How balance a 3 blades propeller?

[BILL2]

Hello!

If you have a good method to balance a 3 blades propeller, I will be glad to know it! 
I'm able to balance my 2 blades prop but with 3 blades the problem is more difficult.

Many thanks for help!

Bill2

[LongEZDaveA]

I would suggest doing a static balance of the propellor alone first.  When you get that as close as you can, do a dynamic balance with everything you are going to run (add the spinner if you are going to use one).  Add any weight necessary to the flywheel during the dynamic balance.

[BILL2]

Hi Dave,

Could you explain how you would balance the prop static? I made a "hub" with a tip in order to find the balance point with all the blade horizontal, but I'm not convinced by the result: if i add 20 g on a blade the balance is the same... not efficient!

What is the method for a dynamic balance?

[BILL2]

Finally, I decided to go this solution: http://www.youtube.com/watch?v=ql0kcghl3UM

We will see during the run up if it is a good method!

[dorr]

I asked Catto about that video method.  Obviously we don't sand down parts of our planes.

He's concerned as follows:

“Well, would not recommend sanding off any of the blade, but the method is correct. You can do the opposite and use the clear coat to balance, but when doing so have to account for the carrier evaporating off. This is why I do not recommend people repaint…their own propeller, as you can see it does not take much to affect the balance. One extra coat of paint on one blade and it is out, enough that you would feel it.

And even more important is the reference point. Never use the 2.25" center hole!!  Always use the 6 bolt lug set to center up on.  Many times with many wood type propellers the hole reference between center hole and the actual mounting lug pattern can be off a few thou, enough to affect balance. The only one I would trust is a metal propeller to balance up on the center hole.

[BILL2]

Many thanks for explanations!