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Aileron flutter

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Rexwinkle

Joined: 01 Dec 2008
Posts: 4
Location: Groveland, CA

Posted: Mon Dec 01, 2008 2:19 pm Post subject: Aileron flutter

Has anyone experienced aileron/wing flutter.  What were your indications?  Where was it felt? In the stick? In the floor?  If you could please share your experiences with me I would appreciate it.  

Thank you,

  Scott

chris Sinfield

Joined: 28 Nov 2006
Posts: 270
Location: Sydney Australia

Posted: Mon Dec 01, 2008 7:12 pm Post subject: Re: Aileron flutter

I see you only just joined did you just buy a kit? .. no offense but its already talked about and there would be no more new talk as yet. read the zenith site for all the info. What's your plans number?? or are you sniffing trying to turn up talk? for the opposition? newspapers?

Chris 

Do not archive.

Rexwinkle

Joined: 01 Dec 2008
Posts: 4
Location: Groveland, CA

Posted: Tue Dec 02, 2008 8:44 am Post subject: Re: Aileron flutter

I have purchased plans for a Zodiac CH 601 XL S/N: 6-7391.  I am trying to gather information on this potential problem that I have been reading about and determine whether or not to proceed.  All of the post that I have read talk about the cable tensions and what may happen if they are not correct.  I am wondering what the warning signs of aileron flutter are, if any.  If I am flying along are there going to be symptoms that I should recognize so that I can land the aircraft and rectify the problem before it becomes catastrophic?  Have there been any design changes in the aircraft as a result of these accidents?  As for your other questions, yes I am trying to turn up talk.  I don't really know what you mean by opposition but I would have to guess no,   and I do not work for any newspaper, magazine, website or any other type of periodical.    Any help that I can get would be greatly appreciated.



Scott

psm(at)att.net
Guest

Posted: Tue Dec 02, 2008 9:06 am Post subject: Aileron flutter

Hi Scott,



I understand your request to be a reasonable one from your 

perspective.  The problem is there have been many unpleasant 

discussions and indeed experiences on this issue so many list members 

are overly sensitive.  Let me try to give you a quick summary of the 

facts as I understand them.



There have been a number of in flight structural failures on Zodiac 

XLs.  Oddly, I believe most of them have occurred with two people 

aboard.  The number of really suspicious ones is something between 3 

and 5 world wide in the last few years.  That accounts for perhaps 

one percent of the XLs flying.



One of the suspicious accidents has just had a "Factual report" done 

by the NTSB.  I am anxiously awaiting the "Probable Cause" report 

which should follow.



There has been a lot of attention lately to aileron cable 

tension.  With the latest "AD" from  Europe and other notifications 

from other sources, all XL flyers and builders should be well aware 

of this issue.  Time will tell if this makes any change in the accident rate.



My knowledge of flutter is not authoritative, but I will give you the 

best answers I can.  Flutter is a deadly problem in airplanes.  It 

happens when one of the controls starts flapping like a flag in a 

high wind.  In many cases this leads quickly to general structural 

failure.  When flutter happens the pilot knows something is going on 

from both noise and vibration but he may not know what it is.  The 

only thing he can do is change the flight situation very quickly and 

hope the flutter stops.  The normal approach is to pull up to reduce 

airspeed but unloading the wings by entering a steep bank might also work.



You must decide for yourself whether to go on with the XL.  Some 

builders have quit while others have continued on.  The Zodiac XL is 

an ideal design from many perspectives.  The problem rate has been 

high enough to be alarming but low enough that it doesn't suggest 

that all XL flyers are taking an unreasonable risk.



Good luck,



Paul

XL getting close

At 08:44 AM 12/2/2008, you wrote:

 	  Quote: 	
		  I have purchased plans for a Zodiac CH 601 XL S/N: 6-7391.  I am 

trying to gather information on this potential problem that I have 

been reading about and determine whether or not to proceed.  All of 

the post that I have read talk about the cable tensions and what may 

happen if they are not correct.  I am wondering what the warning 

signs of aileron flutter are, if any.  If I am flying along are 

there going to be symptoms that I should recognize so that I can 

land the aircraft and rectify the problem before it becomes 

catastrophic?  Have there been any design changes in the aircraft as 

a result of these accidents?  As for your other questions, yes I am 

trying to turn up talk.  I don't really know what you mean by 

opposition but I would have to guess no,   and I do not work for any 

newspaper, magazine, website or any other type of periodical.    Any 

help that I can get would be greatly appreciated.



