Message-ID: <000a01be744a$06f6ebc0$60de47cf@bodsbar02>
From: "Carl Lindros" <350cl@silcom.com>
To: <lancair.list@olsusa.com>
Subject: Lancair IV Nose Gear and Prop Strike Teardowns
Date: Mon, 22 Mar 1999 01:54:48 -0800
Mime-Version: 1.0

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First of all, if anyone out there is still flying with the old style nose
gear which does not self center, ground your airplane and change it NOW to
the new style.  I made 300 successful landings with the old style gear with
no problem and then it happened.....stuck in the up position.  I retracted
the main gear and made an uneventful gear up landing resulting only in skin
damage to that part of the fuselage between the wings.  I only used 10
degrees of flaps to avoid them contacting the runway and the cowling, wings
and tail were not damaged.

I shut the engine off on downwind along with all electrical and fuel.  I
couldn't get the prop to stop windmilling about 200 RPM, even with full
pitch and slowing to 75 kts for a few seconds, so the prop turned 1/3 of a
revolution upon ground strike.  One blade was undamaged as was the hub.  We
dialed in the shaft and it was perfectly true.

Is this time for a tear down.  The factory says definitely yes.  Many A&E's
I spoke to said fly it for a while and moniter the oil carefully, so this is
what I did.  I changed the oil at 15 hours, and luckily, one ball in the
starter drive bearing had lost part of it's bearing surface for whatever
reason and I found three tiny pieces of it in the drain plug and one in the
filter.  I say lucky, since this led to a teardown upon which we found that
the crank had a crack and one day soon my prop was going to part company
with the rest of the plane.  Incidently, oil analysis show nothing unusual.

I learned that Continental hardens the entire crank (different than Lycoming
I am told) and as a result, the end of the shaft is quite brittle and cannot
take the torque that results from the prop sliding on the ground and/or the
stoppage from 200 RPM.  The factory is right about teardowns.

I also learned that TSIO 550 cranks are hard to get.  The factory does not
stock them.  I guess I was lucky again in that it was only two months before
they ran a batch.  The good news is that I'm back in the air after a three
month wait.  How sweet it is.