Today's Message Index:
----------------------
1. 04:40 PM - Re: test (kmccune)
2. 05:28 PM - Re: testtest (Jim McBurney)
3. 05:50 PM - Zenith Family Problems? (Bob Collins)
4. 06:02 PM - Re: Zenith Family Problems? (Craig Payne)
5. 07:21 PM - Re: Zenith Family Problems? (MacDonald Doug)
6. 09:32 PM - Re: Zenith Family Problems? (Bob Percival)
7. 09:53 PM - Re: Zenith Family Problems? (John Marzulli)
Message 1
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:D
The discussion over there makes glad we have a STOL list!
bob(at)frontrange-pc.com wrote:
> I thought that might be the case but didn't want to miss out on any
> constructive STOL conversations.
> I'll resume my role as long time lurker, painfully slow builder.
> Thanks
> Do Not Archive
>
> Bob Percival
> 701/Vair
>
> --
--------
Mark Twain: Twenty years from now you will be more disappointed by the things that
you didn't do than by the ones you did do. So throw off the bowlines. Sail
away from the safe harbor. Catch the trade winds in your sails. Explore. Dream.
Discover.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=239974#239974
Message 2
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Thanks, Matt, for a separate 701801 list. 242 messages in the last four
days in the Zenith list! Thanks again
Blue skies and tailwinds
Jim
CH-801
DeltaHawk diesel
Augusta GA
90% done, 90% left
Message 3
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| Subject: | Zenith Family Problems? |
I have a question for you long-time STOL aficionados. Is there any
reason to worry about flutter of the flaperon on the Zenith STOL designs?
I have been following the "discussion" about potential 601XL aileron
flutter problems on the Zenith-List. One point seems to come through is
that using a mass-balanced aileron is a relatively common practice in
modern designs to reduce/eliminate flutter and, apparently, the 601XL
depends on proper tension on the control cables to satisfy this need
(Zenith has stated this). My personal observation is that, if what I
just stated is true, using mass-balanced ailerons would be preferable
because they require less frequent inspection and oversight.
My current interest is in the CH750, which of course has no history
other than what may be extrapolated from the 701 and 801. I don't see
any evidence of mass-balancing on the STOL models. Now, in many ways the
STOL planes are different than the 600 series designs, but is there any
reason to worry about similar issues on the 750? My first pass
observation is that the STOL planes are slower, have heavier control
surfaces, and the flaperon linkage (probably) has more inherent mass.
These would all point to flutter being less likely a problem on the STOL
designs that on the 600 designs.
In addition to concern about any (potential) real design issues, there
is the effect this whole issue might have on the reputation of Zenith
and the Zenith designs. A strong selling point for the Zenith designs is
the sterling reputation of the chief designer. If there are valid
criticisms of his design choices, particularly in an area that affects
safety, this would affect the whole Zenith ecosystem.
I am interested in your thoughts. Also, for those of you going to
Sun'N'Fun, please report anything you learn that would be of help to us
in the Zenith STOL community.
Thank you,
Bob Collins
Sunnyvale CA USA
Message 4
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| Subject: | Zenith Family Problems? |
Well, the 701 has been flying for a lot longer than the 601XL. I believe
that there hadn't been a fatal accident in the US until a year or two ago
when a new owner died doing some inappropriate low-level maneuvers in front
of his family.
-- Craig (incomplete 601XL and 701)
-----Original Message-----
From: owner-zenith701801-list-server@matronics.com
[mailto:owner-zenith701801-list-server@matronics.com] On Behalf Of Bob
Collins
Sent: Saturday, April 18, 2009 6:50 PM
Subject: Zenith701801-List: Zenith Family Problems?
<bobcollins42@gmail.com>
I have a question for you long-time STOL aficionados. Is there any
reason to worry about flutter of the flaperon on the Zenith STOL designs?
