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Date: Mon, 16 Aug 2010 21:09:50 -0400
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From: Steve Veach <steve.veach@mac.com>
Subject: LNC2 over-center link

Dan,

Copy all.  I was hung up on having to have the drawings but I think  
you're right.  One of Randy's links may be all I need.  I'll post the  
final outcome whenever I figure out what it is and I do it.  Thanks to  
one and all for weighing in.

Cheers,

Steve

Back in '93 when I was getting ready for my inspection and first  
flight of my 235, my hangar mate who had taken off earlier in the week  
for Oshkosh, showed up in the hangar with his wrecked L235 on a  
trailer. In Arizona a main gear over-center link pulled apart on take- 
off (but before he had flying speed) and he took out some runway  
lights with one of his wings - plus a lot of other damage. On the  
early design, the steel fitting to which the lower ball-end was  
attached was epoxied and riveted into the lower aluminum link - and  
that's where the thing came apart.

When I saw where the failure had ocurred, I took my lower over-center  
links to a machinist friend and had him make copies in steel with  
internal threads for a short length of SS threaded rod for the  
connection to the female threaded ball-end. (Incidentally, following  
that incident, I told Lancair about what I had done and they  
immediately changed the design and made steel links available - if  
you've been around Lancair long enough, you may remember when that  
happened). I had the machinist make about a dozen pairs and for a  
bunch of guys still using the original parts, and if I remember  
correctly, they were about $100 per set. Small price to pay to  
eliminate such a really bad potential failure mode - even if the cost  
was two or three times that today.

I'm bringing this up to suggest that having a good machinist make  
copies of your link parts, if you deem it necessary, shouldn't be such  
a big deal - CAD drawings of no. I'm not a machinist but with the  
original part in hand, a good machinist should be able to make an  
exact replica in whatever material you want - or with whatever mods  
you think necessary - as I had done, changing the bearing connection  
to a threaded insert vs. the smooth bore hole which required glueing  
and riveting.

In my opinion, the nose gear link is no more complicated in design  
than the main gear link so it shouldn't be all that difficult to copy.

Just my two cents worth.

Dan Schaefer
LNC-2   N235SP still flying (a lot) today.