Cape lets Batman down (too quickly)

A group of young physicists from the University of Leicester has calculated that Batman’s cape would not allow him to glide to the ground in a safe manner. In fact, the caped crusader – played by Christian Bale in Christopher Nolan’s upcoming blockbuster The Dark Knight Rises – would probably fall to Earth at life-threatening speeds.

Nolan’s Batman wears a cape that becomes rigid when an electrical current is passed through it. This allows the Dark Knight to glide around Gotham City in a similar way to a wingsuit-wearing base jumper. However, in their paper, ‘Trajectory of a falling Batman’, the students found that if the superhero were to jump from a height of 150m, his landing would be equivalent to being struck by a car travelling at 50mph.

I spoke to David Marshall, one of the MPhys students whose work will be published in the University of Leicester’s Journal of Special Physics Topics, to find out how Master Wayne might improve upon his current equipment. I began by asking Marshall whether he suspected that Batman’s cape wasn’t fit for purpose before he embarked upon this project.

"Yes," he replied. "You need a big wingspan to get anywhere when you’re flying. If you look at Batman’s cape you’ll see that it’s not particularly big. For this reason, we expected him to simply fall out of the sky."

At first glance, a question over the efficacy of the Dark Knight’s cape might seem a simple one to answer. However, the fact that this problem can be tackled in a number of ways proved to be a challenge in itself.

"There are a variety of ways in which to approach and solve this problem," said Marshall. "We could have opted for a purely mathematical method – calculating the motion for the flight of the cape – but this would have been quite time-consuming. This project had to be conducted simultaneously alongside the rest of our modules, so we needed to spend our time efficiently. We decided to set up a computer simulation to work out how the motion of the cape would manifest itself. This method provides a pretty crude approximation, but it was sufficient to give us an idea of how Batman would descend."

Of course, in the film Batman Begins, Bruce Wayne proves to be far fitter and stronger than other human beings. I asked Marshall whether Wayne’s physical conditioning might make withstanding an impact at high speeds a realistic possibility, and how the big man might improve his chances of making a successful landing.

"It would help, but when you look at the speed of the impacts based on our approximations, the landing would be more than you’d expect anybody to be able to handle," he explained. "Really, his best bet would be to invest in a bigger cape. Something more like a hang-glider would do a much better job, and a backup parachute wouldn’t be a bad idea."