Today's Message Index:
----------------------
1. 12:38 AM - Fuel tank cushion strips (Craig Payne)
2. 02:42 AM - Re: Recent crashes (chris Sinfield)
3. 03:45 AM - Re: Fw: Re: Bottom Rudder Bracket attachment (David Downey)
4. 03:46 AM - Re: Load testing (Kurt A. Schumacher)
5. 04:33 AM - Re: Fuel tank cushion strips (TxDave)
6. 04:43 AM - Re: Ultimate Load vs. Limit Load (Martin Pohl)
7. 04:55 AM - Re: Re: Floats on CH701 (Carl Bertrand)
8. 05:09 AM - Re: >Re: British 601 Crash (was: 601 Crash) (Southern Reflections)
9. 05:10 AM - Re: Recent crashes (David Downey)
10. 05:20 AM - Re: Fuel tank cushion strips (Robin Bellach)
11. 05:20 AM - Re: Load testing (David Downey)
12. 05:33 AM - Re: Load testing (Jim Hoak)
13. 05:42 AM - Re: accident (ashontz)
14. 05:45 AM - Re: accident (ashontz)
15. 05:57 AM - Re: Recent crashes (Robert N. Eli)
16. 06:21 AM - Re: Recent crashes (ashontz)
17. 06:28 AM - Re: >Re: British 601 Crash (was: 601 Crash) (Kurt A. Schumacher)
18. 06:39 AM - Re: Recent crashes (David Downey)
19. 06:46 AM - Re: Re: Recent crashes (David Mikesell)
20. 07:06 AM - NTSB search for breakup accidents. (Paul Mulwitz)
21. 07:56 AM - Re: Re: Recent crashes (David Downey)
22. 08:09 AM - Re: Load testing (Rosalie DeMeo)
23. 08:14 AM - Re: Recent crashes (ashontz)
24. 08:42 AM - Re: Fuel tank cushion strips (leinad)
25. 09:06 AM - Re: Load testing (John Bolding)
26. 09:08 AM - Re: Re: Recent crashes (David Downey)
27. 09:09 AM - Re: Recent crashes (leinad)
28. 09:31 AM - Re: Re: Recent crashes (David Downey)
29. 09:43 AM - Re: Re: accident (ZodieRocket)
30. 09:59 AM - Re: NTSB search for breakup accidents. (Bill Naumuk)
31. 10:04 AM - Re: Load Testing (MaxNr@aol.com)
32. 10:13 AM - Re: Recent crashes (ashontz)
33. 11:27 AM - sattey wire for turnbuckles (flyingmike9)
34. 11:30 AM - Re: Hood Time for Sport Pilots (Tim Juhl)
35. 12:06 PM - Re: saftey wire for turnbuckles (rickpitcher)
36. 12:08 PM - Re: sattey wire for turnbuckles (Robin Bellach)
37. 12:34 PM - Re: sattey wire for turnbuckles (Kevin L. Rupert)
38. 12:40 PM - Re: saftey wire for turnbuckles (flyingmike9)
39. 12:42 PM - Re: sattey wire for turnbuckles (flyingmike9)
40. 12:43 PM - Re: Ultimate Load vs. Limit Load (Terry Phillips)
41. 02:01 PM - Wing sweep and recent crashes (George Swinford)
42. 02:46 PM - Re: Re: Recent crashes (Southern Reflections)
43. 02:46 PM - Re: Re: saftey wire for turnbuckles (David Downey)
44. 03:04 PM - Re: >Re: British 601 Crash (was: 601 Crash) (Southern Reflections)
45. 03:41 PM - Re: Wing sweep and recent crashes (ihab.awad@gmail.com)
46. 03:49 PM - Re: Wing sweep and recent crashes (ihab.awad@gmail.com)
47. 04:02 PM - Wing sweep and recent crashes (Jeyoung65@aol.com)
48. 04:10 PM - Re:Re:Recent crashes (MaxNr@aol.com)
49. 04:55 PM - 601 load tests (ZodieRocket)
50. 05:43 PM - Re: 601 load tests (Bill Naumuk)
51. 06:49 PM - Wing sweep and recent crashes (Gary Boothe)
52. 06:57 PM - Re: Re: saftey wire for turnbuckles (Juan Vega)
53. 07:26 PM - 178 seconds (ZodieRocket)
54. 07:36 PM - Re: Fuel tank cushion strips (Bryan Martin)
55. 08:23 PM - Cabin Floor and Rudder Pedals (Michael Valentine)
56. 08:35 PM - Re: Wing sweep and recent crashes (kevinbonds@comcast.net)
57. 08:39 PM - Re: Wing sweep and recent crashes (Southern Reflections)
58. 08:55 PM - Re: Recent crashes (kevinbonds@comcast.net)
59. 09:01 PM - Re: Wing sweep and recent crashes (kevinbonds@comcast.net)
60. 09:11 PM - Re: sattey wire for turnbuckles (Rosalie DeMeo)
61. 09:35 PM - Re: Wing sweep and recent crashes (kevinbonds@comcast.net)
62. 09:54 PM - Appologize (kevinbonds)
63. 11:18 PM - Re: acrobatics on 601s (Gift of Wings) (Gary Gower)
Message 1
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| Subject: | Fuel tank cushion strips |
What is the advantage of using the cork strips that Zenith specifies over
silicon rubber (specifically cowling baffle strips). I'm planning the
mounting of my header tank and I have the silicon on-hand.
Also, if I go that with the cork, what is a good source?
-- Craig
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| Subject: | Re: Recent crashes |
Go read the reports people, and stop speculating...
The British one was a factory QB kit and a 601 UL not an XL.
He was doing a Low Fast pass and pulled up sharply to miss a wire when the wings
failed.. He had been reported for doing beat ups before and had even recieved
a letter.. the wing was not an XL wing but the older one with NO flaps.
Read about the damage of the rear attachment bolt holes being ripped Down and Outwards
as it failed due to stress. (The bolt was in)
Now go and read the one doing the test flight after instalation of the wing and
read.. Rear attachment point was undamaged and still attached to the Fuse. IE
no Bolt damage as the wing folded up.
Now read what appears to be the latest VFR flight in IMC conditions.
Now go and read all about the other 601's and XL's flying with no ploblems.
Chris.
Do not archive.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112385#112385
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| Subject: | Re: Fwd: Re: Bottom Rudder Bracket attachment |
thanks!
do not archive
Its a Zodiac XL..
Do not archive.
Chris
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112366#112366
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
---------------------------------
Moody friends. Drama queens. Your life? Nope! - their life, your story.
Play Sims Stories at Yahoo! Games.
Message 4
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Interesting to see. Thatcher correctly differentiates between a design limit
load of 3.8 Gs, and an ultimate load of 5.7 Gs.
> It may be of interest to see an example of load testing.
>From Bobs post I understand only one has been built, unluckily subsequently
destroyed by hurricane Ivan. What scares me is to see is the ultimate 5.7 G
load test on an airframe, which probably has been flown after passing this
test. There is no proof or a timestamp in the JPEG pictures shown on the
load test page, so I can be wrong - and this is not to blame anybody here!
Remember, FAR 23 only requests 3 seconds with ultimate load!
If properly designed to the specs there can (and will) be deformations left
from an ultimate load test. This probably is - aside post wing failure
effects when the debris hit the ground - what later can show up in the
reports e.g. as rivet holes were elongated and oval shaped and must not
necessarily be happened during the mishap which might have lead to a crash.
Conclusion: Please never do load tests beyond the limit load on an airframe,
which will be flown later again!
-Kurt.
---
From: owner-zenith-list-server@matronics.com
[mailto:owner-zenith-list-server@matronics.com] On Behalf Of MaxNr@aol.com
Sent: Saturday, May 12, 2007 6:41 AM
Subject: Zenith-List: Load testing
A lot of discussion about loads on aircraft structures. It may be of
interest to see an example of load testing. Click on this link, then click
on "Load testing." This plane was developed by one of the members of my EAA
chapter. Smaller than a 601XL, but same construction and made of 6061. This
prototype was destroyed in its hangar by hurricane Ivan in 2004. The
fuselage survives on the wall of the Indust Tech shop at Pensacola Jr
College. It still looks airworthy if you stand back 10 feet. I'm not pushing
this plane, but thought some pictures may be of interest.
Bob Dingley
Pace, FL
XL/Lyc Do not archive Click here: Welcome to the home of the
Thatcher CX4
Message 5
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| Subject: | Re: Fuel tank cushion strips |
Hey Craig,
McMaster-Carr has a large selection of cork and rubber including self adhesive
strip. Just type "cork" in the search window.
http://www.mcmaster.com/
Dave Clay
Temple, TX
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112395#112395
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| Subject: | Re: Ultimate Load vs. Limit Load |
Kurt, thank you for clarification of the difference between limit and ultimate/design
load! It seems that not all of the builders are totally aware of this...
Some more thoughts (and a refresher) about structural loads and airspeeds, primarily
maneuvering speed (va):
* We all know that - at va - the load on the airframe can just reach limit load
(e.g. 4g for CH601XL) before the aircraft stalls (and that is for max weight,
lower weights result in lower va!).
* For higher speeds a much higher load can result before the aircraft stalls.
* Example: va = 95kts (common va for CH601XL at MTOW), then fly with v = 120kts,
pull very hard on the stick and you will see a load of 6.4g before you get an
accelerated stall (well, perhaps you will first hear cracks developing in your
spar...). Do the same at v = 130kts and the airplane could aerodynamically
make 7.5g!!!
There was a very good article in one of last years' "AOPA Pilot "written by Rod
Machado about the importance of maneuvering speed!
Cheers Martin
--------
Martin Pohl
Zodiac XL QBK
8645 Jona, Switzerland
www.pohltec.ch/ZodiacXL
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112396#112396
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| Subject: | Re: Floats on CH701 |
Rick,
Here is Chris' letter. Sorry for the delay
Carl
Message 8
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| Subject: | Re: >Re: British 601 Crash (was: 601 Crash) |
Thanks Klaus, Great input. In your opinion would a heaver rear wing root
bracket, and a larger nut and bolt help the condition or hurt it ? thanks
Joe N101HD
----- Original Message -----
From: "Klaus Truemper" <klaus@utdallas.edu>
Sent: Friday, May 11, 2007 4:53 PM
Subject: Zenith-List: >Re: British 601 Crash (was: 601 Crash)
>
> Hi,
>
> Each airplane has a maneuvering speed, which depends on payload.
> Typically, gross weight is assumed for published numbers, which
> are then used throughout the payload range. This is conservative
> and generally agreed upon practice.
>
> When the plane flies at or below the maneuvering speed, then
> the aircraft will stall before the wings or any other component,
> for example, the motor mount, can become overloaded due to full
> deflection of control surfaces.
>
> Now above the maneuvering speed, all bets are off. Thus,
> it is very important that the plane is at or below maneuvering speed
> when anything like severe turbulence is encountered or high G pull ups are
> contemplated.
>
> The following website has a nice discussion about maneuvering speed:
>
> http://selair.selkirk.bc.ca/aerodynamics1/Lift/Page12.html
>
> The website also supplies a formula for the maneuvering speed. For my 601
> HDS plane, which allows for
> +-6Gs, the maneuvering speed is 2.4 (= square root of 6)
> times the stall speed. Due to the wingroot fairings, the stall speed
> is about 42 kts, so maneuvering speed is 103kts. To be on the safe side, I
> never exceed 90 kts
> when encountering turbulence or other high G situations.
