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Old 06-17-2006, 11:08 AM   #76 (permalink)
kgfly
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Join Date: Jun 2006
Default Double-bubble technique for ensuring the flybar is level

Quote:
Originally Posted by Finless
The flybar may tip in any direction... You can hold it level with your hand and move the pitch full in both directions right?
Right.

Quote:
Originally Posted by Finless
The flybar is on a seesaw and is always free to move no matter where the pitch is. If not then you have something wrong....
Bob
OK, it's free to move, so at least I've got that right

I also find that, with a Mode2 Tx, if I move the collective (rhs) control stick in a clockwise circle then the main shaft will start to rotate clockwise (no motor installed) and if I move it in a counter-clockwise direction the main shaft will rotate counter clockwise. Is this OK or a sign of too much friction in the head ? I have read of folks puting a drop of oil on the top of the swashplate to lubricate where the inner plastic plate moves on the metal collar. Is this a good idea ? (I guess by now you can tell I'm a detail-oriented kind-of-guy :wink: )

FYI - Double-bubble technique for ensuring the flybar is level
==========================================
Given that the dining room table is not level and that we want at least +/- 0.5deg accuracy, it seemed to me that just eyeballing if the flybar is level is not reliable. So I came up with the following (although this might be overkill)?:

Assumptions
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1) For the flybar, "level" means at 90deg to the main shaft axis
2) Tail boom is also at 90deg to the main shaft axis (which is why the boom mount is a good place for gyros).

Setup
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a) Rest a bubble level in a fore/aft orientation on the top of the boom mount box (you know, the bad place to mount your gyro).
b) Use (thin) double-sided tape to place a bubble level along one of the flybar paddles

Usage
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Before making head or pitch adjustments ensure that the bubble positions on both levels match. It is not important if the bubbles are not dead-centre (ie the heli is not truly level) just that they are both in the same position.

Regards,
Kenneth
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