### Why Batman needs a bigger cape

Posted by Emma Woollacott

When Batman returns to movie theaters in The Dark Knight Rises later this month, one group of physicists will be tutting in disapproval.

They've calculated that while his cape would allow him to fly just fine, he'd inevitably break some bones - or worse - when he landed.

In Batman Begins, our hero wears a cape which becomes rigid when a current is passed through it, allowing him to glide elegantly over Gotham City.

But four MPhys students from the UK's University of Leicester have published a paper claiming that although it would be possible to glide this way, Batman would likely go splat when attempting to land.

He'd hit the ground, they say, with the same force as being struck by a car travelling at 50 miles per hour.

The 'wingspan' of Batman's cape - at 4.7 metres - is around half that of a hang glider. And if he jumped from a building 150 metres high, he could glide around 350 metres, they calculate.

However, his velocity would increase during his descent, to around 68 miles per hour at first, before reaching a steady 50 miles per hour as he gets down to ground level. And this, they say, would be much too fast for him to land safely, let alone in a fit state for a fight.

The group concludes that Batman should consider taking a parachute with him if he wants to stay in one piece.

"If Batman wanted to survive the flight, he would definitely need a bigger cape. Or if he preferred to keep his style intact he could opt for using active propulsion, such as jets to keep himself aloft," says David Marshall.

"If he really wanted to stick with tradition, he could follow the method of Gary Connery, who recently became the first person to glide to the ground from a helicopter using only a wingsuit - although he only made it down safely using a large number of cardboard boxes."

'Trajectory of a falling Batman' - with all the math - is here.

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