wrote in
:

On Apr 26, 1:50 pm, Bertie the Bunyip wrote:

Actually, there are plenty of airplanes with tabs not much bigger
than trim tabs that use them to fly the airplane. There is no
connection whatsoever between the surface and the stick. All done by
the tab. I don;'t think anyone is making any of them these days. Last
new design I can think of is the DC-8.

Bertie

Servo tabs. Sometimes with a spring onto the surface itself, for
low-speed control, and sometimes with no connection other than the
tab's hinge to the surface. But it does move the control surface,
which is what controls the airplane. The tab itself doesn't fly the
airplane. It actually moves in the opposite direction to the surface.


That's right. Lots of biggies used them in the old days. There are also
balance which just aid a conventionally controlled surface in a similar
way. Those I have flown. Generally htey also have a spring tab which is
adjacent and gears down the action of the servo or balance tab. Without the
spring tab the servo or balance tab would make the control surface more
sensitive at higher speeds, so the spring tab acts as a kind of artificial
feel.


Bertie