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Nov 16, 2012, 05:46 PM
Droner
SebastianJ's Avatar
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Mini-HowTo

Balancing small propellers


Lately I've seen quite a few q's here in the mini forum regarding how to proper balance small propellers, so I decided to start this thread to collect and share whatever ideas, tips and tricks are out there.

I'll do my best to keep this post updated with all relevant information.

Well balanced propellers will vastly improve the stability of your multirotor.
Balanced props will also minimize the risk of loosing or breaking a prop in flight.
Balanced props are less noisy.
Balanced props can potentially extend your flight time.


Here's how I do it -

You'll need the following:
  • Vernier calipers
  • A couple of magnets
  • A sewing needle
  • Scotch tape
  • Scissors
  • Patience

Place the magnets on the vernier as in the photos, hold the vernier by hand or make a fancy cardboard box holder for it.
Cut small strips of tape, different sizes makes it easier to hit the sweet spot without cutting all the time.
I use an Xacto knife or small screwdriver to apply the tape, and more importanltly: To peel it off again if I added too much.

The balancing itself is pretty obvious but here we go:
  • Place the prop on the needle
  • Place the needle between the magnets
  • If a blade drops, add a piece of tape to the opposite blade, keep adding or trimming the tape until the prop sits level.
  • Done, next prop.

Do's and dont's:
  • Keep the vernier as level as possible
  • Keep the magnets perfeclty aligned
  • Use a needle that fits the prop bore as tight as possible, you don't want the prop loose on the needle or rocking on a taper
  • Only the pointed end of the needle should have contact with a magnet
  • Adjust the magnet spacing so that the needle and prop is barely held in place, too much magnetic force will prevent the needle from spinning freely
  • I'll probably think of some more tomorrow when I'm no longer under the influence of alcohol

You can probably use round magnets, I haven't tried it.
You can probably use scissors or pliers or ?? to hold the magnets, I haven't tried it.
Some guys use other things for adding weight to the prop, some will sand the heavier prop blade with sandpaper (Zen masters of patience), I read that some use nail polish (I assume they have girlfriends ), I like to use tape.

Enjoy my crappy late night cellphone pics, and whatever you like to use - Have fun!


Sebastian
Last edited by SebastianJ; Nov 25, 2012 at 05:35 PM.
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Nov 16, 2012, 09:33 PM
Registered User
Quote:
Originally Posted by SebastianJ
Lately I've seen quite a few q's here in the mini forum regarding how to proper balance small propellers, so I decided to start this thread to collect and share whatever ideas, tips and tricks are out there.

I'll do my best to keep this post updated with all relevant information.

Well balanced propellers will vastly improve the stability of your multirotor.
Balanced props will also minimize the risk of loosing or breaking a prop in flight.
Balanced props are less noisy.
Balanced props can potentially prolong your flight time.


Here's how I do it -

You'll need the following:
  • Vernier calipers
  • A couple of magnets
  • A sewing needle
  • Scotch tape
  • Scissors
  • Patience

Place the magnets on the vernier as in the photos, hold the vernier by hand or make a fancy cardboard box holder for it.
Cut small strips of tape, different sizes makes it easier to hit the sweet spot without cutting all the time.
I use an Xacto knife or small screwdriver to apply the tape, and more importanltly: To peel it off again if I added too much.

The balancing itself is pretty obvious but here we go:
  • Place the prop on the needle
  • Place the needle between the magnets
  • If a blade drops, add a piece of tape to the opposite blade, keep adding or trimming the tape until the prop sits level.
  • Done, next prop.

Do's and dont's:
  • Keep the vernier as level as possible
  • Keep the magnets perfeclty aligned
  • Use a needle that fits the prop bore as tight as possible, you don't want the prop loose on the needle or rocking on a taper
  • Only the pointed end of the needle should have contact with a magnet
  • Adjust the magnet spacing so that the needle and prop is barely held in place, too much magnetic force will prevent the needle from spinning freely
  • I'll probably think of some more tomorrow when I'm no longer under the influence of alcohol

You can probably use round magnets, I haven't tried it.
You can probably use scissors or pliers or ?? to hold the magnets, I haven't tried it.
Some guys use other things for adding weight to the prop, some will sand the heavier prop blade with sandpaper (Zen masters of patience), I read that some use nail polish (I assume they have girlfriends ), I like to use tape.

Enjoy my crappy late night cellphone pics, and whatever you like to use - Have fun!


Sebastian
SebastinJ, I love those crappy late night cell phone pics. The message was loud and clear.

I was wondering how to go about balancing myself. I was going to ask, how do you know if you are dead center when you insert the needle, but at closer look at those crappy cell phone pictures, I see that the needle is fat enough that being dead center is not a problem.

Does pushing the needle all the way through the top of the prop cause problems when you put it on the quad or is it a problem of pushing the props down too far?

Good job on figuring out how to go about balancing these tiny props. I will finally get to use my RC boat prop balancer that I got originally to balance the bells of motors.

I would post some crappy cell phone pics but, I don't even have a cell phone.

https://static.rcgroups.net/forums/a...G?d=1353119539

https://static.rcgroups.net/forums/a...G?d=1353119539
Nov 16, 2012, 09:41 PM
RC Connectors dot com
glenn2626's Avatar
Excellent ideas!

I was going to do something similar but with hardened steel drill blanks and a complicated platform/stand/etc, but yours is much more simple & elegant (and just as effective, I suppose.)

Glenn
Nov 17, 2012, 08:52 AM
Tri-Quad-Hexa-Octo-copters!!
Thanks Sebastian
Added to the Props and Vibration and Balancing solutions sections in the Quadrocopter and Tricopter Info Mega Link Index
Cheers,
Jim
Last edited by jesolins; Nov 17, 2012 at 10:55 AM.
Nov 17, 2012, 09:08 AM
Registered User
midelic's Avatar
Original solution with caliper.I was looking for a balancing method for small propellers.I was thinking before using a paper clip, a plier, neodymium magnets and a vice.Your solution is better, caliper is also easy to level.You can use also a small vice holding the caliper on one side allowing the vernier slider for adjusting the length closer to the magnet.
Thanks, for share with us.
Last edited by midelic; Nov 17, 2012 at 09:14 AM.
Nov 17, 2012, 04:28 PM
Registered User
Are there similar tricks to "balance" bent props ?
My micro got loud on one arm/motor after a small crash.
No arms or frame are broken. Vibrations seem to come from the props.
What now without changing to a new set of props?
Nov 17, 2012, 05:13 PM
Finding Creative Ways To Crash
RCCrashTestDummy's Avatar
Sebastian,

Thank you for sharing. It looks like a great way to do this.

-Pat
Nov 17, 2012, 05:57 PM
Registered User
midelic's Avatar
I had the same.I bent back the blade and rotate, bent a little more till is coming in the same line with the opposite side.Now is like new.
I have 2 Walkera props bent and back and working fine.
Only broken props are completely dead.
Btw,balancing is required when the 2 blades of the props have different weight,in a bent props weight don't change.But I think you know that.

Quote:
Originally Posted by mystman
Are there similar tricks to "balance" bent props ?
My micro got loud on one arm/motor after a small crash.
No arms or frame are broken. Vibrations seem to come from the props.
What now without changing to a new set of props?


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