Panjandrum: The 'giant firework' built to break Hitler's Atlantic Wall

BBC News

2 days ago

To make D-Day a success, the Allies thought they might have to break through formidable German defences. One unconventional idea was a "giant firework" that would deliver a one-tonne bomb: the Panjandrum.
After conquering much of Western Europe in the first few years of World War II, Nazi Germany then diverted a huge effort into protecting what it had invaded.
Once the United States entered the war on the side of the Allies in late 1941, the threat of invasion from the sea went from a distinct possibility to certainty.
To prevent it, hundreds of thousands of forced labourers – some of them Russian prisoners captured on the Eastern Front – were set to work. They built walls, tank traps and reinforced-concrete emplacements. The fortifications stretched around 5,000km (3,105 miles) from France's border with Spain all the way to the northern tip of Norway.
Adolf Hitler called it the " Atlantic Wall", and there are still many traces of it, littering beaches from the Bay of Biscay to the sub-Arctic fjords.
Allied military planners had many challenges to wrestle with during their long preparations for the liberation of Europe. Seizing a port made the most sense – it would be easier to get vital supplies to the troops on the beachhead by unloading ships more speedily on the docks. But the ports on the English Channel coast had been heavily fortified by German defenders.
A bold plan to temporarily take over one of these ports – Dieppe, in France – in August 1942 showed how difficult a port would be to capture. Thousands of mostly Canadian troops were killed or captured in a botched attempt to push through defences; supporting tanks became bogged down on loose shingle sand and the built-up surroundings gave the defenders plenty of cover from which to fire on the invading forces.
Dieppe, it turned out, had the wrong kind of beach. The French coast had plenty of beaches firm enough to support tanks and other vehicles coming ashore, but these beaches would be overlooked by the Atlantic Wall defences the Germans were quickly building. How could they be breached, with the minimum loss to Allied soldiers? An eccentric idea was born…
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Nevil Shute Norway was an accomplished aeronautical engineer who had worked on one of Britain's most high-profile airship designs. The R100 airship had been designed by engineer Barnes Wallis – who would later invent the bouncing bomb of Dambusters fame – for engineering firm Vickers, with funding from the government. Norway later took over as chief engineer when Wallis left to work on other projects.
The R100, intended for long-distance voyages across the British Empire, carried out successful publicity tours as far afield as Canada. It was developed alongside a similar airship designed and built by the UK's Air Ministry, called R101; this design was fatally flawed, and crashed with the loss of 48 lives in northern France while on its maiden flight.
News of the crash flashed around the world, killing Britain's emerging airship industry for good, and Norway drifted into more conventional aircraft designs, including the highly successful Oxford trainer designed by his own aircraft company, Airspeed.
The Directorate of Miscellaneous Weapon Development was known informally as the 'wheezers and dodgers'
When war broke out, Norway joined the Royal Navy Volunteer Reserve, initially serving on naval ships. But his flair for engineering took him in a different direction: into the navy's secret department for experimental weapons.
The Directorate of Miscellaneous Weapon Development was known informally as the "wheezers and dodgers". They drew bookish, lab-bound talent from the UK's universities and research institutes and challenged them to come up with new weapons that could be used in the war. No idea, however outlandish, was discouraged.
One of the weapons the British armed forces needed was something that could be deployed from a ship and was powerful enough to breach the strong concrete sea wall now in place across much of Europe. From there, Allied forces could hopefully capture the ports needed to sustain a sea invasion from behind, where they would be less well-defended.
Norway and team did the calculations and arrived at a minimum explosive weight to break through the concrete defences: a tonne of high explosives. Placed against the wall, this should be enough to blow a tank-sized hole that will allow invading troops and vehicles to pour through. But to drive it up across a well-defended beach was likely to be too hazardous.
Norway and the naval research team turns to an unlikely inspiration: a firework known as the Catherine wheel. The firework uses part of the energy of the rocket, which is usually pinned to the structure, to spin; it makes a much more impressive display. Enough rockets, the team calculated, could generate enough energy to propel a one-tonne bomb all the way up to the beach to hit the concrete wall.
