Trim Tabs

chris

Well-Known Member
Hey guys,

Can anyone explain why the trim tab moves in the opposite direction than the elevator? ie) you want to trim nose up... to get nose up using the elevators, the elevators will be deflected upward. However, to trim nose up, the tab is deflected downward.

TIA.
 

pilot602

If specified, this will replace the title that
The tab moves in the opposite direction in order to move the main control surface in the correct direction for the desired action. I.E. the trim tab moves down which in turn forces the elevator up which in turn forces the "tail" down. Just think of the trim tab pointing to the direction the empanage, as a whole, is eventually going to move.
 

cmsick

New Member
Using your example, when the trim tab is moved downward, the force of the airflow strikes the bottom of the tab causing the elevator to move upwards. This works just the opposite also. If you need nose down trim, the trim tab is moved upward allowing the airflow to strike the top of the tab and the elevator moves downward in response.
 
Yeah what they said....

I see this action all the time that I fly SWA or when I'm flying ina DL 737-800.

The 737's have trim tabs on the ailerons.

Anyone else know what other commericial planes have trim tabs on the ailerons?


Matthew
 
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