Following WWII many surplus Lockheed L-18 Lodestars were upgraded with various mods and used as corporate aircraft. One of the mods was an electric trim motor on the elevator tab - Spartan did this particular job.
One ship had the wings fail in the negative G direction during cruise (50s or 60s) - and the trim tab was found in the full-nose-down position. The fix was a slower-turning, lower hp trim motor.
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