Koll Rotor Pro Balancer – As Good As People Say???

[ShaneXman]

How's it going everyone? I am in the midst of trying to decide on a precision blade balancer, and I am highly considering the Koll Rotor Pro Balancer.

I have looked extensively, but have come up completely empty handed on finding anything related to how to use the Koll Rotor Pro. I found the instructions, but they leave something to be desired. There are no videos or "How To" threads of any sort on the Koll.

People rant and rave about this balancer, but I can't help but wonder how it has such extreme accuracy to warrant a cult like following...



When looking at other balancers, such as the DU-BRO Tru-Spin Balancer or SkyRC iMax Balancer (which both incorporate some sort of bearing / precision mechanism), I start to look at how these devices work. From the looks of it, the Koll Rotor Pro Balancer is held together with nuts and bolts, and doesn't have any bearings to help with precision / smoothness.

I understand that it offers additional features that other blade balancers don't offer, such as chord-wise balancing and CG...but what design elements make it so accurate?

Am I not seeing something?? Any and all help / clarification would be greatly appreciated. If someone knows of a "How To" thread, or a video of any sort, that would be even better. Thanks in advance!


-Shane

[ShaneXman]

Anyone? Bueller??


-Shane

[BrianSkilton]

I use one!
They are great piece of kit.
Once you understand the principle of what you are trying to achieve it is very straight forward just need to spend a bit of time.
Should decide to go this route invest in some very good scales!

[ShaneXman]

Originally Posted by BrianSkilton

I use one!
They are great piece of kit.
Once you understand the principle of what you are trying to achieve it is very straight forward just need to spend a bit of time.
Should decide to go this route invest in some very good scales!

Nice. Thanks for the feedback. I have an American Weigh Signature Series Digital Pocket Scale that is capable of weighing up to 100 grams in 0.01 gram increments. It's not very expensive, but it was a recommendation from someone on the forum.

Here it is...
Link: http://www.amazon.com/gp/product/B0012LOQUQ/

What scale are you using? Let me know. Thanks!


-Shane

[BrianSkilton]

I am using the Ohaus Dial-O-Gram

100grams! That is a small blade

[ShaneXman]

Originally Posted by BrianSkilton

I am using the Ohaus Dial-O-Gram

100grams! That is a small blade

I'm just getting into the larger helis, so I will most likely get a better scale. My largest heli right now is a 300 X, but I have a Goblin 500 on order. The Goblin has 500mm blades, which should be less than 100 grams per blade.

My thought with considering the Koll Rotor Pro is to invest in the right tool the first time. With that said, I don't know that I'm at a point where investing ~$200 in a scale (nice scale BTW ) would make much sense.

The other scale I was looking at picking up sooner rather than later was the American Weigh AC Pro 200 Digital Pocket Scale which weighs up to 200 grams in 0.01 gram increments.

Here it is...
Link: http://www.amazon.com/gp/product/B003STEIYY/

Would this not be sufficient? Do I really need a $200 scale? I know this goes against my "invest in the right tool the first time" mentality, but I just can't swing that right now.

Thank you for all of your help and insight thus far.


-Shane

[BrianSkilton]

I will pm you

[ShaneXman]

Originally Posted by BrianSkilton

I will pm you

Thank you sir.


-Shane

[jhamel]

Ron Lund has the best price I am able to find here in the States for the Koll Rotor Balancer; $75.92 when you sign in. I have one, but it does not get a lot of use.

The Koll Rotor Balancer has bearings at the rotational joints (see pic below) for butter smooth operation. Again, mine does not get much use, not because it is not good, but because all quality CF blades I own (Radix, Rail, Align, Edge, Revolution, etc) are very well matched out of the box without any appreciable vibrations or wobbles during flight, at least nothing that the Skookum or VBar logs can capture.



Since folks are also discussing digital scales, I have had success with both the American Weight AC Pro 200 (200g max, 0.01g increments) and the AWS Card V2 600 (600g max, 0.1g increments). See below for a pic of both scales side-by-side with a 200g and a 500g weight, respectively. I have not had to recalibrate either scale since I purchased them over one year ago.

Considering that my smaller Radix 554mm blades weigh about 111.4g, and my Revolution 710mm blades weigh around 191.1g, the 200g/0.01g scale gets the most use of the two scales.

[ShaneXman]

Originally Posted by johnahamelv

Ron Lund has the best price I am able to find here in the States for the Koll Rotor Balancer; $75.92 when you sign in. I have one, but it does not get a lot of use.

