RunRyder - Balancing Flybar

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Audacity Models Pantera 50 - Tiger 50 > Balancing Flybar

darkfa8
Key Veteran
Location: Eatontown, NJ, USA

While my Tiger is down for repairs I'm checking the balance on the flybar.

I have the 3D seesaw, 3D flybar & KSJ white paddles. Each paddle is 135mm out from the aluminum boss inside the fly-bar control arm assembly and are within +/- .20mm of eachother, no threads exposed.

I have the head yoke in my vise, held by the wash-out guide pins (not too tight). Vise is level.

I have two wheel collars on one side and nothing on the other. With a line-level on the control arm, held and balanced by my finger nail, when I put both wheel collars all the way out to the end, it shows it's in balance.

Is this a accurate way of doing this?

- Dan G. -

10-24-2005 Over year old.

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Al Magaloff
rrMaster
Location: 12,199 Posts- Enough Time Wasted. See Ya!

I would HighPoint the whole rotor head without blades.

10-24-2005 Over year old.

darkfa8
Key Veteran
Location: Eatontown, NJ, USA

Al,

I followed your balancing instructions elsewhere and despite the fly-bar being centered to within less then 1mm in the head yoke, the paddles both being 22grams (checked on digital scale) and equidistant within 0.50mm (measured with Mitutoyo Digimarc caliper), on the Dubro TruSpin the fly-bar is angled at a 45*

The assembly is just the main shaft, head yoke, 3D seesaw, Fly-bar control ring, 5mm spindle, dampers, main grips (no linkages, no seesaw arms). All bearings are lubed and free moving.

- Dan G. -

10-24-2005 Over year old.

HOMEPAGE

jvanscoyk
Veteran
Location: Tucson, AZ

Hey Dan,

With the main blades not attached the flybar should be able to stay in any position that you put it in. If it moves on it's own it's out of balance.

Jim

must go faster, must go faster.........

10-24-2005 Over year old.

HOMEPAGE

Al Magaloff
rrMaster
Location: 12,199 Posts- Enough Time Wasted. See Ya!

If the flybar is centered, and the paddles are the same weight, and equidistant from center when mounted on the flybar, then the flybar can't be out of balance. Something else is wrong, if you need two wheel collars out at one end of the flybar.

10-24-2005 Over year old.

darkfa8
Key Veteran
Location: Eatontown, NJ, USA

i'll pull out the main grips, head axle and dampers and see if I can narrow this down tomorrow...

- Dan G. -

10-25-2005 Over year old.

HOMEPAGE

darkfa8
Key Veteran
Location: Eatontown, NJ, USA

ok, pulled what i said I would, re-centered the fly-bar, it was off by 2mm. Then I just checked the balance on the bare head with fly-bar assembly and that came out proper...

then i threaded on both paddles at exactly 140mm out and it's not coming into balance, it keeps dropping down to one paddle and it hangs at a 45* angle no matter where I try and move the bar too or spin it.

Now what? =\

- Dan G. -

10-25-2005 Over year old.

HOMEPAGE

JuanRodriguez
Elite Veteran
Location: Rochester, New York

Close enough for government work....

Go fly....

10-25-2005 Over year old.

darkfa8
Key Veteran
Location: Eatontown, NJ, USA

sorry Juan, I couldn't resist screwing with it 'till it came "in" to balance :P

I got it to where if you move the bar yourself and stick it at any angle it will essentially hold the position with minimal tottering before coming to rest. The paddles are out from the aluminum control arm insert by 142mm on one side and 137mm on the other.

Strange that a 5mm difference with the paddles brings this "in"..especially since the paddles weighed in the same on my digital scale. I guess the CG could be different between the two of them?

- Dan G. -

10-25-2005 Over year old.

HOMEPAGE

hootowl
Elite Veteran
Location: Garnet Valley, Pa.

Reverse the paddles on the flybar and see if the out of balance cond follows the paddles.

Do the nuts weigh the same?

Don't they supply weights for the flybar. You could use them to make adjustments or just try different paddles to prove the problem.

"Any man who says he is an American, but something else also, isn't an American at all.

10-25-2005 Over year old.

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jvanscoyk
Veteran
Location: Tucson, AZ

Hey Dan,

I recently helped a friend build his Tiger and he came out with the same problem. We used 1/8" wheel collars on the the flybar to bring it in to balance.

Even though the paddles are the same weight, the weight must be distributed differently in each paddle. Unfortunately I don't have a picture to show you the detail. I do remember that one collar was almost to the paddle and the other collar was about mid-way through the flybar.

There is good documentation of this technique in Ray's Heli Manual.

I hope this makes sense.

Jim

must go faster, must go faster.........

10-25-2005 Over year old.

HOMEPAGE

darkfa8
Key Veteran
Location: Eatontown, NJ, USA

hootowl... these are the KSJ 3D white paddles, they do not have weights in them and are not secured with nuts on the fly bar like the stock black paddles are.

Jim, ::sigh:: I already installed the assembly into the frames and getting that M3 shouldered bolt through the auto-hub and main shaft was a PIA.

I know it's definitely paddle related since I was able to balance the bare head without the paddles perfectly.

I do have two wheel collars but the catch is I don't own a allen key small enough to tighten the set screws, it's smaller then 1.5mm

With this 5mm distance difference, but it being in balance on the bench, is this going to make the assembly less "precision" to any noticeable effect or do you really feel it's neglible at this point?

I suppose since I spent the time I did to get it perfect I should finalize it with the wheel collars... or I'll wait till the next crash =\

I do have Ray's book, but it's packed in a box in the attic. I do remeber portions of that chapter.

- Dan G. -

10-25-2005 Over year old.

HOMEPAGE

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Audacity Models Pantera 50 - Tiger 50 > Balancing Flybar

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