Obviously, to be able to hold a one-tonne bomb, the device would need to be a very large Catherine wheel, one that could be controlled remotely.
Norway and his team eventually came up with a device that looked like a large film reel, with two wheels 10ft (3m) high, on either side of a large steel tank that contained the explosive charge. Spaced around either side of the two giant wheels were a series of rockets containing cordite (gunpowder) which could be controlled remotely and would propel the device forward once the rockets ignited. The contraption might reach speeds in excess of 60mph (100 km/h), giving it enough momentum to push through any obstacles until it hit the wall. Norway and his team called their device "the Panjandrum".
In its broadest sense the Panjandrum makes a lot of sense – Rob Rumble
The Panjandrum exemplifies the anything-goes attitude that British military thinkers adopted, says David Willey, the recently retired curator at The Tank Museum in Bovington in the UK. And it also feeds into a kind of "national myth", he says, that there is always some kind of unconventional inventor that will save the day.
"We love this idea," he says. "We've got all these boffins with round thick glasses in back rooms all over the place that we task to come up with answers and they're always going to be saying 'If only they'd listened to me earlier'. They're fed questions, they're told the problem."
"This idea of blasting holes in sea walls or major defensive wall is quite a big one," Willey adds. The idea, however far-fetched it sounds now, the idea of some massive Catherine wheel with rockets on and it goes over rolls towards wherever where it's then detonated with a huge charge."
The Panjandrum comes before an age of miniaturised electronics, but in a way it presages the age of the drone – a weapon that can be sent into battle without a human needing to pilot it.
"In its broadest sense the Panjandrum makes a lot of sense because you're delivering a huge amount of explosives to one single point, the concrete encasements and the Atlantic Wall," says Rob Rumble, a curator at the Imperial War Museums in the UK.
He says the Panjandrum had to do three things: it had to be robust enough to carry its heavy load up the beach, it had to be able to carry enough explosives to successfully breach the concrete, and it had to be able to do this accurately – "which was the great failing in the end".
"In many ways, I'm also sceptical as to its ability to roll over those defences as well," adds Rumble. "So in a way, the only thing going for it was the fact that it could carry a huge amount of explosives."
The Panjandrum was built in secret in east London and then transported to the west of England for testing. The first test took place at Westward Ho! in Devon in September 1943. The need to test it on a beach conditions completely scuppered the project's secrecy. The team had to test it in front of a crowd of curious civilians, who ignored military warnings that the machine was possibly hazardous. The Panjandrum was successfully launched from a landing craft, but as it moved up the beach rockets on one of the wheels detached, and the lumbering machine quickly blundered off to the side.
Norway and his team made many modifications to the Panjandrum and its array of rockets, but several more tests fared little better. One video which has been preserved by the Imperial War Museum in London shows the weapon careering over the beach throwing up a huge spray of sand and seawater – all the while being chased by an excited dog. (Panjandrum footage starts at 2.51.)
With the planned invasion of France drawing ever closer, time was running out to finetune the Panjandrum
"You know it always makes me laugh when we see this footage of this top-secret stuff and there seems to be half a dozen families down there sitting around having a picnic at the same time in the background."
With the planned invasion of France drawing ever closer, time was running out to finetune the Panjandrum. In January 1944 – just five months before the eventual D-Day landings – a last test took place in front of a crowd of military observers.
In 1977, the BBC produced a documentary series called The Secret War, and producer Brian Johnson described the final Panjandrum test:
"At first all went well. Panjandrum rolled into the sea and began to head for the shore, the brass hats watching through binoculars from the top of a pebble ridge [...] Then a clamp gave: first one, then two more rockets broke free: Panjandrum began to lurch ominously. It hit a line of small craters in the sand and began to turn to starboard, careering towards [photographer Louis] Klemantaski, who, viewing events through a telescopic lens, misjudged the distance and continued filming. Hearing the approaching roar he looked up from his viewfinder to see Panjandrum, shedding live rockets in all directions, heading straight for him.
