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dfmoeller

Joined: 19 Jun 2006
Posts: 60
Location: Austin, TX

Posted: Wed Mar 12, 2008 5:32 am Post subject: Re: Accident

I've got to throw my $.02 in here:



Every time one of these airplanes goes down with folded wings, the aviation community takes a slightly dimmer view of experimentals in general and Zenith airplanes in particular.  The public already thinks we are crazy for flying homebuilts, and whenever they hear of this sort of thing, it just confirms their suspicions.  (I'm just hoping my wife doesn't hear about this.  She just had a friend auger himself in, in an RV-10, and is taking a dim view of experimentals in general.)



I do believe there is an issue here.  Too many of the limited number of these planes that exist, have gone down with folded wings for whatever reason; the task now is to find out why.  Speculation as to the cause, while running the risk of fueling the flames of hysteria, is the first step in determining the root cause, and as such, should not be stifled, but merely controlled.  What I am trying to say is that, blaming IMC or a bird strike for a wing fold (in at least two cases), is inadequate.  Those are some possible causes, out of many, but those instances may just as easily have actually been caused by dynamic loading within the envelope.  If a dangerous situation exists, hiding from it by blaming possible but vague causes is unacceptable; we should be correcting it, not waiting for it to strike again.  I personally find Andy's suggestions for strengthening the wing to be very useful as food for thought.  I also liked the idea put forward during the last round of this debate, to place a doubler around the aileron rod hole.  I welcome other ideas about areas where the wing could be strengthened.



If these were certificated planes, the FAA would be all over this, and the planes would probably be grounded, but their exp. nature lets the FAA place their priorities elsewhere.   And the lack of info and depth in the NTSB investigations is appalling.



Since we've all already invested heavily in this design, I really don't want to start all over and build something else.  I want to use this one, with whatever fixes might be necessary if something is really amiss.



The experimental nature of this plane causes somewhat of a schizoid outlook on this board.  On the one hand, many here state that we should trust Chris' design implicitly, and I fundamentally agree with them, but......others are very quick to point out that we are the builders and ultimately responsible.  Not exactly a consistent message.  Wherever the truth lies, I would like some peace of mind that the wings I build will not fold, as this is the one biggest nightmares we all have about flying (along with fears of a cockpit fire).  In the certificated aircraft industry, an engineer like Chris would have to have his design signed-off by a stress man and a dynamic analyst before flying.  Our rules are much looser and errors do pop up, sometimes in unexpected places.



Yes, I am an engineer (albeit, not an aircraft structural one, but I have worked in the aviation industry for many years, and have picked up a little info).



We are at the point where, this airplane design NEEDS to undergo a real flight test program with strain gauges, accelerometers, load cells, and proper instrumentation.  If this has already been done, then I withdraw the comment, but would like to see the results.  Stacking sandbags on wings tells almost nothing about dynamic responses - it may be adequate if no evidence of structural failures exist, but we DO have some evidence now.  I believe the only entity in a position to do this is Zenith.  I suspect many here may agree, and that is the reason for the uproar.



The first step is for someone to do a complete survey of all wing fold instances, for whatever reason, along with creation of a table listing all wing options, changes, loading, flying conditions, etc.  The only group that could do this is Zenith since they have the contacts with the builders, and usually know which options were installed.



I call on Zenith to put this to bed.  I thought thats what they were planning the last time, but was disappointed to see sandbags on wings - again.



One clarification here; I intend this in no way as criticism of Zenith, Chris, or their aircraft.  I'm just trying to get to the bottom of this.



Doug

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Mar 12, 2008 5:42 am Post subject: Re: Accident

I'm willing to go in with like minded people to pay for some 3rd party analysis of the design if it's reasonable.



Personally, I think extra ribs and no baggage lockers are in order.



 	  barcusc(at)comcast.net wrote: 	
		  Jay,

  

 WHY IN THE WORLD ARE YOU BUILDING  ONE???



