"The most obsessed leggie I
think I have ever come across"
Sunday, October 07, 2012
More thoughts on Drift
Here's some thoughts on Drift over at a forum I started
don't know what it is Gundalf: perhaps something to do with the 2-piece balls
Sean uses for practice. The seam is quite prominant. Maybe the ball surface has
other characteristics that make it behave that way.
Dave, you'll probably
get your head around it more if you consider that the Magnus effect is at its
maximum when the ball is moving through the air perpendicularly to the axis of
rotation. I've recently been writing about drift and it'll be here with images and diagrams hopefully illustrating what's going on with http://www.mpafirsteleven.blogspot.co.uk/2014/12/wrist-spin-bowling-leg-break.html 30th Dec 2015 Taken at one extreme (top spin) the axis of rotation is
horizontal and across the pitch, so the ball is being forced down throughout its
At the other extreme of pure side spin, the axis of rotation is
along the pitch and the Magnus effect is not active while the ball is moving
essentially parallel to that axis of rotation (ie the first "flat" portion of
flight). It is only when the downward component of the flight starts to increase
that the magnus effect comes into play in this case. As the vertical speed of
the ball increases in the later part of the flight, the ball will start to move
towards the leg side (for a RH leggie) because the ball is now moving
perpendicularly to the axis of rotation more quickly.
For a 45 degree
angle on the seam, there is a component of the Magnus effect working throughout
the flight of the ball, but it's higher on the downward path of the delivery
than the initial upward and flat path.
Because the downward path of the
flight is so vital for drift on a side spinning and 45 degree spinning ball,
it's imperitive that a good loopy flight is offered. Without that initial upward
and subsequent flatter component to the delivery, there will be no late drift in
the flight (there may be constant drift, but it won't be significant nor
particularly tricky to handle).
It all comes down to the flow of air
ACROSS the axis of rotation.
To get drift from a ball that will
also turn off the pitch, there must be a loopy flight so that downward
speed has a chance to increase during the delivery. It's the change in vertical
speed that alters the drift in the air for a side-spinning
I'm still struggling to get my head round drift, but this explanation is quite interesting. The interesting thing I picked up on was the dynamics of the drop from the trajectory and the fact that the 'Drop' aspect adds a different dimention. I've not got time at the minute to try and digest the info and make sense of it, but I may come back to it at some point later.
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