The Grand Slam

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Yesterday I wrote about the Tall Boy bombs that were used in the Second World War. We get to realise how important this bomb was to see where it was used. No other bomb up to this point could penetrate the thick reinforced concrete that the Germans had created around protected targets.

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Once everyone realised how effective the Tall Boy was it is easy to see why they wanted something much bigger and in fact double the size .Barnes Wallis was an aeronautical engineer so he had the skills to make the bombs totally different to what had been developed before him. The only problem was the aircraft as the Grand Slam couldn't fit inside the bomb bay doors so it was attached outside the air craft.

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Tall Boy on the left and Grand Slam on the right.

The bombs were a lot longer than the normal bombs and the tail had offset fins which caused it to spin as it fell stabalizing it as it dropped picking up speed. The concept is similar to a bullet as it spins, the more accurate it will be. The spinning enabled the bomb to pass through the sound barrier and still be stable enough to stay on target.

The Grand Slam was a much more difficult bomb to make. The steel casing took two days to cool down before machining could take place. The hardened casing wouldn't break when hitting a hard object and was designed to go through it first. The Torpex explosives were poured in using buckets and when the casing was full it would take a month for the molten explosive to set.

The only problem the aircrews had was whatever bombs that weren't dropped they were instructed to bring them back.The bomb took a long time to make and weren't allowed to be wasted as they were too valuable. Normally crews would jettison any bombs before landing as it was just too dangerous.

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The first Grand Slam that was dropped was on the Bielefeld railway viaduct and it was completely destroyed. It took one Grand Slam to bring it down. If we look at the photograph we can see how many bombs had been used up until this point.

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The U Boat manufacturing pen in Valentin on the Weser river near Bremen was a prime target as the Germans were building 14 U-boats a month from this facility. Up until now the Allies had nothing that could penetrate the reinforced concrete. Grand Slam and Tall Boys were dropped and the roof of the pen was breached. The Grand Slam and penetrated 4.5 meters into the concrete before exploding, ripping a hole in the concrete roof.The Germans knew now that they were no longer safe from bombing. The submarine base was deemed unusable after the bombing raid. This definitely changed things for the Germans as the protective bases they had built were no longer protected.

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The Grand Slam bomb was also known as the biggest non nuclear bomb of World War Two. This was the first Bunker Buster bomb and bigger ones were being developed and used later in following wars.