  

 Because I bought the kit before these problem came  to light.I searched the FAA archives before the purchase and didn't see of  anything of concern. Before I go any further, I  know the risk involved with building and flying, I am willing to accept  reasonable risks. However, when a few failures happen  in a relatively short period of time showing  a possibility of  a trend I think one  should seek information. The reason for speculation is the fact we  will not get any information from the FAA or Zenith anytime soon, that causes  those of us that want to know to pursue as much information as possible. That  said: I do not believe they have the facts yet, at the same time, if  they have suspicions they are not going to share that with us either, we are on  our own. In my case, I have a dream of offering the chance for my  family ( Probably 6 or 7 will be interested) to learn to fly at a very young age  paying for nothing but fuel. It is one thing to put my life on the line, it is  quite another when it comes to my adult Sons, Daughter and  Grandchildren. I still believe the 601 XL is a well designed  aircraft, but that doesn't mean I will stick my head in the sand  and ignore this. There have been a lot of designs over the years, certified and  experimental, where problems began show up sometime after several have been  flying for a while. Right now, I am debating whether or not to add a BRS System.  I spoke with them on Monday, that will cost $4350.00 including shipping that  does not include the required components to attach to parachute. Then there is a  weight penalty of 35 pounds and a loss of a portion of the baggage compartment,  that is a lot to consider, especially if it turns out to be for nothing. I have  no intention of putting my project on hold, but if someone comes up with a way  to strengthen the wing in the meantime, you can bet I will do it.

  

 Opinion given with all due  respect. 

  

 DO NOT ARCHIVE

  

 Clyde Barcus

601 XL, Continental  Powered

 ---

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Mar 12, 2008 5:43 am Post subject: Re: Accident

You better believe it. So do I.



[quote="bill_dom(at)yahoo.com"]

IMHO, this discussions are an important part of the process of discovering whether or not there is a flaw.



William Dominguez

Zodiac 601XL Plans

Miami Florida

http://www.geocities.com/bill_dom



Jaybannist(at)cs.com wrote:[quote] --> Zenith-List message posted by: Jaybannist(at)cs.com



This a question to all you folks who are so skeptical of the design and safety of the Zodiac CH 601XL:



WHY IN THE WORLD ARE YOU BUILDING ONE???



Jay in Dallas 601XL N2630J "Lil Bruiser"

Do not archive   	  Quote: 	
		  [b]

MHerder

Joined: 11 Feb 2008
Posts: 143
Location: Fort Worth TX

Posted: Wed Mar 12, 2008 5:47 am Post subject: Re: Accident

Thank you mwtucker, 



I second that.  There weren't as many cases of these XL's folding up when I started my project.  These are constructive threads, and placing our heads in the sand doesn't make the issues go away.  I want to look my wife, passenger and children in straight in the eye and be able to say "I have throughly researched ever facet of the design, I have strictly followed and abided by every drawing, I have reviewed every incident that has happened and I have mitigated risk in any way possible. "  I want to be able to continue on to say "the design does not exhibit any abnormalities or anomalies that would suggest that there is a design flaw".   Aside from that I am willing to accept the risks associated with flying.  Frankly I also understand that I am far more likely to kill myself while flying by simply stalling at low altitude unintentionally rather than having my wings fold up.  But this is within MY control.  A million things could happen to me when I am flying and I can accept these risks.   Let us not forget, Mr Heintz is undoubtedly a phenomenal engineer.  MANY  phenomenal engineers recently (9/23/99) sent a multi million  dollar probe to mars to explore the climate...  With all of the millions of dollars that NASA had, an entire team of the best of the best... the damn thing was a total loss.  Why?  Because someone forgot to convert english to metric units.  I am not concerned that there ARE structural failures I AM concerned that there is a DISPROPORTIONATE amount of them for the amt flying.  All the numbers I posted and rattled around in a prior post were just to try and figure out if the amount of incidents aligned with the other major kit manufacturers.



 	  mwtucker wrote: 	
		  It is easy to try and second-guess a design based on some supposed “facts” from media stories and “eyewitnesses”.  Yes, it’s true that most of us are not aeronautical engineers…  But I think that it is constructive to discuss the accidents, keeping in mind that we may not know all the facts.  That said, it does seem that we may want to make note of the fact that wing structural failure seems to be coming up as a common thread.  Has wing structural failure been mentioned in relation to accidents of other aircraft (even certified designs)?  We all know that flight into thunderstorms and/or loss of control can over-stress the airframe and result in failure….



But I must admit that I am a bit concerned about the “supposed” in-flight structural failures on the 601XL.  I know that Chris Heintz did a re-evaluation of the wing structure and loading after two supposed in-flight wing failure accident reports.  But these were static load tests and would not expose any dynamic problems related to flutter or torsional deflections that may lead to wing failure.



