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vibration and wobble from the main shaft? [solved]

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vibration and wobble from the main shaft? [solved]

Old 01-20-2007, 03:07 PM
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Default vibration and wobble from the main shaft? [solved]

Hi all,

I don't know where to continue anymore.

I have the 450XL; all align metal head - besides blade grips; blue gears;
when turning up the revs, the heli is shaking all over.
when hovering, there is always some vibration and the tail bounces up and down.

so I slowly turned the revs up and put a pen next to the plate of the head to mark the direction of the unbalance.
afterwards, one side directed towards the paddles (not blades) was marked.
I did the same with the lower gear and this got marked to the same side.

as it is still pretty slow turning I don't think it is a paddle balancing isue - is it?
what looks strange is that the gear is moving to the same direction.

any hints? could it be the main bearing? ore something with the gears?
I replaced the main shaft and the blades already without success.


any more ideas are very welcome.

thank you all,
M
Old 01-20-2007, 07:13 PM
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Default RE: vibration and wobble from the main shaft?

If your gear is moving it must be fairly bad! I balanced my paddles by making sure its all totally symetrical then i marked one with a marker then without the main blades ran it up slowly to see if there is still vibration, if there is wind in/out the marked one untill it settles. I got a fairly good result from this.

Check to see if your main shaft bearings are good and tight by wiggling the shaft, there should be very little play if any.

make sure that your screws around the main shaft bearings are tight

have a look at your main gears and motor shaft for flaws (out of round/bent).

Finding vibration can be a black art at times, just a process of elimination, good luck.
Old 01-21-2007, 05:26 PM
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Default RE: vibration and wobble from the main shaft?

hi,

bearings are perfect. no movement.

I took all apart and it still goes crazy.
I think it come from the blue main gear. but is NEW.
how can this be? it was replaced including one way bearing and this bearing shaft.
any ideas? I can't imagine that a new part of the SE runs so bad.
It has some movement up and down - not sideways...
Old 01-21-2007, 06:12 PM
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Default RE: vibration and wobble from the main shaft?

How tight is your gear mesh? If its too tight it will vib alot.
When you rotate the main head does it get tight at any point thru the revolution?
Old 01-21-2007, 09:40 PM
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Default RE: vibration and wobble from the main shaft?

hi,

no. this goes pretty smooth
Old 01-21-2007, 10:56 PM
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Default RE: vibration and wobble from the main shaft?

I bet you didn't get the one-way quite straight when you pressed it in to the main gear. Take the gear out and take a look.
Old 01-24-2007, 07:13 PM
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Default RE: vibration and wobble from the main shaft?

ORIGINAL: Andrew McGregor

I bet you didn't get the one-way quite straight when you pressed it in to the main gear. Take the gear out and take a look.
Hi, no. i took it out and even put a spare one-way into a spare gear.
the last thing I changed was the Head-housing itself from plastic to mental (Align).
I can't imagine that this causes a problem but I will remove it now to go back step by step
Old 01-25-2007, 07:25 AM
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Default RE: vibration and wobble from the main shaft?

ok, problem is solved.
the upper main bearing seems to be gone. I took both out and you can feel a 'grinding'....
Old 01-25-2007, 10:24 AM
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Default RE: vibration and wobble from the main shaft?

I had the same problem. Couldnt find the wobble. Finaly found the main shaft berings were shot. replaced them, now smooth as silk. I onlt had about 10 flights. and one minor crash.
Old 01-27-2007, 05:36 PM
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Default RE: vibration and wobble from the main shaft?

so. smooth as silk!

I could have saved a lot of time if I would have checked the main bearings first...

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