On 3/30/2020 8:30 PM, donald january via KRnet wrote:
I think Larry Flesner hit it right on the nose. Hope your HZ is adjustable
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
It really doesn't matter at this point. It is what it is and a trim tab
will resolve the issue. I''m guessing his trim tab is rather small and
limited deflection so not a problem aerodynamically.
To go down another level in this rabbit hole, it's not the tab that puts
the aircraft in trim but the deflection of the elevator. The air loads
on the tab simply hold the elevator at the desired angle with no input
from the control system. That's why the tab (with adjustable tab) moves
in the opposite direction of the direction we want the nose to move.
Nose up, elevator up, tab down. Nose down, elevator down, tab up. We
fly the aircraft to the pitch angle we want and then use the
(adjustable) tab to hold the elevator at that angle without control input.
Next time you're near a low wing piper, check out the tab on the
stabilator. It has two uses. One is to hold the stabilator at the
desired angle and the second is to provide feedback / resistance to
inputs on the pitch control. Control forces with a stabilator can be
very light. If the pilot pulls back on the control yoke the stabilator
trail edge moves up and the full length tab moves up also at an
increasing rate. This provides a force against the input from the
control column to give the pilot an idea of how much he is deflecting
the Stabilator.
I once made a flight to determine the amount of deflection of my tab at
cruise. I set the tab to trim the airplane at cruise and the did not
touch it again for the remainder of the flight. The photo shows the
amount of deflection I needed to trim in cruise for my c.g. location at
that time. If I would of had full fuel instead of partial fuel my c. g.
would have moved back a slight distance (I don't have a header tank) and
the deflection angle would have been less.
https://www.dropbox.com/s/dn8dgb5y836j3um/IMG_8611.JPG?dl=0
Larry Flesner
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