Sender: <marv@lancaironline.net> (Marvin Kaye)
To: lml@lancaironline.net
Date: Mon, 30 Aug 2004 03:29:12 -0400
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From: "Dan Schaefer" <dfs155@adelphia.net>
Subject: Redundancy pays
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For the last several years on the list, I've been touting the values of
redundancy in any system where it could be built in (and probably being a
real pest about the subject). Today, while on a short flight with the wife
for brunch, it paid off - big time!

During my engine installation (normally aspirated Lycoming), I looked at the
mixture control on my good ol' MS carburetor and thought about what could
happen if the control wire in the Bowden cable should break or pull out of
the standard B-nut. I decided it could just as easily vibrate to the lean
cutoff position as not, leaving me with a very quiet engine for such a
simple failure. Not liking the possibility, I added a light spring to the
mixture control arm on the carburetor such that with the once in a million
failure of the wire, at least the mixture would be pulled to the full-rich
position.

During today's flight, as I let down at the destination airport, I noticed
that the mixture control knob felt a bit strange and my fuel flow was a bit
higher than what I usually see. After landing, I pulled the mixture out to
kill the engine and nothing happened! The engine just kept on running and I
had to turn off the mags to shut down. When things cooled down I could reach
up behind the carburetor and just feel the end of the disconnected control
wire. After eleven years, the steel wire had deformed enough to pull out of
the nut (smart-a** little voice in my head saying "I told you so"). After
lunch, we flew home no problem - full rich of course, but I'll take that to
the consequences any day!

My little spring, installed over eleven years ago, had averted what could
probably have been a rather nasty end to an otherwise nice day.

Just thought I'd share this one with the list. And for all of you out there
in Lancair land flying behind a carbureted power plant, if you haven't done
it already, you might think about adding a little 50 cent spring to the
mixture control lever as I did. Mine is now worth a lot more than 50 cents!

Dan Schaefer
N235SP - Home and still in one piece!