I have attended the rudder workshop at Zenith and am getting pretty close to making the commitment to go with a 601XL.  I plan to ask them at Sun-n-Fun about the wing “issue”, although I would imagine that they will not tell me anything that I don’t already know.  Again, we don’t want to jump to conclusions.  I could wait and go with a Vans S-12 or a RANS 19…  But those are new designs and could also have “design” problems.  In fact, one of the reasons I was looking at the 601 XL is that the designer is well-known and respected and the design has been flying for awhile….



Does anyone know if there are any similar “structural failures” on other AB aircraft?  Again, we are assuming that there was, in fact a structural wing failure.  I guess that we don’t really know for sure.



What type of flight testing has the 601XL design been through?  Are there any flight test requirements that subject the airframe to the limits of the loading?  I think the plane is rated to +/- 6 G?  Does flight testing require that to be demonstrated?



As to Jay’s comment “why are we building the 601XLs in light of the alleged in-flight structural failures?”  I imagine that most people who are in the process of building a 601XL started their kits before they were aware of the several accidents in question.



Some responses on the forum are suggesting that the aircraft will be fine as long as it is flown properly…  In a 172, I once ran into clear-air turbulence over the mountains of Pennsylvania and it scared me to death.  There was nothing I could do to prevent that incident.  Can the 601XL survive an upset like that?



Let me close in saying that we don’t really know for sure about the “potential” structural failures.  It’s possible that they could all be explained by airframe failure due to loss of control by the pilot (e.g. birdstrike, flight into storm, accidental rapid movement of the controls, etc.).



Thanks, Mike

_________________
Zodiac 601 HD
Jabiru 3300
Wood Sensinich 64x47
Finally Flying

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Mar 12, 2008 5:48 am Post subject: Re: Accident

Well put.



 	  dfmoeller wrote: 	
		  I've got to throw my $.02 in here:



Every time one of these airplanes goes down with folded wings, the aviation community takes a slightly dimmer view of experimentals in general and Zenith airplanes in particular.  The public already thinks we are crazy for flying homebuilts, and whenever they hear of this sort of thing, it just confirms their suspicions.  (I'm just hoping my wife doesn't hear about this.  She just had a friend auger himself in, in an RV-10, and is taking a dim view of experimentals in general.)



I do believe there is an issue here.  Too many of the limited number of these planes that exist, have gone down with folded wings for whatever reason; the task now is to find out why.  Speculation as to the cause, while running the risk of fueling the flames of hysteria, is the first step in determining the root cause, and as such, should not be stifled, but merely controlled.  What I am trying to say is that, blaming IMC or a bird strike for a wing fold (in at least two cases), is inadequate.  Those are some possible causes, out of many, but those instances may just as easily have actually been caused by dynamic loading within the envelope.  If a dangerous situation exists, hiding from it by blaming possible but vague causes is unacceptable; we should be correcting it, not waiting for it to strike again.  I personally find Andy's suggestions for strengthening the wing to be very useful as food for thought.  I also liked the idea put forward during the last round of this debate, to place a doubler around the aileron rod hole.  I welcome other ideas about areas where the wing could be strengthened.



If these were certificated planes, the FAA would be all over this, and the planes would probably be grounded, but their exp. nature lets the FAA place their priorities elsewhere.   And the lack of info and depth in the NTSB investigations is appalling.



Since we've all already invested heavily in this design, I really don't want to start all over and build something else.  I want to use this one, with whatever fixes might be necessary if something is really amiss.



The experimental nature of this plane causes somewhat of a schizoid outlook on this board.  On the one hand, many here state that we should trust Chris' design implicitly, and I fundamentally agree with them, but......others are very quick to point out that we are the builders and ultimately responsible.  Not exactly a consistent message.  Wherever the truth lies, I would like some peace of mind that the wings I build will not fold, as this is the one biggest nightmares we all have about flying (along with fears of a cockpit fire).  In the certificated aircraft industry, an engineer like Chris would have to have his design signed-off by a stress man and a dynamic analyst before flying.  Our rules are much looser and errors do pop up, sometimes in unexpected places.



Yes, I am an engineer (albeit, not an aircraft structural one, but I have worked in the aviation industry for many years, and have picked up a little info).



