Today's Message Index:
----------------------
1. 04:24 AM - Re: Flying Times (The Minearts)
2. 06:32 AM - Re: NTSB letter and flutter. (Gig Giacona)
3. 07:24 AM - Re: Re: NTSB letter and flutter. (Paul Mulwitz)
4. 08:54 AM - Re: Additional NTSB Documents (Stephen Smith)
5. 09:15 AM - Re: Flying Times (KC7HFA)
6. 11:10 AM - Re: Re: Additional NTSB Documents (Terry Turnquist)
7. 12:51 PM - Re: Additional NTSB Documents (Sabrina)
8. 12:54 PM - Re: Re: Additional NTSB Documents (Greg Cox)
9. 04:13 PM - rear spar reinforcement (paul baker)
10. 04:26 PM - Re: Additional NTSB Documents (sonar1@cox.net)
11. 08:09 PM - Re: Additional NTSB Documents (John Smith)
Message 1
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| Subject: | Re: Flying Times |
N164SM has been flown approximately 10 of her first 18 hours this year,
since 7/30 has been down for installation of a Gold Oil system and Weseman
5th Bearing kit, now ready to resume flying.
Steve Mineart
CH-601XL/ WW Corvair
Message 2
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| Subject: | Re: NTSB letter and flutter. |
psm(at)att.net wrote:
>
>
> The letter itself says: "It appears . . .flutter . . . likely source". This
is a country mile away from a statement that flutter caused the accidents.
It is merely a conjecture that is presented for further consideration and testing.
>
> Paul
> XL awaiting engineering changes
>
> -
Well the same letter also said this, "There is substantial circumstantial evidence
that flutter occurred in some, if not all, of the above-cited accidents."
Which about a city inch from saying flutter was the cause.
--------
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270102#270102
Message 3
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| Subject: | Re: NTSB letter and flutter. |
It is an unfortunate truth that there are many different ways to
interpret complex statements in our language. For people whose
reading is primarily entertainment/literature or newspaper articles
it is useful to ignore many of the words in each sentence to get the
core meaning. In technical writings this will lead you down the wrong path.
If you ignore the qualification that the "Evidence" is substantial
and circumstantial in "substantial circumstantial evidence" and you
already hold the belief that flutter is behind the accidents then
that statement can be comforting. However, if the writer really
believed there was enough evidence to establish the fact he would not
have used the qualifications of "Substantial" and "Circumstantial" in
his statement. This removes his assertion two different times from a
direct statement.. He is really saying (in technical jargon) flutter
is a candidate for the cause of the accidents. However there is no
actual evidence but there is circumstantial suggestion that supports
this notion. In addition, the circumstantial evidence isn't really
consistent but only somewhat supporting the notion which means it is
substantial rather than convincing. He further reduces the
confidence by referring to "Some" of the accidents instead of "All" of them.
Just like the opening paragraph of the letter, the writer uses two
qualifying phrases to limit his confidence in the statement that
flutter is behind the accidents. Once again the statement is an
argument for further study rather than a definitive assertion.
I have heard comments that the ZBAG group reached the conclusion that
flutter was the cause of all the problems with Zodiac XLs and somehow
got the NTSB to consider this conclusion. For them, the NTSB letter
can provide support for their conclusion. For someone who carefully
reads the NTSB letter without already being convinced of the flutter
argument the letter says just the opposite thing. It allows for the
possibility that flutter is the cause but carefully refrains from
actually supporting that conclusion.
What the NTSB letter is crystal clear about - with no qualifying
language at all - is that there have been a lot of fatal accidents
and the fleet should be grounded.
Paul
XL awaiting engineering changes
At 06:31 AM 10/30/2009, you wrote:
>psm(at)att.net wrote:
> > The letter itself says: "It appears . . .flutter . . . likely
> source". This is a country mile away from a statement that flutter
> caused the accidents. It is merely a conjecture that is presented
> for further consideration and testing.
> >
> > Paul
> > XL awaiting engineering changes
> >
> > -
>
>Well the same letter also said this, "There is substantial
>circumstantial evidence that flutter occurred in some, if not all,
>of the above-cited accidents." Which about a city inch from saying
>flutter was the cause.
Message 4
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| Subject: | Re: Additional NTSB Documents |
Interesting information. The location of failure is for sure a weak spot on the
wing. I noted this weakness before my plane even flew. I always thought it
odd that such a large hole would be placed in a critical component but I figured
someone knew that it was OK; maybe not...
The PDFs are careful not to say the deformation occurred in flight. They
even suggest that the deformation may have occurred on impact. However
should the deformation occur in flight the aileron and flap would lock
together so that the aileron would no longer move. A crash would result
without a doubt.
I have looked at the PDFs three times. I conclude that if the NTSB knew
what the deformation "meant" in the crash investigation, they would say
something more definitive. I think this is a symptom, not a cause; probably
not interesting nor an area to fix on our planes. I would not fault anyone
for adding a bit a aluminum in that spot to make it stronger however. I
wonder what the 650 looks like in this area.
Steve
--------
Steve Smith
N601WF
Zenair Zodiac XL
Jabiru 3300
600+ hours
Sensenich composite - ground adjustable
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270120#270120
Message 5
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| Subject: | Re: Flying Times |
I've put on 26 hours since March 2009. The flight down to Quality Sport Planes
(in Cloverdale Ca) fly-in this October was great!