The Koll Rotor Balancer has bearings at the rotational joints (see pic below) for butter smooth operation. Again, mine does not get much use, not because it is not good, but because all quality CF blades I own (Radix, Rail, Align, Edge, Revolution, etc) are very well matched out of the box without any appreciable vibrations or wobbles during flight, at least nothing that the Skookum or VBar logs can capture.

Since folks are also discussing digital scales, I have had success with both the American Weight AC Pro 200 (200g max, 0.01g increments) and the AWS Card V2 600 (600g max, 0.1g increments). See below for a pic of both scales side-by-side with a 200g and a 500g weight, respectively. I have not had to recalibrate either scale since I purchased them over one year ago.

Considering that my smaller Radix 554mm blades weigh about 111.4g, and my Revolution 710mm blades weigh around 191.1g, the 200g/0.01g scale gets the most use of the two scales.

This is a great bit of info, exactly what I was looking for. Your bearing picture answers a lot of the questions I had about this balancer, so thank you kindly for that.

Your 200g scale is the exact one I have been eyeing for quite some time now, so it's nice to see another Freaker has been using it with good success. I think I may be OK for the time being, seeing as my largest blades are 500mm and less than 100g each.

If by any chance, when you find yourself balancing (span-wise, chord-wise or both) or finding CG of any of your blades, if you wouldn't mind putting together a short "How-To" picture post or video...I would be greatly appreciative.

I've been looking at the Koll Rotor Pro on Ron's site a lot as of late, but I don't see the $75.92 price that you see, mine shows up as $87.26 (even when I'm logged in). Maybe you're a Ron Lund VIP.

It's this statement that makes me wonder if I REALLY need this balancer...

Originally Posted by johnahamelv

Again, mine does not get much use, not because it is not good, but because all quality CF blades I own (Radix, Rail, Align, Edge, Revolution, etc) are very well matched out of the box without any appreciable vibrations or wobbles during flight

...or if I could get by with something like the DU-BRO Tru-Spin Prop Balancer considering the more consistent blade manufacturing nowadays?? Thoughts?

Thanks again for your time and insight.


-Shane

[jhamel]

Originally Posted by ShaneXman

I've been looking at the Koll Rotor Pro on Ron's site a lot as of late, but I don't see the $75.92 price that you see, mine shows up as $87.26 (even when I'm logged in). Maybe you're a Ron Lund VIP.

Shane. I am not sure what's going on with Ron's website. I was logged-in on your account. I even took a screen shot.



I promise I did not buy too many things under you name.

Still, I get a better price under my account.



All I can think off is that you have not made a purchase before, so should be eligible for a 10%off first purchase discount.

[jhamel]

This is the instructions manual for the Koll Balancer.

[jhamel]

Originally Posted by ShaneXman

...or if I could get by with something like the DU-BRO Tru-Spin Prop Balancer considering the more consistent blade manufacturing nowadays?? Thoughts?

I also own the DuBro Tru-Spin. I am a sucker for tools. This one was recommended by many of the veterans in the hobby to include John Salt, Ray Hostetler, and the geriatric folks at the field.

The Tru Spin seems to be geared mostly towards airplane props. The Tru Spin has a role in balancing a flybar, where it may be challenging to just rely on a ruler. However, balancing blades using the Tru Spin is more difficult, as there is always a possibility to introduce error into the measurement by either the non-blade components, or just not having the lead/lag of the blades perfectly at 180°.

My Tru Spin is struggling to remain part of the team in an isolated shelf corner.

[ShaneXman]

Originally Posted by johnahamelv

Shane. I am not sure what's going on with Ron's website. I was logged-in on your account. I even took a screen shot.

I promise I did not buy too many things under you name.

Still, I get a better price under my account.

All I can think off is that you have not made a purchase before, so should be eligible for a 10%off first purchase discount.

John,

That's crazy! Oddly enough, when I clicked the link in your first post it said "Welcome back, JOHN HAMEL"...which threw me for a loop. I couldn't quite place it (not thinking that it was you who was somehow logged in on my computer), but I quickly logged out and logged in under my account. That's a little disconcerting, but hopefully nothing bad will come of this glitch for Ron. I'm glad to hear you didn't buy too many things though, but everything is good in moderation. LOL

And you are correct, I have not made a purchase from Ron as of yet, so I should definitely be eligible for that 10% off. Good looking out.


-Shane

[ShaneXman]

Originally Posted by johnahamelv

This is the instructions manual for the Koll Balancer.

Oh sweet! These are wayyy more current instructions than the others I have found on the internet. The other variations I've found were dated 1998, and the pictures were black & white. Not to mention, they looked like a horrible fax / photocopy, and you couldn't even make out what the pictures were trying to convey. So thank you, this brings much needed clarification to my questions.

