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Diferential throw on surfaces -- How to get rid of it!!!

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Old 08-22-2003, 09:39 PM
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Futurase
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Default Diferential throw on surfaces -- How to get rid of it!!!

Guys,
I have a UCANDO3D and I am running elevator and gear channels to to the two servos on each elevator half. I get differential throws. I am using a 10X and I have a 8103 and both do the same. Both show equal moment on the servo screen on the radios. I set the elevator as master and the gear as slave like it should be and set the mix at 100% and I set the mix till both elevator halves go the same direction at the same time. What am I missing??? The elevator halves do not move the same at all. I think I am missing something on setup on the plane. I try to get the arms on the servo centered in about the same place. The linkages are different lengths as the servos are in different spots on the plane on both sides. I have the horn the exacts same spot on both elevator halves. What am I over looking???

Thanks,

Scooter Ross
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Old 08-22-2003, 10:29 PM
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mr.rc-cam
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Default Diferential throw on surfaces -- How to get rid of it!!!

Remove the dual rate mix on the elevator channel. Be sure T-ADJ's are equal on both channels and in both directions.
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Old 08-22-2003, 11:01 PM
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Phil Cole
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Default Diferential throw on surfaces -- How to get rid of it!!!

The first thing I'd look as is whether the servos have the same travel over the same input range.

Plug each servo into the same channel in turn and measure the travel at the servo. You can attach a long pointer to the servo to make differences more easily seen.

If the servos are different, use the subtrim and travel adjustments on each channel to get the elevator halves to track.

There will be a small difference in travel due to the different pushrod lengths. You can use the travel adjustments to tune this out at the ends of the travel but there will be slight discrepancies at intermediate points. If this is a problem (it probably isn't) then use a curve mix to line up the elevators at the points on the curve mix.
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Old 08-27-2003, 10:12 PM
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Default Diferential throw on surfaces -- How to get rid of it!!!

tape a few pieces of carbon rod or music wire to the elevator halves so they point towards each other about a foot behind the tail, use sub trim and travel adjust to get the center and endpoints the same, and adjust the servo speeds with the 10X to get the rods to stay paralell with each other throughout the travel, make sense? theres an artical about this in MA magazine Project Extra.


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