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Flutter Testing shows 601/650 OK

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tonyplane(at)bellsouth.ne
Guest

Posted: Fri May 22, 2009 8:09 pm Post subject: Flutter Testing shows 601/650 OK

See Below:

 ((Heck!  I only took mine up to 195 mph (314  kph) during my Phase I testing))

  

 Tony Graziano

 601XL/Jab3300; N493TG: 492 hrs

  

  

ZENAIR EUROPE NEWS  http://www.zenairulm.com/News/index_files/Page1128.htm<?xml:namespace prefix = o  ns = "urn:schemas-microsoft-com:office:office" /> 

  

Update of May 15, 2009 

  

 

The results of the German-led GVT (Ground Vibration  Tests) are in and they are unequivocal: The Zodiac CH 601 XL and CH 650 E are  not subject to flutter if built, maintained and flown as intended by Zenair. The  linear flutter tests confirmed this for all speeds up to 400 km/h and with  aileron control cable tension down to less than ten pounds. Chris Heintz and  representatives from Zenair Europe will be meeting with DAeC engineers in  Germany during the coming week to review results of the recently concluded tests  and to discuss the process for lifting remaining flight limitations on the  LTF-UL certified aircraft. 

 “I am pleased with the results of the GVT” said  Zodiac designer Chris Heintz, “with the integrity of the design confirmed, we  now need to ensure that pilots don’t forget that all aircraft have limitations”.  Zenair is currently planning an education campaign aimed at informing and  sensitizing pilots of its designs to the importance of understanding and  respecting aircraft limitations (i.e. the Zodiac is not designed for high stress  or aerobatic maneuvers). 

Nick Heintz of Zenair Europe says he expects that  with the new GVT results in hand, temporary limitations placed on the Zodiac  model by various CAA agencies around Europe will soon be reversed: “These were  put in place after a negative report from the Dutch Safety Board last year  suggested that the aircraft was prone to flutter – these new Ground Vibration  Tests, carried out by a leading world-wide expert in the field of material  fatigue and vibrations, now clearly proves otherwise”. He stated that all  interested CAA offices will soon have an opportunity to review results from the  tests. Additional information will be posted here very shortly. 

  



   [quote][b]

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Sat May 23, 2009 6:11 pm Post subject: Re: Flutter Testing shows 601/650 OK

Well that is not unexpected news.  I am really glad to hear it.  It is really a shame all this even took place just because of a few uninformed whiners.  Well I guess we can all move forward now, (i never stopped).

_________________
Ron Lendon
WW Corvair with Roy's Garage 5th bearing
CH 601 XLB
N601LT - Flying
http://www.mykitlog.com/rlendon
Corvair Engine Prints:
https://sites.google.com/site/corvairenginedata/

jmaynard

Joined: 27 Feb 2008
Posts: 394
Location: Fairmont, MN (FRM)

Posted: Sat May 23, 2009 6:48 pm Post subject: Flutter Testing shows 601/650 OK

On Sat, May 23, 2009 at 07:11:46PM -0700, Ron Lendon wrote:

 	  Quote: 	
		   Well that is not unexpected news.  I am really glad to hear it.  It is

 really a shame all this even took place just because of a few uninformed

 whiners.


	


Okkay, fine. How do YOU explain the inflight breakups? Bear in mind that

builder and pilot error cannot explain every 601XL inflight breakup.

-- 

Jay Maynard, K5ZC, PP-ASEL, CFI-SP   http://www.conmicro.com

http://jmaynard.livejournal.com       http://www.tronguy.net

Fairmont, MN (KFRM)                        (Yes, that's me!)

AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml

_________________
Jay Maynard, K5ZC
AMD Zodiac XLi N55ZC

jaybannist(at)cs.com
Guest

Posted: Sun May 24, 2009 5:08 am Post subject: Flutter Testing shows 601/650 OK

Says who ?  That is no more a "given" than the NTSB's flutter was.

 

   

 Jay Bannister

 DO NOT ARCHIVE

 

   	  Quote: 	
		  

Bear in mind that builder and pilot error cannot explain every 601XL inflight breakup.

-- 

Jay Maynard, K5ZC, PP-ASEL, CFI-SP   http://www.conmicro.com

http://jmaynard.livejournal.com       http://www.tronguy.net

Fairmont, MN (KFRM)                        (Yes, that's me!)

AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml

	
 

      Email message sent from CompuServe - visit us today at http://www.cs.com 

  [quote][b]

jeffrey_davidson(at)earth
Guest

Posted: Sun May 24, 2009 6:55 am Post subject: Flutter Testing shows 601/650 OK

Jay,  

      I understand your very human need for an explanation.  We all want to find out what caused these accidents.  This is particularly true if one cause is responsible.  Actually, we want to learn from all accidents, particularly fatal ones.  But that doesn't mean that the need for an answer justifies grabbing at whatever theory comes along and holding that up as the true cause.  We need to proceed on facts and at this time, we have no choice but to realize that we don't have the facts to conclusively explain what has happened despite multiple extensive investigations.  You need to realize that we may never have the ultimate answer despite all our efforts.  