>
> From the Zenith website, the 601 XL also has +-6 G as ultimate load
> factor, and stall speed is listed at
> 51 mph, which is 44 kts. Thus the maneuvering speed is 105 kts. Here, too,
> I would try to be conservative
> and stay quite a bit below that figure in turbulence or sudden pull ups.
>
> Happy flying,
>
> Klaus Truemper
>
> --
> Klaus Truemper
> Professor Emeritus of Computer Science
> University of Texas at Dallas
> Erik Jonsson School of Engineering and
> Computer Science EC31
> P.O. Box 830688
> Richardson, TX 75083-0688
> (972) 883-2712
> klaus@utdallas.edu
> www.utdallas.edu/~klaus
>
>
>
Message 9
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Kevin, sometyhing that has bothered me since I decided to build the XL is the "slight"
forward sweep of the wings. As stated before this is a consequence of
the canted spardesign coupled with dihedral effect.
The problem (perhaps I should say the question) in my mind is this.
There is a phenomenon called structural divergence - or something like that.
Simply put, it is easy to design structure for a multi beam cantilever panel like
a common straight wing that will twist during uniform loading to either maintian
tip angle of attack or reduce the tip angle of attack. This results in
the wing "auto-unloading" aerodynamically as it bends; the forces generating the
bending are reduced by twisting the nose of the wing down as the panel flexes
up and up as the panlel flexes down. In the case of a forward swept wing this
phenomenon is reversed with conventional metal structure and it as the panel
flexes upward the tip twists to a greater angle of attack increasing the bending
load,increasing the increase in angle of attack, increasing the bending load.....
With the exception of the german WWII research planes and a german corporate
jet in the 60s, forward swept wings have never been feasible until carbon composites
came along - and the only reason that they made it possible without massive
structure is that you can orient the fibers to result in bending/twist modes
that are opposite the normal.
In the case of a structurally divergent design, onset to failure can be virtually
instantaneous - especialy if prior damage has been accumulated unseen.
I have to admit, after a 30+ year career in Aerospace Materials Engineering at
the biggest manufacturer, the series of catastrophic failures for what appear
to be stupid triggers worries me some.
I think when I get my plane done and have it licensed I will add equip or ballast
to ensure tat I only operate in the forward half of the CG range. I keep
reading that the XL has very powerful and sensitive elevator control - staying
nose heavy will help me avoid PIOs and other upset/onset related issues to some
degree. And, other than stalling faster and having to land a little faster
due to the reduced stab/elevator authority, I see no issue with that plan. Anyone
disagree?
Thanks.
kevinbonds <kevinbonds@comcast.net> wrote:
I read CH's letter after the Cali crash. He states that hundreds of these
designs have been flying--some for more than 20 years. This is true to an
extent. I have the utmost respect for him, but my concern is with the XL
which I do not think has been around that long, and I'm not sure how many
examples of it are flying. The success of his designs, certainly speaks well
of his skills as a designer but doesn't guarantee that some gremlin can't
exist in one of his newest designs.
Look, I'm not trying to find fault, I'm just trying to be diligent and
consider the worst case scenario in my planning. So worst case scenario;
there is a design flaw or a fault in a published number. How do we rule out
that possibility? In the event we can't, what changes do we make?
Does the UL in the UK have flaps? Have there been any cases of damaged wings
during abrupt maneuvers that didn't come off? How abrupt were those
maneuvers? Or is it like coming to the edge of a cliff there is either no
damage or rapid, irreversible advance toward the catastrophic. Can we do
something to at least slow it down long enough so that someone might live to
tell about it?
Kevin Bonds
Nashville TN
601XL Plans building.
http://home.comcast.net/~kevinbonds
do not archive DO NOT ARCHIVE
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
---------------------------------
Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news,
photos & more.
Message 10
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| Subject: | Re: Fuel tank cushion strips |
Would not one consideration be that the cork is substantially lighter?
DO NOT ARCHIVE
----- Original Message -----
From: "Craig Payne" <craig@craigandjean.com>
Sent: Saturday, May 12, 2007 2:36 AM
Subject: Zenith-List: Fuel tank cushion strips
>
> What is the advantage of using the cork strips that Zenith specifies over
> silicon rubber (specifically cowling baffle strips). I'm planning the
> mounting of my header tank and I have the silicon on-hand.
>
> Also, if I go that with the cork, what is a good source?
>
> -- Craig
>
>
>
>
>
>
Message 11
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One of the things that botherresd me about the one XL crash investigation where
they pointed out that the wing skin rivet holes were elongated, is that the rivets
CH uses are pretty poor in head retention, and I would suspect that the
inversion of the head with the accompanying increase in work hardening of the
barrel to head corner does not make that situation any better.
The very fact that the rivet holes were elongated overall suggests poor workmanship
and the "unzipping" of the rows of rivets as the heads pop off one after
the other in a single smooth fluid run. I have seen this many times in static
test failures - and those in products designed by the big ones.
Of course if the holes were sloppy in the first place the rivets were more brittle
than design calls for as well...
"Kurt A. Schumacher" <Kurt.Schumacher@schumi.ch> wrote:
Interesting to see. Thatcher correctly differentiates between a design limit
load of 3.8 Gs, and an ultimate load of 5.7 Gs.
> It may be of interest to see an example of load testing.
>From Bobs post I understand only one has been built, unluckily subsequently
destroyed by hurricane Ivan. What scares me is to see is the ultimate 5.7 G
load test on an airframe, which probably has been flown after passing this
test. There is no proof or a timestamp in the JPEG pictures shown on the
load test page, so I can be wrong - and this is not to blame anybody here!
Remember, FAR 23 only requests 3 seconds with ultimate load!
If properly designed to the specs there can (and will) be deformations left
from an ultimate load test. This probably is - aside post wing failure
effects when the debris hit the ground - what later can show up in the
reports e.g. as rivet holes were elongated and oval shaped and must not
necessarily be happened during the mishap which might have lead to a crash.
Conclusion: Please never do load tests beyond the limit load on an airframe,
which will be flown later again!
-Kurt.
---
From: owner-zenith-list-server@matronics.com
[mailto:owner-zenith-list-server@matronics.com] On Behalf Of MaxNr@aol.com
Sent: Saturday, May 12, 2007 6:41 AM
Subject: Zenith-List: Load testing
A lot of discussion about loads on aircraft structures. It may be of
interest to see an example of load testing. Click on this link, then click
on "Load testing." This plane was developed by one of the members of my EAA
chapter. Smaller than a 601XL, but same construction and made of 6061. This
prototype was destroyed in its hangar by hurricane Ivan in 2004. The
fuselage survives on the wall of the Indust Tech shop at Pensacola Jr
College. It still looks airworthy if you stand back 10 feet. I'm not pushing
this plane, but thought some pictures may be of interest.
Bob Dingley
Pace, FL
XL/Lyc Do not archive Click here: Welcome to the home of the
Thatcher CX4
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
---------------------------------
Get the Yahoo! toolbar and be alerted to new email wherever you're surfing.
Message 12
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| Subject: | Re: Load testing |
Listers,
A side note on the Thatcher CX4 which may or may interest you. At Sun N
fun 2007 the designer had a flying example on the field. This
information has no bearing on the ongoing 601XL accident thread, and you
can just disregard this message rather than going on further so as to
save your time. Those who may be interested in the CX4, read on.
Several builders of the type came through the Basic Sheetmetal Workshop.
I am the CoChairman of this workshop so I had an interest in their
questions and comments. They were asking advise about the riveting
technique that Mr. thatcher was using. I always make an effort to talk
with the designer of the various aircraft types so that we provide the
correct information to builders as they come through our workshop
seeking information and help.
I had a short visit with Mr Thatcher at his airplane. There were several
folks there asking questions. I first asked him about the technique he
was using, where he calls for countersinking .020" skin and installing
flush Avdel-Avex rivets, because this was not a normal procedure with
such thin skin. He advised me and I later confirmed by looking at his
information package that he also uses T-88 adhesive in the metal joints
where he uses the flush rivets with the countersunk .020" skin. There is
a sequence that he goes through in this process, so as to avoid "making
the holes in the skin too big".
Here is an intersting item that some of the builders made me aware of as
they came through the shop. Mr. Thatcher offers an alternative riveting
method which he also mentions in his information package. That
alternative method is "The Zenith Aircraft Procedure" of reshaping the
head of the rivet during the installation and NOT countersinking the
.020" skin. He noted that he just liked the look of the flush rivets and
the smooth finish it produces. Mr. Thatcher confirmed the alternate
method with me as we talked. I didn't ask him why he used both methods.
Please accept this as just general information which has limited value.
do not archive
Jim Hoak 601HD
----- Original Message -----
From: MaxNr@aol.com
To: Zenith-List@matronics.com
Sent: Friday, May 11, 2007 11:41 PM
Subject: Zenith-List: Load testing
A lot of discussion about loads on aircraft structures. It may be of
interest to see an example of load testing. Click on this link, then
click on "Load testing." This plane was developed by one of the members
of my EAA chapter. Smaller than a 601XL, but same construction and made
of 6061. This prototype was destroyed in its hangar by hurricane Ivan in
2004. The fuselage survives on the wall of the Indust Tech shop at
Pensacola Jr College. It still looks airworthy if you stand back 10
feet. I'm not pushing this plane, but thought some pictures may be of
interest.
Bob Dingley
Pace, FL
XL/Lyc Do not archive Click here: Welcome to the home of the
Thatcher CX4
**************************************
See what's free at http://www.aol.com.
Message 13
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I agree. I read the whole thing and the only thing that I remember hearing was
that the main attach points were still secure, implying (because that's all you
get) that the wing structure itself failed. Now whether it failed due to over
stressing or something structurally/design wrong with it, we don't know. It's
good to know that those attach points are strong though.
msherman95632(at)yahoo.co wrote:
> Mr. No Name.
>
> I read the NTSB report you listed and the nice letter from Chris H. I don't
see where either says the rear channel pulled through. If I missed it, please
point it out to me. The final NTSB report said the wing failed with both main
and rear attach points secure. I must be missing something.
>
> Mark S. ( not scared to post my name)
> 701/912ULS
>
>
> ---
--------
Andy Shontz
CH601XL - Corvair
www.mykitlog.com/ashontz
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112411#112411
Message 14
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I realize this. That's what I'm saying. So basically when we take away the 'happy
talk' selling points and compare them apples to apples and TRUE flight load
factor to flight load factor, the Cessna 150 is actually a bit beefier.
bryanmmartin wrote:
> You are comparing apples to oranges. The published load factor for the
> Cessna 150 is the FLIGHT load factor, the published load factor for the
> CH601 is the DESIGN load factor. The design load factor is 1.5 times the
> flight load factor so the FLIGHT load factor of the 601 is +-4 G NOT +-
> 6G. The C-150 is certificated in the utility category so it's flight
> load factor is +4.4 -2.2 G, so it's actually a bit stronger in positive
> G loading. It also has much more drag so it's harder to build up enough
> speed to put you at high risk of structural damage during abrupt maneuvers.
>
> ashontz wrote:
>
> >
> >
> > Yes, those 3 and then this most recent one. That's 4. Even though it could
be totally the pilots fault, I'd still be more comfortable with soe new testing.
> >
> > There's tons of 1975 Cessna 150s that have been beat to shit by student pilots
over the years that are still flying without shedding a wing. What's the
difference between them and thes new by comparison 601s. The 601 is rated for
+-6G. A 150, something like +3.8 and -1.8 G.
