NTSB urges grounding of all Zodiac CH-601XL's

http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl

" wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl

I'm assuming they are only talking about the handful of SLSA Zodiacs,
because I don't think the ones built as experimental aircraft can be
identified in any unambiguous way - and they don't have any common
manufacturer. I presume they'd have to try and hunt them all done manually
(somehow?) and presumably revoke or suspend each aircraft's airworthiness
certificates or otherwise change their operations limitations.

wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl

Ouch! Control flutter and reduced sick force per G at high g

Well, this is homebuilders heaven - so I suppose we could use a
reminder that balancing control surfaces, specially tail feathers,
can help stop the onset of flutter, that loose control wires
and rods can encourage.....

Brian W

On Apr 14, 8:36*pm, Brian Whatcott wrote:
wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl

Ouch! * Control flutter and reduced sick force per G at high g

Well, this is homebuilders heaven - so I suppose we could use a
reminder that balancing control surfaces, specially tail feathers,
* can help stop the onset of flutter, that loose control wires
* and rods can *encourage.....

Brian W

How do you balance ailerons that aren't hinged?

150flivver wrote:
On Apr 14, 8:36 pm, Brian Whatcott wrote:
wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl
Ouch! Control flutter and reduced sick force per G at high g

Well, this is homebuilders heaven - so I suppose we could use a
reminder that balancing control surfaces, specially tail feathers,
can help stop the onset of flutter, that loose control wires
and rods can encourage.....

Brian W

How do you balance ailerons that aren't hinged?


Well they are hinged just that the hinge is an extension of the upper
skin of the aileron. Interesting point though. It seems that most if not
all of the accident aircraft did use a more traditional piano hinge?

150flivver wrote:
On Apr 14, 8:36 pm, Brian Whatcott wrote:
wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl
Ouch! Control flutter and reduced sick force per G at high g

Well, this is homebuilders heaven - so I suppose we could use a
reminder that balancing control surfaces, specially tail feathers,
can help stop the onset of flutter, that loose control wires
and rods can encourage.....

Brian W

How do you balance ailerons that aren't hinged?


You've got me: how DO the ailerons work on a CH-601XL?

Brian W

Brian Whatcott wrote:
150flivver wrote:
On Apr 14, 8:36 pm, Brian Whatcott wrote:
wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl
Ouch! Control flutter and reduced sick force per G at high g

Well, this is homebuilders heaven - so I suppose we could use a
reminder that balancing control surfaces, specially tail feathers,
can help stop the onset of flutter, that loose control wires
and rods can encourage.....

Brian W

How do you balance ailerons that aren't hinged?


You've got me: how DO the ailerons work on a CH-601XL?

Brian W

Go here and scroll about half way done the page.

But as I mentioned most if not all the accident aircraft had regular
hinges.

Gig 601Xl Builder wrote:
150flivver wrote:
On Apr 14, 8:36 pm, Brian Whatcott wrote:
wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.
Karl
Ouch! Control flutter and reduced sick force per G at high g

Well, this is homebuilders heaven - so I suppose we could use a
reminder that balancing control surfaces, specially tail feathers,
can help stop the onset of flutter, that loose control wires
and rods can encourage.....

Brian W

How do you balance ailerons that aren't hinged?


Well they are hinged just that the hinge is an extension of the upper
skin of the aileron. Interesting point though. It seems that most if not
all of the accident aircraft did use a more traditional piano hinge?


Ah yes, a flex-hinge - a neat concept.
To balance a surface hinged with whatever, there are several choices.
1) (traditional) a leading horn outboard or inboard of the fixed
surface with a lead weight up front.
2) a lower aileron surface that comes further forward than the upper
surface, and that's leaded on its front seam. Like the Cessnas.
3) an aero and mass balanced extension - often seen on rudders:
a leading extension that balances the rudder mass, that reduces torque
along the rudder, and reduces pedal force. Some extensions are just for
aero effect.

Brian W

Gig 601Xl Builder wrote:


You've got me: how DO the ailerons work on a CH-601XL?

Brian W

Go here and scroll about half way done the page.

But as I mentioned most if not all the accident aircraft had regular
hinges.


I've flown a 701 with the hingless hinges.

The ailerons felt very stiff in flight.

I can well believe that set-up would prevent flutter -
or at least move the resonant response way up there.

Jim Logajan wrote:
" wrote:
http://www.cnn.com/2009/US/04/14/nts...ane/index.html
Designed by Zenair.
Just saw it on CNN.

I'm assuming they are only talking about the handful of SLSA Zodiacs,
because I don't think the ones built as experimental aircraft can be
identified in any unambiguous way - and they don't have any common
manufacturer. I presume they'd have to try and hunt them all done manually
(somehow?) and presumably revoke or suspend each aircraft's airworthiness
certificates or otherwise change their operations limitations.

You're right, I don't think they can formally take action against the
Experimental Amateur-Built Zenairs. And if they do, it wouldn't last
long.... the "manufacturer" of the aircraft can "correct the condition"
any way they see fit.

I count about 480 total Zenair 601s on my January 2009 edition of the
FAA registration database, of which about 360 actually have
airworthiness certificates (my assumption is that the rest are
homebuilts under construction). Of those, 54 are listed as SLSAs.

Ron Wanttaja