Today's Message Index:
----------------------
1. 06:52 AM - Re: rear spar reinforcement (Jim Belcher)
2. 07:11 AM - Re: Additional NTSB Documents (Sabrina)
3. 09:01 AM - Re: Additional NTSB Documents (dougsire)
4. 09:17 AM - Re: Re: Additional NTSB Documents (Paul Mulwitz)
5. 09:54 AM - XL rear spar (jaybannist@cs.com)
6. 10:43 AM - Re: XL rear spar (Terry Turnquist)
7. 10:49 AM - Re: XL rear spar (Jim Belcher)
8. 11:25 AM - Re: Additional NTSB Documents (Sabrina)
9. 11:42 AM - Re: XL rear spar (jaybannist@cs.com)
10. 12:23 PM - Re: XL rear spar (Jim Belcher)
11. 02:52 PM - Re: 601 nose gear (Thruster87)
12. 03:26 PM - Complete 601XL kit for sale. (Walter Carey)
13. 03:55 PM - Re: Re: 601 nose gear (Greg Cox)
14. 04:10 PM - Re: 601 nose gear (Ron Lendon)
15. 07:50 PM - Re: 601 nose gear (Thruster87)
Message 1
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| Subject: | Re: rear spar reinforcement |
I find this a much more logical thing to do than any of the things espoused by
the LAA. It actually fixes something that might be a problem (I think it is a
problem, but that's an opinion, and should be considered such).
On Friday 30 October 2009 18:11, paul baker wrote:
> 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
--
============================================
Do not archive.
============================================
Jim B Belcher
BS, MS Physics, Math, Computer Science
A&P/IA
Retired aerospace technical manager
Mathematics and alcohol do not mix.
Do not drink and derive.
============================================
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| Subject: | Re: Additional NTSB Documents |
Looking back on it, an easy fix would be to purchase flap hinges that are about
a foot longer than the flaps, using the forward portion of the outboard last
foot of the flap hinge to reinforce the lower rear spar cap, discarding the aft
portion of this new flap hinge extension.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270221#270221
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| Subject: | Re: Additional NTSB Documents |
I think the real question to be answered here is not where the compression buckling
occurred, but rather why did it occur. What physical force caused this
damage? Personally I think this area is in need of strengthening and some of
the suggestions are very good. After seeing these photos for the first time
a couple of weeks ago I had the same thought as Sabrina regarding extending
both the spar side of the aileron and flap hinge so they overlap.
But the compression buckling alone did not bring these aircraft down; it is just
the result, or signature, of some other force. I would say that the damage
either had to have been present on the ground before the aircraft took off and
the pilot did not notice it (not likely), or it occurred during flight, or it
occurred as it hit the ground or water. Take a closer look at the damage to
the left wing in the photos of the Markermeer (Dutch) accident (pgs 2-5).
In this accident, the right wing folded over the aircraft, and the left wing
was relatively straight. Could this damage have occurred as it hit the water?
You can see from the damage to the leading edge D cell which is crushed that
it took the bulk of the impact energy, so it likely hit somewhat parallel to
the water.
The skin on both the top and bottom of the wing is indented outward at the damage
spots. Conceivably if the wing had hit the earth at the wing tip just right,
it might have caused this type of buckling, but that clearly did not happen.
Maybe if the wing hit the water primarily at the outboard end of the leading
edge, that would have bent the outboard end of the rear spar back some and
caused it. However, if it did that, we would expect to see the aileron angled
back and hitting the flap. The photo at the bottom of page 4 shows that not
to be the case. There is a consistent gap between the aileron and flap.
So what might be the most plausible explanation? Well, since it is well documented
that flutter can occur in unbalanced ailerons, and that it could easily
cause an upward and downward motion of the outboard end of the wing which could
cause the damage shown (at the weakest spot on the rear spar), I would have
to say that flutter is the most likely force which caused the compression damage.
And of course since it is also well known that left unchecked, flutter can
quickly destroy an aircraft, I dont see any explanation other than flutter
as the cause.
--------
Doug Sire 601XL
Do Not Archive
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270234#270234
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| Subject: | Re: Additional NTSB Documents |
Hi Sabrina,
I don't get it.
Why use a hinge part instead of just cutting some aluminum to
reinforce the rear channel?
Also, why not reinforce both sides of the rear channel - both the top
and bottom? After all, the web has been essentially removed in that
area. Perhaps it is the web that should get a doubler rather than the flange.
Paul
XL Awaiting engineering changes
At 07:10 AM 10/31/2009, you wrote:
>Looking back on it, an easy fix would be to purchase flap hinges
>that are about a foot longer than the flaps, using the forward
>portion of the outboard last foot of the flap hinge to reinforce the
>lower rear spar cap, discarding the aft portion of this new flap
>hinge extension.