> >
> >
> >
> >
>
>
> --
> Bryan Martin
> Zenith 601XL N61BM
> Ram Subaru, Stratus redrive
> Do Not Archive
--------
Andy Shontz
CH601XL - Corvair
www.mykitlog.com/ashontz
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112412#112412
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| Subject: | Re: Recent crashes |
David,
I have been reading the discussions on the wing failure topic for some
time (without comment, until now). I believe you are on to something
that I have also been thinking about. One of the crashes was associated
with a ground observation of a severe wing flutter-like phenomena an
instant before the wing was observed to fold upwards. Another 601 pilot
reported a sudden severe vibration of the wings when over flying a
powerplant cooling tower, which he believed was so serious that he felt
lucky to have not sustained a structural failure. I believe that the
structural divergence phenomena is something that needs to be
investigated immediately to see if the 601 wing does in fact have this
behavior. If it does, it would be a common thread that could explain all
the failures. I don't believe for a minute that all of these failures
can be blamed on pilot or builder errors. It seems entirely plausible
to me (as another aerospace engineer) that a wing having the structural
characteristics you describe could be made to produce a divergent
torsional oscillation that would lead to destruction in less than a
second or two under the right conditions. Any sudden maneuver, that
produces enough initial twist, under the right conditions, could
initiate the divergent oscillation that would be almost impossible to
predict, or to correct once it starts.
Bob Eli
----- Original Message -----
From: David Downey
To: zenith-list@matronics.com
Sent: Saturday, May 12, 2007 8:09 AM
Subject: RE: Zenith-List: Recent crashes
Kevin, sometyhing that has bothered me since I decided to build the XL
is the "slight" forward sweep of the wings. As stated before this is a
consequence of the canted spardesign coupled with dihedral effect.
The problem (perhaps I should say the question) in my mind is this.
There is a phenomenon called structural divergence - or something like
that. Simply put, it is easy to design structure for a multi beam
cantilever panel like a common straight wing that will twist during
uniform loading to either maintian tip angle of attack or reduce the tip
angle of attack. This results in the wing "auto-unloading"
aerodynamically as it bends; the forces generating the bending are
reduced by twisting the nose of the wing down as the panel flexes up and
up as the panlel flexes down. In the case of a forward swept wing this
phenomenon is reversed with conventional metal structure and it as the
panel flexes upward the tip twists to a greater angle of attack
increasing the bending load,increasing the increase in angle of attack,
increasing the bending load.....
With the exception of the german WWII research planes and a german
corporate jet in the 60s, forward swept wings have never been feasible
until carbon composites came along - and the only reason that they made
it possible without massive structure is that you can orient the fibers
to result in bending/twist modes that are opposite the normal.
In the case of a structurally divergent design, onset to failure can
be virtually instantaneous - especialy if prior damage has been
accumulated unseen.
I have to admit, after a 30+ year career in Aerospace Materials
Engineering at the biggest manufacturer, the series of catastrophic
failures for what appear to be stupid triggers worries me some.
I think when I get my plane done and have it licensed I will add equip
or ballast to ensure tat I only operate in the forward half of the CG
range. I keep reading that the XL has very powerful and sensitive
elevator control - staying nose heavy will help me avoid PIOs and other
upset/onset related issues to some degree. And, other than stalling
faster and having to land a little faster due to the reduced
stab/elevator authority, I see no issue with that plan. Anyone disagree?
Thanks.
kevinbonds <kevinbonds@comcast.net> wrote:
I read CH's letter after the Cali crash. He states that hundreds of
these
designs have been flying--some for more than 20 years. This is true
to an
extent. I have the utmost respect for him, but my concern is with
the XL
which I do not think has been around that long, and I'm not sure how
many
examples of it are flying. The success of his designs, certainly
speaks well
of his skills as a designer but doesn't guarantee that some gremlin
can't
exist in one of his newest designs.
Look, I'm not trying to find fault, I'm just trying to be diligent
and
consider the worst case scenario in my planning. So worst case
scenario;
there is a design flaw or a fault in a published number. How do we
rule out
that possibility? In the event we can't, what changes do we make?
Does the UL in the UK have flaps? Have there been any cases of
damaged wings
during abrupt maneuvers that didn't come off? How abrupt were those
maneuvers? Or is it like coming to the edge of a cliff there is
either no
damage or rapid, irreversible advance toward the catastrophic. Can
we do
something to at least slow it down long enough so that someone might
live to
tell about it?
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| Subject: | Re: Recent crashes |
I didn't realize the wings on the XL were swept forward. Are you talking about
the fact that the leading edge is straight and the trailing edge tapers producing
a swept forward appearance. I don't see how the wings could be swpt forward
otherwise.
Good to hear and actual aeronautical engineer on here though. Something just doesn't
sound right about all this stuff.
[quote="robert.eli(at)comcast.net"]David,
I have been reading the discussions on the wing failure topic for some time (without
comment, until now). I believe you are on to something that I have also
been thinking about. One of the crashes was associated with a ground observation
of a severe wing flutter-like phenomena an instant before the wing was
observed to fold upwards. Another 601 pilot reported a sudden severe vibration
of the wings when over flying a powerplant cooling tower, which he believed
was so serious that he felt lucky to have not sustained a structural failure.
I believe that the structural divergence phenomena is something that needs
to be investigated immediately to see if the 601 wing does in fact have
this behavior. If it does, it would be a common thread that could explain all
the failures. I don't believe for a minute that all of these failures can be
blamed on pilot or builder errors. It seems entirely plausible to me (as another
aerospace engineer) that a wing having the structural characteristics you
describe could be made to produce a divergent torsional oscillation that would
lead to destruction in less than a second or two under the right conditions.
Any sudden maneuver, that produces enough initial twist, under the right
conditions, could initiate the divergent oscillation that would be almost impossible
to predict, or to correct once it starts.
Bob Eli
> ---
--------
Andy Shontz
CH601XL - Corvair
www.mykitlog.com/ashontz
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112415#112415
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| Subject: | Re: >Re: British 601 Crash (was: 601 Crash) |
Dear Joe,
Do you have seen any proof, report or eye witnessed...
- the rear spar bolts have shared or broken?
- the thread from either the nut or the bolt ripped out (if not destroyed
when mounting the wings)?
- the nut been ripped from or through the bracket?
- the rear bracket failed in flight or on a hard landing?
Answer these questions for yourself. From the accident reports, there is no
evidence.
Making a small part (here or elsewhere) of the design to hard or to stiff
will change the complete structural behavior, and create new issues.
-Kurt.
-----Original Message-----
From: owner-zenith-list-server@matronics.com
[mailto:owner-zenith-list-server@matronics.com] On Behalf Of Southern
Reflections
Sent: Saturday, May 12, 2007 2:08 PM
Subject: Re: Zenith-List: >Re: British 601 Crash (was: 601 Crash)
<purplemoon99@bellsouth.net>
Thanks Klaus, Great input. In your opinion would a heaver rear wing root
bracket, and a larger nut and bolt help the condition or hurt it ? thanks
Joe N101HD
----- Original Message -----
From: "Klaus Truemper" <klaus@utdallas.edu>
Sent: Friday, May 11, 2007 4:53 PM
Subject: Zenith-List: >Re: British 601 Crash (was: 601 Crash)
>
> Hi,
>
> Each airplane has a maneuvering speed, which depends on payload.
> Typically, gross weight is assumed for published numbers, which
> are then used throughout the payload range. This is conservative
> and generally agreed upon practice.
>
> When the plane flies at or below the maneuvering speed, then
> the aircraft will stall before the wings or any other component,
> for example, the motor mount, can become overloaded due to full
> deflection of control surfaces.
>
> Now above the maneuvering speed, all bets are off. Thus,
> it is very important that the plane is at or below maneuvering speed
> when anything like severe turbulence is encountered or high G pull ups are
> contemplated.
>
> The following website has a nice discussion about maneuvering speed:
>
> http://selair.selkirk.bc.ca/aerodynamics1/Lift/Page12.html
>
> The website also supplies a formula for the maneuvering speed. For my 601
> HDS plane, which allows for
> +-6Gs, the maneuvering speed is 2.4 (= square root of 6)
> times the stall speed. Due to the wingroot fairings, the stall speed
> is about 42 kts, so maneuvering speed is 103kts. To be on the safe side, I
> never exceed 90 kts
> when encountering turbulence or other high G situations.
>
> From the Zenith website, the 601 XL also has +-6 G as ultimate load
> factor, and stall speed is listed at
> 51 mph, which is 44 kts. Thus the maneuvering speed is 105 kts. Here, too,
> I would try to be conservative
> and stay quite a bit below that figure in turbulence or sudden pull ups.
>
> Happy flying,
>
> Klaus Truemper
>
> --
> Klaus Truemper
> Professor Emeritus of Computer Science
> University of Texas at Dallas
> Erik Jonsson School of Engineering and
> Computer Science EC31
> P.O. Box 830688
> Richardson, TX 75083-0688
> (972) 883-2712
> klaus@utdallas.edu
> www.utdallas.edu/~klaus
>
>
>
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| Subject: | Re: Recent crashes |
Bob; You are thinking alongside me. The problem as I see it is that CH is extraordinarily
qualified to have performed this design - if indeed HE did the complete
design. When you look at the almost haphazard way that the tailwheel modifications
are superimposed on the basic design, there is some indication that
he did not do the whole thing.
Another thing that bothers me a little is that the skin bearing/rivet shear/head
pop balance may have been terrific for the 1604 rivet with the upset factory
head when used with 0.016" thick skins but what happens when you increase the
gauge of the skins to 0.020" or 0.025" as appears to have happened several
places...
"Robert N. Eli" <robert.eli@comcast.net> wrote:
David,
I have been reading the discussions on the wing failure topic for some time (without
comment, until now). I believe you are on to something that I have also
been thinking about. One of the crashes was associated with a ground observation
of a severe wing flutter-like phenomena an instant before the wing was
observed to fold upwards. Another 601 pilot reported a sudden severe vibration
of the wings when over flying a powerplant cooling tower, which he believed
was so serious that he felt lucky to have not sustained a structural failure.
I believe that the structural divergence phenomena is something that needs to
be investigated immediately to see if the 601 wing does in fact have this behavior.
If it does, it would be a common thread that could explain all the failures.
I don't believe for a minute that all of these failures can be blamed on
pilot or builder errors. It seems entirely plausible to me (as another aerospace
engineer) that a wing having the structural
characteristics you describe could be made to produce a divergent torsional oscillation
that would lead to destruction in less than a second or two under the
right conditions. Any sudden maneuver, that produces enough initial twist, under
the right conditions, could initiate the divergent oscillation that would
be almost impossible to predict, or to correct once it starts.
Bob Eli
----- Original Message -----
From: David Downey
To: zenith-list@matronics.com
Sent: Saturday, May 12, 2007 8:09 AM
Subject: RE: Zenith-List: Recent crashes
Kevin, sometyhing that has bothered me since I decided to build the XL is the
"slight" forward sweep of the wings. As stated before this is a consequence of
the canted spardesign coupled with dihedral effect.
The problem (perhaps I should say the question) in my mind is this.
There is a phenomenon called structural divergence - or something like that.
