Mechanics of Elevator Trim. In Detail.

On Jun 8, 9:17*pm, Michael Henry
wrote:
Capt. Geoffrey Thorpe wrote:
I assume you are most familiar with the use of a servo tab. Can you name
at least two other ways that it is commonly done in light aircraft?

The J-3 Cub has a moving stabilizer. Although you specifically said
"light aircraft" it's interesting to note that many airliners also us a
moving stabilizer.

This and another method are mentioned in this article:

http://flighttraining.aopa.org/learn.../articles/0209...

Yikes - that's it. The answer is in that link.

Since no other students responded...

...when I first started used/read about trim tab, I figured it was
"more of the same", meaning that there was some complex mechanism in
the aircraft where trim tab simply did more of whatever the elevator
was doing, but some how figured out how to release pressure on the
yoke.

Well that's true, but a more correct interpretation is that the trim
tab does not participate in elevating the aircraft really, but serves
to aerodynamically set the angle of the elevator, at which point the
elevator does its job. I learn this in MSFS by trying various
movements and watching outside the aircraft how control surfaces
responded. The trim tab was moving in opposite direction that I
thought it would. I also saw that on C172, there is an asymmetric,
with only one tab.

All obvious to pilots, but interesting for students, for me at least.

-Le Chaud Lapin-