On Thu, 3 Jun 2004 16:47:43 -0400, "Bob Chilcoat"
wrote:

If the stabilator on the Aztec is the same as that on the Cherokee, the
antiservo tab isn't the sole thing driving the stabilator, although it looks
like it. If you take the top half of the tail cone off, you can see a large
tubular rod extending forward into the tail from the main pivot for the
stabilator. I'm told that this has a counterweight on the end inside the
tail, and that the main control (don't know if it's a rod or cables) from
the yokes attach to this. The only cables going to the trim jackscrew are
the ones from the trim control between the seats. If the trim jackscrew
stripped out, you would not lose the ability to move the stabilator with the
yoke, but you might lose all antiservo action of the tab, depending on the
failure mode. This may or may not be a complete disaster. The reason there
is antiservo action is so that the forces on the stabilator don't result in
positive feedback as you move the stabilator away from the neutral position.
Since the center of pressure moves with AOA, without the antiservo action
the normal aerodynamic action would be to push the stabilator farther from
neutral the farther you move it, the opposite of what you want. At least
that's the way I understand it. Can you fly with it like that? Don't know.
Don't want to find out.

We're rapidly reaching the conclusion that we should get it sooner rather
than later.

I have pulled one of these apart to replace the bobbin.
your description is exactly correct.
btw when you replace the bobbin, if the trim indicator doesnt seem to
be in exactly the old positions you have come to know when you
reassemble it all, then old son you have done what we did and put it
in upside down. it is almost totally symetrical and the only
indication that it is in upside down is that the trim indicator sits
out of position.

the counterweight is a large lump of cast iron.

amazing to think that the entire tailplane is held to the fuselage by
two AN3 hinge bolts isnt it :-)
Stealth Pilot