REFLECTOR: anyone know the story behind this-musthavemissedit.....

[steve korney]

Ok... Let me get this straight...Are we talking about Winglet flutter, or 
rudder flutter...???

Best... Steve



----Original Message Follows----
From: "Al Gietzen" <ALVentures at cox.net>
Reply-To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
To: "'Velocity Aircraft Owners and Builders list'" <reflector at tvbf.org>
Subject: RE: REFLECTOR: anyone know the story behind 
this-musthavemissedit.....
Date: Wed, 9 Nov 2005 22:38:12 -0800





Looking at the outside shape of the winglet and rudder, one will notice a
slight cuff (concave shape).  Builders sometimes mistakenly believe the
concave area should be filled in with micro in order to make a straight
surface along the winglet and rudder outside line.  Wrong.  The cuff is part
of the "wing" shape and is designed in this fashion for a purpose - and that
is, to allow the winglet to create lift in a horizontal direction towards
the fuselage.  The winglet forces mimic that of a person pushing the winglet
from the outside towards the fuselage.  This "loads" the winglet and adds to
stability.  It also creates a design that does not support flutter.  It is
very important that builders who build from the basic kit make absolutely
sure that the toe-in of the winglets are built according to the construction
manual.  Straight winglets and the absence of a slight concave line on the
outside of the winglet invite flutter.  This is what happened with Brendan
and the first "Brazil" set of wings.  The toe-in was reduced by a fraction
of an inch and the shape of the outside of the winglet did not feature a
concave feature.  It was just enough to begin winglet flutter, which once
started - could not be stopped once the rudder cables broke.

SB



Scott;



I put a straight edge on my Alan Shaw winglets, and find that the outside is
flat, no "slight concave line". I certainly don't want to be inviting
flutter.  I assume they have the correct 'toe-in' for a positive AOA; but
have no way of knowing.  How concerned should I be? I suppose a rudder
shimmed just slightly outward from flat would constitute slight concavity.



Any cases of flutter with wings built by Alan?



Al



_______________________________________________
To change your email address, visit 
http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives: http://www.tvbf.org/archives/velocity/maillist.html