Prop balancing - How to?
 

Hi,

I just received a couple of wood props for my new plane. I'll be using a 10x6 for brake-in, so I put it on the Dubro balancer last night. Found out it was way out of balance, so I started grinding the tip with a hobby knife. It took some time to get it to balance, and I am left with a prop that is shorter on one side, by about 3/8" Seem a lot to me.

Could youtell me what is the right way to balance a wood prop. If you have to remove material, where do you take some off?

Thank you,
Remy

RE: Prop balancing - How to?
 

First, throw that prop away.

Rather than shorten one side, it is better to sand a little off the back of the prop. Or, you can add some clear nail polish (Varnish, polyurethane, etc) to the back side of the light blade.

Or, you can do a combination of both.

RE: Prop balancing - How to?
 

Yes, toss that prop immediately. I don't remove material from my props. I use a varnish for my giant scale props and clear nail polish for the smaller stuff. Dab a little on the end of the light blade and smooth out. Let it dry (a couple minutes) and rebalance. Repeat if necessary.

RE: Prop balancing - How to?
 

Yeah don't change the shape of your props. I add clear nail polish to the light side, and make sure it's dry before I re-balance.

RE: Prop balancing - How to?
 

I have found some of my Master Airscrew props were unbalanced around the hub, so I have have removed some of the hub with a dremel.

RE: Prop balancing - How to?
 

Many thanks to all for the replies. I kind of knew what I was doing was wrong. I'm glad I have spare props.

RE: Prop balancing - How to?
 

FYI wooden props break very easily. If you are in the learning process and think you might be having a few prop strikes, etc. then you might want to invest in some the nylon or glass-filled props. Master Airscrew can take a beating, APC is better performing, not quite as tough. Wooden props are great, but hit the ground and they're done.

RE: Prop balancing - How to?
 

Something is wrong with your balancing method / technique / equipment if you had to remove 3/8" from any 10x6 prop. Having flown AMA combat for over 20 years and prepping my share of props, there is nothing wrong with removing material from one extreme end. Usually it takes less than a 1/8" to get the job done.
If you are talking about balancing an APC or Scimitar Series wood prop with the pointed tips, then you don't want to alter the shape. I've used sandpaper to balance and re-pitch APCs. It isn't brain surgery, check your results at full throttle while you hold the model. If it runs smooth, then that's all you need.

RE: Prop balancing - How to?
 

My thought is that while taking wood off the end will "balance" the prop, this practice throws the prop way out of dynamic balance.

RE: Prop balancing - How to?
 

Shortening one blade has worked for hundreds of guys who have flown thousands of matches on 120 mph planes that operate in the 18-21,000 rpm range where balance is critical. When I was first shown the simple technique I thought it looked barbaric, but it was already proven to work by my mentors. Those days of buying Top Flite wood pylon props by the bag and reworking them are over. APC props don't need much attention at all in the diameters I use.
Most any technique has it's drawbacks and advantages.....you might even find that some engines that are either over or under balanced run smoother with the heavy blade phased a certain way [instead of using a balanced prop]. The bottom line is reaching an acceptable level of smoothness and there are several ways to get there that work.
I think 3/8" is excessive to hack off of one blade of a 10 inch prop...something is wrong with the balancing set up.

RE: Prop balancing - How to?
 

How much did you take off [&:]

Next time add to the opposite side insted much safer...

Steven