Originally Posted by johnahamelv

I also own the DuBro Tru-Spin. I am a sucker for tools. This one was recommended by many of the veterans in the hobby to include John Salt, Ray Hostetler, and the geriatric folks at the field.

The Tru Spin seems to be geared mostly towards airplane props. The Tru Spin has a role in balancing a flybar, where it may be challenging to just rely on a ruler. However, balancing blades using the Tru Spin is more difficult, as there is always a possibility to introduce error into the measurement by either the non-blade components, or just not having the lead/lag of the blades perfectly at 180°.

My Tru Spin is struggling to remain part of the team in an isolated shelf corner.

Well then, that's that...I'm definitely not getting a DU-BRO. I don't have a flybarred heli, nor do I have any airplane props. I'm certainly not looking for a dust collector, or anything to further complicate my life. LOL I guess I'm back at square one...

The question remains though, with today's blade manufacturing consistency, is it worth it to pick up a Koll Rotor Pro Balancer? Some people swear by a vice-grip and a razor blade, but much like you, "I'm a sucker for tools". As a matter of fact, a good buddy of mine on the forum likes to heckle me about it, so I'm right there with you.

Decisions...decisions. Thanks for everything bud, you've been a great help.


-Shane

[ChasCS]

Hi Shane,
I found this vid, and several others on YT.
[ame]http://www.youtube.com/watch?v=lVPOZ6UM7gE[/ame]

Not sure if it can be benefitial for you at this time. But perhaps it could help others here.
One draw back, it's not in English, thankfully it's mostly visual instruction.

So, watch it at your convenience. Or not if that's your choice.
I'll try and find you something better.
From another post elsewhere:
I use the Koll Rotor Pro Balancer and a GOOD gram scale to balance ALL my blades. So far the claims of perfectly matched blades right out of the box has not been true for me! The weight may be the same but the CG is always WAY off!

The instructions are confusing at best and I don't do it their way.

If your blades came finished than the weights should already be installed and visible through the cover. IF they have weights! Some don't!

Check the weight of each blade. One may be heavier. If it is note the difference in the weights and mount it on the rotor pro. This will be your master blade. Balance it on the rotor pro. Mark the CG through the hole in the bottom of the rotor pro. Now remove the master and mount the slave blade on the rotor pro. You will now just place a piece of tape (equal to the difference in the blade weights) on the slave blade in a spot that centers the bubble level. At this time just set the tape temporarily on the blade.

Now both blades should be the same weight and balance span wise.

Mark a spot on the span wise CG on both blades. Now turn the rotor pro sideways and slide in the master blade centering it on the spot you just made. Level to get the chord wise CG. Mark the chord wise CG from below. Slide your span wise CG mark to match the chord wise position thereby combining the two marks into one. This will be your master blade CG point. Remove the master and check the slave. If you're lucky they will match. Most likely they wont! Try and position the your piece of tape toward the lite side of the blade to get the chord wise CG to match. If it does you're done. If it doesn't you will have to add more tape to the lite side until it does. Of coarse this extra piece of tape will make the slave blade heavier than the master and you will have to add a equal weight of tape to the CG of the master blade to get them back in balance. This is easy to do, just center it on your span wise/chord wise CG mark on the master blade. This will increase the weight but not change the CG so both blades should still match. Check one against the other to be sure.

Now although I told you the points are the blades CG the truth is there not. Why? Because the rotor pro is also being balanced with the blade. But it doesn't matter because what you're doing is getting the blades to match in weight/span wise CG/chord wise CG and they are. Its just that the actual CG although they are the same they will not be on your marks. Don't let this confuse you. Both blades are now exactly the same!

You can use any kind of tape. Tracking tape, clear tape just as long as it wont come off. Sometimes I just use Scotch Brand tape and so far its not come off.

If your blades are much different in weight you may not be able to do this with tape. That's when it gets tough! Drilling holes to glue in brass dust and all that! I don't mess with all that. I don't find the new built blades to be that out of balance as far as the weights are concernered. But if you build your own it can happen. And for that reason I don't bother building blades anymore. It doesn't hurt to take your rotor pro and gram scale to the hobby shop and check the blades before you buy if you can! You might get lucky and find that so called perfect set!

I think most people just check the weight difference, bolt them on and fly. But if you've already got the rotor pro you might as well do it right. At least you wont be wondering if that vibration is coming from your blades.

Chas

[Ace Dude]

I have Koll Rotor Pro. It's probably 14 years old. I don't use it often, but I wouldn't be without it either. It is the best tool for balancing blades I have ever come across. I also have an Ohaus digital gram scale. 0.1g resolution is good enough for balancing blades.

