Reply-To: <glcasey@gte.net>
Reply-To: lancair.list@olsusa.com
From: "Gary Casey" <glcasey@gte.net>
To: <lancair.list@olsusa.com>
Subject: impulse couplings
Date: Sun, 27 Jan 2002 10:02:19 -0800
Message-ID: <NEBBIBKBKLGPNKKOGMMBGELCEEAB.glcasey@gte.net>
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>>
<<The way my ignition/start wiring is set-up, I couldn't make use of the
impulse capabilities of the right side anyway. Didn't like the idea of extra
stuff going along for the ride while not contributing, so I swapped it out
for a non-impulse unit and kept the new one as a spare for the left.>>

Interesting comment in view of the recent engine failure which was
apparently "caused" by dual impulse coupling failures.  Let's imagine that
the oil system got a slug of air, causing an engine overspeed.  The impulse
couplings, having all those weights, links and other stuff centrifuged
themselves to bits.  Now there is no power at all even though the engine
survived the overspeed, making a bad situation turn terminal.  If there were
one direct-drive mag on board it almost certainly would have survived the
overspeed (assuming it wouldn't have slung the magnets off) and the engine
would have kept running.  I like the idea of only having one impulse
coupling for a dual mag setup (I know, then why do I fly behind a Bendix "D"
mag?).

Gary Casey
C177RG, ES project


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