Prop balancing

ahrma_581 wrote:
This only good for checking the blades balance, if the hub is grossly out to one side or the other at the center, it won't show up. And it only works on smaller props, but has worked ok for my purposes.

I don't understand this statement. What you've described works basically on the same principle as any prop balancer. As far as the balancer jig is concerned, ANY imbalance is the same as ANY OTHER imbalance - surely? Am I missing something here? Whilst my balancer jig looks different, it does its job the same way, and I've been using it to balance props - the whole prop. I need to know if I'm doing it wrong.

Sometimes the bolt hole isn't completely central or perpendicular
to the Hub.

To answer Jims question my fave is the Dubro balancer which
Although not cheap works brilliantly on 010 props up to
and no doubt beyond my 50cc's 23x8.
A man of your caLIBre will suss it out even before you
Remove it from it's packging

The DuBro is an excellent balancer. The method used was originally on the "High Point" balancer, which I believe has been extinct for years...possibly bought out, and improved upon, by DuBro. I don't have one, but someday...

I use the Top Flite magnetic balancer. It will find a heavy blade and a heavy (off center) hub. For the hub, the blades will be horizontal, but one side of the hub will seek bottom.

There are three possible fixes for an off-center hub. First, you can clamp the prop and redrill it, then add a tubing shim for prop screw size; next you can fill the hole with epoxy and completely redrill; and finally you can discard it. Your choice.

Then there is dynamic balancing which is done with something like the Prather Prop Guage which is used to check pitch at various places, allowing you to match sides. Most of us don't go this far. perhaps we should.

George

I tried the hub balancing and ended up tossing a bunch cause I made them worse or ruined the prop all together. Now its just a blade balance with a magnetic suspension balancer and the proper length of masking tape wrapped over the leading edge till it balances.

Forgot to mention, when you have an off-center hub, make sure you check both sides. I have read reports of the hole being crooked.

Also, if you do any drilling make sure the prop is clamped. Don't try to drill it while holding it with your hand. Seldom works. Yup...I've tried it!

George