Spin rate and spin characteristics are significant for most sports projectiles. The infamous Adidas Jabulani 2010 World Cup ball has been replaced by the Brazuca ball for Brazil. Although the Jabulani ball was felt to be too light, the main problem was the unpredictability of its flight. Although goalkeepers were confused, mostly it affected accuracy on long shots. No word from Adidas but I expect the pattern on the eight panel construction adversely affected the laminar flow across the surface and hence the spin rate, and/or there was less grip on the boot. Whatever it will be replaced by the Brazuca ball with a new crazily patterned six panel design which Adidas says has a more consistent flight.
The performance of a golf ball is affected by spin more than any other projectile. The first golf balls were made of various materials with a rough surface and when they started to mould them with a smooth surface they didn't fly so far. A golf ball climbs up in the air and therefore carries further due the back spin imparted by the slight downward path of the club and the angle of the clubface. The rough surface helped reduce the drag on the ball so the first moulded balls were made with small raised squares which evolved into the familiar dimples as they were more durable and easier to clean.
The spin of a cricket ball affects the flight but more important for swing is the seam. The trick is to deliver the ball without spin such that the seam causes much greater drag on one side of the ball compared with the other. One is allowed to clean the ball which means one side can be polished although it is illegal to rough up the other side, although this is common practice. I was taught that the smooth side should go through the air more quickly; I suspect the opposite is true, anyone tested this?
Picking at the seam of a cricket ball is illegal as is tampering with the feathers on a shuttlecock. However, in both cases cleaning or smoothing is allowed and this makes it difficult to be sure what is going on. Consistency of performance such that people know that a particular action will have a predictable result is all important as skill levels increase. Consistency in the flight of a shuttle is paramount at a high level where centimetres can be crucial and, as good as feathers feel, people do get frustrated when their perfectly weighted clear drifts out for the umpteenth time.
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