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Trimmable horizontal stabilizer (THS) and trim tab serve the similar purpose for two entirely different control architectures: Trim tab neutralizes the force on the pitch control for a reversible control system. THS neutralizes the pitch position (and, in the process, the force) for an irreversible control system (e.g. hydraulically/electromechanically ...


I've been around light airplanes for about 45 years and I've never seen a trimable stab and trimable elevator using a tab together. The closest I can come to that is the elevator trim bungee that is included with the jackscrew stab trim on the Piper Super Cub. The Super Cub has a moveable stabilizer that is the primary trim device, but also has a spring ...


It's unlikely that any airplane with a THS also has trim tabs. The benefit of adding them is slight (partial protection against failure of hydraulics), while the cost is extra mechanical complexity and extra drag. The extra drag is particularly important for airliners.

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