I've noticed some confusion here on just what sort of tab is on a particular airplane so I thought I would at least explain how the difference was explained to me.
Trim Tab; The simplest of all, a small tab screwed, riveted or welded to the trailing edge of a control surface that can be bent to correct for heaviness or correct cruse flight trim.
Cockpit controlled Trim Tab; A hinged variant of the Trim Tab that is attached with a linkage of some sort that allows the pilot to set the tab to a specific point in flight.
Balance Tab; A hinged tab that is linked in such a way that it moves in the opposite direction of the control surface to reduce or "Balance" the control forces. Usually ground adjustable.
Balance/Trim Tab; Used with a cockpit controlled device that allows the pilot to trim the airplane in addition to providing reduced control forces.
Servo Tab; A tab that is rigged into the control system in such a way that the initial movement of the control only moves the Tab and the Tab drives the control surface through a specified range requiring very little force on the control input. The linkage provides that larger control inputs move the control surface.
Anti Servo Tab; Used on stabilators (Piper) to return the control surface to neutral as I understand them but I am least familiar with how these work.
Any one with a more technical explanation is welcome to comment.
Edited by: Neil