Simply put, it is easy to design structure for a multi beam cantilever panel like
a common straight wing that will twist during uniform loading to either maintian
tip angle of attack or reduce the tip angle of attack. This results in
the wing "auto-unloading" aerodynamically as it bends; the forces generating the
bending are reduced by twisting the nose of the wing down as the panel flexes
up and up as the panlel flexes down. In the case of a forward swept wing this
phenomenon is reversed with conventional metal structure and it as the panel
flexes upward the tip twists to a greater angle of attack increasing the bending
load,increasing the increase in angle of attack, increasing the bending load.....
With the exception of the german WWII research planes and a german corporate
jet in the 60s, forward swept wings have never been feasible until carbon composites
came along - and the only reason that they made it possible without massive
structure is that you can orient the fibers to result in bending/twist modes
that are opposite the normal.
In the case of a structurally divergent design, onset to failure can be virtually
instantaneous - especialy if prior damage has been accumulated unseen.
I have to admit, after a 30+ year career in Aerospace Materials Engineering at
the biggest manufacturer, the series of catastrophic failures for what appear
to be stupid triggers worries me some.
I think when I get my plane done and have it licensed I will add equip or ballast
to ensure tat I only operate in the forward half of the CG range. I keep
reading that the XL has very powerful and sensitive elevator control - staying
nose heavy will help me avoid PIOs and other upset/onset related issues to some
degree. And, other than stalling faster and having to land a little faster
due to the reduced stab/elevator authority, I see no issue with that plan. Anyone
disagree?
Thanks.
kevinbonds <kevinbonds@comcast.net> wrote:
I read CH's letter after the Cali crash. He states that hundreds of these
designs have been flying--some for more than 20 years. This is true to an
extent. I have the utmost respect for him, but my concern is with the XL
which I do not think has been around that long, and I'm not sure how many
examples of it are flying. The success of his designs, certainly speaks well
of his skills as a designer but doesn't guarantee that some gremlin can't
exist in one of his newest designs.
Look, I'm not trying to find fault, I'm just trying to be diligent and
consider the worst case scenario in my planning. So worst case scenario;
there is a design flaw or a fault in a published number. How do we rule out
that possibility? In the event we can't, what changes do we make?
Does the UL in the UK have flaps? Have there been any cases of damaged wings
during abrupt maneuvers that didn't come off? How abrupt were those
maneuvers? Or is it like coming to the edge of a cliff there is either no
damage or rapid, irreversible advance toward the catastrophic. Can we do
something to at least slow it down long enough so that someone might live to
tell about it?
---------------------------------
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href="http://www.matronics.com/Navigator?Zenith-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
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| Subject: | Re: Recent crashes |
I built a 601HD many years ago and will build a new one next year, great
plane. I also see tons of incidents with all kinds of planes and I still
keep flying. I can understand all the people who seem to be getting
emotional because some think there might be something wrong with the XL when
3 clear incidents of wings failing........don't get emotional just be
practical. 3 XL's lost structual integrity in the wings during flight, some
in IMC, some in VFR. One in the pattern and one in a flyby, and one just
flying. Just saying "he was flying faster than Va in turbulent weather" may
explain one, but not the other two because only one was IMC conditions. I
agree lets wait and see if the NTSB comes up with a answer, but I am sure
they won't. Chris's designs are wonderfully strong and great flying planes.
Maybe the failure is related to the building, maybe something in the plans
are as clear as they need to be?
Lets keep emotions out of the discussions so they can be clear and to the
point.
David Mikesell
23597 N. Hwy 99
Acampo, CA 95220
209-224-4485
skyguynca@skyguynca.com
www.skyguynca.com
----- Original Message -----
From: "chris Sinfield" <chris_sinfield@yahoo.com.au>
Sent: Saturday, May 12, 2007 2:40 AM
Subject: Zenith-List: Re: Recent crashes
> <chris_sinfield@yahoo.com.au>
>
> Go read the reports people, and stop speculating...
>
> The British one was a factory QB kit and a 601 UL not an XL.
> He was doing a Low Fast pass and pulled up sharply to miss a wire when the
> wings failed.. He had been reported for doing beat ups before and had even
> recieved a letter.. the wing was not an XL wing but the older one with NO
> flaps.
>
> Read about the damage of the rear attachment bolt holes being ripped Down
> and Outwards as it failed due to stress. (The bolt was in)
>
> Now go and read the one doing the test flight after instalation of the
> wing and read.. Rear attachment point was undamaged and still attached to
> the Fuse. IE no Bolt damage as the wing folded up.
>
> Now read what appears to be the latest VFR flight in IMC conditions.
>
> Now go and read all about the other 601's and XL's flying with no
> ploblems.
> Chris.
> Do not archive.
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=112385#112385
>
>
>
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| Subject: | NTSB search for breakup accidents. |
I just completed a search of the NTSB accident database. I was
looking for fatal accidents involving 601XLs. I also included RVs so
I could compare results for the two different families of kit
planes. I am not sure how to interpret the results, but I am happy
to report the data I found.
For the period from January 1, 2005 I found 135 fatal accidents in
the database where home built airplanes were involved. 23 involved
either CH601 or RV and 3 involved CH601s. (one 601HDS was involved
in a mid air collision, and one 601XL that was made by AMD had a
breakup but was not included in the 135 accident count)
There were three in flight structure failures for XLs (N10028,
N158MD, N105RH) and only one for RVs (N43EM). There was an
explanation that a service bulletin for the RV-3 involving wing
weakness was not complied with for the RV-3 failure, but no
explanation for any of the XL failures.
The RV accidents seemed to be a random assortment of
misadventures. One particularly notable problem with RVs was 4
accidents related to formation flying. ALL OF THE FATAL ACCIDENTS
WITH XL'S INVOLVED IN FLIGHT STRUCTURE FAILURES.
I don't feel qualified to draw any firm conclusions from this little
study. However, I feel some anecdotal comments are in order. The
total number of fatal accidents for XLs compared to RVs seems to
reflect the much larger number of RVs in the air. That leads to the
conclusion that flying an XL is no more life threatening than flying
an RV. However, the failure mode in the XL fatal accidents is
alarming. Compared to RV fliers, XL fliers seem to be at a much
higher risk of experiencing structural failure.
I am afraid I don't have any action to recommend for XL owners. It
would seem that ballistic parachutes might help us survive a
structure failure, but the accidents seemed to happen at low
altitudes where the ballistic 'chutes might not be much use.
It would be nice if a design study could reveal the actual cause of
the structure failures. That could lead to a design change which
might reduce the chances of future fatalities. So far, there isn't
even a clue about why the XL tends to break up in flight. There are
many speculations, but not a single piece of evidence to support them.
Paul
XL fuselage
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| Subject: | Re: Recent crashes |
Andy;
Imagine that you have the outer wing panels and the centersection built as a
single continuous element. When the spar web is oriented parallel to the Y axis
or straight up and down, the wing leading edge would be straight when viewed
from above. Take that same assembly and tip it forward the 12 or so degrees from
the Y axis that it is in the carry through, add the constant chord leading
edge ribs, and now when viewed from above the leading edge is swept forward a
small amount - as is the outer spar.
ashontz <ashontz@nbme.org> wrote:
I didn't realize the wings on the XL were swept forward. Are you talking about
the fact that the leading edge is straight and the trailing edge tapers producing
a swept forward appearance. I don't see how the wings could be swpt forward
otherwise.
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
---------------------------------
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| Subject: | Re: Load testing |
The report of elongated holes concerns me. Can the impact cause that?
Or was it in the construction of the plane? I wish the NTSB would do a
study on that aspect of the plane to determine whether the elongation
was caused by the impact or something else.
Brad
On Saturday, May 12, 2007, at 05:19 AM, David Downey wrote:
> One of the things that botherresd me about the one XL crash
> investigation where they pointed out that the wing skin rivet holes
> were elongated, is that the rivets CH uses are pretty poor in head
> retention, and I would suspect that the inversion of the head with the
> accompanying increase in work hardening of the barrel to head corner
> does not make that situation any better.
> -
> The very fact that the rivet holes were elongated overall suggests
> poor workmanship and the "unzipping" of the rows of rivets as the
> heads pop off one after the other in a single smooth fluid run. I have
> seen this many times in static test failures - and those in products
> designed by the big ones.
> -
> Of course if the holes were sloppy in the first place the rivets were
> more brittle than design calls for as well...
>
> "Kurt A. Schumacher" <Kurt.Schumacher@schumi.ch> wrote:
>
>
> Interesting to see. Thatcher correctly differentiates between a design
> limit
> load of 3.8 Gs, and an ultimate load of 5.7 Gs.
>
> > It may be of interest to see an example of load testing.
>
> >=46rom Bob=92s post I understand only one has been built, unluckily
> subsequently
> destroyed by hurricane Ivan. What scares me is to see is the ultimate
> 5.7 G
> load test on an airframe, which probably has been flown after passing
> this
> test. There is no proof or a timestamp in the JPEG pictures shown on
> the
> load test page, so I can be wrong - and this is not to blame anybody
> here!
> Remember, FAR 23 only requests 3 seconds with ultimate load!
>
> If properly designed to the specs there can (and will) be deformations
> left
> from an ultimate load test. This probably is - aside post wing failure
> effects when the debris hit the ground - what later can show up in the
> reports e.g. as =93rivet holes were elongated and oval shaped=94 '
and
> must not
> necessarily be happened during the mishap which might have lead to a
> crash.
>
> Conclusion: Please never do load tests beyond the limit load on an
> airframe,
> which will be flown later again!
>
> -Kurt.
>
> ---
>
> From: owner-zenith-list-server@matronics.com
> [mailto:owner-zenith-list-server@matronics.com] On Behalf Of
> MaxNr@aol.com
> Sent: Saturday, May 12, 2007 6:41 AM
> To: Zenith-List@matronics.com
> Subject: Zenith-List: Load testing
>
> A lot of discussion about loads on aircraft structures. It may be of
> interest to see an example of load testing. Click on this link, then
> click
> on "Load testing." This plane was developed by one of the members of
> my EAA
> chapter. Smaller than a 601XL, but same construction and made of 6061.
> This
> prototype was destroyed in its hangar by
<image.tiff>
>
> Get the Yahoo! toolbar and be alerted to new email wherever you're
> surfing.
>
>
Bradford J. DeMeo
Attorney At Law
Estates and Trusts
565 West College Avenue
Santa Rosa, CA 95401
(707) 545-3232
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| Subject: | Re: Recent crashes |
So you're saying because of the 9 degree forward incline on the main spar in conjunction
with the dyhedral in effect creates a forward sweep? Yes, I can see
that now. A few posts back I had wondered why the main spar was inclined forward
9 degrees. Now I know. It does in effect create a forward sweep slightly. With
that arrangement the outer tip of the wing would in fact be maybe about 60m
forward of the root, just a rough guess. So that was intentional to give it
a slight forward sweep. Sounds a little hairy to me. How is the 601HD wing spar.
Is that truly vertical, or does it also have a slight sweep forward?
[quote="planecrazydld(at)yahoo.co"]Andy;
Imagine that you have the outer wing panels and the centersection built as a
single continuous element. When the spar web is oriented parallel to the Y axis
or straight up and down, the wing leading edge would be straight when viewed
from above. Take that same assembly and tip it forward the 12 or so degrees from
the Y axis that it is in the carry through, add the constant chord leading
edge ribs, and now when viewed from above the leading edge is swept forward a
small amount - as is the outer spar.
ashontz wrote:
>
> I didn't realize the wings on the XL were swept forward. Are you talking about
the fact that the leading edge is straight and the trailing edge tapers producing
a swept forward appearance. I don't see how the wings could be swpt forward
otherwise.
