Hello all,
I have just installed the trim servo / bellcrank and trim tab link rod.
On checking the relative movement of trim tabs and tailplanes (starting
with tabs level with tailplanes in neutral position and trim servo mid
position), the movements are as specified in the manual with the
tailplane moved trailing edge up 12 degrees (TP 12 degrees up, tab 27.6
degrees up or 15.6 relative to tailplane, exactly the specified amount).
But moving the tailplane 4 degrees down, the tab moves 8.5 degrees down
or 4.5 deg relative to the tailplane. This is less than the acceptable
range of 4.8 to 6 degrees specified in the manual. I have the specified
6 degrees movement each way with the trim servo.
The manual doesn't say what to do about this though. The manual says the
tab should move relative to the tailplane with a ratio of 1.3 to 1. But
looking at the design, it seems that the relative movement of the tabs
must progressively reduce as the tailplane moves trailing edge down
because the link rod is moving closer to the torque tube.
Can anyone tell me whether this is a real problem, and if so how to
correct it?
Regards,
Keith Hickling
New Zealand
Kit 613
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