prop balancing

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prop balancing

Postby 97corvette » Sat Mar 03, 2007 2:56 pm

i acquired a Du Bro prop balancer but no instructions. using logic, i am able to get some results balancing a prop. i would like to hear thoughts on the proper use of a prop balancer and maybe some inside techniques to get the best balance. also, how far out of balance does a prop have to be before it is too far out? Can an out of balance prop cause vibrations that can cause the fuel to "foam" and lean the engine on a control line plane?
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Postby gossie » Sun Mar 04, 2007 2:45 am

I believe the finer the balance on any prop. is the way to go.
If it's 'out of balance', then it's out of balance, period.

I have heard/read in the past of people 'balancing' engines with big heavy crank webs etc. and using an out of balance prop. to try and address the situation.
My way to fix that would be attack the inside of the engine and put a properly balanced prop. on it after it gets 'the fix'.

You have a great balancer, so use it to get them as near perfect as possible. Good luck. :)
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Postby Frank Klenk » Mon Mar 05, 2007 5:00 pm

97

The bigger the prop the more important it is to balance it properly. In my opinion all props regarless of size should be balanced. You have the right balancer so that's a good start.
1 place the prop horizontal in your balancer and balance it tip to tip. Some guys remove material (sanding) from the rear of the blade to accomplish this and that's what I do. Once your prop will sit in this position your half way there.
2 Now let's balance the hub ... turn the prop to the 2 and 8 oclock position and you'll notice that it will turn. If it turns c/w then the bottom of the hub is heavy. If it's a large prop I have glued a piece of velcro on the light side and carefully add ca. Spin it to 10 and 4 oclock and recheck. Keep checking it this way until your prop stays and 2 and 8 and 10 and 4. If it's a small prop then add ca directly to the hub. It takes a bit of practise but you'll be surprised how vibration free you can make an airframe.
And since a picture is worth a thousand words I have attached a link to show the procedure. Follow it and you'll get results. Have fun.
http://www.Monkey.com/don3.wmv

Regards ... Frank :)
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Postby chiefss » Sun Feb 10, 2013 3:45 pm

I'm getting so sick of this guy. Frank, do something.
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Postby Frank Klenk » Sun Feb 10, 2013 4:20 pm

What's wrong Bruce?
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Postby chiefss » Sun Feb 10, 2013 6:05 pm

Some guy from Saudi Arabia was posting all kinds of spam. Took up pages
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Postby SteveM » Sun Feb 10, 2013 6:14 pm

The location info from all those spam-bots is bogus and is not reliable. When I checked the IP address on several of them, they originated in the USA.
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Postby chiefss » Sun Feb 10, 2013 6:22 pm

Steve, can we put a "contract" out on them? That's a joke but it might not be a bad idea.
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Postby collie » Sat Mar 23, 2013 2:30 am

[quote="Frank Klenk"]97

The bigger the prop the more important it is to balance it properly. In my opinion all props regarless of size should be balanced. You have the right balancer so that's a good start.
1 place the prop horizontal in your balancer and balance it tip to tip. Some guys remove material (sanding) from the rear of the blade to accomplish this and that's what I do. Once your prop will sit in this position your half way there.
2 Now let's balance the hub ... turn the prop to the 2 and 8 oclock position and you'll notice that it will turn. If it turns c/w then the bottom of the hub is heavy. If it's a large prop I have glued a piece of velcro on the light side and carefully add ca. Spin it to 10 and 4 oclock and recheck. Keep checking it this way until your prop stays and 2 and 8 and 10 and 4. If it's a small prop then add ca directly to the hub. It takes a bit of practise but you'll be surprised how vibration free you can make an airframe.

Pylon racers tell me if u remove material from the BACK of the face you change the pitch???? and pitch is what is important!
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Postby Frank Klenk » Sun Mar 24, 2013 8:00 pm

Collie

The amount of material removed is minimal. Actually another method I use now is to just spray a bit of clear coat on the light blade. Works well and it doesn't take much.
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Balancing Props

Postby C/L Fan » Wed May 08, 2013 4:49 am

All I do is take a bit off the trailing edge(s). - Saves the old digits especially with a diesel. Another option is to sand one of the tips (2 blade only); but only do this if you know what you're doing!

DON'T drill the hub in an attempt to make one side lighter, props do break!
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