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Old Jan 06, 2006, 06:36 PM
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Question
DuBro Prop Balancer

Which is the correct way to attach the two balancing cones ?

Prop1 or Prop2, or doesn't it make a difference ?

OR

What balancer do you recommend? Don't tell me the one with magnets becuse they're too weak to work with the bigger props.

Thanks,
Ed
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Old Jan 06, 2006, 07:56 PM
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Both cones should go into the prop hub to ensure it is centralized (especially if, as it will be in most cases, the hub is bored larger than the shaft on the balancer!). Thin hubs are a problem though - you may need to add a nylon washer or two to effectively "thicken" the hub, so that the two cones don't meet in the middle!

My Top Flite magnetic works just fine even with heavy 13" APC E props!
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Old Jan 06, 2006, 08:13 PM
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Quote:
Originally Posted by Dr Kiwi
Both cones should go into the prop hub to ensure it is centralized (especially if, as it will be in most cases, the hub is bored larger than the shaft on the balancer!). Thin hubs are a problem though - you may need to add a nylon washer or two to effectively "thicken" the hub, so that the two cones don't meet in the middle!

My Top Flite magnetic works just fine even with heavy 13" APC E props!
Dr. Kiwi:

Thanks for the reply. I thought both the cones should go in but because of the hole size they were a sloppy fit. Your suggestion about the nylon washer is a great idea and I will do that. That's a 17" prop in the pictures and I tried it on a friends Top Flite balancer and it was too heavy. Maybe the newer ones have more strength.

Thanks again,

Ed
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Old Jan 06, 2006, 10:50 PM
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Either way you have it should be fine, if the hub isn't thick enough that is how I do it. Putting a washer in the front of it then putting the cone in that wouldn't be any different than turning one of the cones backwards as it will still be sitting flat on the face of the prop and getting the reading from there.
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Old Jan 07, 2006, 12:20 AM
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Quote:
Originally Posted by Steve H.
Either way you have it should be fine, if the hub isn't thick enough that is how I do it. Putting a washer in the front of it then putting the cone in that wouldn't be any different than turning one of the cones backwards as it will still be sitting flat on the face of the prop and getting the reading from there.
Steve:

I was able to use one of the adapter rings that comes with the APC prop which had a smaller hole. That way it fit iside the prop and the cone doesn't bottom out any more when you put it in.

Since I've done this, the heavy side has stopped at the almost identical position 6 times in a row so I feel comfortable that I'm getting a consistent reading. Now I can balance it with a little more confidence in the fact that it is accurate.

Thanks,
Ed
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Old Jan 07, 2006, 12:40 AM
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Were you not getting a good reading with one of the cones turned around?

Putting the smaller diameter ring in the prop, like you did, so the cone didn't go quite as far in would work the best if its possible, some are just too thin though for that to work.

If you look at the instructions that came with the Dubro balancer it shows to turn one of them around when balancing a spinner as a backplate on a spinner is not thick enough to put the cones together just like the thinner prop.
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Old Jan 07, 2006, 12:45 AM
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Quote:
Originally Posted by edkoz
Which is the correct way to attach the two balancing cones ?

Prop1 or Prop2, or doesn't it make a difference ?

OR

What balancer do you recommend? Don't tell me the one with magnets becuse they're too weak to work with the bigger props.

Thanks,
Ed
I cant see anything wrong in the way you have it set up apart that you may wish to rotate the disc holder closest to the prop 180 degrees so it is as close to the prop as possible in case there is any flex in the shaft and make sure the shaft is dead level.imho.
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Old Jan 07, 2006, 01:34 AM
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If you find a chunk of iron bar or music wire close to the hub diameter, cut to a handy length, sharpen tips by drilling at angle against a file, you don't need any cones and a mag balancer will hold up a 5 pound ,any number of blades prop and balance so well that your breath condensing on a blade will read!
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Old Jan 07, 2006, 02:36 AM
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Quote:
Originally Posted by jwgilliand2
If you find a chunk of iron bar or music wire close to the hub diameter, cut to a handy length, sharpen tips by drilling at angle against a file, you don't need any cones and a mag balancer will hold up a 5 pound ,any number of blades prop and balance so well that your breath condensing on a blade will read!
Which Mag Balancer for the 5 pounds ?
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Old Jan 07, 2006, 02:41 AM
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Quote:
Originally Posted by Steve H.
Were you not getting a good reading with one of the cones turned around?