Scott

z601(at)anemicaardvark.co
Guest

Posted: Tue Dec 02, 2008 9:08 am Post subject: Aileron flutter

On Tuesday 02 December 2008 10:44, Rexwinkle wrote:

 	  Quote: 	
		   

 <scottrexwinkle(at)yahoo.com>



 I have purchased plans for a Zodiac CH 601 XL S/N: 6-7391.  I am trying to

 gather information on this potential problem that I have been reading about

 and determine whether or not to proceed.  All of the post that I have read

 talk about the cable tensions and what may happen if they are not correct. 

 I am wondering what the warning signs of aileron flutter are, if any.  If I

 am flying along are there going to be symptoms that I should recognize so

 that I can land the aircraft and rectify the problem before it becomes

 catastrophic?  Have there been any design changes in the aircraft as a

 result of these accidents?  As for your other questions, yes I am trying to

 turn up talk.  I don't really know what you mean by opposition but I would

 have to guess no,   and I do not work for any newspaper, magazine, website

 or any other type of periodical.    Any help that I can get would be

 greatly appreciated.


	


Scott, this whole issue is in its infancy, as far as the Zenith 601XL is 

concerned. It is not certain that aileron flutter is at fault, although some 

things point that way. 



For instance, there have been accident(s) in which the aileron separated from 

the aircraft. That is a possible indicator of aileron flutter. A number of 

the aircraft not involved in accidents have been found to have improperly 

tensioned (too loose) control cables. That could be a cause of aileron 

flutter.



But if there has been an official finding of aileron flutter in any of the 

accidents, I'm not aware of it. The most recent preliminary finding of the 

NTSB in the case of one accident (suspected by some to have been aileron 

flutter) cites so many things done incorrectly by the operator, that it is 

going to be difficult to fix the blame, IMHO. Sad, but that's how the report 

appears to read.



Since the only firm indication of a problem that could point in this direction 

has been the loose control cables, the designer has released a service 

bulletin asking owners to check their cable tensions regularly, which they 

should probably have been doing anyway.  That's more of a precautionary move 

than anything else.



Without knowing what, if anything, in the design, is causing this spate of 

problems, it is probably premature to make design changes. Or too firm a set 

of judgements of any type.



As for the rest of your question, the usual sign of aileron flutter is exactly 

that: the aileron begins moving rapidly on its own. I would expect to sense 

significant vibration in the airframe and the controls. 



What do you do if this happens? An obvious thing is to slow down, if you can 

do it quickly enough. Without energy being pumped into the system, it is 

going to be harder to sustain the flutter. Try to get into slow, straight and 

level flight, and land as soon as practical.



As for whether or not you should proceed, all I can tell you is that I'm just 

starting on the kit, and I don't plan to stop based on these reports. They're 

just too fragmentary and inconclusive. Like you, I would like to know the 

cause of the problems, if there is a common cause, and what we can do to 

prevent it.

==============================================

Those who can, do. Those who can't, sue.

=================================================

               Jim B. Belcher

    BS, MS Physics, math, Computer Science

                  A&P/IA

           Instrument Rated Pilot

     General Radio Telephone Certificate

=================================================

larry(at)macsmachine.com
Guest

Posted: Tue Dec 02, 2008 9:15 am Post subject: Aileron flutter

Scott,

Work to keep your aircraft in good shape. Inspect the normal things like 

you would any other aircraft. Do keep your cables tensioned as per spec. 

and

don't fly over max speeds, over-load the aircraft or pull excessive G 

loads and you'll be fine. Zenith XL is a good aircraft. Do these things 

and you'll

never see flutter and probably wouldn't have anyway.