>
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
> [b]
--------
Andy Shontz
CH601XL - Corvair
www.mykitlog.com/ashontz
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112429#112429
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| Subject: | Re: Fuel tank cushion strips |
I bought mine from McMaster, and I got a few samples of alternative materials while
I was at it. The cork is by far the lightest. Like Dave mentioned I got
the self adhesive cork strips.
Dan (on the 5 year build from scratch plan :o)
--------
Scratch building XL with Corvair Engine
Read this topic online here:
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| Subject: | Re: Load testing |
One of the reasons that we can afford these airplanes is because the
government ( Big Brother) does NOT do what you are wishing for. When
that happens it called a certified airplane and we know how much those
cost.
Several yrs ago the Adventurer amphib had a breakup in flight on one of
it's early completions. A group of concerned builders pooled their
dollars and hired a competent composite engineer that had an aero
background ,or maybe it was an aero engineer that had a composite
background( Martin Hollman) to find the cause. He did. Came up with a
fix .Everybody happy.
I REALLY don't see any help coming from anywhere except from outside.
Those that are affected (601 builders)can choose a leader and attack the
problem or you can turn this into a Scotchbrite thing and type it into
submission. Your choice.
Couple yrs ago before the Corvairs started breaking cranks I tried to
get the Corvair group ( about a thousand) to each contribute $20-100 so
we could get a professional analysis done of the torsional vibration
signature of the crank. Had it all lined up with Rousch Industries, had
them send a copy of the quote to William. Only 2 people bellied up to
the bar. Mark Lankford, who was later to experience a broken crank and
Dan Bensen, engineer type who KNOWS whats going on with all the drive
line changes made to the engine.
OK guys Fish or cut bait.??
LOW&SLOW John Bolding
The report of elongated holes concerns me. Can the impact cause that?
Or was it in the construction of the plane? I wish the NTSB would do a
study on that aspect of the plane to determine whether the elongation
was caused by the impact or something else.
Brad
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| Subject: | Re: Recent crashes |
Not having plans but having reviewed the sample stuff at Zenith, I believe that
the spar is oriented vertically on the HD. Many of the builders that post on
here will certainly know that beyond speculation.
So you're saying because of the 9 degree forward incline on the main spar in conjunction
with the dyhedral in effect creates a forward sweep? Yes, I can see
that now. A few posts back I had wondered why the main spar was inclined forward
9 degrees. Now I know. It does in effect create a forward sweep slightly. With
that arrangement the outer tip of the wing would in fact be maybe about 60m
forward of the root, just a rough guess. So that was intentional to give it
a slight forward sweep. Sounds a little hairy to me. How is the 601HD wing spar.
Is that truly vertical, or does it also have a slight sweep forward?
[quote="planecrazydld(at)yahoo.co"]Andy;
Imagine that you have the outer wing panels and the centersection built as a single
continuous element. When the spar web is oriented parallel to the Y axis
or straight up and down, the wing leading edge would be straight when viewed from
above. Take that same assembly and tip it forward the 12 or so degrees from
the Y axis that it is in the carry through, add the constant chord leading edge
ribs, and now when viewed from above the leading edge is swept forward a small
amount - as is the outer spar.
ashontz wrote:
>
> I didn't realize the wings on the XL were swept forward. Are you talking about
the fact that the leading edge is straight and the trailing edge tapers producing
a swept forward appearance. I don't see how the wings could be swpt forward
otherwise.
>
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
> [b]
--------
Andy Shontz
CH601XL - Corvair
www.mykitlog.com/ashontz
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112429#112429
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
---------------------------------
Take the Internet to Go: Yahoo!Go puts the Internet in your pocket: mail, news,
photos & more.
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| Subject: | Re: Recent crashes |
I've always assumed the tilt in the spar was an artifact left over from the 601
HD wing, which had the landing gear mounted to the spar. This gave the landing
gear the tilt that put the wheels behind the center of rotation, just as the
tilted firewall puts the front wheel forward of the firewall. I think all
601 wings have had the tilted main spar, thus slightly forward sweep to the wing.
Dan (plans building XL)
--------
Scratch building XL with Corvair Engine
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112439#112439
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| Subject: | Re: Recent crashes |
Hi Dan;
If you look at the attached files they show the main spar vertical and the aft
spar canted slightly.
leinad <leinad@hughes.net> wrote:
I've always assumed the tilt in the spar was an artifact left over from the 601
HD wing, which had the landing gear mounted to the spar. This gave the landing
gear the tilt that put the wheels behind the center of rotation, just as the
tilted firewall puts the front wheel forward of the firewall. I think all 601
wings have had the tilted main spar, thus slightly forward sweep to the wing.
Dan (plans building XL)
--------
Scratch building XL with Corvair Engine
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112439#112439
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
---------------------------------
You snooze, you lose. Get messages ASAP with AutoCheck
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I have read everything that has been discussed, my view has been stated
by others so I have little to add. I tried to discuss what-if's and
maybe so's in the past as a builder like yourselves. However, my name is
attached to Company line, so I must only speak of the facts I know. At
present All I have heard is from this list. Zenith does not brief me on
such issues and I only get involved when Transport Canada calls upon me,
so if anything happens outside of Canada, I'm useless for information.
The last time I made a statement about aerobatics in a 601 I was flamed
personally and online. Something about stepping on personal freedoms. I
have voiced my opinion in the past, I will be flying my 601XL very soon
and I will enjoy it very much. I choose this plane for my children to
learn in, I will be letting my daughter learn this fall. The boy has to
grow up a little more.
Have we heard of accidents in the past with 601's, yes, every make has
had builders mistakes and pilot errors, this is the human nature, that
is why I am a big proponent to having as many inspections as necessary
to make you feel confident. For some reason it is possible to run out of
gas in an hours flight or just out doing circuits.
Now we are hearing more 601XL's, this would also be expected, remember
there are more 601XL kits out there then the 601 UL, HD and HDS
combined. The AMD facility is pumping out flying birds at an
extraordinary rate and we are backed up in builders assistance and we
have a waiting list for Ready to Fly planes. Not to mention 601XL QBK's
and kits with mostly pre-drilled holes. The old 601 kits came with plans
and a few bent pieces.
SO if I am going to hear about an accident in a 601 then I expect it to
be an XL by about 80%, this is solely due to numbers flying and hours
being flown on them, personally I believe there is 10 hours XL flying
time for every hour put into the HD.
It is also because the plane is capable of reaching it's limits, the
601HD and HDS would have a hard time reaching Vne in a dive, the XL is
fully capable of surpassing it. I even remember someone on this list
spouting on the fact that his XL made it to 200mph+ in a dive! Isn't the
Vne 180, who would we blame if his wings came off?
Others seeing video's from you tube showing loops and hammerheads and
tail overs, are these moves possible? Yes, I believe so, but by those
who know how and how to be safe in doing so. Unfortunately, people with
no experience in aerobatic recovery, but built up confidence in the
plane will try these maneuvers. Others will continually fly their plane
near the edges and over time fatigue the structure.
Fly your plane into a T-Storm, many Cessna parts from that mistake have
been found on the ground.
Will we hear anything soon, I doubt it, the FAA must be the ones to make
judgment. They are the ones you need to pressure. I can't offer any
information, and now I can't even offer opinions, and that is really
hard for me.
Mark Townsend Alma, Ontario
Zodiac 601XL C-GOXL, CH701 just started
www.ch601.org / www.ch701.com / www.Osprey2.com
-----Original Message-----
From: owner-zenith-list-server@matronics.com
[mailto:owner-zenith-list-server@matronics.com] On Behalf Of Steve Shuck
Sent: Saturday, May 12, 2007 12:18 AM
Subject: Re: Zenith-List: Re: accident
I find it interesting how Zodie Rocket has been so quiet during all this
discussion.
----- Original Message -----
From: "David Mikesell" <skyguynca@skyguynca.com>
Sent: Friday, May 11, 2007 8:31 PM
Subject: Re: Zenith-List: Re: accident
> <skyguynca@skyguynca.com>
>
> I thought there were 3 in a very short period and 14 months is really
> short. Maybe it is something to look into.
>
> David Mikesell
> 23597 N. Hwy 99
> Acampo, CA 95220
> 209-224-4485
> skyguynca@skyguynca.com
> www.skyguynca.com
> ----- Original Message -----
> From: "Paul Mulwitz" <p.mulwitz@worldnet.att.net>
> To: <zenith-list@matronics.com>
> Sent: Friday, May 11, 2007 7:36 PM
> Subject: Re: Zenith-List: Re: accident
>
>
>> <p.mulwitz@worldnet.att.net>
>>
>> Hi Gig,
>>
>> I thought I have heard of 4 breakups in the last year or so, but when
I
>> went searching for details I ran into computer problems. (The NTSB
>> search page is still loading after an hour of SLOW data transfer). I
did
>> find 3 references in old emails I had on my PC.
>>
>> N105RH 2/08/2006 Oakdale,CA Traffic pattern inflight breakup
>> http://www.ntsb.gov/ntsb/brief.asp?ev_id 060217X00209&key=1
>>
>> N158MD 11/4/2006 Yuba City, CA in flight breakup (explosion?)
>> http://www.ntsb.gov/ntsb/brief.asp?ev_id 061115X01677&key=1
>>
>> N10028 5/2/2007 Canadien, TX in flight breakup (IMC?)
>> http://www.ntsb.gov/ntsb/brief.asp?ev_id 070509X00539&key=1
>>
>> I intend to keep looking once the computer starts cooperating a
little
>> better. I will post anything interesting I find.
>>
>> Paul
>> XL fuselage
>>
>>
>>
>> At 04:43 PM 5/11/2007, you wrote:
>>><wr.giacona@suddenlink.net>
>>>
>>>Paul, your definition of "a lot" seems to be different than mine or
you
>>>know about some accidents that I don't.
>>>
>>>I know of only 2 XLs that have failed in this way. The California
crash
>>>that has been mentioned today and this most recent accident in Texas.
>>>
>>>Can you point me towards info on any others?
>>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
7:34 PM
7:34 PM
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| Subject: | Re: NTSB search for breakup accidents. |
Paul-
As long as everyone is speculating and since you've already found the
sources, how many HD/HDS outboard wings have failed? A lister reported 0 for
the 701, but that configuration isn't even close to the 601.
The reason I ask is because there are 3 radical wing design differences
between the XL and HD/HDS-
1. The shorter outboard wings and shorter distance to the attach points
of the HD/HDS result in a shorter moment of arm and consequently less stress
on the attach points and pull on the rivets spanwise.
2. HD/HDS wing spars have no fore or aft tip angle I'm aware of.
3. No flaps on the HD/HDS.
To answer the first thought that comes to mind, yes, I'm trying to
convince myself that this problem is restricted to the XL. The HD/HDS was
notorious early on for nose gear problems, which I've done my best to
compensate for with builder/Zenith upgrades. I doubt it, but if it turns out
my outboards need attention, the time to address the problem is when they're
30" rather than 2000' off the ground.
Bill Naumuk
HDS Fuse/Corvair
Townville, Pa
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| Subject: | Re: Load Testing |
This aircraft was flown first, then load tested and retired. Then came the
hurricane. (Which also destroyed my Beech) There are several dozen kits under
construction. One by my Shop instructor who is in the first picture.
