Find More Posts by crobar
Registered User
crobar's Avatar
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?
Old Oct 30, 2010, 06:20 PM
Bruce Abbott is offline
Find More Posts by Bruce Abbott
We want... Information!
Bruce Abbott's Avatar
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.
Old Oct 30, 2010, 06:33 PM
Gamma is offline
Find More Posts by Gamma
Gamma
Gamma's Avatar
Check out the DuBro video on prop balancing.

Gamma
Old Oct 30, 2010, 07:04 PM
RobC(UK) is offline
Find More Posts by RobC(UK)
**** 37130 ****
RobC(UK)'s Avatar
If you use solvent based spray varnish you will need to re-balance one the varnish has dried and all the solvent has evaporated!
Old Oct 31, 2010, 06:36 PM
crobar is offline
Find More Posts by crobar
Registered User
crobar's Avatar
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?
Old Mar 31, 2011, 08:43 PM
grosbeak is offline
Find More Posts by grosbeak
Illegitimi non carborundum
grosbeak's Avatar
Quote:
Originally Posted by Gamma View Post
Check out the DuBro video on prop balancing.

Gamma
DuBro video on prop balancing.
Old Jul 10, 2011, 06:40 PM
lbrinson is offline
Find More Posts by lbrinson
Learning is worth the effort
Here is a good link on balancing props and hubs.

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


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion How to balance cells when building battery pack? ch2s Batteries and Chargers 1 Jun 27, 2007 11:26 AM
Question How to balance a prop? Jimmy Hoffa Electric Plane Talk 15 Dec 17, 2005 07:06 AM
How to select a prop when moving from brushed To BL eran_k Power Systems 2 Jul 14, 2005 01:36 AM
How to balance a prop (??!) headless Power Systems 9 May 18, 2004 11:41 PM
How Hot should 500AR's get when Peak Charged? Joe Elston Electric Plane Talk 5 Jun 24, 2001 07:05 AM