X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Mon, 16 Aug 2010 09:19:18 -0400 Message-ID: X-Original-Return-Path: Received: from imr-da05.mx.aol.com ([205.188.105.147] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTP id 4432395 for lml@lancaironline.net; Mon, 16 Aug 2010 09:14:20 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.147; envelope-from=Sky2high@aol.com Received: from imo-da02.mx.aol.com (imo-da02.mx.aol.com [205.188.169.200]) by imr-da05.mx.aol.com (8.14.1/8.14.1) with ESMTP id o7GDDeM5021004 for ; Mon, 16 Aug 2010 09:13:40 -0400 Received: from Sky2high@aol.com by imo-da02.mx.aol.com (mail_out_v42.9.) id q.eff.32d0e33 (44223) for ; Mon, 16 Aug 2010 09:13:39 -0400 (EDT) Received: from magic-m27.mail.aol.com (magic-m27.mail.aol.com [172.20.22.200]) by cia-dd08.mx.aol.com (v129.4) with ESMTP id MAILCIADD081-acbf4c693982aa; Mon, 16 Aug 2010 09:13:38 -0400 From: Sky2high@aol.com X-Original-Message-ID: <11272.5f3114b7.399a9382@aol.com> X-Original-Date: Mon, 16 Aug 2010 09:13:38 EDT Subject: Re: [LML] Re: LNC2 over-center link X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_11272.5f3114b7.399a9382_boundary" X-Mailer: AOL 9.5 sub 155 X-AOL-IP: 24.15.17.119 X-Spam-Flag:NO X-AOL-SENDER: Sky2high@aol.com --part1_11272.5f3114b7.399a9382_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Dan, Righto! The only thing holding the main gear from collapsing outward is the over center link. Crosswind landings and takeoffs can certainly place a great deal of stress on those links. By the time I had finished building my 320 in '96, Lancair made a new outboard link available with the rod end actually screwed into it. I still have the old original ones in my "don't you ever use these parts" box. I remember that it was hard to drill the rivet holes and go through the center of the rod end that slipped into the link. While folks may want to refer to replacement "steel", the actual links are made from some pretty tough alloy beyond simple aluminum. Were I to have some sort of copy made I would try to find out what the alloy composition is. Scott Krueger In a message dated 8/16/2010 7:46:57 A.M. Central Daylight Time, dfs155@roadrunner.com writes: 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. -- I am using the free version of SPAMfighter. We are a community of 7 million users fighting spam. SPAMfighter has removed 789 of my spam emails to date. Get the free SPAMfighter here: http://www.spamfighter.com/len The Professional version does not have this message -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --part1_11272.5f3114b7.399a9382_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Dan,
 
Righto!  The only thing holding the main gear from collapsing ou= tward=20 is the over center link. Crosswind landings and takeoffs can certainly pla= ce a=20 great deal of stress on those links.  By the time I had finished=20 building my 320 in '96, Lancair made a new outboard link=20 available with the rod end actually screwed into it.  I still have th= e old=20 original ones in my "don't you ever use these parts" box.  I remember= that=20 it was hard to drill the rivet holes and go through the center= of the=20 rod end that slipped into the link. 
 
While folks may want to refer to replacement "steel", the=20 actual links are made from some pretty tough alloy beyond simple= =20 aluminum.  Were I to have some sort of copy made I would try to find= out=20 what the alloy composition is.
 
Scott Krueger
 
In a message dated 8/16/2010 7:46:57 A.M. Central Daylight Time,=20 dfs155@roadrunner.com writes:
Back in=20 '93 when I was getting ready for my inspection and first flight of
m= y 235,=20 my hangar mate who had taken off earlier in the week for Oshkosh,
sh= owed=20 up in the hangar with his wrecked L235 on a trailer. In Arizona a
ma= in=20 gear over-center link pulled apart on take-off (but before he had
fl= ying=20 speed) and he took out some runway lights with one of his wings -
pl= us a=20 lot of other damage. On the early design, the steel fitting to which the=20 lower ball-end was attached was epoxied and riveted into the lower=20
aluminum link - and that's where the thing came apart.

When= I saw=20 where the failure had ocurred, I took my lower over-center links
to= a=20 machinist friend and had him make copies in steel with internal threads= =20
for a short length of SS threaded rod for the connection to the fema= le=20
threaded ball-end. (Incidentally, following that incident, I told La= ncair=20
about what I had done and they immediately changed the design and ma= de=20 steel
links available - if you've been around Lancair long enough,= you may=20
remember when that happened). I had the machinist make about a dozen= pairs=20
and for a bunch of guys still using the original parts, and if I rem= ember=20
correctly, they were about $100 per set. Small price to pay to elimi= nate=20
such a really bad potential failure mode - even if the cost was two= or=20 three
times that today.

I'm bringing this up to suggest that= having=20 a good machinist make copies of
your link parts, if you deem it nece= ssary,=20 shouldn't be such a big deal -
CAD drawings of no. I'm not a machini= st but=20 with the original part in hand,
a good machinist should be able to= make an=20 exact replica in whatever
material you want - or with whatever mods= you=20 think necessary - as I had
done, changing the bearing connection to= a=20 threaded insert vs. the smooth
bore hole which required glueing and= =20 riveting.

In my opinion, the nose gear link is no more complicate= d in=20 design than the
main gear link so it shouldn't be all that difficult= to=20 copy.

Just my two cents worth.

Dan Schaefer
LNC-2 =  =20 N235SP still flying (a lot) today.


--
I am using the fre= e=20 version of SPAMfighter.
We are a community of 7 million users fightin= g=20 spam.
SPAMfighter has removed 789 of my spam emails to date.
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