I have been following the "discussion" about potential 601XL aileron
flutter problems on the Zenith-List. One point seems to come through is
that using a mass-balanced aileron is a relatively common practice in
modern designs to reduce/eliminate flutter and, apparently, the 601XL
depends on proper tension on the control cables to satisfy this need
(Zenith has stated this). My personal observation is that, if what I
just stated is true, using mass-balanced ailerons would be preferable
because they require less frequent inspection and oversight.
My current interest is in the CH750, which of course has no history
other than what may be extrapolated from the 701 and 801. I don't see
any evidence of mass-balancing on the STOL models. Now, in many ways the
STOL planes are different than the 600 series designs, but is there any
reason to worry about similar issues on the 750? My first pass
observation is that the STOL planes are slower, have heavier control
surfaces, and the flaperon linkage (probably) has more inherent mass.
These would all point to flutter being less likely a problem on the STOL
designs that on the 600 designs.
In addition to concern about any (potential) real design issues, there
is the effect this whole issue might have on the reputation of Zenith
and the Zenith designs. A strong selling point for the Zenith designs is
the sterling reputation of the chief designer. If there are valid
criticisms of his design choices, particularly in an area that affects
safety, this would affect the whole Zenith ecosystem.
I am interested in your thoughts. Also, for those of you going to
Sun'N'Fun, please report anything you learn that would be of help to us
in the Zenith STOL community.
Thank you,
Bob Collins
Sunnyvale CA USA
Message 5
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| Subject: | Re: Zenith Family Problems? |
Bob, I am by no means an aeronautical engineer but my thumbnail engineering opinion
would be becasue of the mounting method of the flapperons on the STOL design,
they have semi mass balanced flapperons. Since they are mounted on the flapperon
spar line, there is a significant portion of their mass infront of the
mounting point.
Do Not Archive
Doug MacDonald
CH-701 Scratch builder
NW Ontario, Canada
> I have a question for you long-time STOL aficionados. Is
> there any reason to worry about flutter of the flaperon on
> the Zenith STOL designs?
>
Message 6
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| Subject: | Zenith Family Problems? |
Bob,
I'm no expert, but a quick browse of the NTSB accident database over the
last 20 years returned 27 '701' accidents. As Craig said, only one
fatality and a quick read of the probable cause on that accident would
not lead you to suspect the design. I saw no mention of flutter or
vibration in any of the reports. However, it appears that dead stick
landing technique might be worth practicing.
Bob Percival
701/Vair
-----Original Message-----
From: owner-zenith701801-list-server@matronics.com
[mailto:owner-zenith701801-list-server@matronics.com] On Behalf Of Bob
Collins
Sent: Saturday, April 18, 2009 6:50 PM
Subject: Zenith701801-List: Zenith Family Problems?
<bobcollins42@gmail.com>
I have a question for you long-time STOL aficionados. Is there any
reason to worry about flutter of the flaperon on the Zenith STOL
designs?
I have been following the "discussion" about potential 601XL aileron
flutter problems on the Zenith-List. One point seems to come through is
that using a mass-balanced aileron is a relatively common practice in
modern designs to reduce/eliminate flutter and, apparently, the 601XL
depends on proper tension on the control cables to satisfy this need
(Zenith has stated this). My personal observation is that, if what I
just stated is true, using mass-balanced ailerons would be preferable
because they require less frequent inspection and oversight.
My current interest is in the CH750, which of course has no history
other than what may be extrapolated from the 701 and 801. I don't see
any evidence of mass-balancing on the STOL models. Now, in many ways the
STOL planes are different than the 600 series designs, but is there any
reason to worry about similar issues on the 750? My first pass
observation is that the STOL planes are slower, have heavier control
surfaces, and the flaperon linkage (probably) has more inherent mass.
These would all point to flutter being less likely a problem on the STOL
designs that on the 600 designs.
In addition to concern about any (potential) real design issues, there
is the effect this whole issue might have on the reputation of Zenith
and the Zenith designs. A strong selling point for the Zenith designs is
the sterling reputation of the chief designer. If there are valid
criticisms of his design choices, particularly in an area that affects
safety, this would affect the whole Zenith ecosystem.