      Jeff Davidson  

    

   

Time: 07:48:22 PM PST US  

From: Jay Maynard <jmaynard(at)conmicro.com>  

Subject: Re: Zenith601-List: Re: Flutter Testing shows 601/650 OK  

   

   

On Sat, May 23, 2009 at 07:11:46PM -0700, Ron Lendon wrote:  

 	  Quote: 	
		   Well that is not unexpected news.  I am really glad to hear it.  It is   

 really a shame all this even took place just because of a few   

 uninformed whiners.  

   
	


Okkay, fine. How do YOU explain the inflight breakups? Bear in mind that builder and pilot error cannot explain every 601XL inflight breakup.  

       [quote][b]

jmaynard

Joined: 27 Feb 2008
Posts: 394
Location: Fairmont, MN (FRM)

Posted: Sun May 24, 2009 7:11 am Post subject: Flutter Testing shows 601/650 OK

On Sun, May 24, 2009 at 08:52:25AM -0400, jaybannist(at)cs.com wrote:

 	  Quote: 	
		   Jay Maynard wrote:

 > Bear in mind that builder and pilot error cannot explain every 601XL

 > inflight breakup.

  Says who ?? That is no more a "given" than the NTSB's flutter was.

Okkay, then, explain N158MD's breakup. Be sure to account for the fact that

it was built in a part 23 certified factory and that it broke up in straight

and level flight, on a flight where its 79-year-old owner was taking his

wife up for the first time (and therefore wasn't going to be doing things

like 3G pullups from a high speed low pass, or other extreme maneuvers).

Until someone comes up with an explanation that accounts for the known facts

of *all* the crashes, I will remain unconvinced. It's too easy to say

"builder error and pilot error account for all of the crashes" when there

are facts that strongly argue otherwise.

I'm quite happy that Zenair has gotten a documented engineering study that

shows the Zodiac is not susceptible to flutter. That, however, leaves the

bigger question unanswered: why are Zodiacs breaking up in flight?

One of the things that the FAA wants CFIs to know is that there are

hazardous attitudes toward risk that pilots adopt and that need to be

guarded against and countered. One of those is invulnerability: "it can't

happen to me". I'm seeing a lot of that on this list (not from you, Jay; I

know you know better). It can and does happen, to anyone. I just hope it

won't happen again - but I suspect that hope will be in vain.

-- 

Jay Maynard, K5ZC, PP-ASEL, CFI-SP   http://www.conmicro.com

http://jmaynard.livejournal.com       http://www.tronguy.net

Fairmont, MN (KFRM)                        (Yes, that's me!)

AMD Zodiac CH601XLi N55ZC http://www.tronguy.net/N55ZC.shtml

_________________
Jay Maynard, K5ZC
AMD Zodiac XLi N55ZC

tigerrick(at)mindspring.c
Guest

Posted: Sun May 24, 2009 7:34 am Post subject: Flutter Testing shows 601/650 OK

Good points, Jeff. One thing that has been haunting me lately has been the uptick of LSA accidents that seem to center around airframe failures in flight. LSAs as a group had a pretty good safety record for awhile, and now appear to be trending up in break-ups. And it's not just the Zenith 600 series.



By nature, our new LSAs are very light airplanes, strong for sure, but not built to withstand the same kind of rigors as a Part 23 design. The engineering specs on paper may be close, but all you have to do is actually look at and compare how these airplanes are constructed and it's pretty obvious how designers manage to actually get a reasonable useful load out of an LSA.



I think we've grown up flying rugged, forgiving, overbuilt spam cans that manage to come through things like icing and severe turbulence and excessive G loading even when the book says they shouldn't. Now we're flying airframes of much lighter design and construction, and there's no way we can subject them to the same abuse without consequence.



Old habits die hard, but I really think that it's up to us as pilots to be realistic about what kind of flying conditions we're prepared to challenge with this latest batch of LSAs. And maybe we need to recognize that these light little airplanes may need a bit more diligence where periodic maintenance is concerned.  Just my $0.02, FWIW.



Rick Lindstrom

ZenVair N42KP



--

jaybannist(at)cs.com
Guest

Posted: Sun May 24, 2009 8:09 am Post subject: Flutter Testing shows 601/650 OK

--> Zenith601-List message posted by: Jay Maynard <jmaynard(at)conmicro.com (jmaynard(at)conmicro.com)>

   	  Quote: 	
		  

Okkay, then, explain N158MD's breakup. Be sure to account for the fact that

it was built in a part 23 certified factory and that it broke up in straight

and level flight, on a flight where its 79-year-old owner was taking his

wife up for the first time (and therefore wasn't going to be doing things

like 3G pullups from a high speed low pass, or other extreme maneuvers).



