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jaybannist(at)cs.com
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 Posted: Tue Dec 23, 2008 9:08 am Post subject: Zodiac CH601XL "Problems" |
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Here is my take on the Zodiac CH 601XL “problem”:
Chris Heintz designed quite a number of airplanes; for factory assembly, kit construction and plans building. There are thousands of airplanes of his designs flying, including CH601XLs registered in the USA as LSA, E-LSA, EAB and an extremely confusing array of registration designations in other countries.
There is a lot of discussion about whether the CZAW kits and airplanes are identical to the ones from the USA. There are those that claim that they are identical...except blah, blah & blah. They simply can’t be identical if there are exceptions. I suspect (another personal opinion) that there are differences that observers either will not; or, more likely, can’t recognize. For instance, can a builder tell the difference between 6061-T6 aluminum and 6061-Txx? Absolutely not. Can a builder tell the difference between the Avex rivets that Zenith supplies and substandard imitators? No. Yet these differences can be significant and can certainly effect the structural integrity of the airframe. The same applies to the different angle of incidence of the wing. Is the angle of the wing spar center section changed or is the wing twisted to change the angle? (The latter is the case) Analyzing the weight differences and plain old common sense tells me that there are more differences yet. In short, all CH601XLs are NOT identical, and cla iming so is simply engaging in fantasy.
European builders have given the argument that Chris Heintz’s name on all the drawings as evidence that Heintz is totally responsible for their airplanes. However, they assert that the drawings are the same as those in the USA....except for the added drawings by CZAW. Drawings supplied by CZAW with Chris Heintz name on all of them do NOT establish absolute responsibility for the finished product. That would require certification that the kit materials or the complete airplane strictly adheres to the requirements stated in those drawings, either by CZAW or the kit builder. CZAW obviously can’t make that certification, and I don’t know of any builder that has the technical expertise nor the materials documentation to make that certification. Therefore, the owner / builder has the final responsibility for their airplane.
As I recall, CZAW was started by an American in the Czech Republic as a program to assist builders to quickly assemble Zodiac kits. CZAW then morphed into a company that manufactured complete Zodiac airplanes and sold kits. It is unclear where the materials CZAW used actually originated. The Zenair - CZAW relationship ended for a reason. I don’t know what that reason was, but I strongly suspect (my opinion strictly) that it was because the CZAW organization did not exercise adequate quality control, especially over the materials they used and or supplied to kit builders.
So why are CH601XLs cr ashing? Is there a design flaw? The design has been verified several times over, through analysis and through testing. You can advance all sorts of convoluted arguments against this but the design simply does not have a flaw that causes a wing to fold. The XL design, as ALL aircraft designs, is based on clearly stated operating limitations. Operating outside the design limitations of ANY aircraft subjects that aircraft to structural failure; and many of them have failed and crashed.
So are there problems with the way pilots are operating? We all know the limitations, but some pilots forget about them, or fly into bad climate situations, or have untenable equipment malfunctions, or simply choose to ignore the limitations, because others have “gotten away with it”.
Are there problems with the materials used? I am personally confident in the materials supplied by Zenith. I do not have the same confidence in the materials supplied by CZAW.
Summation (Definitely my opinion): The Zodiac CH601XL “problem” is not design. The “Problems” are:
1) The way some pilots choose to fly the airplane, either on purpose or accidentally,
2) Possible substandard materials and unsound design changes (from CZAW) and,
3) Construction and maintenance errors on the part of builders/owners.
These are highly personal opinions and not cold hard facts.
A Merry Christmas and a Happy New Year to all !!!
J ay Bannister (alias Jay in Dallas)
Zodiac CH 601XL N2630J “Lil Bruiser”
BTW, I have crashed in a Zodiac CH 601XLi (not mine). It had nothing to do with the design and the wings did not fall off.
Email message sent from CompuServe - visit us today at http://www.cs.com
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notsew_evets(at)frontiern
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| Posted: Tue Dec 23, 2008 9:52 am Post subject: Zodiac CH601XL "Problems" |
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All sounds reasonable to me..
As many of you know, I ve been wrestling with my Weight and Balance. My rear CG is right at 450mm.
