Message-Id: <3.0.3.32.19980929134113.0070e8f4@mail.digital.net>
Date: Tue, 29 Sep 1998 13:41:13 -0400
To: lancair.list@olsusa.com
From: John Cooper <heyduke@digital.net>
Subject: NLG Ground Lock Fixture
Mime-Version: 1.0

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For most builders, there will be a period of time between when the plane is
sitting on the landing gear, and the hydraulic system is completely
functional. Even afterwards, while testing of the various systems is going
on, there is a danger that the nose landing gear might be inadvertently
retracted, dumping your beautiful project on it's beautiful cowling, and
sticking your beautiful tailfeathers into the ceiling of your workshop.

You should also realize that your gas strut will almost certainly be "flat"
by the time you finish your project and begin to count on the darn thing to
keep the NLG extended - they seem to last only a few of years before they
quit working.

Anyway, because I trust neither the gas spring nor my own bad habits, I
fabricated a piece of 1"x1"x.125" angle aluminum that I bolted to the NLG
overcenter link which locks it in the down position. It simply bolts to the
upper half of the link through the tooling hole, and extends down to where
the lower half of the link connects to the oleo strut. Other than the 1/4"
hole matching the tooling hole, it is only necessary to drill one more hole
(1/2" I think) to allow the ground lock fixture to slip over the head of
the elbow-bolt where the two halves of the links are joined.

I'm not sure whether the aluminum would withstand an attempt to use the
hydraulic cylinder to retract the NLG, and I really don't want to find out.
Steel would be better.

If one had access to welding equipment, one could make this fixture out of
steel and place a slight bend in the middle to conform exactly to the
bottom profile of the two over center links. If I were to get fancy, I
would use a pip-pin to attach it, and put a "remove before flight" streamer
on it.

Lance: Please feel free to steal this idea and have Mike Snow weld you up
some of these to offer in your catalog <G>