We are at the point where, this airplane design NEEDS to undergo a real flight test program with strain gauges, accelerometers, load cells, and proper instrumentation.  If this has already been done, then I withdraw the comment, but would like to see the results.  Stacking sandbags on wings tells almost nothing about dynamic responses - it may be adequate if no evidence of structural failures exist, but we DO have some evidence now.  I believe the only entity in a position to do this is Zenith.  I suspect many here may agree, and that is the reason for the uproar.



The first step is for someone to do a complete survey of all wing fold instances, for whatever reason, along with creation of a table listing all wing options, changes, loading, flying conditions, etc.  The only group that could do this is Zenith since they have the contacts with the builders, and usually know which options were installed.



I call on Zenith to put this to bed.  I thought thats what they were planning the last time, but was disappointed to see sandbags on wings - again.



One clarification here; I intend this in no way as criticism of Zenith, Chris, or their aircraft.  I'm just trying to get to the bottom of this.



Doug

larry(at)macsmachine.com
Guest

Posted: Wed Mar 12, 2008 6:18 am Post subject: Accident

Paul,

There are designers, engineers and aeronautical engineers of all types.  

It doesn't take a high degree to analyze problems with a design.

It just isn't rocket science.  The difference between the HD series and 

the XL series is huge. Going from a 10 inch spar, 8-ft center section 

and 7 foot wings to

a full length wing that has half the spar thickness may be a part of the 

problem, but the folding action has more to do with structural rigidity 

of the wing

at the fuselage and center spar wing attachments.  One odd thing 

suggests these planes had just a few hours on them. Another factor is 

what percentage were

kits and how many were SLA.  The question of who built them and what 

common error or variation might have caused this series of mishaps.  

There's more

to look at than just the design.  I'd absolutely not vary from the plans 

one bit. In fact, I'd pay more attention to fine detail to get it right.



Larry McFarland 601HDS at www.macsmachine.com

do not archive

skyguynca(at)skyguynca.com wrote:

[quote] Paul, there really are sooooo many arm chair engineers with solutions. 

 Your right and I agree I believe Chris Henitz is a great designer. 

 Other designers have missed things and miscalculated so lets not 

 forget we are all human and he could have made a error. Me I look at 

 the fact of so many XL accidents versus very few HD and HDS accidents, 

 maybe a flaw creeped in on the new design?



     ---

John Bolding

Joined: 23 May 2006
Posts: 281

Posted: Wed Mar 12, 2008 6:45 am Post subject: Accident

I've got no dog in this hunt as I'm building a 701,   however, I mentioned a 

year ago that if you XL guys are SERIOUS about getting to the bottom of this 

then 3RD party analysis is your best bet. Zenith has shown they are 

unwilling or not capable of anything other than redoing what they already 

did and that proves nothing.



Many years ago the Adventurer Amphib had a wing failure and after ONE such 

incident the builders got together and hired Martin Holman to do a flutter/ 

vibration/structure analysis.  He found that with the wing tanks at a 

certain % of fuel the wing had an unstable mode at a speed well within 

cruise speeds,   a fix was determined and life was good, at least as good as 

the rest of the airplane which was a POS.



SOMEBODY needs to belly up to the bar and DO SOMETHING instead of just whine 

and moan.   Find an engineer capable of this project, pass the hat, send him 

a set of drawings and see what shakes out.  It ain't going away folks.  The 

FAA isn't going to help, the NTSB isn't going to help, the ball is on YOUR 

side of the net.



John

---

barcusc(at)comcast.net
Guest

Posted: Wed Mar 12, 2008 7:04 am Post subject: Accident

Well put John! I would be willing to contribute if enough guys jump in to 

make it reasonable, if so, I also think we should approach Zenith for a 

contribution. An independent evaluation like the one suggested by John is 

the way to go, this issue needs to be put to rest and that cannot be done 

with sandbags. I am sure the uncertainty will cause some to hold off buying 

or go with another company.

Clyde Barcus

601 XL, Continental Powered

---

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Mar 12, 2008 7:06 am Post subject: Re: Accident

I suggested awhile back hiring a third party. How many people here are willing to pony up some money. Get a quote divide by the number of people interested and we'll see if that's reasonable for everyone. Then if we've got the money submit it to someone who knows what they're doing.



