The Dambusters

On the night of May 16-17, 1943, 19 Lancaster bombers of the RAF’s specially formed 617 Squadron carried out an attack on the Möhne, Eder and Sorpe dams in Germany’s industrial heartland, using the famous “bouncing bomb” designed by Barnes Wallis


400km 250 miles
UK 
Scampton 
Ruhr region
GERMANY


Modified Avro Lancaster bomber
Bomb
2m 6.5ft


BOUNCING BOMB

Arms: Swing open to drop bomb

1.5m

Weight: 4.2 tonnes (3 tonnes of Torpex*)

Drive belt

Electric motor: Ten minutes from target, motor starts to spin bomb counter-clockwise at up to 500rpm


BOUNCE THEORY

10° entry angle

Spin stabilises flight so bomb lands parallel to surface after each bounce

Momentum creates water surge ahead of bomb – velocity carries it up “ramp” and back into air


BOMB RUN

Altitude: Aircraft approaches at just 18m – spotlights used to determine correct height

Release: Bomb dropped 390m from target, hits water at 370km/h

Anti-torpedo nets

Clay bank

Back-spin: Helps bomb bounce further and hugs it close to dam while sinking – it detonates at depth of 9m

Dam breaks

Masonry

48m


*Explosive 50% more powerful than TNT


Source: RAF Museum
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