psm(at)att.net
Guest
|
 Posted: Thu Jul 31, 2008 7:26 am Post subject: 1 Last Post-open to critizism both constructive & otherw |
 |
|
Hi Sabrina,
I agree with your analysis and conclusions.
By lowering the trailing edge ZAC has not only increased the
decalage, they have also changed the wing incidence angle as compared
to the fuselage. I think both approaches (yours and theirs) add a
bit to the pitch stability compared to the original design.
From the comments posted by others, I think ZAC's goal was not to
increase the stability but rather to increase the forward
visibility. By changing the incidence they have made a bigger impact
on the airspeed capability of the plane. The fuselage (or wing,
depending on how you hold your head) has more parasitic drag because
of the incidence change.
In short, I think you have traded stability for drag while they have
traded forward visibility and stability for even more drag.
I don't know what happens if they align the engine thrust with the
longerons rather than the wing. I guess throttle changes will have
more impact on elevator trim. I have no opinion on your pre-loading
point with regard to the spar angle.
However, I still think (as I posted a few days ago) they are hoping
the bad publicity associated with the XL will all go away because
they changed the model name.
Paul
XL getting close
At 07:29 AM 7/31/2008, you wrote:
| Quote: | The decalage change still bothers me...
I increased the decalage, be it aerodynamic or geometric, by
pitching my horizontal stabilizer down two degrees.
Zenith has now increased the decalage by lowering the rear of the
wing and maintaining the status quo on the horizontal stabilizer. I
am told, second hand, this is done without ANY change to the main
spar set angle (that is why I wanted to compare plans.)
Both the 650 and Sabrina are inherently more stable than the 601
with this increased decalage giving it the ability to dampen larger
vibrations/oscillations. We both loose performance. The 601 is
more efficient. Correct?
With a factory O-200A engine mount, the engine mount aligns the
center of trust with the main longerons.
Does the twisting of the 650 main spar (if indeed it remains as
speced in the 601 plans) add strength to the structure by pre-loading it?
I lowered the leading edge of the my horizontal stabilizer to better
balance the airplane so will it fly level without trim (heavy
engine) compared to the line of thrust and main longerons. The
added benefit was additional stability.
By lowering the rear spar, the aircraft will fly more nose
down. To fly level, the 650, with a 601 engine mount, no longer
flies along its line of thrust or main longerons. Correct?
Comments?
|
| | - The Matronics Zenith-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Zenith-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