 	  John Bolding wrote: 	
		  I've got no dog in this hunt as I'm building a 701,   however, I mentioned a 

year ago that if you XL guys are SERIOUS about getting to the bottom of this 

then 3RD party analysis is your best bet. Zenith has shown they are 

unwilling or not capable of anything other than redoing what they already 

did and that proves nothing.



Many years ago the Adventurer Amphib had a wing failure and after ONE such 

incident the builders got together and hired Martin Holman to do a flutter/ 

vibration/structure analysis.  He found that with the wing tanks at a 

certain % of fuel the wing had an unstable mode at a speed well within 

cruise speeds,   a fix was determined and life was good, at least as good as 

the rest of the airplane which was a POS.



SOMEBODY needs to belly up to the bar and DO SOMETHING instead of just whine 

and moan.   Find an engineer capable of this project, pass the hat, send him 

a set of drawings and see what shakes out.  It ain't going away folks.  The 

FAA isn't going to help, the NTSB isn't going to help, the ball is on YOUR 

side of the net.



John

---

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Mar 12, 2008 7:33 am Post subject: Re: Accident

 	  Sabrina wrote: 	
		  

What are people paying for XL insurance, $30,000 hull coverage and $1M liability?



My 150 comes in just over $600, whereas the quotes for the XL winged aircraft now exceed $2,000, they won’t insure Phase 1 for hull damage, they won’t insure a solo student pilot, or anyone without 10 hours of dual in the aircraft or 40 hours in type. 	




I'm guessing the more expensive insurance is due to the fact that it's a homebuilt. I could be wrong, but just from an actuarial viewpoint that would make sense.



Personally, I'm my own hull insurance and will carry only liability.

pavel569

Joined: 21 Dec 2007
Posts: 77

Posted: Wed Mar 12, 2008 7:48 am Post subject: Re: Accident

I'm in.



 	  ashontz wrote: 	
		  I suggested awhile back hiring a third party. How many people here are willing to pony up some money. Get a quote divide by the number of people interested and we'll see if that's reasonable for everyone. Then if we've got the money submit it to someone who knows what they're doing.

_________________
Pavel
CA
Zodiac 601XL
Stratus Subaru EA-81
Tail, flaps, ailerons, wings, fuselage, canopy done ...
"do not archive"

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Wed Mar 12, 2008 7:51 am Post subject: Re: Accident

Here's a thread simply for signing up for a structural analysis

http://forums.matronics.com/viewtopic.php?p=169266#169266



 	  pavel569 wrote: 	
		  I'm in.



 	  ashontz wrote: 	
		  I suggested awhile back hiring a third party. How many people here are willing to pony up some money. Get a quote divide by the number of people interested and we'll see if that's reasonable for everyone. Then if we've got the money submit it to someone who knows what they're doing.

Terry Phillips

Joined: 11 Jan 2006
Posts: 346
Location: Corvallis, MT

Posted: Wed Mar 12, 2008 8:21 am Post subject: Accident

Count me in.



I feel like I'm too far into this project to start over with a different 

airplane. But, I'm at a point where I would not be comfortable inviting my 

loved ones to join me for a flight (way down the road when I actually have 

a flying airplane). This needs to be resolved, sooner rather than later.



Terry

At 08:06 AM 3/12/2008 -0700, you wrote:

 	  Quote: 	
		  I suggested awhile back hiring a third party. How many people here are 

willing to pony up some money. Get a quote divide by the number of people 

interested and we'll see if that's reasonable for everyone. Then if we've 

got the money submit it to someone who knows what they're doing.

John Bolding wrote:

 > I've got no dog in this hunt as I'm building a 701,   however, I 

 mentioned a

 > year ago that if you XL guys are SERIOUS about getting to the bottom of 

 this

 > then 3RD party analysis is your best bet. Zenith has shown they are

 > unwilling or not capable of anything other than redoing what they already

 > did and that proves nothing.

 >

 > Many years ago the Adventurer Amphib had a wing failure and after ONE such

 > incident the builders got together and hired Martin Holman to do a 

 flutter/

 > vibration/structure analysis.  He found that with the wing tanks at a

 > certain % of fuel the wing had an unstable mode at a speed well within

 > cruise speeds,   a fix was determined and life was good, at least as 

 good as

 > the rest of the airplane which was a POS.