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Let's put this hole in the rear spar in perspective. See attached pdf.
Comments??
Jay Bannister
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| Subject: | Re: XL rear spar |
Another approach might be to use .032 instead of .025.
Terry Turnquist
________________________________
From: "jaybannist@cs.com" <jaybannist@cs.com>
Sent: Sat, October 31, 2009 11:53:56 AM
Subject: Zenith601-List: XL rear spar
Let's put this hole in the rear spar in perspective. See attached pdf. Comments??
Jay Bannister
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| Subject: | Re: XL rear spar |
I realize that castellated beams and truss structures are common in
architecture, but I would not personally use either one for a spar. Someone
else might.
If I remember correctly, a truss uses cross members for bracing, and is trying
to make the overall structure stronger. When a hole is cut in a solid piece
of metal for an aircraft, I seem to recall that the loads must flow around
the hole, and the hole must neither be too big, nor too close to the edge of
the material for this to work as intended.
If the hole in your spar came out - to scale - no bigger than your sketch, I'm
glad for you. It would still be too close to the edge for my comfort. I think
my spar hole for aileron pushrod access, when cut to the size shown on the
plans, is proportionally bigger.
I could probably go dig up the data on hole size vs material width, edge
distance, etc, but I'd bet the hole in the Zenith spar (at least on my
aircraft) wouldn't meet the criteria. Before my bird flies, I want to take a
hard look at this. I'm not about to ground the bird, hoping for engineering
changes that may or may not come, but I am going to fix anything I establisdh
to my own satisfaction is wrong.
Obviously, everybody is entitled to their own view. This is mine.
On Saturday 31 October 2009 11:53, jaybannist@cs.com wrote:
> Let's put this hole in the rear spar in perspective. See attached pdf.
> Comments??
>
> Jay Bannister
--
============================================
Do not archive.
============================================
Jim B Belcher
BS, MS Physics, Math, Computer Science
A&P/IA
Retired aerospace technical manager
Mathematics and alcohol do not mix.
Do not drink and derive.
============================================
Message 8
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| Subject: | Re: Additional NTSB Documents |
I hope the NTSB and FAA realize that much of the fault rests with builders and
pilots.
I have seen aircraft where the rear spar attach area was mis-cut and patched, I
have seen main spars where the bolt holes have been notched and chewed up, and
now this UT plane with no primer on bare steel parts, patches over holes in
the rear spar that don't completely cover the mis-cut hole. Ouch!
The 38mm hole centered 20mm from the lower edge compromises the rear spar. That
does not mean that it will fail, just that the designer made compromises.
However, when pilots or builders add their own mistakes to design compromises,
bad things can happen.
We, as a group, should be working on/around these critical design compromises CH
has bestowed upon us.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270250#270250
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| Subject: | Re: XL rear spar |
Jim,
I do respect your opinion. I didn't intend to start something, nor to agi
tate anyone. I am obviously defending the design, but I am not an aeronaut
ical engineer. However, I want to point out that structures answer to the
same laws of physics, whether in a bridge, a building or an airplane. The
compressive and tensile loads in a beam are primarily carried by the flan
ges. The web primarily locates the flanges and resists horizontal shear,
which is minimal, as evidenced by the configuration of a bar joist. That
is the load you say "must flow around the hole", and it must not be close
to the flange to work right. But look at how large the "holes" are and
how close to the flange they are in a bar joist. Additionally, the flang
es must be stabilized to resist buckling, which in this case is done by th
e wing skins; and the way they are fastened, they also contribute to the
compressive and tensile strength of the flanges. That is why I am not at
all concerned by this hole in the rear spar.
And BTW, there are many, many examples of trusses used in aircraft constru
ction; especially in fuselages, but also in wing spars.
My drawing of the rear spar is to scale - though not the same scale as the
beam or the truss.
Jay Bannister
m>
I realize that castellated beams and truss structures are common in
architecture, but I would not personally use either one for a spar. Someon
e
else might.
If I remember correctly, a truss uses cross members for bracing, and is tr
ying
to make the overall structure stronger. When a hole is cut in a solid piec
e
of metal for an aircraft, I seem to recall that the loads must flow around
the hole, and the hole must neither be too big, nor too close to the edge
of
the material for this to work as intended.
If the hole in your spar came out - to scale - no bigger than your sketch,
I'm
glad for you. It would still be too close to the edge for my comfort. I th
ink
my spar hole for aileron pushrod access, when cut to the size shown on the
plans, is proportionally bigger.
I could probably go dig up the data on hole size vs material width, edge
distance, etc, but I'd bet the hole in the Zenith spar (at least on my
aircraft) wouldn't meet the criteria. Before my bird flies, I want to take
a
hard look at this. I'm not about to ground the bird, hoping for engineerin
g
changes that may or may not come, but I am going to fix anything I establi
sdh
to my own satisfaction is wrong.