I am interested in your thoughts. Also, for those of you going to
Sun'N'Fun, please report anything you learn that would be of help to us
in the Zenith STOL community.
Thank you,
Bob Collins
Sunnyvale CA USA
Checked by AVG - www.avg.com
04/18/09 09:55:00
Message 7
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| Subject: | Re: Zenith Family Problems? |
Our EAA chapter is lucky to have Ron Wantaja speak to us from time to time.
I asked him once if he had found anything interesting about Zeniths during
his safety studies. His insight was the Zeniths have a much higher rate of
auto-conversions engines. When you subtract out the autoconversion
accidents, the fleet safety is much better than the EAB average. The engine
failures are more likely the result of the R&D part of creating a new
conversion/installation than anything else.
Personally I am planning on have more than a few people look over my Rotax
installation.
Safe flying.
John Marzulli
http://www.GenevieveMarzulli.org/
http://marzulli.smugmug.com/
http://701Builder.blogspot.com/
http://www.JohnMarzulli.net/
On Sat, Apr 18, 2009 at 9:49 PM, Bob Percival <bob@frontrange-pc.com> wrote:
> bob@frontrange-pc.com>
>
> Bob,
>
> I'm no expert, but a quick browse of the NTSB accident database over the
> last 20 years returned 27 '701' accidents. As Craig said, only one
> fatality and a quick read of the probable cause on that accident would
> not lead you to suspect the design. I saw no mention of flutter or
> vibration in any of the reports. However, it appears that dead stick
> landing technique might be worth practicing.
>
> Bob Percival
> 701/Vair
>
> -----Original Message-----
> From: owner-zenith701801-list-server@matronics.com
> [mailto:owner-zenith701801-list-server@matronics.com] On Behalf Of Bob
> Collins
> Sent: Saturday, April 18, 2009 6:50 PM
> To: zenith701801-list@matronics.com
> Subject: Zenith701801-List: Zenith Family Problems?
>
> <bobcollins42@gmail.com>
>
> I have a question for you long-time STOL aficionados. Is there any
> reason to worry about flutter of the flaperon on the Zenith STOL
> designs?
>
> I have been following the "discussion" about potential 601XL aileron
> flutter problems on the Zenith-List. One point seems to come through is
> that using a mass-balanced aileron is a relatively common practice in
> modern designs to reduce/eliminate flutter and, apparently, the 601XL
> depends on proper tension on the control cables to satisfy this need
> (Zenith has stated this). My personal observation is that, if what I
> just stated is true, using mass-balanced ailerons would be preferable
> because they require less frequent inspection and oversight.
>
> My current interest is in the CH750, which of course has no history
> other than what may be extrapolated from the 701 and 801. I don't see
> any evidence of mass-balancing on the STOL models. Now, in many ways the
>
> STOL planes are different than the 600 series designs, but is there any
> reason to worry about similar issues on the 750? My first pass
> observation is that the STOL planes are slower, have heavier control
> surfaces, and the flaperon linkage (probably) has more inherent mass.
> These would all point to flutter being less likely a problem on the STOL
>
> designs that on the 600 designs.
>
> In addition to concern about any (potential) real design issues, there
> is the effect this whole issue might have on the reputation of Zenith
> and the Zenith designs. A strong selling point for the Zenith designs is
>
> the sterling reputation of the chief designer. If there are valid
> criticisms of his design choices, particularly in an area that affects
> safety, this would affect the whole Zenith ecosystem.
>
> I am interested in your thoughts. Also, for those of you going to
> Sun'N'Fun, please report anything you learn that would be of help to us
> in the Zenith STOL community.
>
> Thank you,
>
> Bob Collins
> Sunnyvale CA USA
>
>
> Checked by AVG - www.avg.com
> 04/18/09 09:55:00
>
>
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