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Old 05-25-2011, 04:23 PM   #1 (permalink)
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Default Balancing problem

I have a trex 550 and never had problems balancing the blades but i bought a used trex 500 and it came with a balancer the 500 blades have a 3mm hole so i used this new balancer (see the picture) here is the problem if i put the blades on one way they are balanced if i swap sides one blade is alot heaver. what am i missing here. i followed Bob's balancing 101 video and these blades are perfect with each other, center of gravity right on, they look identical. anyone know whats wrong, i think the balacer is wacked but without the blades it is level? thanks for the help.
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Old 05-25-2011, 04:33 PM   #2 (permalink)
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Default Balancing Problem

did you check to see if the counter is level .
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Old 05-25-2011, 04:38 PM   #3 (permalink)
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Yes the counter is level, i moved to the island just to be sure but got the same result
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Old 05-25-2011, 05:03 PM   #4 (permalink)
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Did you check to see if the sesaw part of the balancer from center to center
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Old 05-25-2011, 05:36 PM   #5 (permalink)
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Yes the seasaw balances out with no blades on them. but it has to be somthing with this balancer. i have always used the Align balancer where you bolt the 2 blades together and teeder them on a shaft, that always worked fine but the one i have is a 4mm and these blades are 3mm. so you put the blades on this balancer and they are balanced, take the blades off and switch mounting sides, now they dont balance out. strange???
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Old 05-25-2011, 07:03 PM   #6 (permalink)
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what i'm saying check the distance from center to blade bolt and they should be the same if not if you swich the blades from one side to the other they would not be balanced
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Old 05-26-2011, 03:49 PM   #7 (permalink)
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Well that is the thing i said from the start these blades are identical, no difference in the blades at all. I'm not a total rookie i have checked the obvious things and i dont see it. it has to be this leveling tool. i took the blades to a friends house last night and he has a good scale, the blades weight the same. the balancer is wacked
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Old 05-30-2011, 10:27 PM   #8 (permalink)
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The center shaft in the balancer may be bent slightly.
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Old 06-02-2011, 04:27 PM   #9 (permalink)
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To be honest, these types of blade balancers are pretty much useless for a precise balancing job. The design of this seesaw is not a practical arrangement. In reality the blade mounts and the pivot point of the seesaw need to be in the same plane and should not be offset.
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Old 06-02-2011, 08:40 PM   #10 (permalink)
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Quote:
Originally Posted by thevirginian View Post
To be honest, these types of blade balancers are pretty much useless for a precise balancing job. The design of this seesaw is not a practical arrangement. In reality the blade mounts and the pivot point of the seesaw need to be in the same plane and should not be offset.
i agree.
i think the more accurate way is the align balancer and two cups.
always works.
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Old 06-08-2011, 12:19 AM   #11 (permalink)
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i agree.
i think the more accurate way is the align balancer and two cups.
always works.
Yes you are correct IMO. my Align works much better.
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Old 06-17-2011, 12:37 PM   #12 (permalink)
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Yes you are correct IMO. my Align works much better.
use the helimax blades balancer
its really good with these sizes
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Old 06-23-2011, 03:04 PM   #13 (permalink)
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I guess this style of balancer just does not work. a friend said he has a century balancer and it works great. so i found one, it looks well built. Check out the pictures, this think has a nut weight on the end to help you balance it and i can move the nut all the way out on one side and still move the balancer to any position i want and it will stay there. what is up with that? i lubed the bearings real good.

The same thing goes for putting my main blades for my trex 500, i can still move the blades and get them to stay where ever i want. Thats not balancing thats
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Old 07-05-2011, 05:45 AM   #14 (permalink)
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i can move the nut all the way out on one side and still move the balancer to any position i want and it will stay there. what is up with that? i
Then the bearings are no good.

High quality scales use a "knife edge" fulcrum instead of bearings. It's perhaps the best way of ensuring a pivot that won't bind, as long as the knife edges aren't damaged by overloading or shock.

I have a Helimax balancer. It uses bearings. But the pivots are independent of each other. To work accurately, the pivot bearings have to be precisely parallel. So I glued the pivot supports to a piece of Plexiglass. That solved most of the problem, but the balance is still not perfectly accurate, and I have to double-check to see if there's a problem with one blade being heavier than the other.

Also, cast plastic isn't nearly as accurate to manufacture as something milled. But there's that cost factor to consider, too.

All that said, I get good results with the Helimax. According to my Skookum SK-720, my vibration levels are very, very low.

You might look at possibly replacing the bearings in your balancer. Maybe get a set of precision ceramic bearings?

The only other way would be to make a set of knife-edge fulcrums.
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Old 07-05-2011, 05:47 AM   #15 (permalink)
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BTW, I like the Helimax balancer because it allows me to have the CG's of each blade matched prior to balancing one blade against the other. Getting the CG's of the main rotor blades to match is a critical step in the balancing process.
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