Trim type, jackscrew or trim tab

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Trim type, jackscrew or trim tab

Postby ZENO » Sat May 06, 2006 11:49 pm

I'm building a small aerobatic biplane that has jackscrew type stab trim. There are plenty of these flying, but in the interest of ease to build I would like to use a elevator trim tab. I know what the neutral position of the stab should be and the structural method of attaching the stab fixed. I planned on using a tab design similar to the Pitts and sized proportionally to the elevator sq. ft.

Am I missing other ramifications of using one type or the other...or anything else to consider?

ZENO 8)
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Postby billski » Tue Oct 30, 2007 10:52 am

Both types work.

The jack screw method is probably heavier overall.

When you use controllable tabs, it puts more weight in the elevator, which in turn requires more mass when you balance it.  Tabs are nice because you can trim with one, and tune control feel with the other one - If you want lighter forces, you rig the second one as a servo tab, and as an anti-servo tab to increase control gradients.

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