skyhawk172n

My Feedback: (3)

I'm sure this has been covered before, but my search turned up no real info, and who better to ask than a bunch of precision flyers! I would like some detailed info on balancing "small" props(10 to 16 inch). I've been flying for better than 20 years and have always balanced them to some degree, and want to get it done right. Mostly, I use APC's or wood.
Thanks for all answers,
Roy

ooooo

check this link
http://www.rcuniverse.com/forum/m_25...tm.htm#2584856

Here's what I do....
APC Props
1 Leave the edges sharp....I like my finger carrots sliced evenly
2 Put prop in balancer....heavy side will drop.
3 Spray bomb paint the lighter tip with red paint......makes it a bit more visible and gives a realistic effect when chopping your fingers
4 You may want to balance your spinner also...there is a thread here that tells you exactly how to do it.

Wooden Props
1 Will still do a number on your fingers...not as good as APC
2 Put prop on balancer....heavy side will drop
3 Spray bomb varnish on lighter side...let dry and rebalance until the prop is balanced.
4 You can also use a mixture of 5 min epoxy thinned down with rubbing alcohol and paint this onto the light side with a brush.
5 You can also use white paint on the lighter side until balanced.

One thing to remember though...some guys may differ here......
Apply paint, varnish or epoxy thinly to the front of the prop blade near the tip.... It changes the shape to the back of the blade slightly and since the blade is an airfoil basically, it will swirl the prop wash/disturbance over the wings and stab. Hmmmm...dunno if I got that out correct.
Again...some guys prefer to sand the heavy part of the prop blade when balancing. To me..that weakens the prop.
It's your choice basically.....what ever turns your crank... er...prop?
Cheers.

checksix

My Feedback: (4)

For APC props, instead of sanding or painting, just jam some bits of lead into the hollow ring on the back of the hub. When you've got the prop balanced, put on a drop of CA to secure the lead.
--Derek

Neo02

If it's not heavily unbalanced, a small strip of scotch tape on the back of the prop will help. That's how I do mine, from small electric to big pattern props.

Regards,
-Fabrizio

ooooo

WHAT sounds like a fix for balancing car wheels...

ooooo

If it's not heavily unbalanced I'd leave it....but if you use scotch tape...what happens when you clean it? The prop does pick up dirt, dead bugs blood, oil, grass stains etc. The tape will become shredded, lifted at the edges, change the shape of the prop foil at the back and create turbulence over the control/flying surfaces. IMHO the prop would have worst tendencies than before when it was unbalanced. Dirt on the prop also contributes to a prop being unbalanced and should be cleaned after each day of flight.
I'm not trying to say putting tape is wrong, if it works for you then fine.
I'm just pointing out that when cleaning the prop the tape will eventually lift and deteriorate...then you have to remove the prop and rebalance again.

skyhawk172n

My Feedback: (3)

Sorry for starting a thread then leaving it for 2 days; had to leave unexpectedly. I appreciate the input, and will read the attachments. Got in 4 flights on the Conquest VI and 2 on th Pizazz this wknd Just haven't got the YS91 tuned out just right yet.. Darned thing just won't run when the hydrocarbon supply is empty.
Thanks, everyone
Roy

jamesjoneill

I do it by sanding back the heavier blade, and have never had any structural issues. As for altering the section, it won't be any worse than painting the light blade!

When it is balanced, however you do it, try turning it through 90 degrees about the length of the prop. If it then appears to be slightly out of balance it is due to the hub being out of balance. The side of the hub that is uppermost when it is out of balance is the one that is heavy so sand that side back. You might be surprised how much out of balance the hub is. Again, I have never had any issues with prop strength by removing material like this.

Also, if possible, try balancing the spinner. Most will be out of balance by at least as much as the prop was, it can be balanced byt drilling small holes as necessary in the backplate.

blw

My Feedback: (3)

Good point on drilling out backplates, but I'm getting ready to switch over everything to aluminum ones instead of plastic. I always try to cross balance the backplate heavy side to the prop light side first. Then, I start sanding the prop. I then mark the prop and backplate so they match sides if I have to remove them.

I've tried paint, Top Flight self stick sheets, and sanding. Sanding seems to work best...but I hate the way my APC props look. I've been thinking about lightly spraying the props black with white tips and see if this is durable with tail draggers.

ooooo

Ok Ok....since there is so much interest in balancing spinners....here ya go... the best I've seen

http://www.rcuniverse.com/forum/m_11...tm.htm#1115188

Enjoy.

skyhawk172n

My Feedback: (3)

That is some good info on spinner balancing. I had come across it recently, and saved it. My questions are about where to sand, drill or weight a prop that remains horizontal, but will not stay vertical. Some have talked about grinding on the hub, but I'm not clear whether to grind on the front or back. I seem to remember from sonewhere that this is a front to back balance problem, not a spanwise problem. Anybody got the good info about this part?
Thanks,
Roy

jamesjoneill

You are right it is not a spanwise issue, it is the hub. It is what I was trying, perhaps rather un-eloquently to describe earlier. You need to sand the side of the hub, not the front or rear faces of it. If it will not stand vertical then the side of the hub that is falling to the underside is the heavy side so sand this away. It works best with a block sander - sand it flat until it does not rotate any more.

James

RichD

the folks over at Down on the Deck dot com (guess they are still having issues with RCU as we STILL cant make direct links to them) put together a great [link=http://66.219.108.118/don3.wmv]video[/link] on how to properly balance a prop. It is a larger prop though, but I guess the theory is the same for smaller props.

skyhawk172n

My Feedback: (3)

James and RichD,

Perfect!!! Both of you have hit the bullseye with your posts. I appreciate your help in answering the questions.
Thanks again, guys,
Roy

blw

My Feedback: (3)

good tip on the hub