lml@lancaironline.net Mailing List Archive

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

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