X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 14 Aug 2010 16:39:31 -0400 Message-ID: X-Original-Return-Path: Received: from imr-ma04.mx.aol.com ([64.12.206.42] verified) by logan.com (CommuniGate Pro SMTP 5.3.8) with ESMTP id 4430622 for lml@lancaironline.net; Sat, 14 Aug 2010 08:54:46 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.206.42; envelope-from=Sky2high@aol.com Received: from imo-ma01.mx.aol.com (imo-ma01.mx.aol.com [64.12.78.136]) by imr-ma04.mx.aol.com (8.14.1/8.14.1) with ESMTP id o7ECrtup027784 for ; Sat, 14 Aug 2010 08:53:55 -0400 Received: from Sky2high@aol.com by imo-ma01.mx.aol.com (mail_out_v42.9.) id q.c3c.7b9b6867 (37554) for ; Sat, 14 Aug 2010 08:53:48 -0400 (EDT) Received: from magic-m17.mail.aol.com (magic-m17.mail.aol.com [172.21.147.70]) by cia-mb03.mx.aol.com (v129.4) with ESMTP id MAILCIAMB033-92b24c6691dcfd; Sat, 14 Aug 2010 08:53:48 -0400 From: Sky2high@aol.com X-Original-Message-ID: <70657.1729bf6c.3997ebdc@aol.com> X-Original-Date: Sat, 14 Aug 2010 08:53:48 EDT Subject: Re: [LML] LNC2 over-center link X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_70657.1729bf6c.3997ebdc_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_70657.1729bf6c.3997ebdc_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Steve, There are many 320/360 Lancairs operating with the original link. Assuming the nose gear mounting blocks and spacer allow proper operation, the main problem can occur at the nose-gear-tab and final over-center-link connecting bolt since the bolt-tab-link are bearing surfaces. The problem shows itself as looseness of this connection that can lead to failure. Think about operating on rough surfaces and the beating that this connection would take as it becomes looser and looser. 0. Rigging - the gas spring should exert enough pressure that one should have to muscle the last half inch of the raising the link assembly to allow the bolt to go through it and the tab. The nose gear actuator must reach its own physical stop without putting undue pressure on the link - it should just stop the link from coming undone when over center. Excess pressure can lead to failure - especially at the top of the nose gear wheel well where the actuator is attached. 1. At each annual the looseness condition can be checked while the aircraft is on jacks by wiggling the nose gear fwd and aft. It shouldn't wiggle. 2. The bolt length specified by Lancair is too short and bolt threads can quickly wear down against the tab hole. Using extra washers, make sure the body of the bolt is bearing on both tabs. Replace this bolt if it becomes worn (excessive practice landings ;-)). 3. Of course, one should be using a drilled bolt and castle nut since the bolt may turn. It should be only tightened enough that there is no added friction between the tab and link. 4. Keep this joint lubricated -- I am fortunate (?) that my engine produces a minor nuisance oil leak - just enough to keep the nose gear system oily. Grayhawk In a message dated 8/14/2010 7:17:31 A.M. Central Daylight Time, steve.veach@mac.com writes: Fellow 320/360 owners, builders, and operators (and anyone else caring to comment): Does anyone out there think it is worth my while to have a nose gear over-center link manufactured out of a different material? Mark Ravinski's unfortunate incident made me wonder. I believe Mark attributes his to time in service and perhaps poor maintenance. it seems the follow on posts mostly support that conclusion along with possible installation problems. I have investigated this enough to know that it is a fairly expensive proposition especially without CAD drawings. I reviewed the archives and noted that someone was going to produce them in steel and make them available way back when. Does anyone recall if that actually happened? Does anyone out there actually have the CAD drawings? Ross at Lancair was unable to help in that regard. Any interest in any sort of a group buy? I hope to fully utilize this little beauty if I ever get it done to include landing on grass. That said, should I suck it up and get the part made or am I being a total nervous Nelly? Any and all comments welcome! Thanks, Steve Veach 75% done, 75% to go -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --part1_70657.1729bf6c.3997ebdc_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
Steve,
 
There are many 320/360 Lancairs operating with the original=20 link.  Assuming the nose gear mounting blocks and spacer allow proper= =20 operation, the main problem can occur at the nose-gear-tab and final= =20 over-center-link connecting bolt since the bolt-tab-link are bearing=20 surfaces.  The problem shows itself as looseness of this=20 connection that can lead to failure.  Think about operating on rough= =20 surfaces and the beating that this connection would take as it become= s=20 looser and looser.
 
0. Rigging - the gas spring should exert enough pressure that one sho= uld=20 have to muscle the last half inch of the raising the link assembly to allo= w the=20 bolt to go through it and the tab.  The nose gear actuator must= reach=20 its own physical stop without putting undue pressure on the link - it shou= ld=20 just stop the link from coming undone when over center.  Excess press= ure=20 can lead to failure - especially at the top of the nose gear wheel we= ll=20 where the actuator is attached. 
 
1. At each annual the looseness condition can be checked while= the=20 aircraft is on jacks by wiggling the nose gear fwd and aft.  It= =20 shouldn't wiggle.
 
2. The bolt length specified by Lancair is too short and bolt threads= can=20 quickly wear down against the tab hole.  Using extra washer= s,=20 make sure the body of the bolt is bearing on both tabs.  Replace this= bolt=20 if it becomes worn (excessive practice landings ;-)). 
 
3. Of course, one should be using a drilled bolt and castle= nut=20 since the bolt may turn.  It should be only tightened enough that the= re is=20 no added friction between the tab and link. 
 
4. Keep this joint lubricated -- I am fortunate (?) that my engi= ne=20 produces a minor nuisance oil leak - just enough to keep the nose gear sys= tem=20 oily.
 
Grayhawk
 
 
 
 
 
In a message dated 8/14/2010 7:17:31 A.M. Central Daylight Time,=20 steve.veach@mac.com writes:
Fellow=20 320/360 owners, builders, and operators (and anyone else caring  to=20 comment):

Does anyone out there think it is worth my while to hav= e a=20 nose gear 
over-center link manufactured out of a different=20 material?  Mark 
Ravinski's unfortunate incident made me= =20 wonder.  I believe Mark 
attributes his to time in service= and=20 perhaps poor maintenance.  it 
seems the follow on posts= mostly=20 support that conclusion along with 
possible installation=20 problems.  I have investigated this enough to 
know that= it is a=20 fairly expensive proposition especially without CAD 
drawings.&= nbsp;=20 I reviewed the archives and noted that someone was going to 
pr= oduce=20 them in steel and make them available way back when.  Does =20
anyone recall if that actually happened? Does anyone out there = =20
actually have the CAD drawings?  Ross at Lancair was unable to= help=20 in 
that regard.  Any interest in any sort of a group buy?=  =20 I hope to 
fully utilize this little beauty if I ever get it do= ne to=20 include 
landing on grass. That said, should I suck it up and= get the=20 part made 
or am I being a total nervous Nelly?  Any and= all=20 comments welcome!

Thanks,

Steve Veach

75% done, 75%= to=20 go

--
For archives and unsub=20 http://mail.lancaironline.net:81/lists/lml/List.html
--part1_70657.1729bf6c.3997ebdc_boundary--