Larry McFarland 601HDS at www.macsmachine.com

do not archive



Rexwinkle wrote:

 	  Quote: 	
		   



 I have purchased plans for a Zodiac CH 601 XL S/N: 6-7391.  I am trying to gather information on this potential problem that I have been reading about and determine whether or not to proceed.  All of the post that I have read talk about the cable tensions and what may happen if they are not correct.  I am wondering what the warning signs of aileron flutter are, if any.  If I am flying along are there going to be symptoms that I should recognize so that I can land the aircraft and rectify the problem before it becomes catastrophic?  Have there been any design changes in the aircraft as a result of these accidents?  As for your other questions, yes I am trying to turn up talk.  I don't really know what you mean by opposition but I would have to guess no,   and I do not work for any newspaper, magazine, website or any other type of periodical.    Any help that I can get would be greatly appreciated.



 Scott





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p 17353#217353

ggower_99(at)yahoo.com
Guest

Posted: Tue Dec 02, 2008 10:02 am Post subject: Aileron flutter

My only advice to date: 

  

 Like any other homebuilt airplane.  Build to plans,  rig correcty,  do a good preflight every time, fly the plane inside parameters and give a good mantainance.  

  

 Also not to forget: Once you have it glying, Check the weather, and plan carefully your gasoline range. 

  

 Enjoy your building and later your flying.

  

 Saludos

 Gary Gower,

 Flying from Chapala, Mexico,

  

 



--- On Tue, 12/2/08, Rexwinkle <scottrexwinkle(at)yahoo.com> wrote:



  	  Quote: 	
		  From: Rexwinkle <scottrexwinkle(at)yahoo.com>

Subject: Re: Aileron flutter

To: zenith601-list(at)matronics.com

Date: Tuesday, December 2, 2008, 11:44 AM



 	  Quote: 	
		  --> Zenith601-List message posted by: "Rexwinkle"

<scottrexwinkle(at)yahoo.com>



I have purchased plans for a Zodiac CH 601 XL S/N: 6-7391.  I am trying to

gather information on this potential problem that I have been reading about and

determine whether or not to proceed.  All of the post that I have read talk

about the cable tensions and what may happen if they are not correct.  I am

wondering what the warning signs of aileron flutter are, if any.  If I am flying

along are there going to be symptoms that I should recognize so that I can land

the aircraft and rectify the problem before it becomes catastrophic?  Have there

been any design changes in the aircraft as a result of these accidents?  As for

your other questions, yes I am trying to turn up talk.  I don't really know

what you mean by opposition but I would have to guess no,   and I do not work

for any newspaper, magazine, website or any other type of periodical.    Any

help that I can get would be greatly appreciated.



Scott





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p 17353#217353





	
	


         [quote][b]

chris Sinfield

Joined: 28 Nov 2006
Posts: 270
Location: Sydney Australia

Posted: Wed Dec 03, 2008 4:00 am Post subject: Re: Aileron flutter

welcome Scott to XL building.



Sorry if my first response sounded cold. As someone else said there is a person who has joined a lot of lists of late and its almost like a mass email message badmouthing the XL and all things Zenith.



I for one think the XL is a great plane and am 3/4 the way through building. Am I going to continue, yes. why..  



1. The Hinze family believe it is safe, Chris lets his own kids fly in the planes he designed. what parent would not put the safety of their kids first.



2. the XL plane has been looked at intensely by a number of organizations FAA LAA RAA ect ect. if it passes their design criteria  without a major change then to me thats going to be a great safety advertising and selling point. if they find something even better, as once the change is made it is been checked and safe to fly..



3. reality check, I saw a Cesnna crashed the other day. all planes may crash if flown outside the design envelope.



4. Flutter.. saw it happen on a balanced C130 Aileron, plane nearly crashed . 



Build it fly it learn it and enjoy it. . 

Chris.

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Thu Dec 04, 2008 5:05 am Post subject: Re: Aileron flutter

The fact that the factory plane is flying with no problems (as well as many other XLs) points to sloppy building/maintenance/piloting in incident airplanes. The XL is basically  high performance plane which when poor piloting and sloppy building are combined could lead to a problem. Again, not the plane, but poor building, maintenance, and piloting are what I believe to be the suspicious factors in the accidents that did occur.

