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HomeAircraftHelicopterMain Discussion › how do you balance tail blades?
04-25-2011 03:13 AM  7 years agoPost 1
bj660raptor

rrNovice

Las Vegas,NV

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I have some carbon 95mm tail blades and I have no idea how to balance tail
blades please help,I've got a tail vibe and I think that the reason why. Thanks

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04-25-2011 03:22 AM  7 years agoPost 2
kcordell

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O Fallon, MO

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Easiest way to to take off the tail hub with the blades on it and balance it as a whole unit,just like you would the rotorhead.

Team Futaba, Team Synergy/Rail, Team Scorpion, Team Castle Creations, YS Engines, VelTye

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04-25-2011 03:28 AM  7 years agoPost 3
MartyH

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USA

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If you are chasing a tail vibration you will end up having to balance the whole tail so go ahead and take the tail apart at the hub and balance the whole thing. If you change blades, remember to balance as an assemly, not just the new blades.

Marty

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04-25-2011 03:51 AM  7 years agoPost 4
jschenck

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La Vista, NE.

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This is how I balance my tail blades - quick

http://www.alignrcusa.com/index.php...products_id=354

and I use this as a place to place them for balancing

http://www.alignrcusa.com/index.php...products_id=446

and 250 mains/450 tail blades

http://www.alignrcusa.com/index.php...roducts_id=1164

They all fit in the little box that the main blade balancer comes in.

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04-25-2011 05:18 AM  7 years agoPost 5
bj660raptor

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Las Vegas,NV

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So I just apply a little tape to the tip on the leading edge of the light side?

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04-25-2011 01:13 PM  7 years agoPost 6
jschenck

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La Vista, NE.

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That's all I do. I've made several sets of mis-matched singles fly with this technique.

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04-25-2011 01:25 PM  7 years agoPost 7
bj660raptor

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Las Vegas,NV

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Just trying to do the blades and couldn't see much but balanced the whole assembly and it moves those blades out farther and I could see s problem so ill give it a go, thanks alot

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04-25-2011 01:58 PM  7 years agoPost 8
CX1

rrKey Veteran

Canada

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try using a weigh scale
if they weigh the same balance should not be an issue

when I chase down a vibe i Remove all blades and spin it up to check

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04-25-2011 04:28 PM  7 years agoPost 9
Justin Stuart (RIP)

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Plano, Texas

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1+ for balancing the whole assembly.

Avant RC
Scorpion Power Systems
Thunder Power RC
Kontronik Drives

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04-25-2011 06:13 PM  7 years agoPost 10
Heli_KV

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Ottawa, Canada

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+1 for balance of the whole assembly.

Additionally, I balance dynamically. Spool up, disconnecting tail servo push rod and of course no main blades, better no head at all and apply a bit of tape to some blade, then spool up and see difference. If worse, then tape to another blade. Using VBar analyser - best of all. After several attempts it starts to be easy task.

But of there are vibes without tail blades, first of all that should be chased.

Good luck!

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04-25-2011 06:46 PM  7 years agoPost 11
Richardmid1

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Leeds, England

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To dynamically balance them you just (very basically) add the tape to the lightest blade on the C of G point of the blade, not the tip. These blades are spinning fast remember so its important that they are dynamically balanced.

However I have never needed to balance tail blades, even cheap plastic ones. I think you have to be pretty anal to do so.

60% of the time, it works every time!

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04-25-2011 07:21 PM  7 years agoPost 12
Dr.Ben

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Richmond, VA, USA

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However I have never needed to balance tail blades, even cheap plastic ones. I think you have to be pretty anal to do so.
Guilty as charged. One thing I learned when going to electrics is how much you can HEAR vibration ever when you can't see it in the model. It's amazing how much noise an out of balance t/r assembly will cause in a model.

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

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04-25-2011 08:06 PM  7 years agoPost 13
Heli_KV

rrKey Veteran

Ottawa, Canada

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Just my latest today's fix, installing new blade grips and new tail blades.

Weighted blades, found the lightest, cut proper piece of tape to get equal weight and applied it to the tip. Spooled up, looked at VBar analyser. It showed peak at tail rotor frequency. No visible vibs, just a bit noisy sound as Dr.Ben indicated. Applied the same tape to CG, spooled up - better. Reapplyed the same tape near the root - vibs gone of what analyser happily reported. So I have equal blades weight and probably near equal CG. It all took me around 10 min.

PS. Tail push rod - disconnected. Main blades - removed.

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04-25-2011 10:07 PM  7 years agoPost 14
GMPheli

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W. Bridgewater, MA USA

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I balance them just like main blades. Weigh em up, and then check the spanwise cg by laying them on the edge of a something flat with a sharp edge. Lay them tip to tip, trail edges almost touching, as close to perpindicular to the edge of the surface as you can. Slide them off evenly until you find the balance points. It is easy to compare cg's this way. And add weight accordingly. Remember they both have to weigh the same, and have the same cg's. On wood tail blades I have had to add the same amount of material to both blades, at opposite ends to get them right. You can even loosely tack them both to the wall, and see if they hang together to check chordwise cg.

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04-25-2011 11:34 PM  7 years agoPost 15
Mike Fortin

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USA

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Might be faster and easier to just pop on another set of tail blades which will give you your answer pretty quickly and probably cheaper than buying everything that you will need to balance them properly.

Have Rotors, Will Fly!

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04-26-2011 01:00 AM  7 years agoPost 16
Dr.Ben

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Richmond, VA, USA

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GMPheli,

That's the gold standard way to do it or you can use a Koll to the same effect as well.

In any case, it's amazing how much smoother a model runs when you take the time to do the job.

Ben Minor

Peak Aircraft/Team Minicopter Team Futaba Team Kontronik USA

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04-26-2011 03:20 AM  7 years agoPost 17
dkshema

rrMaster

Cedar Rapids, IA

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and probably cheaper than buying everything that you will need to balance them properly.
So just how expensive are single-edged razor blades these days?

Single-edge razor blade in a hobby vise:

The yellow tape is only for the pictures, to make the result more visible:

Balance the blade at at 45 degree angle to the razor blade, then press lightly to make a mark on the surface:

Turn blade 90 degrees, balance again, press lightly to make a second mark:

The marks intersect at the CG...

The CGs want to be in the same location -- from the mounting bolt AND the leading edge. Most blades these days, are very close out of the box.

If the CGs are where they need to be, but one blade is lighter than the other, use a bit of Trim Monokote AT THE CG of the light blade to bring things into balance.

If the CGs are off, you CAN add weight in the right place to bring them into compliance, but that is a bit more work.

-----

Want to check the balance of the entire TR assembly but don't want to spring for something like a TruSpin balancer? A couple of ice cubes placed on a paper towel to keep them from sliding around, and a shaft of the right diameter that fits through the TR hub will do in a pinch:

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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