Bob
**************************************
See what's free at http://www.aol.com.
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| Subject: | Re: Recent crashes |
601HD, vertical spar. Personally, I consider an inclined spar that gives forward
sweep to the wing to be a design flaw. If it's meant to give better responsveness
to the ailerons, I could care less about ailerons effectiveness if I don't
even have wings left on the plane.
Had I know this I would have considered another design. Forward sweep is not how
you create better aileron effectiveness; you design a better aileron, perhaps
larger and lengthen the flaps to meet the lengthened aileron and reduce the
flap deployment angle accordingly.
leinad wrote:
> I've always assumed the tilt in the spar was an artifact left over from the 601
HD wing, which had the landing gear mounted to the spar. This gave the landing
gear the tilt that put the wheels behind the center of rotation, just as
the tilted firewall puts the front wheel forward of the firewall. I think all
601 wings have had the tilted main spar, thus slightly forward sweep to the
wing.
>
> Dan (plans building XL)
http://www.601hd.com/wings.htm
--------
Andy Shontz
CH601XL - Corvair
www.mykitlog.com/ashontz
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112449#112449
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| Subject: | sattey wire for turnbuckles |
does any bodyout there have a picyure of how to saftey wire the turn buckles
do you have to drill a hole or just wrap the wire round the shaft then through
the hole in the middle any help would be grateful is there a book that can be
recommended
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112452#112452
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| Subject: | Re: Hood Time for Sport Pilots |
VFR requirements for a sport pilot are three miles visibility. Hood time is not
a training requirement. That said, I for one would heartily recommend it for
anyone who will be flying an aircraft other than a powered chute or simple ultralight.
If you don't have an attitude indicator, you can still learn basic
instrument flight with a turn and bank, altimeter and compass.... enough to
get you turned around and heading out of trouble. The only alternative is to
have the discipline not to fly when conditions might be marginal.
Tim
--------
DO NOT ARCHIVE
______________
CFII
Champ L16A flying
Zodiac XL - Jabiru 3300A
Working on wings
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| Subject: | Re: saftey wire for turnbuckles |
flyingmike9 wrote:
> does any body out there have a picture of how to saftey wire the turn buckles
> do you have to drill a hole or just wrap the wire round the shaft then through
the hole in the middle any help would be grateful is there a book that can be
recommended
Here's the best book you can find, and it's FREEEEE!
AC 43.13-B index:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99C827DB9BAAC81B86256B4500596C4E?OpenDocument
Chapter 7 talks about safety wiring, with some diagrams of turnbuckles:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2007.pdf
Rick
Read this topic online here:
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| Subject: | Re: sattey wire for turnbuckles |
FAA ADVISORY CIRCULAR AC43.13-1B ACCEPTABLE METHODS, TECHNIQUES, AND
PRACTICES - AIRCRAFT INSPECTION AND REPAIR.
If there is ever any consensus on this list, I think everyone might agree
that no one should be building an aircraft without it!
----- Original Message -----
From: "flyingmike9" <mlloyd9@csi.com>
Sent: Saturday, May 12, 2007 1:26 PM
Subject: Zenith-List: sattey wire for turnbuckles
>
> does any bodyout there have a picyure of how to saftey wire the turn
> buckles
> do you have to drill a hole or just wrap the wire round the shaft then
> through the hole in the middle any help would be grateful is there a book
> that can be recommended
>
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| Subject: | Re: sattey wire for turnbuckles |
Mike,
Try AC 43.13. Tells ya all about and has pictures too,
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| Subject: | Re: saftey wire for turnbuckles |
thanks a lot
very useful reading, excellent because as you say its free
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| Subject: | Re: sattey wire for turnbuckles |
thanks a lot guys
will be reading all night now
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| Subject: | Re: Ultimate Load vs. Limit Load |
Kurt
Thank you for a very clear concise explanation of 601 design load factors.
That info is really helpful.
Terry
At 12:50 AM 5/12/2007 +0200, you wrote:
>Dear friends,
>
>Somewhat wondering about the mentioned +-6G for the CH 601 HDS quoted here
>on the list here these hours. Ok, the
>http://www.zenithair.com/zodiac/601-hds.html says for the Super ZODIAC CH
>601 HDS (lower table, full MTOM)
>
>DESIGN LOAD FACTOR (ultimate) +/- 6 "G"
>
>Here what JAR 23 / FAR 23 define for limit and ultimate load:
>
>...limit loads are the maximum loads to be expected in service [i.e. the
>highest load expected in normal operations] and ultimate loads are limit
>loads multiplied by a safety factor [of 1.5]. The structure must be able to
>support limit loads without detrimental, permanent deformation. At any load
>up to limit loads, the deformation may not interfere with safe operation.
>The structure must be able to support ultimate loads without failure for at
>least three seconds...
>
>Let us now extend ZAC datasheet accordingly:
>
>DESIGN LOAD FACTOR (ultimate) +/- 6 "G"
>SUSTAINED LOAD FACTOR (limit) +/- 4 "G"
>
>Aha. This looks different now. The CH 601 HDS is for sure not an aerobatic
>category aircraft (starts at +6.0/-4.0 limit load) - despite whatever
>maneuvers seen on Youtube. Then, it is cannot qualified to the utility
>category, e.g. training aircraft with spin certification (+4.4/-2.2 limit
>load). The same is true for other 601 models; the 601 XL comes with similar
>numbers. All 601 models are excellent standard category aircraft if operated
>well within the limits.
>
>Please review your aircraft OPS manual, Pilot's Manual - and correct
>accordingly in case only ultimate numbers are printed.
>
>What does this mean to you as a customer - and then to you as the pilot in
>command?
>
>Correct: You never exceed the sustained limit load factor in flight! The
>safety factor is _really_ used to cover additional gust loads and is not
>available to the pilot control inputs, e.g. when a G meter is available.
>
>Everything beyond limit load can (and often will) lead to detrimental,
>permanent deformation. This will not make you falling from the skies yet.
>However, if you _are_ going to ultimate load, there are probably just three
>seconds left up there, plus some more to follow the other 9.81 m/s2 always
>in place. However, in this case you do better arrange a structural engineer
>to review your plane.
>
>Then, please keep in mind that the sustained load factor only applies to a
>factory new airplane. Any repairs, ageing, unreported and unrecorded abuse,
>and poor maintenance - to which an aircraft has been exposed since leaving
>the factory - may (and will) decrease the strength, the structural integrity
>at least considerably.
>
>This is aviation standard, not related to the pilots age or license - and
>not limited to Chris Heintz' designs.
>
>Fly safe!
>
>-Kurt.
Terry Phillips
ttp44~at~rkymtn.net
Corvallis MT
Just starting a 601 kit
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| Subject: | Wing sweep and recent crashes |
Hello list:
Before we unleash a hurricane of opinion on the subject of sweep, let's
agree on a definition of the term. A textbook definition of sweep angle
is the difference between 90 degrees and the angle the 25 percent chord
line of the wing (seen in planform) makes with the centerline of the
fuselage. If that angle is 90 degrees,the wing has zero sweep. This
means that a tapered wing with the leading edge at a right angle to the
fuselage centerline actually has forward sweep. A tapered wing with the
trailing edge at a right angle to the fuselage centerline is swept back.
For the range of speeds and airfoil thicknesses we are concerned about a
few degrees of sweep either way will probably not have enough effect on
the wing structure to explain the wing failures we are trying to
understand.
George Swinford
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| Subject: | Re: Recent crashes |
Ashontz, they are swept foward, We are getting what I consider great input,
hope to get more...Joe N101HD 601 XL
----- Original Message -----
From: "ashontz" <ashontz@nbme.org>
Sent: Saturday, May 12, 2007 9:20 AM
Subject: Zenith-List: Re: Recent crashes
>
> I didn't realize the wings on the XL were swept forward. Are you talking
> about the fact that the leading edge is straight and the trailing edge
> tapers producing a swept forward appearance. I don't see how the wings
> could be swpt forward otherwise.
>
> Good to hear and actual aeronautical engineer on here though. Something
> just doesn't sound right about all this stuff.
>
> [quote="robert.eli(at)comcast.net"]David,
>
> I have been reading the discussions on the wing failure topic for some
> time (without comment, until now). I believe you are on to something
> that I have also been thinking about. One of the crashes was associated
> with a ground observation of a severe wing flutter-like phenomena an
> instant before the wing was observed to fold upwards. Another 601 pilot
> reported a sudden severe vibration of the wings when over flying a
> powerplant cooling tower, which he believed was so serious that he felt
> lucky to have not sustained a structural failure. I believe that the
> structural divergence phenomena is something that needs to be investigated
> immediately to see if the 601 wing does in fact have this behavior. If it
> does, it would be a common thread that could explain all the failures. I
> don't believe for a minute that all of these failures can be blamed on
> pilot or builder errors. It seems entirely plausible to me (as another
> aerospace engineer) that a wing having the st!
> ructural characteristics you describe could be made to produce a
> divergent torsional oscillation that would lead to destruction in less
> than a second or two under the right conditions. Any sudden maneuver,
> that produces enough initial twist, under the right conditions, could
> initiate the divergent oscillation that would be almost impossible to
> predict, or to correct once it starts.
>
> Bob Eli
>
>
>> ---
>
>
> --------
> Andy Shontz
> CH601XL - Corvair
> www.mykitlog.com/ashontz
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=112415#112415
>
>
>
Message 43
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| Subject: | Re: saftey wire for turnbuckles |
while you are at it downl;oad the AC65-9, AC 65-12, and the AC65-15 - all mandatory
for A&Ps
thanks a lot
very useful reading, excellent because as you say its free
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=112462#112462
Dave Downey
Harleysville (SE) PA
Zodiac 601XL/Corvair?
---------------------------------
Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase.
Message 44
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| Subject: | Re: >Re: British 601 Crash (was: 601 Crash) |
Kurt, I under stand what you are saying,and is good common sense. I remember
reading about the " cooling tower event a few mo. ago.I also remember that a
lot people thought he was full of IT....I dont feel that Kevin Bonds,or
David Downey,are far off the mark, time will tell .Hope we get more good
input on this matter Thanks for yours . Joe N101HD 601XL
----- Original Message -----
From: "Kurt A. Schumacher" <Kurt.Schumacher@schumi.ch>
Sent: Saturday, May 12, 2007 9:27 AM
Subject: RE: Zenith-List: >Re: British 601 Crash (was: 601 Crash)
> <Kurt.Schumacher@schumi.ch>
>
> Dear Joe,
>
> Do you have seen any proof, report or eye witnessed...
>
> - the rear spar bolts have shared or broken?
> - the thread from either the nut or the bolt ripped out (if not destroyed
> when mounting the wings)?
> - the nut been ripped from or through the bracket?
> - the rear bracket failed in flight or on a hard landing?
>
> Answer these questions for yourself. From the accident reports, there is
> no
> evidence.
>
> Making a small part (here or elsewhere) of the design to hard or to stiff
> will change the complete structural behavior, and create new issues.
>
> -Kurt.