[ShaneXman]

Originally Posted by ChasCS

Hi Shane,
I found this vid, and several others on YT.
http://www.youtube.com/watch?v=lVPOZ6UM7gE

Not sure if it can be benefitial for you at this time. But perhaps it could help others here.
One draw back, it's not in English, thankfully it's mostly visual instruction.

So, watch it at your convenience. Or not if that's your choice.
I'll try and find you something better.
From another post elsewhere:
I use the Koll Rotor Pro Balancer and a GOOD gram scale to balance ALL my blades. So far the claims of perfectly matched blades right out of the box has not been true for me! The weight may be the same but the CG is always WAY off!

The instructions are confusing at best and I don't do it their way.

If your blades came finished than the weights should already be installed and visible through the cover. IF they have weights! Some don't!

Check the weight of each blade. One may be heavier. If it is note the difference in the weights and mount it on the rotor pro. This will be your master blade. Balance it on the rotor pro. Mark the CG through the hole in the bottom of the rotor pro. Now remove the master and mount the slave blade on the rotor pro. You will now just place a piece of tape (equal to the difference in the blade weights) on the slave blade in a spot that centers the bubble level. At this time just set the tape temporarily on the blade.

Now both blades should be the same weight and balance span wise.

Mark a spot on the span wise CG on both blades. Now turn the rotor pro sideways and slide in the master blade centering it on the spot you just made. Level to get the chord wise CG. Mark the chord wise CG from below. Slide your span wise CG mark to match the chord wise position thereby combining the two marks into one. This will be your master blade CG point. Remove the master and check the slave. If you're lucky they will match. Most likely they wont! Try and position the your piece of tape toward the lite side of the blade to get the chord wise CG to match. If it does you're done. If it doesn't you will have to add more tape to the lite side until it does. Of coarse this extra piece of tape will make the slave blade heavier than the master and you will have to add a equal weight of tape to the CG of the master blade to get them back in balance. This is easy to do, just center it on your span wise/chord wise CG mark on the master blade. This will increase the weight but not change the CG so both blades should still match. Check one against the other to be sure.

Now although I told you the points are the blades CG the truth is there not. Why? Because the rotor pro is also being balanced with the blade. But it doesn't matter because what you're doing is getting the blades to match in weight/span wise CG/chord wise CG and they are. Its just that the actual CG although they are the same they will not be on your marks. Don't let this confuse you. Both blades are now exactly the same!

You can use any kind of tape. Tracking tape, clear tape just as long as it wont come off. Sometimes I just use Scotch Brand tape and so far its not come off.

If your blades are much different in weight you may not be able to do this with tape. That's when it gets tough! Drilling holes to glue in brass dust and all that! I don't mess with all that. I don't find the new built blades to be that out of balance as far as the weights are concernered. But if you build your own it can happen. And for that reason I don't bother building blades anymore. It doesn't hurt to take your rotor pro and gram scale to the hobby shop and check the blades before you buy if you can! You might get lucky and find that so called perfect set!

I think most people just check the weight difference, bolt them on and fly. But if you've already got the rotor pro you might as well do it right. At least you wont be wondering if that vibration is coming from your blades.

Chas

Chas,

Thank you for this very informative and thorough post.

I actually purchased the Koll Rotor Pro a few days after posting this thread. I haven't had a chance to use it just yet, but I most definitely will be in the not so distant future. I'm waiting on my new Goblin 500 to arrive, so that will be my first helicopter to test and use this fabulous tool on.


-Shane

[ShaneXman]

Originally Posted by Ace Dude

I have Koll Rotor Pro. It's probably 14 years old. I don't use it often, but I wouldn't be without it either. It is the best tool for balancing blades I have ever come across. I also have an Ohaus digital gram scale. 0.1g resolution is good enough for balancing blades.

Oddly enough, this is the most common response from a Koll Rotor Pro owner that I've heard. It's a tool people value highly, but it's not needed as much these days as it once was. You don't see many people parting with their Koll's, and I'm sure there is good reason.

I look forward to joining the club.


-Shane

[Ace Dude]

I stared in the hobby in 1996 and my first several sets of blades I made, well assembled myself. You used to have to glue in the lead weights yourself at the tips of the blades. I still have several sets I made, but have never flown in my parts box. Just around that time reasonable priced pre-made blades started to become available. Back then pre-made blades weren't perfect and it was always critical to check the balance. The composite blades made today are so good most never balance them unless there is a problem. Now, if you do have that rare problem today the Koll is the best way to validate and correct it. I think you'd be even hard pressed to even find a set of woodies today. Maybe someday I'll turn the set in my parts box into a clock.