[stardustertoo]

When I balance them I remove the material from the curved airfoil face, not the flat section so the pitch doesn't change

Do NOT do it like this. You are ruining the efficiency of that propeller. A prop, in reality is nothing more than 2 small wingsm spinning around on the front of the plane. It is that airfoil shape on the front of the prop that does the work........NOT simply the back of the prop "shoving" the air. Everyone knows how important the airfoil shape of the wing is, and we don't randomly sand areas to a different shape......why do the same on a prop??? Furthermore, you are not affecting the pitch by sanding the back side of the prop. The pitch is set in the blades by the amount of twist from root to tip, right from the time the prop is manufactured. I bet the small amount of sanding needed to balance will change the pitch by 0.01" at most, in other words, negligible. By screwing with the airfoil on the front you are doing WAY more damage than the amount of "pitch change" when sanding the back.

When I balance a prop, I usually start by removing the flashing from the molds, and then lightly sand the back of the heavy blade until close. I sometimes will give the tips a light coat of some "safety" color too and I can fine tune the balance using the paint. As for the hub, I have never worried about that. Right until I got my first gasser, I had never run a prop bigger than 14", so there is no need on props that small.

An interesting idea regarding painting the tips. If each tip is painted a different amount, the difference will cause a stroboscopic effect when spinning, enhancing visibility. What I mean by this, is on the light blade, do the stripe from the tip inwards 1/2 inch, and the heavy blade, do from the tip in 1 inch. That 1/2 difference will "flash" when spinning. It does work better at low RPM's, but still works a bit even at high RPM.

[OLD PRAIRIE RED NECK]

Originally Posted by flynte

For awhile I wasn't sure how to balance a prop hub untill I came across this vid which helped.

http://www.redwingrc.com/video/propvid.htm


flynte

The link didn't work for me. But I am interested...

[OLD PRAIRIE RED NECK]

Originally Posted by Frank Klenk

Don't you guys balance the hub?

Please explain Frank. The last time I checked the hubs were not seperate from the blades so not sure how to balance them before the blades.

My feeling is that when done balancing, if the prop stops randomly the whole thing as a unit is in balance.

Or perhaps you are differentiating between lateral and longitudinal balance?

[Guest]

Try this one:

You Tube

You Tube

[JKovats]

I balance my props as well as I can. I usually remove the flashing etc and give the edges a sanding with some wet paper. I always paint the tips ond often paint the whole prop a colour to go with the plane. I usually water sand my colours and get the balance close and then use clear coat on the tips etc to do the finalising.

Here is my comment. It's really a matter of personal choice how you do it, but it is good practise to do it. It's just like radios, servos and everything else. Personal choice. I have yet to be able to identify a plane flying by as to what kind of equipment it is using. Nor have I been able to identify whether a prop was balanced or not balanced by sanding, scraping, changing airfoils or adding ca, clear or whatever, scotch tape??? It's personal choice, A gram here and a gram there won't make a ton of difference if you do regular maintenance and inspections. Sometimes at dusk when I land I got so much blood and guts from the bugs, on the prop, I figure it is either way out of balance or exactly self balanced. Who knows anyway.

[OLD PRAIRIE RED NECK]

Thanks Brent, that clears it up! Good video! Yes I do that except that I am not in the habit of adding wieght, I just do it all with sand paper like he explained. I hadn't heard the "balance the hub" expression before. Sorry guys!

[flynte]

Much better vid Brent, Thanks! Does show ideas how to get to the end result, nice.

flynte

PS.. OPRN..sorry the link didn't work for you, but this is a MUCH better vid

[pipercub17]

Bet you are happy I showed you that one hey what tree
I always balance the hub and then use clear coat on the blades
With the big gas engines balancing the hub makes a huge difference

[william storzuk]

VBR=vess-balance-ring with Du-bro balancer, where you can balance the prop,back plate,bolts and spinner all at the same time. A valuable tool to have!!!!!

[OLD PRAIRIE RED NECK]

A chap told me once that a single cylinder engine cannot be perfectly balanced, they shake & vibrate anyway so he didn't believe in prop balancing!

While that may be true, I like others here like to do as much as can to make things better. Even if sometimes it's hard to tell the difference!