Rexwinkle

Joined: 01 Dec 2008
Posts: 4
Location: Groveland, CA

Posted: Thu Dec 04, 2008 8:13 am Post subject: Re: Aileron flutter

Actually in the US two of the crashes were factory built and two were home built.

z601(at)anemicaardvark.co
Guest

Posted: Thu Dec 04, 2008 8:19 am Post subject: Aileron flutter

On Thursday 04 December 2008 10:13, Rexwinkle wrote:

 	  Quote: 	
		   

 <scottrexwinkle(at)yahoo.com>



 Actually in the US two of the crashes were factory built and two were home

 built.


	


Which might, repeat, might, suggest the problem is one of maintenance rather 

than construction.

==============================================

Those who can, do. Those who can't, sue.

=================================================

               Jim B. Belcher

    BS, MS Physics, math, Computer Science

                  A&P/IA

           Instrument Rated Pilot

     General Radio Telephone Certificate

=================================================

planecrazydld(at)yahoo.co
Guest

Posted: Thu Dec 04, 2008 8:24 am Post subject: Aileron flutter

Hi Andy;



Completely agreed, but I think the sentence should have said something like: "The XL is basically a  high performance plane being sold in a low performance arena (LSA) which when poor pilot judgement/skill and less than optimal building techniques are combined could lead to a problem.



The very slippery design can easily exceed all of the LSA limits imposed on it - and under those conditions all bets are off.



David L. Downey

  Harleysville (SE) PA, USA



  

--- On Thu, 12/4/08, ashontz <ashontz(at)nbme.org> wrote:

[quote]From: ashontz <ashontz(at)nbme.org>

Subject: Re: Aileron flutter

To: zenith601-list(at)matronics.com

Date: Thursday, December 4, 2008,         [quote][b]

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Thu Dec 04, 2008 8:27 am Post subject: Re: Aileron flutter

Exactly. I suggested 3 possible areas (a 4th could be the plane itself, but I didn't list that because that's most likely NOT the problem as evidenced by the fact that the factory demonstrator as well as many other XLs have experienced NO problems). So the 3 possible areas are, builder error, maintenance error, pilot error.



 	  z601(at)anemicaardvark.co wrote: 	
		  On Thursday 04 December 2008 10:13, Rexwinkle wrote:

 	  Quote: 	
		   

 <scottrexwinkle>



 Actually in the US two of the crashes were factory built and two were home

 built.



	


Which might, repeat, might, suggest the problem is one of maintenance rather 

than construction.

==============================================

Those who can, do. Those who can't, sue.

=================================================

               Jim B. Belcher

    BS, MS Physics, math, Computer Science

                  A&P/IA

           Instrument Rated Pilot

     General Radio Telephone Certificate

=================================================

jmaynard

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

Posted: Thu Dec 04, 2008 8:38 am Post subject: Aileron flutter

On Thu, Dec 04, 2008 at 10:20:09AM -0600, Jim Belcher wrote:

 	  Quote: 	
		   On Thursday 04 December 2008 10:13, Rexwinkle wrote:

 > Actually in the US two of the crashes were factory built and two were home

 > built.

 Which might, repeat, might, suggest the problem is one of maintenance rather 

 than construction.


	


Might. Note also that the two factory aircraft were built by two different

factories: one by AMD, one by CZAW.

-- 

Jay Maynard, K5ZC, PP-ASEL           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

jmaynard

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

Posted: Thu Dec 04, 2008 8:41 am Post subject: Aileron flutter

On Thu, Dec 04, 2008 at 08:24:03AM -0800, David Downey wrote:

 	  Quote: 	
		   The very slippery design can easily exceed all of the LSA limits imposed

 on it - and under those conditions all bets are off.


	


What LSA limits can it exceed? The only one that matters in this discussion

is a Vh of 120 knots, and that's not a speed of anything other than

regulatory interest. *ANY* airplane can exceed Vno easily; this is hardly

limited to the Zodiac. I've never gotten close to Vne, even in a power-on

descent in still air.



The LSA limits aren't ones relating to structural strength; they're there to

make sure the aircraft can be safely flown by pilots with limited

experience.

-- 

Jay Maynard, K5ZC, PP-ASEL           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

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Thu Dec 04, 2008 8:45 am Post subject: Re: Aileron flutter

 	  jmaynard wrote: 	
		  

Might. Note also that the two factory aircraft were built by two different

factories: one by AMD, one by CZAW. 	




And only God knows what how CZAW built them considering the financial issues that have come out about them.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

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