The name ‘Barnes Wallis’ instantly brings the Dambuster Raid to mind, and rightly so, since both the concept and execution of the raid were some of the most audacious in war history. However, Barnes Wallis had helped to design the Vickers Wellington before ‘dambusting’ had even been thought of, and his design for the impressive Grand Slam bomb, thought to be an impossibility before the success of the Ruhr bombing, was eventually manufactured and spawned the even more widely used Tallboy Bomb.
Dr Barnes Wallis’s first widely-lauded invention was conceived before the war began. Having first worked on the R100 airship, which successfully made a return flight to Canada but had to be broken up after its sister ship (designed by another company entirely) crashed, he moved on to work on aeroplanes for the Vickers aircraft factory. His light, strong Geodetic design framework, inspired by his work on airships, was incorporated in the fuselages and wing structures of many bomber aircraft designed by Rex Pierson, including the Wellesley, the Wellington, and during the war the larger Warwick and Windsor.
Encouraged by his successes, Dr Barnes Wallis took it upon himself to draft “A Note on a Method of Attacking the Axis Powers” in 1941, a proposal for a very large 10-tonne bomb that could be used to shake massive concrete structures to pieces. Since none of the aircraft of that time were capable of carrying such a large bomb, or of achieving the necessary altitude to drop it from for maximum effect, this idea was regarded with scepticism; however, one of Barnes Wallis’s concepts struck a chord. He had the idea that one way to impact Germany might be to try to destroy vital dams within the country. On the back of this idea the Air Attack on Dams Committee was formed, and the idea was explored further, but it was reluctantly dismissed as unfeasible in July 1942.
This, Flight-Lieutenant Alfred Price writes in ‘History of the Second World War, Volume 7’, did not discourage Barnes Wallis. Instead, he set to work thinking of how the same effect could be achieved with a less powerful bomb. What he eventually came up with was the ‘bouncing bomb’. He worked out that the way to maximise an explosion would be to somehow press the charge hard against the dam wall, so that the weight of the water would help to break the structure. Experimenting with marbles in his water tank, he found that a spherical bomb, released from a low altitude and induced to spin backwards as it was dropped, could bounce over the surface of the water, rebound forwards after it hit the wall, then sink down to a depth where the water could lend maximum assistance to the explosion. After some small-scale tests, he was given the approval to design a full-sized weapon.
The resulting bomb, weighing 5 tonnes, and measuring 5ft lengthwise, 4ft across, would be carried in a special cradle beneath a Lancaster bomber, but it could only be successfully launched by a meticulous and extremely skilled pilot. As ‘Witness to World War Two’ by Karen Farringdon explains, the only way to get it to the target dams in the first place would be to fly in at a dangerously low altitude, to avoid the German radar, then release it at precisely 60 ft (18m) above the water and 425 yards (388m) from the dam wall, while maintaining a speed of 220mph. Only then would the bomb sink to exactly 30 ft (9m) before exploding, inflicting the maximum possible damage. All that was quite an ask, even without the added complication of negotiating ground defences.
‘The Bomber Command War Diaries’ by Martin Middlebrook and Chris Everitt explains that, on 21st March 1943, Wing Commander Guy Gibson formed 617 Squadron from the best crews in 5 Group, who then trained for 6 weeks to make sure they knew exactly how the bomb should be released. Gibson also conceived the ‘Master Bomber Technique’, whereby a lead pilot would remain over the target for the duration of the raid, ensuring marker flares were placed in the right location, and that each following pilot knew precisely where their bomb should be released in relation to the marker. To achieve the necessary level of precision, angled lights were placed on the nose and rear fuselage of each Lancaster; the beams would meet on the water’s surface when the plane was at precisely the right height.
The Möhne Dam had always been intended as a target, and additionally three other dams in the industrial Ruhr area of Germany were to be attacked, the Eder, Sorpe, and Ennepe Dams. Just after 8.30pm on 16th May, 1943, 19 Lancasters, all armed with the brand new bomb, took off from RAF Scampton in three waves. One struck the sea, tearing off its bomb, and was forced to turn back; five were shot down or crashed before ever reaching their targets, and another was so badly damaged by flak that it too turned back to Britain. 12 planes made it to the Ruhr Valley. The first wave of five aircraft, including WC Gibson’s, attacked the Möhne Dam, successfully breaching it despite heavy fire from the ground. Gibson was awarded the Victoria Cross after the operation, not only for his work in training the team but for his bravery in flying to attack the guns and protect his fellow pilots after his own bomb had been released. The Eder Dam was also successfully breached, but the other two proved harder to destroy (the Sorpe Dam had to be bombed with traditional bombs, as the earth-and-concrete structure would have been impervious to the ‘bouncing bomb’. Three more planes were shot down after the bombing, so eight of the original 19 Lancasters were lost, along with 56 crew (only three of whom survived to be taken prisoner). In terms of impact, 1,294 German citizens were drowned in the tidal waves that resulted from the breach, and it took three months to repair the damage, which was done by directing valuable resources away from the construction of the Atlantic Wall; had the Sorpe been breached, it would have been much worse. The most important success of the raid was actually the morale boost it gave to the spirits of the British public, and 34 pilots were later decorated alongside WC Gibbs.
‘Operation Chastise’ was dubbed a success, and more of Barnes Wallis’s ideas were given the go-ahead for development. As ‘History of the Second World War, Volume 7’ explains, his other inventions, though less famous, were actually used more effectively. Since there was still no plane capable of carrying a 10-tonne bomb to a height of 40,000 feet, he first designed a six-tonne bomb with a tough outer casing that could hit the ground at the speed of sound without being destroyed. This deep penetration weapon was called the Tallboy, and was first used on 8th June 1944 to destroy the Saumur railway tunnel, then later to cave in underground weapon stores and bunkers and pierce U-boat pens. Most famously, on November 12 1944 they were used to pulverise the battleship Tirpitz. 854 of these devastating bombs would be dropped by the war’s end, along with 41 Grand Slams.
The latter were the 10-tonne bombs Barnes Wallis had originally dreamed of, though they still could not be dropped from the height he wanted. Still, since the Grand Slam bomb was very tough, and reached even higher speeds than the Tallboy, so it was very powerful. It was first used in March 14 1945 on the Bielefeld Viaduct, and it was found that the bomb could devastate a target even without a direct hit thanks to its ability to simulate a severe yet localised earthquake. The bomb was used with great effect in the last two months of the war, notably to destroy the Arnsberg, Arbergen and Neinburg bridges being the most powerful weapon yet seen prior to the atom bomb’s shattering debut. Barnes Wallis’s first brainchild was arguably his most inspired, and its full potential may one day be revealed, since the desired altitude can now be achieved.