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Re. mono gear collapse - One way to make the lever stiffer

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stephan(at)scassel.se
Guest

Posted: Sun Mar 04, 2007 3:20 am Post subject: Re. mono gear collapse - One way to make the lever stiffer

Hi   

   

I think both David and Graham have made the right conclusions.  

    	  Quote: 	
		  The key thing is to make the gear lever as stiff as possible and no play when it is in gear-down locked position. One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight.[/b] Moment may twist the lever, not much but enough to introduce a small play when forces in not in one plan. The optional strut will help but the strut is quite week. And Dural gets much softer when you try to bend it. The trick is to mount the lever on the other side[/b] of LG08S and use one counter sink bolt and file the edge of the lever slightly, see link below http://scassel.se/europa/cap4/images/DSCN1129.JPG (The smallest distance between lever and the landing gear frame will be about 2 mm) 	
  

The lever will then go throw the tunnel exactly as per manual.  

   

http://scassel.se/europa/cap4/images/DSCN1130.JPG  

   

And, as David Joyce said, the joint between lever and LG08S must be solid as rock. Sanded contact surfaces and Araldite 420 make that possible.  

   

   

   

Regards Stephan  

   

LN –STE. Permit to fly.   

First flight when weather permits and then Pete Jeffers will kindly take here up for the virgin flight.   

   

   

   

   

   

   

   

   

       [quote][b]

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pjeffers(at)talktalk.net
Guest

Posted: Sun Mar 04, 2007 7:04 am Post subject: Re. mono gear collapse - One way to make the lever stiffer

Hi Stephan,  

   

As you say it is essential that the gear lever joint is absolutely rigid.  There is the optional mod, or the ‘bonded’ approach or indeed both.  Together with the solid joint must go the proviso, as clearly defined in the instructions, that there is positive contact at both downlock stops. This should ensure a safe downlock configuration.  

   

To ensure that this situation does not change over time and especially after ‘heavy’ landings, regular inspections need to be carried out.  During the course of inspections on a couple of Europas I have found this positive stop contact to have been lost on  one side.  I have no reason to think that they were originally built this way but have got that way in service.  The effectiveness of the over centre lock is negated if one side makes contact early.  

   

On the matter of ‘keeping it straight’ then this would seem fine just providing that at the up and locked position the gear handle is firmly sprung loaded into the detent in the gear lever slot. IE spring loaded to the right!  

If not there is a nasty tendency for the gear to come out of the ‘up’ position  in flight, particularly in turbulence. This can happen at 165 kts! (flap limit speed?)  

   

How is the weather in Norway this weekend?  I bet is was OK.  Grrrrrrrrr.  

   

Pete Jeffers  

   

         

  

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Stephan Cassel

 Sent: 04 March 2007 11:19

 To: europa-list(at)matronics.com

 Subject: Re: Re. mono gear collapse - One way to make the lever stiffer   

  

   

Hi   

   

I think both David and Graham have made the right conclusions.  

    	  Quote: 	
		  The key thing is to make the gear lever as stiff as possible and no play when it is in gear-down locked position. One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. Moment may twist the lever, not much but enough to introduce a small play when forces in not in one plan. The optional strut will help but the strut is quite week. And Dural gets much softer when you try to bend it. The trick is to mount the lever on the other side of LG08S and use one counter sink bolt and file the edge of the lever slightly, see link below http://scassel.se/europa/cap4/images/DSCN1129.JPG (The smallest distance between lever and the landing gear frame will be about 2 mm) 	
  

The lever will then go throw the tunnel exactly as per manual.  

   

http://scassel.se/europa/cap4/images/DSCN1130.JPG  

   

And, as David Joyce said, the joint between lever and LG08S must be solid as rock. Sanded contact surfaces and Araldite 420 make that possible.  

   

   

   

Regards Stephan  

   

LN –STE. Permit to fly.   

First flight when weather permits and then Pete Jeffers will kindly take here up for the virgin flight.   

   

   

   

   

   

   

   

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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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     --  Date: 03/03/2007 08:12 

  

--

 03/03/2007 08:12

     [quote][b]

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robh(at)hyperion-ef.com
Guest

Posted: Mon Mar 05, 2007 7:20 am Post subject: Re. mono gear collapse - One way to make the lever stiffer

Being a Tri-Gear builder I can’t comment on the mono, but I can correct a minor misunderstanding regarding aluminum (aka, aluminium and, rarely, Dural).  

   

Aluminum alloys work harden; that is, when deformed the material gets stronger, not softer as stated.  Dural literally applies to the 2000 series alloys and the lever in question is most likely 6061 not 2024 as implied.  Further, stiffness is not the same as hardness and stiffness being a property of the base metal, is not affected by alloying, work hardening or heat treatment.  In technical terms, all aluminum alloys have the same modulus of elasticity.  

     

Best regards,  

   

Rob Housman  

Europa XS Tri-Gear  

S/N A070  

Airframe complete  

  

       

From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of Stephan Cassel

 Sent: Sunday, March 04, 2007 3:19 AM

 To: europa-list(at)matronics.com

 Subject: Re: Re. mono gear collapse - One way to make the lever stiffer   

  

  

   

Hi   

   

I think both David and Graham have made the right conclusions.  

    	  Quote: 	
		  The key thing is to make the gear lever as stiff as possible and no play when it is in gear-down locked position. One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. Moment may twist the lever, not much but enough to introduce a small play when forces in not in one plan. The optional strut will help but the strut is quite week. And Dural gets much softer when you try to bend it. The trick is to mount the lever on the other side of LG08S and use one counter sink bolt and file the edge of the lever slightly, see link below http://scassel.se/europa/cap4/images/DSCN1129.JPG (The smallest distance between lever and the landing gear frame will be about 2 mm) 	
  

The lever will then go throw the tunnel exactly as per manual.  

   

http://scassel.se/europa/cap4/images/DSCN1130.JPG  

   

And, as David Joyce said, the joint between lever and LG08S must be solid as rock. Sanded contact surfaces and Araldite 420 make that possible.  

   

   

   

Regards Stephan  

   

LN –STE. Permit to fly.   

First flight when weather permits and then Pete Jeffers will kindly take here up for the virgin flight.   

   

   

   

   

   

   

   

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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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		  One way to make the lever much stronger is NOT to bend the lever as per manual. Keep it straight. 	
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       [quote][b]

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