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

[Richard Riley]

>
>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?

I can't speak to Velocity wings, but I have some experience with this 
in Berkut, Long EZ and Cozy wings.

The flutter is very violent, very loud and feels like you've thrown a 
prop blade.  It is easily curable by pressing on the rudder pedals - 
it doesn't take much.

Having a rudder cable break at that moment would be the absolute 
definition of a bad day.

It can be cured by shimming the stop, so the rudder ends up slightly 
deployed.  It can also be cured with a stronger rudder return spring 
or a gurney flap - a small strip on the rudder on the outboard side, 
on the very trailing edge.

See http://berkut13.com/berkut50.htm#Rudders%20Un-porting%20at%20High%20Speed 


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