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Options for Already-Certified 601XL's

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a.s.elliott(at)cox.net
Guest

Posted: Wed Dec 02, 2009 5:48 am Post subject: Options for Already-Certified 601XL's

Folks:

  

 I have started a discussion on the zenith.aero site specifically directed  toward builder/flyers of already-certified 601XL's.  The topic of this  discussion group is what are *reasonable* options for already flying  aircraft.  I invite builder/flyers to visit this discussion and add their  own point of view.  One or other of the two links below ought to  work.

  

 http://www.zenith.aero/forum/topics/what-about-alreadyflying-eab?page=1&commentId=2606393%3AComment%3A40159&x=1#2606393Comment40159

  

 http://tinyurl.com/yg3gddu

  

 Also, I have posted a rather long open letter about this topic at the  following location:

  

 http://members.cox.net/n601ge/mods/

  

 Thanks,

 Andy Elliott, Mesa, AZ

N601GE,601XL/TD,Corvair

   [quote][b]

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Pete54

Joined: 27 Aug 2009
Posts: 19
Location: Scotland

Posted: Wed Dec 02, 2009 9:09 am Post subject: Re: Options for Already-Certified 601XL's

Whilst I would agree with many of the points raised there are some fundamental inaccuracies in your 'information' regarding the UK aircraft.  (I have tried to sign-up with zenith.aero but for some reason it will not work).



None of the UK aircraft are microlights - they are all experimental, with a mauw of 1232lbs.  The rest of the European population of xls are generally microlights with 'self declared' weights of 1050lbs.  (self declared is important because there is no way an xl could actually met the microlight empty weight limits!).



None of the UK aircraft fit this category.



The European aircraft which crashed and caused the UK (and Germany, Dutch groundings) was a microlight version.  



The UK aircraft are not built from much lighter materials than the US aircraft (although the Czech landing gear is much lighter), all the thickness' are the same as the US version.  However the 600kg US version already has a number of areas where the thickness' have already been increased from the 560kg version - Zenith's reasons for this are various (and to my mind not convincing!).



The LAA modifications were based upon an independent engineering analysis and the need to make the mods which could be easily retrofitted.  They have resulted in restrictions to the maximum fuselage weight of 1086lbs.  This is to meet the requirments of CS-VLA at 3.8g - not 6g!  So the LAA analysis shows that the centre section did not meet the CS-VLA requirments.



All of the UK aircraft are supposed to meet the requirements of the CS-VLA, this states that flutter must NOT BE possible and so the LAA insisted upon the counter balance because the analysis showed that if aileron tension was lost, flutter could/might result.



To suggest that the CAA and LAA were not under political pressure is naive in the extreme.  The Dutch accident inspectors have yet to report, but the Dutch airworthiness authority have repeatedly written to the other European authorities stating the airframe is not strong enough........  The LAA have also been hanging off all of the reports coming from the US, particularly the recent load test in Canada.



From my point of view this has left things as a bit of a shambles.  There are now multiple populations of xls at different stages of modification to differing design codes (or in the case of US experimental no design code).



Tonight when I get home I should have a new 'permit to fly' for my xl siting in the postbox.  



As a UK homebuilt, built with a rigorous independent inspection process, it has been grounded for over a year largely on the basis of uncertainty.  The checks of the design have shown it did not meet the CS-VLA code and it now does (apart from trimming in flight).



So I now have a legal in the UK xl.  I can only wish you all well in meeting the various and now much differing requirements for your aircraft.

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Pete Morris

leinad

Joined: 19 Sep 2006
Posts: 283
Location: Central Virginia

Posted: Wed Dec 02, 2009 4:53 pm Post subject: Re: Options for Already-Certified 601XL's

Andy,

Even though I'm not flying my XL yet, I read your statement.  I was nearly done plans building my airframe when the FAA made their proclamation.   What I told the EAA when I took their poll and will repeat here is that the thing that bothers me most about this situation is that with little fuss the FAA has eliminated one of my freedoms.  The freedom to build and fly an experimental aircraft has suddenly been greatly restricted.  I'm not allowed to make the modifications I see fit, but must make the ones directed by Zenith.  What happened?

Dan

[quote="a.s.elliott(at)cox.net"]Folks:

  

 I have started a discussion on the zenith.aero site specifically directed  toward builder/flyers of already-certified 601XL's.  The topic of this  discussion group is what are *reasonable* options for already flying  aircraft.  I invite builder/flyers to visit this discussion and add their  own point of view.  One or other of the two links below ought to  work.

  

 http://www.zenith.aero/forum/topics/what-about-alreadyflying-eab?page=1&commentId=2606393%3AComment%3A40159&x=1#2606393Comment40159

  

 http://tinyurl.com/yg3gddu

  

 Also, I have posted a rather long open letter about this topic at the  following location:

  

 http://members.cox.net/n601ge/mods/

  

 Thanks,

 Andy Elliott, Mesa, AZ

N601GE,601XL/TD,Corvair

    	  Quote: 	
		  [b]

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Scratch building XL with Corvair Engine

alex_001

Joined: 14 Jan 2007
Posts: 61

Posted: Sat Dec 05, 2009 2:44 pm Post subject: Re: Options for Already-Certified 601XL's

all my (3 off in total) 601 xl weight between 298kg and 314kg empty the later weight was with all extras AP, wheelfairings, full instruments BRS etc.

so no problem to meet microlight weight limit of MTOW 472.5kg

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Pete54

Joined: 27 Aug 2009
Posts: 19
Location: Scotland

Posted: Mon Dec 07, 2009 1:56 am Post subject: Re: Options for Already-Certified 601XL's

To be a legal microlight in the UK the maximum empty weight is 268kg, somewhat short of numbers you are talking.  The 472 figure also has to include a ballistic chute which adds a bit of weight.



With full tanks an xl would be a single seater with the numbers you quote.  Mine weighs 304kg empty.



A UK microlight must be able to carry two 86kg people and an hours fuel - this is what leads to the 268kg empty weight restriction.

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Pete Morris

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