 >

 > SOMEBODY needs to belly up to the bar and DO SOMETHING instead of just 

 whine

 > and moan.   Find an engineer capable of this project, pass the hat, 

 send him

 > a set of drawings and see what shakes out.  It ain't going away 

 folks.  The

 > FAA isn't going to help, the NTSB isn't going to help, the ball is on YOUR

 > side of the net.

 >

 > John


	




Terry Phillips

ttp44~at~rkymtn.net

Corvallis MT

601XL/Jab 3300 s .. l .. o .. o .. w build kit - Tail, flaps, & ailerons 

are done; working on the wings

http://www.mykitlog.com/N47TP/

_________________
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings.

barcusc(at)comcast.net
Guest

Posted: Wed Mar 12, 2008 8:40 am Post subject: Accident

I'm in.



Clyde Barcus

601 XL, Continental Powered

From: "ashontz" <ashontz(at)nbme.org>

To: <zenith-list(at)matronics.com>

Sent: Wednesday, March 12, 2008 10:51 AM

Subject: Re: Accident

 	  Quote: 	
		   



 Here's a thread simply for signing up for a structural analysis

 http://forums.matronics.com/viewtopic.php?p=169266#169266

 pavel569 wrote:

> I'm in.

> ashontz wrote:

> > I suggested awhile back hiring a third party. How many people here are 

> > willing to pony up some money. Get a quote divide by the number of 

> > people interested and we'll see if that's reasonable for everyone. Then 

> > if we've got the money submit it to someone who knows what they're 

> > doing.

>

 --------

 Andy Shontz

 CH601XL - Corvair

 www.mykitlog.com/ashontz





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=169267#169267

psm(at)att.net
Guest

Posted: Wed Mar 12, 2008 8:54 am Post subject: Accident

To my recollection, NASA has a long history of screwing up nearly 

everything they ever did.  I attribute this to the fact they are a 

government bureaucracy, they buy most of their stuff from the lowest 

bidder, and they have no profit motive to move them toward perfection 

or even a satisfactory outcome.  They are much more motivated by 

political and publicity pressures than anything else.  I would never 

give even remote consideration to an offer to ride in a NASA space 

craft.  (These are also the guys who spend millions of our dollars 

each year trying to develop a personal airplane that can fly itself 

so the masses can enjoy personal flight without learning how to be a pilot.)



I agree that discussion of the facts and even some conjecture about 

the XL design is healthy.  Where I get concerned is when someone with 

about zero qualifications as an aircraft designer offers one 

ridiculous design change after another to fix problems that have not 

even been indicated let alone established as fact.  I realize most 

readers of the list can tell when someone is making ridiculous 

suggestions, but I am afraid there are some who might implement some 

of those design changes and suffer the outcome.



I am convinced that Chris Heintz has done a wonderful job designing 

this airplane.  I am also convinced that any design changes 

considered by a kit or plans builder should be approved by one of the 

engineering support people readily available to us to consider such 

changes.  While this is not a perfect system, it is the only 

reasonable one we have.



Paul

XL fuselage

At 06:47 AM 3/12/2008, you wrote:

 	  Quote: 	
		  Let us not forget, Mr Heintz is undoubtedly a phenomenal 

engineer.  MANY  phenomenal engineers recently (9/23/99) sent a 

multi million  dollar probe to mars to explore the climate...  With 

all of the millions of dollars that NASA had, an entire team of the 

best of the best... the damn thing was a total loss.  Why?  Because 

someone forgot to convert english to metric units.

amyvega2005(at)earthlink.
Guest

Posted: Wed Mar 12, 2008 9:23 am Post subject: Accident

on my XL I am paying around $1500.00 per annum for $50,000 coverage on hull and gen Liability.

Certainly cheaper than a Piper Arrow.



Juan



--

Matt Ronics

Joined: 30 Apr 2007
Posts: 22

Posted: Wed Mar 12, 2008 11:15 am Post subject: Re: Accident

 	  psm(at)att.net wrote: 	
		  To my recollection, NASA has a long history of screwing up nearly 

everything they ever did.  	




Well, hopefully Paul will lend his considerable talents to NASA to assist in the fixing the myriad of challenges that would be simple for Paul to fix.



