Re: [Paddlewise] Paddle flutter

From: "Steve Scherrer" <Flatpick_at_teleport.com>

> Flutter could be described as a very fast sculling stroke
> in the vertical plane.  The leading edge of the paddle blade changes
> direction rapidly.  

If you choose to define flutter your own way, it can mean anything you want.
You're taking any form of instability to be flutter.  If you can't agree on a standard
terminology, there's no point is discussing anything.  Flutter as I've been discussing
it is caused by Karman vortex shedding.  Leading edge directional instability can 
be caused by other factors.  Most people I know will accept flutter to be a form
of instability when the power face is drawn through the water, normal to the 
face.  The change in direction of the power face cycles rapidly about the initial, 
nominally symmetric position.

>  I agree with Nick, it's something the paddler does or in Mike's case doesn't do. 

If you take a paddle and tie a string round the shaft and draw it straight through 
the water, power face forward, it will flutter.  When testing a paddle, I simulate 
that with an open lower hand - no grip at all - and push the non-power side of 
the shaft.  There isn't anything I am or am not doing to change the flutter.  
Moderate flutter can be controlled easily by a good grip, a stiff paddle shaft 
and/or good join between paddle and blade etc.  Just increasing shaft diameter 
can decrease the apparent degree of flutter by enabling the paddler to control 
with less force.  But the basic blade shape will determine the susceptibility of the 
paddle to flutter.  

As Nick and I have both said, the problem in this case could be a defective paddle, 
bad technique or other factors.  What I'm saying is that John needs to know the 
problem before he can devise a solution.  That's why trying different paddles may
help, and why I asked a few questions in my second to last post.

A long paddle with a slender shaft held with a close hand position (say, shoulder
width apart) will exhibit more flutter than the same paddle with a shorter shaft
held with hands far apart.  Is John using a long paddle as in the first case while
the others without the problem use a shorter paddle as in the second?  I don't
know - but if this is true, the problem could be that the paddle is a poor fit to
what John wants without either his technique needing to be changed nor the
paddle being defective (though I would suggest widening his hand position.)
 
We also haven't objectively determined what John's perception of excessive
flutter is - testing other paddles will help there as well.  But his experience with
the Carlisle suggests that isn't the problem.

Mike

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