Putting the smaller diameter ring in the prop, like you did, so the cone didn't go quite as far in would work the best if its possible, some are just too thin though for that to work.

If you look at the instructions that came with the Dubro balancer it shows to turn one of them around when balancing a spinner as a backplate on a spinner is not thick enough to put the cones together just like the thinner prop.
Steve:

I saw the pictures on the package when I bought the balancer.

I wasn't getting consistent readings. If I checked it 5 times, the prop wouldn't settle in the same position twice. The new method seems to be working great.

Thanks,
Ed
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Old Jan 09, 2006, 03:03 AM
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Edkos, for props up to 24" dia.(5/8 " shaft hole) up to 1/4lb weight, i use the pocket size Top Flight "power point" precision magnetic balancer. For big heli rotors i just clamp a couple junk alnico woofer magnets aross from each other on saw horse ,(basically a 2x4 with legs). The trick is to fill the shaft hole with a ferrous (magnetically conductive) metal, like iron. The more the crossectional area, and the less the length, the more mass a magnetic field in the shaft will support against gravity. And remember to keep the shaft from touching both magnets. Its point on one end offers little friction against magnet, and the other end no friction, as the weight is being supported by flux field channeled thru the ferrous shaft (not a ferrous hairpin with rubber cones). Keep the gap on the open end as small as possible without touching. It doesen't matter which point on which end of shaft, front or back of prop, top or bottom of rotor, is the one touching, just not both at the same time.
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Old Aug 02, 2014, 09:02 PM
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du bro balance tool

Quote:
Originally Posted by edkoz View Post
Which is the correct way to attach the two balancing cones ?

Prop1 or Prop2, or doesn't it make a difference ?

OR

What balancer do you recommend? Don't tell me the one with magnets becuse they're too weak to work with the bigger props.

Thanks,
Ed
Where can i get a manual.?
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Old Aug 02, 2014, 09:07 PM
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du bro balace tool

Quote:
Originally Posted by edkoz View Post
Which is the correct way to attach the two balancing cones ?

Prop1 or Prop2, or doesn't it make a difference ?

OR

What balancer do you recommend? Don't tell me the one with magnets becuse they're too weak to work with the bigger props.

Thanks,
Ed
I have one, where can i get a manual, no time to learn,Vital, Thanks
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Old Aug 06, 2014, 11:24 PM
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Quote:
Originally Posted by Dr Kiwi View Post
Both cones should go into the prop hub to ensure it is centralized (especially if, as it will be in most cases, the hub is bored larger than the shaft on the balancer!). Thin hubs are a problem though - you may need to add a nylon washer or two to effectively "thicken" the hub, so that the two cones don't meet in the middle!

My Top Flite magnetic works just fine even with heavy 13" APC E props!
Sorry, I don't follow how this could work. I agree with Steve H that this just effectively turns the two cones pointing towards each other into the setup pictured in post #1. You still have the valid question of which side of the prop gets the pointy end cone and which side gets the "slidy" flat non-centered connection.

Pic #1 is correct, at least for APC style props. The APC website has instructions on this, and indicates that the larger hole in back of the hub (the one that accepts the rings) is a precision milled /centered hole. From the front of the hub, that smaller hole is just molded in and may NOT be on the same axis as the rear hole. Thus pointing both cones in could put the prop at a very slight off-axis angle. It all depends on which hole the front cone contacts, and whether the two different diameter holes are exactly on axis.

This is certainly a problem when you have to ream out the hole from the front, in order to use one of the thinner rings for a large prop shaft. In that case, you're very likely to get that front hole off-center and off-axis. I would not want a cone centered on that hole, knowing my reaming abilities.

I go by APC's recommendations and set up as in pic #1. This forces you to balance the prop in the same position and orientation that it rides on your prop shaft. Makes sense. Other brand props sometimes require some pondering.
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Old Aug 07, 2014, 07:10 AM
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Wow! Nice idea turning the front cone around. I bought a balancer two years ago, and have not been able to use it on my APC props because of the off-center front hole. I have been intending to machine an adapter, but this is too simple. I often have a hard time seeing the simple way.
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