>
> -----Original Message-----
> From: owner-zenith-list-server@matronics.com
> [mailto:owner-zenith-list-server@matronics.com] On Behalf Of Southern
> Reflections
> Sent: Saturday, May 12, 2007 2:08 PM
> To: zenith-list@matronics.com
> Subject: Re: Zenith-List: >Re: British 601 Crash (was: 601 Crash)
>
> <purplemoon99@bellsouth.net>
>
> Thanks Klaus, Great input. In your opinion would a heaver rear wing root
> bracket, and a larger nut and bolt help the condition or hurt it ? thanks
> Joe N101HD
> ----- Original Message -----
> From: "Klaus Truemper" <klaus@utdallas.edu>
> To: "Zenithlist" <Zenith-List@matronics.com>
> Sent: Friday, May 11, 2007 4:53 PM
> Subject: Zenith-List: >Re: British 601 Crash (was: 601 Crash)
>
>
>>
>> Hi,
>>
>> Each airplane has a maneuvering speed, which depends on payload.
>> Typically, gross weight is assumed for published numbers, which
>> are then used throughout the payload range. This is conservative
>> and generally agreed upon practice.
>>
>> When the plane flies at or below the maneuvering speed, then
>> the aircraft will stall before the wings or any other component,
>> for example, the motor mount, can become overloaded due to full
>> deflection of control surfaces.
>>
>> Now above the maneuvering speed, all bets are off. Thus,
>> it is very important that the plane is at or below maneuvering speed
>> when anything like severe turbulence is encountered or high G pull ups
>> are
>
>> contemplated.
>>
>> The following website has a nice discussion about maneuvering speed:
>>
>> http://selair.selkirk.bc.ca/aerodynamics1/Lift/Page12.html
>>
>> The website also supplies a formula for the maneuvering speed. For my 601
>> HDS plane, which allows for
>> +-6Gs, the maneuvering speed is 2.4 (= square root of 6)
>> times the stall speed. Due to the wingroot fairings, the stall speed
>> is about 42 kts, so maneuvering speed is 103kts. To be on the safe side,
>> I
>
>> never exceed 90 kts
>> when encountering turbulence or other high G situations.
>>
>> From the Zenith website, the 601 XL also has +-6 G as ultimate load
>> factor, and stall speed is listed at
>> 51 mph, which is 44 kts. Thus the maneuvering speed is 105 kts. Here,
>> too,
>
>> I would try to be conservative
>> and stay quite a bit below that figure in turbulence or sudden pull ups.
>>
>> Happy flying,
>>
>> Klaus Truemper
>>
>> --
>> Klaus Truemper
>> Professor Emeritus of Computer Science
>> University of Texas at Dallas
>> Erik Jonsson School of Engineering and
>> Computer Science EC31
>> P.O. Box 830688
>> Richardson, TX 75083-0688
>> (972) 883-2712
>> klaus@utdallas.edu
>> www.utdallas.edu/~klaus
>>
>>
>>
>>
>>
>>
>
>
>
Message 45
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| Subject: | Re: Wing sweep and recent crashes |
On 5/12/07, George Swinford <grs-pms@comcast.net> wrote:
> Before we unleash a hurricane of opinion on the subject of sweep, let's
> agree on a definition of the term. ...
For the purposes of this problem, I suspect the relevant issue is this
(and please correct me if I'm wrong): Viewed from the top, the center
of lift of the wing traces a roughly spanwise line, and the structural
centroid of the wing also traces a roughly spanwise line. Where do
these lines lie in relation to one another?
Ihab
--
Ihab A.B. Awad, Palo Alto, CA
Message 46
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| Subject: | Re: Wing sweep and recent crashes |
On 5/12/07, ihab.awad@gmail.com <ihab.awad@gmail.com> wrote:
> For the purposes of this problem, I suspect the relevant issue is this
> (and please correct me if I'm wrong): ...
No sorry ... I typed too soon. Consider the case of a perfectly
rectangular wing with zero sweep, with the center of lift behind the
structural centroid, and thus stable. Now sweep that same wing
forwards. Now the action of lift, to increase dihedral along the axis
of the wing, also acts to increase angle of attack and can make the
wing unstable. Hence my analysis is too simplistic. Never mind.
Ihab
--
Ihab A.B. Awad, Palo Alto, CA
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| Subject: | Wing sweep and recent crashes |
Could it be the angle of the spar is to set the angle of incidence? Jerry GA
_http://en.wikipedia.org/wiki/Angle_of_incidence_
(http://en.wikipedia.org/wiki/Angle_of_incidence)
DO NOT ARCHIVE"
************************************** See what's free at http://www.aol.com.
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| Subject: | Re:Re:Recent crashes |
I am uncertain if the swept forward 601XL wing lends it self to load testing
with sand bags. How do you duplicate that twisting feature? I would like to
see what if any load testing that ZAC has done. I posted some pictures of
testing done on a relatively rare airframe after the builder decided to "kit" this
plane. No. He never rebuilt it and put it back in the air as some suggest.
Testing to failure was a responsible course to take when he offered it to the
public. Has ZAC done this?
A friend told me that when he was a Beechcraft test pilot in the early 60's,
witnessed a load test on a Beech 23 Musketeer. The wing and fuselage were
supported four feet above the floor. A great deal of weight was applied until the
belly touched the floor. For about an hour. The weight was removed, belly came
up and a straight edge used on the wing. Zero deformation. Nothing cracked.
Although the 23 was not his project, (his was the big engine, armed T-34) he
did ride with the project pilot through some wild aerobatics and observed the
wing tips flex several feet under high G. Several feet. He was a WW2 fighter
pilot that flew every US, Brit, German & Italian fighter that he could. The Be
23
has a laminar flow airfoil that looks somewhat like the 601XL. The skin
forward of the spar is bonded with no rivets. I've never heard of a structural
failure.
I've been doing loops since puberty and would like to do one on my birthday.
(70th) The last thing I want to have to do is add Piper Pawnee lift struts or
Fly-Baby flying wires. My wife has restricted me to no more than 2 G because
of my age. One G when she is aboard.
Do not archive
Bob Dingley
Pace, FL
XL
**************************************
See what's free at
http://www.aol.com.
Message 49
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HYPERLINK
"http://www.zenithair.com/zodiac/6-photo-testing.html"http://www.zenitha
ir.com/zodiac/6-photo-testing.html
To All please visit this link to see pictures of the 601=92s load tests.
We do not need to destroy another plane in testing as one already has
been done.
Mark Townsend Alma, Ontario
Zodiac 601XL C-GOXL, CH701 just started
HYPERLINK "http://www.ch601.org"www.ch601.org / HYPERLINK
"http://www.ch701.com"www.ch701.com/ HYPERLINK
"http://www.Osprey2.com"www.Osprey2.com
7:34 PM
7:34 PM
Message 50
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| Subject: | Re: 601 load tests |
Mark-
Why did you bother painting the plane?
Incidentally, out of curiosity I searched the NTSB archives for the
HD/HDS back to 1980. Only 2 reported accidents, neither of which was
structurally related.
Bill Naumuk
HDS Fuse/Corvair
Townville, Pa
----- Original Message -----
From: ZodieRocket
To: zenith-list@matronics.com
Sent: Saturday, May 12, 2007 7:54 PM
Subject: Zenith-List: 601 load tests
http://www.zenithair.com/zodiac/6-photo-testing.html
To All please visit this link to see pictures of the 601=92s load
tests. We do not need to destroy another plane in testing as one already
has been done.
Mark Townsend Alma, Ontario
Zodiac 601XL C-GOXL, CH701 just started
www.ch601.org / www.ch701.com/ www.Osprey2.com
7:34 PM
7:34 PM
Message 51
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| Subject: | Wing sweep and recent crashes |
MAN! With all your theorizing, conjecturing and armchair quarterbacking, you
guys can take a half story and twist it 9 ways from Sunday! Without knowing
anything but a small portion of the facts you are willing to question the
basics of the CH designs!
What I think is really happening, is that some 'educated' people are using
this list to expound their knowledge and education. If you don't like the
601XL design.DON'T BUILD IT!!
As for me, I put my $$$ on Mr. Heintz. I'm not building an XL, but I happen
to think the airplane is designed as is for a reason.a reason I don't
understand, because, if I did, I would design and build my own! Here's a
thought: If you don't understand why the wing is swept forward, maybe Chris
Heintz knows more than you.
Don't bother telling me that an 'intelligent' builder should question
everything. Am I willing to just blindly follow? Uh, yeah (see above).
My vote is that this is a useless thread that will do little or nothing to
help anyone.
Gary Boothe
Cool, CA
601 HDSTD, WW Conversion 90% done,
Tail done, wings done, working on c-section
Message 52
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| Subject: | Re: saftey wire for turnbuckles |
i looked over the plans, and i think you guys are going down the wrong path. the
wings are not swept forward, they are zero on the front, with a taper from
the rear fuselage to the rear tip of the airleron. no sweep as you suggest. the
wings are canted up for turn stability.
show me in the plans where it says to forward sweep the wings A set number of
degrees.
Another point before you guys give yourselves a heart attack, not to beat on the
dead but, check the flight experience of the people that crashed a 601.
I think the findings will e that it is a very capable LSA aircraft with acciednts
due to people getting to over confident in the plane's ability, it is a plane
that gets easy to fly at well past manauvering speed with an easy tendency
to fly little too aggressively.
LETS GET BACK TO BUILDING!!!
jUAN
-----Original Message-----
>From: David Downey <planecrazydld@yahoo.com>
>Sent: May 12, 2007 5:46 PM
>To: zenith-list@matronics.com
>Subject: Re: Zenith-List: Re: saftey wire for turnbuckles
>
>while you are at it downl;oad the AC65-9, AC 65-12, and the AC65-15 - all mandatory
for A&Ps
>
>
>thanks a lot
>very useful reading, excellent because as you say its free
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=112462#112462
>
>
> Dave Downey
> Harleysville (SE) PA
> Zodiac 601XL/Corvair?
>
>
>
>---------------------------------
>Looking for a deal? Find great prices on flights and hotels with Yahoo! FareChase.
Message 53
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|
In the case of the last accident, might I suggest that we take a
different route ,the information that we have so far support this view.
178 Seconds to Live
How long can a licensed VFR pilot who has little or no instrument
training expect to live after he flies into bad weather and loses visual
contact? In 1991 researchers at the University of Illinois did some
tests and came up with some very interesting data. Twenty VFR pilot
"guinea pigs" flew into simulated instrument weather, and all went into
graveyard spirals or roller coasters. The outcome differed in only one
respect - the time required until control was lost. The interval ranged
from 480 seconds to 20 seconds. The average time was 178 seconds -- two
seconds short of three minutes.
Here's the fatal scenario. . . . . . .
The sky is overcast and the visibility is poor. That reported five mile
visibility looks more like two, and you can't judge the height of the
overcast. Your altimeter tells you that you are at 5500 feet but your
map tells you that there's local terrain as high as 3200 feet. There
might be a tower nearby because you're not sure how far off course you
are so you press on.
You find yourself unconsciously easing back just a bit on the controls
to clear those towers. With no warning, you're in the soup. You peer so
hard into the milky white mist that your eyes hurt. You fight the
feelings in your stomach that tell you're banked left, then right! You
try to swallow, only to find your mouth dry. Now you realize you should
have waited for better weather. The appointment was important, but not
all that important. Somewhere a voice is saying, "You've had it -- it's
all over!" You've only referred to you instruments in the past and have
never relied on them. You're sure that this is just a bad spot and
you'll break out in a few minutes. The problem is that you don't have a
few minutes left.
You now have 178 seconds to live.
