World Cup ball makers say bumps keep it accurate

Hans-Peter Nuernberg quietly studied Friday's opening match between South Africa and Mexico, his eyes tracking the way the ball bounced, swerved, and performed in headers, free kicks and saves.
Despite all the criticism and uproar surrounding the so-called Jabulani, the 2010 World Cup ball, Nuernberg liked what he saw.
Nuernberg is the lead engineer of the Jabulani, which features high-tech innovations designed to correct anomalies in the behavior of normal footballs.
``I really enjoyed the match but of course I closely watched the path of the ball,'' Nuernberg said after watching the 1-1 draw from a seat close to the pitch at Soccer City. ``It was a special moment full of good emotions to see our baby flying perfectly through the air.''
German sports company Adidas has made the World Cup ball since 1970 and is contracted through 2014.
Its latest edition is one of the most controversial yet. It uses eight panels, down from the classic 32, that are seared together, not stitched, and covered with a rash of tiny bumps aimed at stabilizing flight. The panels are already raised before they are seared together. Also new is the cushioned synthetic material intended to soften impact for headers.
Nuernberg said the new ball was inspired by a dashboard manufacturing process used by carmakers.
``I first got the idea in 2002,'' Nuernberg said. ``I went to an industrial fair and then I visited a factory which applied that process. I thought: Why not make a ball like this?''
Feedback has not always been kind. Several World Cup goalkeepers and players blasted the high-tech ball as behaving unpredictably.
Spain goalie Iker Casillas called it ``appalling,'' while Brazil striker Luis Fabiano said it was ``very weird.''
Adidas officials insist the only change is higher performance, and maintain the innovations are here to stay.
``The new way of designing the surface means it has a stable trajectory,'' Nuernberg said. ``We can now freely design the surface of the ball - we are not limited by the panel shape.''
The Jabulani, from the Zulu word meaning to rejoice, sells at $150. A cheaper replica version retails for $20. FIFA uses 15 balls at each match and five backups.
Key to the ball's development were trials at Loughborough University's Sports Technology Institute in England.
Senior lecturer Andy Harland, who headed the testing, said the ball was held stationary on a six-axis sensor in a wind-tunnel to perfect patterns of the tiny bumps and grooves.
``If you have big smooth areas on the ball it will not fly true. Spheres are not aerodynamic shapes,'' Harland said.
He said practical tests remain vital as the math of football aerodynamics is still too complex for computer simulation.
``If you ask the computer to simulate airflow - and we asked software manufacturers about this - they saw the detail that went into this and they said 'don't start.'''
The micro-bump technology could be used in future designs of fuel efficient cars, said Harland, who for now is happy to test design secrets and watch football for a living.
``We have so many prototypes in our cupboards. But we can't destroy them or give them away,'' he said. ``It's a fantastic job. But I do spend the first 20 minutes of every game just watching the ball.''