Jay,



That accident is one that has a very extensive report.  When you say that it 

was in straight and level flight, I think you are overlooking the fact that,

just prior to the break up, there was a rather sudden increase in altitude - 

at 700 fpm, from 2,000 to 2,800 ft.  That is not "level flight". I know it is

total speculation, but isn't it possible that the pilot tried to overcome

a surprise, uncommanded increase in altitude with a sudden, drastic control input?

I'm not saying that is what happened, but if you are looking for an explanation,

you can't simply overlook pertinent facts and expect to get a valid answer.



Jay Bannister

DO NOT ARCHIVE



	
 

      Email message sent from CompuServe - visit us today at http://www.cs.com 

  [quote][b]

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Sun May 24, 2009 8:23 am Post subject: Flutter Testing shows 601/650 OK

It did not break up in straight and level flight, the radar track  

shows that it was maneuvering. And what makes you think a 79 year old  

is immune to the "hey watch this" syndrome. Then there is also the  

possibility of sudden incapacitation. Or a sudden maneuver to avoid a  

bird strike. It is also quite likely that there is no common cause for  

these accidents. With so few accidents to account for it is entirely  

within the realm of possibility that this is a statistical fluke.

On May 24, 2009, at 11:05 AM, Jay Maynard wrote:

 	  Quote: 	

 >

 On Sun, May 24, 2009 at 08:52:25AM -0400, jaybannist(at)cs.com wrote:

> Jay Maynard wrote:

>> Bear in mind that builder and pilot error cannot explain every 601XL

>> inflight breakup.

> Says who ?? That is no more a "given" than the NTSB's flutter was.

 Okkay, then, explain N158MD's breakup. Be sure to account for the  

 fact that

 it was built in a part 23 certified factory and that it broke up in  

 straight

 and level flight, on a flight where its 79-year-old owner was taking  

 his

 wife up for the first time (and therefore wasn't going to be doing  

 things

 like 3G pullups from a high speed low pass, or other extreme  

 maneuvers).

 Until someone comes up with an explanation that accounts for the  

 known facts

 of *all* the crashes, I will remain unconvinced. It's too easy to say

 "builder error and pilot error account for all of the crashes" when  

 there

 are facts that strongly argue otherwise.

-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

tigerrick(at)mindspring.c
Guest

Posted: Sun May 24, 2009 9:04 am Post subject: Flutter Testing shows 601/650 OK

Hi, Bryan. I just went back and reread the full NTSB narrative on 158MD, and there's no shortage of possible contributing factors. As much as I hate like hell to get sucked into the speculation game, the NTSB report contains many references to advanced heart disease, really excessive negative G loading (broken seat belts, shattered canopy, wings and stab torn away), sloppy airframe and engine construction among others.



Given all the published data in the report, I don't think this one accident should implicate the entire 600 series fleet of Zeniths. It actually bolstered my faith in the design integrity of my own aiplane, reading about all of the inconsistancies found during the investigation. No shortage of factors.



Rick



--

psm(at)att.net
Guest

Posted: Sun May 24, 2009 9:38 am Post subject: Flutter Testing shows 601/650 OK

Another speculation for these facts is that the plane was vibrating 

so the pilot thought it was experiencing flutter.  The standard way 

to stop flutter is to quickly reduce airspeed which might show up on 

radar as a quick increase in altitude.



I can't account for the German pronouncement that flutter can't 

happen, but we all know some sort of vibration can take place since 

several list members have reported it.



Paul

XL grounded

At 09:08 AM 5/24/2009, you wrote:

 	  Quote: 	
		  isn't it possible that the pilot tried to overcome

a surprise, uncommanded increase in altitude with a sudden, drastic 

control input?

Ron Lendon

Joined: 10 Jan 2006
Posts: 685
Location: Clinton Twp., MI

Posted: Sun May 24, 2009 12:34 pm Post subject: Re: Flutter Testing shows 601/650 OK

 	  Quote: 	
		  Okkay, fine. How do YOU explain the inflight breakups? Bear in mind that

builder and pilot error cannot explain every 601XL inflight breakup. 	




Jay,



Not all things in life are explainable, there are some things we will never understand, this just may be one of those things.  I accept the fact I may never know what brought those planes down and will endeavor to minimize my risk at every opportunity.

graeme(at)coletoolcentre.
Guest

Posted: Sun May 24, 2009 2:35 pm Post subject: Flutter Testing shows 601/650 OK

one Question have all the air craft that crashed in the US and Europe had 

the canopy at the crash sight?

here in Australia two of the ch601 that crashed may have had canopy failure 

which could have incapacitated the pilot or caused damage to the

aircraft causing 4 fatalities.



graemecns



---

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