Your aircraft "feels" on even keel but your compass turns slowly. You
push a little rudder and add a little pressure on the controls to stop
the turn but this feels unnatural and you return the controls to their
original position. This feels better but now your compass is turning a
little faster and your airspeed is increasing slightly. You scan your
instruments for help but what you see looks somewhat unfamiliar. You are
confused so you assume the instruments must be too. You are now
experiencing full blown Spatial Disorientation. Up feels like down and
left feels like right. You feel like you are straight and level again
but you're not. The spiral continues.
You now have 100 seconds to live.
You glance at your altimeter and you are shocked to see it unwinding.
You're already down to 3000 feet. Instinctively, you pull back on the
controls but the altimeter still unwinds. You don't realize that you are
in a graveyard spiral and it only gets worse. Your plane is almost
sideways you're just tightening the turn by pulling back on the yoke,
but all you can see is that altimeter going lower, lower, lower. The
engine is into the red and growling and the airspeed is dangerously
high. The sound of the air passing by begins to resemble a scream.
You now have 45 seconds to live.
Now you're sweating and shaking. There must be something wrong with the
controls; pulling back only moves the airspeed indicator further into
the red. It's supposed to do the opposite! You can hear the wind tearing
at the aircraft. Rivets are popping as the load on the wings and tail
far exceeds design specifications. 1800, 1500, 1100 feet...... down you
go.
You now have 10 seconds to live.
Suddenly you see the ground. The trees rush up at you. You can now see
the horizon if you turn your head far enough but it's at a weird angle
-- you're almost inverted! You open your mouth to scream but. . . . . .
Your time is up!
Next time:
LEVEL THE WINGS, REDUCE THROTTLE AND PULL THE NOSE UP TO THE HORIZON!
YOUR WINGS PRODUCE ALL THE LIFT BUT THEY CANNOT CARRY YOU OUT OF DANGER
IF THEY ARE AT A STEEP ANGLE! GET YOUR EYES OFF OF THE ALTIMETER AND
LOOK AT YOUR ATTITUDE INDICATOR. THEN LEVEL THE WINGS! LEVEL THE WINGS!
LEVEL THE WINGS!
HYPERLINK
"http://www.tc.gc.ca/publications/EN/TP2228/PDF/HR/TP2228E_1.pdf"http://
www.tc.gc.ca/publications/EN/TP2228/PDF/HR/TP2228E_1.pdf
Mark Townsend Alma, Ontario
Zodiac 601XL C-GOXL, CH701 just started
HYPERLINK "http://www.ch601.org"www.ch601.org / HYPERLINK
"http://www.ch701.com"www.ch701.com/ HYPERLINK
"http://www.Osprey2.com"www.Osprey2.com
7:34 PM
Message 54
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| Subject: | Re: Fuel tank cushion strips |
And the cork costs less.
Robin Bellach wrote:
>
> Would not one consideration be that the cork is substantially lighter?
>
> DO NOT ARCHIVE
>
> ----- Original Message ----- From: "Craig Payne" <craig@craigandjean.com>
> To: <zenith-list@matronics.com>
> Sent: Saturday, May 12, 2007 2:36 AM
> Subject: Zenith-List: Fuel tank cushion strips
>
>
>>
>> What is the advantage of using the cork strips that Zenith specifies over
>> silicon rubber (specifically cowling baffle strips). I'm planning the
>> mounting of my header tank and I have the silicon on-hand.
>>
>> Also, if I go that with the cork, what is a good source?
>>
>> -- Craig
>>
--
Bryan Martin
Zenith 601XL N61BM
Ram Subaru, Stratus redrive
Do Not Archive
Message 55
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| Subject: | Cabin Floor and Rudder Pedals |
Listers - I am done with my firewall (thanks for the help) and on to the
cabin floor. Unfortunately, some guy on his first day at the factory must
have made the floor (6B10-1) because it is pretty shoddy. The bends of the
"wings" are a couple mm off, leading to some problems with the centerline
and edges in relation to the holes. But, so far I have been able to make
everything work. Until now.
I just drilled the central pedal bearing (6b9-4) holes. The factory pilot
holes were so far off that I had to squeeze one pilot hole way over to the
side of the center bearing hole and the other pilot hole way over to the
other side of the other hole (the aft hole) just to get the pilot holes
inside the 3/16 holes. It almost worked. I am going to have to talk with
Zenith about drilling one of the holes out to a AN4 instead of an AN3.
But, the real problem is that despite trying to line everything up and make
the holes fit, the bearing is at a tiny bit of an angle. Thus, when I put
the rudder pedals in the bearing, the pilot side pedals aim slightly aft.
When I go to slide the lateral pedal bearing (6B9-5) over the end of the
pedal tube, it won't fit. The pedal comes too close to the edge of the
channel so the channel interferes with the lateral bearing. (I don't think
the other side really matters because it is just sitting in the open part of
the channel, but I will ask.)
As I am writing this at almost midnight on Saturday, I obviously have not
contacted the factory yet. But, do you all think it would work with the
right tools/shop/help to slightly bend the rudder pedal tube. If I put a
slight bend it, I could inch it away from the channel edge. (Even as I type
this, I realize that such a route might cause a bit of trouble if the pedal
is not high enough off the floor so that the bend rubbed as the pedals
rolled in and out, but I could probably figure out before hand if that will
be a problem.)
Anyway, if anyone wants to take the time to visualize this mess and pass on
a suggestion, I would appreciate it. With all the holes drilled in every
piece, my only other option is probably to get all new parts for the cabin
floor. (How annoyed should I be at Zenith if this happens? Would you buy
or request new parts?)
Thanks, Michael in NH
601XL
Message 56
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| Subject: | Re: Wing sweep and recent crashes |
Good question. With a tapered wing having a spar that is parallel to the leading
edge . . . hmmm.
-------------- Original message ----------------------
From: ihab.awad@gmail.com
>
> On 5/12/07, George Swinford <grs-pms@comcast.net> wrote:
> > Before we unleash a hurricane of opinion on the subject of sweep, let's
> > agree on a definition of the term. ...
>
> For the purposes of this problem, I suspect the relevant issue is this
> (and please correct me if I'm wrong): Viewed from the top, the center
> of lift of the wing traces a roughly spanwise line, and the structural
> centroid of the wing also traces a roughly spanwise line. Where do
> these lines lie in relation to one another?
>
> Ihab
>
> --
> Ihab A.B. Awad, Palo Alto, CA
>
>
>
>
Message 57
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| Subject: | Re: Wing sweep and recent crashes |
DON'T HOLD BACK Gary, tell us what you really think...
----- Original Message ----- Joe N101HD 601XL
From: Gary Boothe
To: zenith-list@matronics.com
Sent: Saturday, May 12, 2007 9:47 PM
Subject: Zenith-List: Wing sweep and recent crashes
MAN! With all your theorizing, conjecturing and armchair
quarterbacking, you guys can take a half story and twist it 9 ways from
Sunday! Without knowing anything but a small portion of the facts you
are willing to question the basics of the CH designs!
What I think is really happening, is that some 'educated' people are
using this list to expound their knowledge and education. If you don't
like the 601XL design.DON'T BUILD IT!!
As for me, I put my $$$ on Mr. Heintz. I'm not building an XL, but I
happen to think the airplane is designed as is for a reason.a reason I
don't understand, because, if I did, I would design and build my own!
Here's a thought: If you don't understand why the wing is swept
forward, maybe Chris Heintz knows more than you.
Don't bother telling me that an 'intelligent' builder should question
everything. Am I willing to just blindly follow? Uh, yeah (see above).
My vote is that this is a useless thread that will do little or
nothing to help anyone.
Gary Boothe
Cool, CA
601 HDSTD, WW Conversion 90% done,
Tail done, wings done, working on c-section
Message 58
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Message 59
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| Subject: | Re: Wing sweep and recent crashes |
Message 60
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| Subject: | Re: sattey wire for turnbuckles |
I bought the Standard Aircraft Handbook. On page 190 are illustrations
on how to safety wire turnbuckles. You can get the book on Amazon.com
or off the shelf at any Borders or big bookstore.
Brad
On Saturday, May 12, 2007, at 11:26 AM, flyingmike9 wrote:
>
> does any bodyout there have a picyure of how to saftey wire the turn
> buckles
> do you have to drill a hole or just wrap the wire round the shaft then
> through the hole in the middle any help would be grateful is there a
> book that can be recommended
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=112452#112452
>
>
Bradford J. DeMeo
Attorney At Law
Estates and Trusts
565 West College Avenue
Santa Rosa, CA 95401
(707) 545-3232
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| Subject: | Re: Wing sweep and recent crashes |
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Something about the Comcast, Web based mail client seems to sometimes remove
the body of my emails. I apologize to everyone. I'll stick to Outlook.
Kevin Bonds
Nashville TN
601XL Plans building.
<http://home.comcast.net/~kevinbonds> http://home.comcast.net/~kevinbonds
do not archive DO NOT ARCHIVE
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| Subject: | Re: acrobatics on 601s (Gift of Wings) |
Hi all.
I am building my 601 XL, so no have much time for emails... :-) Yes a month
and a half later. but reading all of them.
This is a GREAT book to read, all chapters are a short story. Great book.
Even the translation to Spanish ("El Don de Volar") has the idea perfectly...
Saludos
Gary Gower
Flying from Chapala, Mexico.
PS. Translations are as men: Good ones are not faithfull, faithfull ones are
not good. :-)
paulrod36@msn.com wrote:
YEA, VERILY YEA!! I strongly recommend all personnel herein involved,
obtain and read carefully, Richard Bach's "A Gift Of Wings." In there you
will find a short story, "Found at _______ (Can't remember the place) . Bach
hits this discussion spot-on, from thirty years ago.
Paul Rodriguez
----- Original Message -----
From: Jim Norton
To: zenith-list@matronics.com
Sent: Sunday, March 25, 2007 6:20 PM
Subject: Zenith-List: acrobatics on 601s
It seems to me that people have two opposing views to personal safety
vs. individual rights. The old school would say that an individual has
the unalienable right to do stupid things as long as they don't do
damage to other people's life or property. The new school would
say that we must provide adequate protection for people who are too
lazy, stupid, or too easily duped into doing unsafe acts which would
hurt them or others.* Remember in the old days when we had swing sets
on the school playground. Some of us would swing as high as we could,
others just like a more casual motion.
The tension between the two poles is illustrated in the idea that
we need to have a license to fly a plane. A industrious person would do
all he could do to learn about flying before s/he got behind the stick.
Other idiots would get behind the stick and think "i can do this" and
attempt to fly without any preparation. Who is right? The tension
can be further illustrated by the designation of the 601 i.e.
experimental/recreational. The old school says I have the right to
experiment anyway I /deem fit/ with this aircraft. (note the emphasis
on deem fit). The new school thinks a recreational plane should be
/made and used/ in such that it would be as absolutely safe as
possible. Unfortunately, most of us who are fliers are tend to be old
school. Courts, government officials, laws etc. tend to be new school
These are polar views, the way it all shakes out in time and society is
somewhere in between Not all pilots are Evil Kneivels, nor are all
others walking around in pads, bubbles and bullet proof vests, it just
seems that way. It's not all bad that the daredevils aren't allowed to
do whatever they please - likewise its not all bad that some of us like
to push the envelope. We probably will never resolve the
tension/conflict between the two camps, but maybe we can exer==============================================title=http://www.matronics.com/Navigator?Zenith-List href="http://www.matronics.com/Navigator?Zenith-List">http://www.matronics.=============================================== Same great content now also available via the Web Forums!http://forums.matro==========================================
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