--------
Ron Asbill
N601ZX - CH-601 XL
Jabiru 3300
Completed and Flying!~
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270128#270128
Message 6
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| Subject: | Re: Additional NTSB Documents |
This is what I did to beef up that area. I'm not advocating this for anyone else..use
your own discretion.Terry Turnquist
----- Original Message ----
From: Stephen Smith <sRoydSmith@hotmail.com>
Sent: Fri, October 30, 2009 10:54:17 AM
Subject: Zenith601-List: Re: Additional NTSB Documents
Interesting information. The location of failure is for sure a weak spot on the
wing. I noted this weakness before my plane even flew. I always thought it
odd that such a large hole would be placed in a critical component but I figured
someone knew that it was OK; maybe not...
The PDFs are careful not to say the deformation occurred in flight. They
even suggest that the deformation may have occurred on impact. However
should the deformation occur in flight the aileron and flap would lock
together so that the aileron would no longer move. A crash would result
without a doubt.
I have looked at the PDFs three times. I conclude that if the NTSB knew
what the deformation "meant" in the crash investigation, they would say
something more definitive. I think this is a symptom, not a cause; probably
not interesting nor an area to fix on our planes. I would not fault anyone
for adding a bit a aluminum in that spot to make it stronger however. I
wonder what the 650 looks like in this area.
Steve
--------
Steve Smith
N601WF
Zenair Zodiac XL
Jabiru 3300
600+ hours
Sensenich composite - ground adjustable
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270120#270120
Message 7
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| Subject: | Re: Additional NTSB Documents |
With respect to 6-W-7,
I drilled a 25mm aileron control rod hole rather than a 38mm hole.
I drilled the 25mm hole 100mm outboard of RR7 rather than 92mm
I placed the BOTTOM (not the center) of the hole 20mm from the lower edge.
With respect to 6-W-6,
I drilled the Aileron Bellcrank support pivot hole 24 mm from the lower surface,
rather than 20. I used 1 1/4" rather than 1" angle.
This bellcrank support then rests on an .040 doubler rather than directly on the
rib.
If you center a 38mm diameter hole 20mm from the bottom, per plans, you have compromised
the rear spar.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270149#270149
Message 8
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| Subject: | Re: Additional NTSB Documents |
The rear spar on a CH650 has this hole positioned 92mm outboard of RR#7 and
20mm up from the bottom radius. The hole is 38mm OD and therefore we have
2mm edge distance to the bottom radius and is 36% of the 106m rear spar web.
Is it necessary that this hole be so large or could it be reduced?
Greg Cox
Zenith Zodiac CH650, VH-ZDC
Sydney, Australia (Cecil Hills)
-----Original Message-----
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of Stephen
Smith
Sent: Saturday, 31 October 2009 2:54 AM
Subject: Zenith601-List: Re: Additional NTSB Documents
<sRoydSmith@Hotmail.com>
Interesting information. The location of failure is for sure a weak spot on
the wing. I noted this weakness before my plane even flew. I always
thought it odd that such a large hole would be placed in a critical
component but I figured someone knew that it was OK; maybe not...
The PDFs are careful not to say the deformation occurred in flight. They
even suggest that the deformation may have occurred on impact. However
should the deformation occur in flight the aileron and flap would lock
together so that the aileron would no longer move. A crash would result
without a doubt.
I have looked at the PDFs three times. I conclude that if the NTSB knew
what the deformation "meant" in the crash investigation, they would say
something more definitive. I think this is a symptom, not a cause; probably
not interesting nor an area to fix on our planes. I would not fault anyone
for adding a bit a aluminum in that spot to make it stronger however. I
wonder what the 650 looks like in this area.
Steve
--------
Steve Smith
N601WF
Zenair Zodiac XL
Jabiru 3300
600+ hours
Sensenich composite - ground adjustable
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270120#270120
Message 9
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| Subject: | rear spar reinforcement |
After looking at the pictures of the wing failures, I am glad
I made a simple reinforcement of the rear spar where the
pushrod goes through the spar.The hole is rather large and
is very close to the bottom spar cap. I have flown 100 hrs
so far this year and I always fly within the limitations of the
airplane. After 61 years of flying I find It is best to read the
book and do what it says.You can find the attachment at
http:/members.cox.net/n601ge/drawings/rearspar.html
It is well written and very easy to do.
paul baker cfi
Message 10
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| Subject: | Re: Additional NTSB Documents |
I didn't like the looks of this hole when I built my 601, but didn't make any changes.
I am actually happy that this inspector has followed up on this. Seems
that this could be a problem especially with any quick aileron inputs with the
piano-hinged ailerons.
This is certainly a lot easier to fix than counter-weights on the ailerons.
The strength is in the top and bottom (like an I beam) so an extra plate on the
top and bottom of the wing would be all that would be required.
Fred Sanford...N9601....
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270178#270178
Message 11
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| Subject: | Re: Additional NTSB Documents |
I used the leftover outboard-rear spar cut-off to "double-up" the rear sp
ar aileron rod hole area.- The holes do not need to be that large but the
y need to be close to the bottom of the rear spars to clear the aileron rod
s.=0A=0A=0A
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