It’s Rocket Science

A Kenyan professor of aerodynamics working for NASA in California has emerged as the mystery man behind Australia’s newest weapon in the quest to regain the Ashes
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“Contrast swing” is the brainchild of Dr Rabi Mehta, and on Tuesday it reached out 13,000km from his laboratory in California’s Silicon Valley to play a key role in Australia’s miraculous second Test win at the Adelaide Oval.

Through Australian bowling coach Troy Cooley, Dr Mehta’s scientific work guided Australia’s fast bowlers as their reverse and contrast swing backed up Shane Warne’s spinning blitz to decimate hapless England.

After reverse swing played a huge part in England regaining the Ashes last season, contrast swing is set to become the new buzz word among the world’s fast bowlers.

A leading expert in aerodynamics – specifically aircraft turbulence – Dr Mehta works at the Ames Research Centre, NASA’s premier research laboratory, which has supported projects from the Apollo moon landings to today’s space shuttle missions and interplanetary probes.

It hardly seems the place to find world cricket’s fast-bowling guru, but Dr Mehta grew up loving the game from his school days in British colonial Nairobi.

Educated in England, where he opened the bowling with Imran Khan at the Royal Grammar School in Worcester, Dr Mehta dreamed of playing professional cricket in England.

“I used to be able to hurl it down at a fair pace, but my dad wasn’t very impressed when I told him I wanted to play cricket,” Dr Mehta told The Sunday Mail on Friday, as his NASA colleagues concentrated on a space shuttle launch.

A graduate of London’s Imperial College, Dr Mehta combined his academic and sporting loves to start wind tunnel tests on the aerodynamics of the cricket ball.

Those experiments have evolved the art of reverse swing into something completely different from what Pakistani champions Imran and Wasim Akram pioneered almost by accident on the subcontinent 25 years ago.

Dr Mehta’s interest was sparked in 1980 when Imran told him he occasionally made the ball swing “the wrong way”, although he had no idea why it happened.

“At the time I honestly didn’t believe that such a phenomenon could occur and I could not explain it scientifically,” Dr Mehta said. “In the following year, when we conducted our wind tunnel experiments, the mystery was revealed.

“If you take a ball and bowl it with the seam angled towards first slip it will swing away from the right-handed batsman.

“For true reverse swing, everything is the same but the ball will swing towards fine leg You can even do it with a brand new ball if you can bowl at high speeds, over 90mph (145km/h). As the ball gets older, the speed you need to get reverse swing comes down as low as 60-70mph (96-112km/h).

“Contrast swing started thanks to talks I had with (then England bowling coach) Troy Cooley when I was in England during the 2005 Ashes.

“It happens when the seam is held upright and the contrast between the surface roughness of the ball produces the swing.

“From a batsman’s point of view, if the seam is angled it is reverse swing and if it is straight up it is contrast swing.”

Tasmanian-born Cooley is credited with schooling England’s pacemen in the “dark art” of reverse or contrast swing, which played a huge part of its first Ashes series win in 12 years.

He switched back to his homeland to become Australia’s bowling coach this year.

While he has not been specifically working on reverse swing with Glenn McGrath, Brett Lee, Stuart Clark and Co, Cooley notes that any modern paceman who is not keen to master the skill is being left behind.

“You practise every aspect of your trade, and reverse swing is definitely a key aspect of fast bowling today,” Cooley said.

“If you’re a fast bowler and you’re not practising reverse, you certainly should be.

“It is an art to get the ball in the right position, and it’s one that has to be practised.”

Cooley agreed that, while most cricket followers would be aware of the results of reverse swing, few understood the mechanics behind it. That’s because so much of the field is still being researched by experts like Dr Mehta.

The point at which reverse swing occurs is defined by how fast the delivery is. Brett Lee’s speed enables him to produce reverse swing earlier than Stuart Clark or Glenn McGrath.

Contrast swing can be produced at any speed, meaning even military medium bowlers can use it as a new weapon.

Conventional wisdom has always been that it is easier to reverse swing the Duke brand balls used in England than Australia’s Kookaburra ball, but Cooley believes it has more to do with our grounds.

“The seams do appear a bit different and that may have an effect,” Cooley said.

“The Kookaburra is a bit flatter while the Duke seam sits up a bit more. The different ways they prepare the leather and the type of leather may also play a part, and not every cricket ball is perfectly round and you need a very balanced ball to get reverse.

“But really it is the ground condition that plays the biggest part. If you have a greenish wicket and a well-grassed outfield, like in Brisbane, no one will get contrast swing with any type of ball.

“You saw what happened in Adelaide where the batters were on top for four days until the pitch began to break up on the fifth day, the ball got roughed up and it tripped over to reverse.”

And for young fast bowlers who are struggling to get any movement at all, Dr Mehta has a final word from the wind tunnel.

“With a new ball, the point between conventional and reverse swing is 80mph (128km/h).

“But if you bowl at exactly that speed, there is no swing at all. It does not matter how perfectly the ball is delivered, it is not possible to swing a cricket ball at 80mph.”