Cambridge engineers reveal secrets of the bouncing bomb

A team led by a Cambridge University academic said it built a “bouncing bomb” then staged a re-run of the 1943 Dambusters raid over a lake in British Columbia, Canada.

Hugh Hunt, who is based at Cambridge University’s department of engineering and who led the team, said it was the first time that the “engineering complexity” of the raid had been examined.

“There’s no massive mystery in a theoretical sense but the fact that no one has been able to repeat the mission meant that there was no one alive who knew whether it was difficult, easy, or indeed possible,” said Dr Hunt.

Pilot Guy Gibson led the raid by Lancasters from the RAF’s 617 Squadron in May 1943 – attacking dams feeding Germany’s industrial heartland with “bouncing bombs” created by scientist Barnes Wallis.

“While the mission itself has gone down as one of the most iconic episodes in Britain’s wartime story, few details about how the bouncing bomb was built remain,” said a Cambridge University spokesman.

“Most of Barnes Wallis’s original calculations, designs and results were lost; many of them in a flood in the 1960s. The physics of ‘ricochet’ (the bouncing of objects on water) is quite well understood but actually doing it has been a different matter.”

Drawing heavily on a 1976 paper by his Cambridge colleague, Professor Ian Hutchings, which proposed a model for how the bouncing bomb was made, Hunt set to work trying to build one.

He started by firing cricket balls from a bowling machine at the Jesus Green open air swimming pool in Cambridge to test Hutchings’ theories.

He sad: “The biggest challenge was making the bomb itself spin. Barnes Wallis’s original device bounced cleanly and was stabilised because it was rotating at a rate of 500 revolutions per minute (RPM) when it hit the water. “

Cambridge University said a Channel 4 documentary about the experiment – Dambusters: Building The Bouncing Bomb – would be shown at 8pm tonight.