Obviously, everybody is entitled to their own view. This is mine.
Message 10
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| Subject: | Re: XL rear spar |
On Saturday 31 October 2009 13:39, jaybannist@cs.com wrote:
> Jim,
>
> I do respect your opinion. I didn't intend to start something, nor to
> agitate anyone.
Jay, I'm neither offended nor agitated. You asked for comments; you got 'em. I
feel the design is a compromise at this point, and needs some beef up. I'd
love to have Chris Heintz take on this, and possibly his beef up.
But barring that information, I intend to do a bit of research, and see what
is allowable in this case. I suspect this exceeds the allowable. I seem to
remember having some tables somewhere that address this issue.
I deeply respect Chris' abilities. But he is human, and not beyond error. A
problem I've sometimes seen in one-man designs is that there is no oversight,
and no one verifying the design on a step by step basis. Whether that is true
here or not, I cannot say. But I wonder.
============================================
Do not archive.
============================================
Jim B Belcher
BS, MS Physics, Math, Computer Science
A&P/IA
Retired aerospace technical manager
Mathematics and alcohol do not mix.
Do not drink and derive.
============================================
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| Subject: | Re: 601 nose gear |
My original nose leg measured 0.080" wall thickness [come with the kit in 10/2007]
which bent due to nose fork collapse.Received a new leg and it measures 0.060"
wall thickness which corresponds to the drawings specifications on the plans.Does
anyone know if there was an up date of the nose leg wall thickness
???? Cheers T87
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270269#270269
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| Subject: | Complete 601XL kit for sale. |
If anyone is interested or knows of someone thinking of buying a 601 kit, t
he following is for sale:
-
Complete 601XL kit, including-aux 12 gal fuel tanks (48 gal total), landi
ng/nav/strobe lights, ect. Wings 90 %,-flaps 100%, ailerons 100%, empenna
ge 100%, fuselage 25% complete. Built to plans.-Workmanship rated "excell
ent" on both EAA Technical Advisor visits, and "excellent" by NAAA (Nationa
l Aircraft Appraisers Association)-appraiser in-Jun -09.-
-
$10,000 firm. Contact Walt Carey at 937-426-8095 or at www.careywf@sbcgloba
l.net. Located Dayton, Ohio.
Message 13
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| Subject: | Re: 601 nose gear |
There is a complete listing of the drawing updates on the ZAC site in
builders resources.
http://www.zenithair.com?zodiac/xl/xl-up-drawings.html
I have attached the last 2 update lists.
Regards,
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 Thruster87
Sent: Sunday, 1 November 2009 8:50 AM
Subject: Zenith601-List: Re: 601 nose gear
My original nose leg measured 0.080" wall thickness [come with the kit in
10/2007] which bent due to nose fork collapse.Received a new leg and it
measures 0.060" wall thickness which corresponds to the drawings
specifications on the plans.Does anyone know if there was an up date of the
nose leg wall thickness ???? Cheers T87
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270269#270269
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| Subject: | Re: 601 nose gear |
My prints and a crosscheck to the builders website confirms the XL 6-G-1-1 Nose
Gear Leg is 2" O.D. X .065" wall 4130N round seamless tubing.
6-G-1 01/08 NOSE GEAR STRUT ASSEMBLY
1. Spacers have been lengthened to 33.4mm for proper fit inside the bearing
seal.
2. Drain hole added to the bottom plate of Nose Gear Leg 6G1-1 also added
to Wheel Fork 6G1-2 and Fork Doubler 6G1-5.
3. plate welded to the top of 6G1-2 nose gear leg with 2 nuts welded to it has
been removed.
--------
Ron Lendon, Clinton Township, MI
WW Corvair with Roy's Garage 5th bearing
Zodiac XL, ScrapBuilder ;-)
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
http://home.comcast.net/~rlendon/site/
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=270279#270279
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| Subject: | Re: 601 nose gear |
Ron Lendon wrote:
> My prints and a crosscheck to the builders website confirms the XL 6-G-1-1 Nose
Gear Leg is 2" O.D. X .065" wall 4130N round seamless tubing.
>
>
> 6-G-1 01/08 NOSE GEAR STRUT ASSEMBLY
> 1. Spacers have been lengthened to 33.4mm for proper fit inside the bearing
> seal.
> 2. Drain hole added to the bottom plate of Nose Gear Leg 6G1-1 also added
> to Wheel Fork 6G1-2 and Fork Doubler 6G1-5.
> 3. plate welded to the top of 6G1-2 nose gear leg with 2 nuts welded to it has
> been removed.
What does it mean??? also added
to Wheel Fork 6G1-2 and Fork Doubler 6G1-5. statement number 2 Cheers
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