As to the XL wing issue, if there has been stronger builder defense for such a suspect design in experimental aviation history, I do not know.  Maybe there were droves of BD-5 kit owners in the mid-70's with undying support for Jim Bede (but none in the late 70s).  RV builders on the other hand asked immediate serious questions on RV wing and nosegear problems.



Christ Heinz is without a doubt a great designer.  Nonetheless, should third-party or Zenith analysis conclude that there is a design problem, Zenith would likely sink given the financial burden addressing the issue would cost the company (i.e. providing replacement parts etc).  If they didn't produce them at no/low-cost, lawsuit would surely ensue.  Thus not a lot of impetus for Zenith to go digging into the issue.



Even Van has been reluctant to address his nosegear issues (i.e. nosegear 'catching' and flipping planes).  But he has.



In the meantime, let's just keep having this same discussion on the XL wing as the planes go in every few months under questionable circumstances.

planecrazydld(at)yahoo.co
Guest

Posted: Wed Mar 12, 2008 11:29 am Post subject: Accident

Sorry to keep fueling the argument, but, in addition to the "committee" that reviews the design and the static testing that proves the assumptions, all of the majors that I have worked for in 35 years fatigue test the crap out of wing designs at the very least. Having built several of those test wings as well as having participated in failure analysis, I am just left with a "bad feeling" that there is some crazy little sensitivity to a particular flight load, however transient, whether caused by intentional horsing of the aircraft or gust loads in flight, or...



dfmoeller <dfmoeller(at)austin.rr.com> wrote: 	  Quote: 	
		   --> Zenith-List message posted by: "dfmoeller" 



...In the certificated aircraft industry, an engineer like Chris would have to have his design signed-off by a stress man and a dynamic analyst before  flying.  Our rules are much looser and errors do pop up, sometimes in unexpected places.... 	


  Dave Downey

  Harleysville (SE) PA

  100 HP Corvair

        Be a better friend, newshound, and   [quote][b]

n85ae

Joined: 14 Mar 2007
Posts: 403

Posted: Wed Mar 12, 2008 11:50 am Post subject: Re: Accident

Hmm...



I worked as an assembly technician on the NASA UARS project which

launched on shuttle flight STS-48,  I'll just bluntly state you don't know 

what you're talking about. 



Almost every NASA project is something completely new, the 

standards are extremely high, much more so than the aircraft industry.

Go get yourself a job on one of these projects, and get NASA certified

in your skill, and I guarantee you'll be talking much differently. They

DO have failures, but considering what a space flight entails, not very

many. 



The fact is when they don't have failures, which is most of the time you

don't hear about it much. When they do have failures, they do make the

news in a big way. A lot of people want risk free, cheap space flight. 

The fact is, it is a VERY dangerous business. So considering how well

they do, I'd say they aren't screwing "everything" up.



If you don't believe me, take one of your electronics assemblies down 

to the local paint shop and put it in a paint shaker for an hour and then

turn it on and see if it still works. Oh, not to mention after you baked

it in an oven, and then a refrigerated vacuum. 



Sorry if this is a rant, but I know how hard a lot of people in the Space 

industry work.



Jeff

 	  Quote: 	
		  To my recollection, NASA has a long history of screwing up nearly

everything they ever did. I attribute this to the fact they are a

government bureaucracy, they buy most of their stuff from the lowest

bidder, and they have no profit motive to move them toward perfection

or even a satisfactory outcome. They are much more motivated by

political and publicity pressures than anything else. I would never

give even remote consideration to an offer to ride in a NASA space

craft. (These are also the guys who spend millions of our dollars

each year trying to develop a personal airplane that can fly itself

so the masses can enjoy personal flight without learning how to be a pilot.)

Matt Ronics

Joined: 30 Apr 2007
Posts: 22

Posted: Wed Mar 12, 2008 12:02 pm Post subject: Re: Accident

 	  planecrazydld(at)yahoo.co wrote: 	
		   Having built several of those test wings as well as having participated in failure analysis, I am just left with a "bad feeling" that there is some crazy little sensitivity to a particular flight load, however transient, whether caused by intentional horsing of the aircraft or gust loads in flight, or...

	




...or possibly (as I've mentioned before) some crazy little design issue that is not tolerant of subtle variances in building technique.  While totally conjecture, it could explain why some structures will never have a problem whereas others may experience failure, irrespective of flying technique.

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