Originally Posted by
AfricanSkies
Maybe in a 737, But it's wasn't in other jets, like the Fokkers. The trim wheel is just geared ..again question the 737 design..are so many clack clack clack turns necessary?
Late reply, but:
It is needed because of the force required to move the THS at high speed due to the hinge being at the back end. This causes the airflow to incraese the required trim force, had the THS been hinged at the front and and the jackscrew at the trailing edge of the THS the force required to trim would have decreased with an increase in speed. I am not a designer so I have no idea if you could even have built it that way, but I believe aerodynamically speaking this is the reason so many revolutions are required.