Message-ID: <000001c1a99b$d3632640$af193e44@rocsth01.mi.comcast.net>
From: "Edmond de Chazal" <edechazal@home.com>
To: "Lancair List" <lancair.list@olsusa.com>
References: <20020129061212.AAA6201@pop3.olsusa.com>
Subject: High speed vibration in a 360
Date: Tue, 29 Jan 2002 14:22:11 -0500
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Reply-To: lancair.list@olsusa.com

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Well, after a year and a half, I've just about removed all of the known bugs
from my 360.  The ELT triggering from COM2 should be fixed now that I've
relocated the antenna away from the COM2 antenna and I've finally gotten the
canopy rollover sealed (with half inch quarter round rubber extrusion).  The
heat in the airplane is more than adequate if the canopy's sealed it turns
out.

There's one remaining 'characteristic' that concerns me.  At 195 - 200 kts
indicated, there is a vibration that suddenly comes in.  I can hear it (low
frequency) as well as feel it.  I feel it more through the seat than the
controls.  It's disconcerting enough to cause me to immediately reduce speed.
This is well into the yellow arc and only achievable by going downhill with
cruise power (which is how I found it).

Have any of you with 360s encountered this?  How far into the yellow arc have
you guys flown?  All of my control surfaces are balanced (although I did not
personally confirm this after paint - the painter said they were fine).  I
noticed this problem prior to painting anyway, and paint did not affect it.
This plane has the large tail.  The vertical fin has probably more mass than
stock due to one side needing to be built out to fit with the rudder (the
trailing edge of the fin was too narrow and off center relative to the
rudder).  A substantial rudder trim tab was needed.  On the other hand, the
rudder weighs less since all of the lead is in the counterweight nose and none
along the leading edge (balance was achieved by extending the counterweight
nose.) So the tail did not go together as cleanly as I would have hoped and
might be a problem source.  Or maybe it's gear doors flapping somehow.  Or....

Any thoughts out there?

Regards,
Ed de Chazal


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