Yet I read from the UK ( its on the UK Zenith website) that the CG in that country for the 601XL, is from 300 to 520mm.
Same configuration as I have, same kit, same engine.....
I ve forwarded the info to Zenith and they dont belive it. Said they will get back to me...
One would think, Zenith knows..........
The reason I keep bringing this subject up is that I dont get it either...
The 1600mm on the W&B is NOT in the "average" baggage area spot. My "baggage is right smack at 1850mm....
If a pilot put the baggage at the rear of the compartment I m sure the W&B will be waaaay out......
Any ideas??????
SW
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alex_001
Joined: 14 Jan 2007
Posts: 61
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| Posted: Wed Dec 24, 2008 6:43 am Post subject: Re: Zodiac CH601XL |
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i just would like to point out that i have been several times to the CZAW factory
have a look yourself (www.czaw.cz)
for the material i only can say when the stores where shown to me i did see mostly American spec materials.also they way the planes where build look good to me as the have a proper production line system there.
Workforce has been former LET personal.
all the panels i can see on my xl it seem to be US made panels (print in the alloy)
i think the reason the relationship was terminated was the CZAW Sportscruiser if i would be CH i would be also pi... off
i looked close to it and it is like a development of the 601xl many many similar parts.
the unprimed angle i installed when i installed the AP
if there is a problem with the xl that is for sure not down to the material spec.
my first xl has been weighing 298 kg with bare instruments (no avionics) no wheelcovers, no seats rotax 912s no airbox, no carpets etc, carbon fibre engine cover incl. BRS, no lights strobs etc when the plane is complete with avionics more instruments etc it is about 315kg
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s.clive.richards(at)homec
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| Posted: Wed Dec 24, 2008 8:53 am Post subject: Zodiac CH601XL "Problems" |
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Steve
What is the web address of this Zenith site in UK you refer to I am in the UK & no of no such site there is a Zenair Europe site http://www.zenairulm.com/Home/index.htm & lists outstanding European ADs but refers back to US site for technical details. For the 601 HD our LAA have reduced the rear limit we can use.
Clive
do not archive
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notsew_evets(at)frontiern
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| Posted: Wed Dec 24, 2008 9:40 am Post subject: Zodiac CH601XL "Problems" |
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Clive
email me direct so I can get it from my docs and upload it to you.
Today I also receive an email from a Mr. Lewis ( I believe from France) and he states that he has a letter from CH himself which approves the 520mm.
I ll upload that also. Its still not proof of why the USA version is at 450mm, but I think its very interesting....
notsew_evets(at)frontiernet.net (notsew_evets(at)frontiernet.net)
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jetboy
Joined: 22 Jul 2006
Posts: 233
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| Posted: Wed Dec 24, 2008 1:44 pm Post subject: Re: Zodiac CH601XL |
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Hi all, getting the correct figures for the various configurations is a difficult proposition.
I have a CZAW 701 airframe and as far as I can tell its made from all the usual USA 49% kit parts, Matco wheels etc. Wherever alterations are made there is an extra page in the plans detailing the CZAW mod and reason (usually to comply with the BCAR-S design rules used in Europe) and some of these mods have been incorporated in subsequent ZAC plans revisions, for example the seatbelt attach points.
There is however, very little guidance as to any new loading / flight airspeeds that must arise from some changes. When the CH701 flap travel was reduced to 16 deg. there is no change to the USA vfe 52 Kts however CZAW have it at 55 Kts which seems more realistic. I wrote to ZAC and dealers about this and got nil response. Maybe I missed something because I dont get "Zenair news" but it seems a little odd that there is no updated design information available from source. This is similar to the situation that exists when owners are upgrading their CH600 series to the new weights. They get a note saying its OK to operate with reduced G loading ( in effect cutting out the factor of safety margins ) however there is no guidance or requirement to re-placard the airspeed and operating limitations. In New Zealand they are just waking up to this sort of thing with topdressing aircraft that have been breaking up in part due to the 31% overload rules that were applied some years back.
http://www.caa.govt.nz/GA/Ag_Aviation/Ag_Aircraft_Safety_Review.htm
take care out there
ralph
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Ralph - CH701 / 2200a |
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