"As he ran for his life, he glimpsed the assembled admirals and generals diving for cover behind the pebble ridge into barbed-wire entanglements. Panjandrum was now heading back to the sea but crashed on to the sand where it disintegrated in violent explosions, rockets tearing across the beach at great speed."
Panjandrum had failed for the final time, and the project was quietly scrapped.
The idea of a weapon that would make its way to its target under its own steam was outlandish for the time, but makes far more sense today, says Rumble. "In its concept the Panjandrum was a good idea, you know, the sort of indirect unmanned weapons that you see today but in much more advanced form with drone warfare. But otherwise, the technology to drive and navigate the machine just wasn't there at the time."
"Hindsight is wonderful," says Willey. "'This one doesn't work.' Lots of experiments we do don't work. Now, that doesn't mean to say all those experiments are therefore failures. Because number one is you're writing something off the list. So often technology jumps from one project to another, you'll see that happening loads of times.
"In many ways, it baffles me to a certain extent, that the, the solid rocket power was even considered an idea," says Rumble. "Little solid booster rockets aren't 100% an exact science either, depending on how much fuel you have in each one, and how successfully they ignite."
In recent years, some non-military minds have decided to give the idea another pass
In the end, success on the D-Day beaches came partly due to another unconventional weapon – modified tanks collectively known as " Funnies". Led by the eccentric Percy Hobart, normal tanks were modified to do everything from swim to shore using canvas floatation devices, clear minefields with whirling chains, lay steel matting over soft sand or lob dustbin-sized shells at concrete emplacements. They played a massive part in making the landings on 6 June 1944 a success.
As for Norway? Panjandrum was a failure, but other projects Shute Norway masterminded during his time in the Navy – such as an anti-submarine depth charge system called " Hedgehog" – were far more successful. But engineering was just one of his callings. Since the 1920s, he had been publishing stories and novels, writing under a pen name because he worried his fiction could detract from the seriousness of his engineering. His pen-name? Nevil Shute. In the years after the war, he became one of the world's most popular novelists.
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The Panjandrum remains a dazzling example of an unconventional approach to warfare, abandoned when tests proved its shortcomings. But could it have been made to work?
In recent years, some non-military minds have decided to give the idea another pass, such as Adam Savage, the former Mythbusters host who now fronts the TV programme Savage Builds. In 2020, Savage decided to see if he could improve the design enough that it might be able to carry out a peacetime mission, building a miniature Panjandrum. Putting five rockets on each wheel generated more than 10 times the thrust-to-weight ratio, and a slight delay in one of the rockets firing caused the machine to careen wildly off course. Cutting it down to three rockets each side helped, but the results were still far from successful.
Another, bigger Panjandrum was built in 2009 to mark the 65th anniversary of the D-Day landings. Constructed for the Appledore Book Festival, it was created by Skyburst, an industrial pyrotechnics company based in Bristol in the UK.
"We got contacted by a chap from the book festival, to say, 'You know, we're thinking of doing this, is this something you could help with?'" says Alan Christie, the owner of Skyburst. "I mean, we love doing fireworks, but it's always great to have something different, you know."
Skyburst's Panjandrum, like Savage's, did not contain an explosive charge. But it was much bigger, with the wheels reaching 6ft high (1.8m). Christie knew very little about the Panjandrum, and had do a crash course in the weapon's design. "It was really good to actually get involved and learn more about it."
It looked spectacular. I think it actually looked better than the originals did – Alan Christie
Christie says wistfully that it was "a shame" they couldn't use the same kind of solid-fuel rockets as the wildly unpredictable original. The centre of their Panjandrum was a large cable drum, to which the team from Skyburst attached a number of rocket motors, before it was moved down to the beach and launched.
"It probably took us about five, six hours in total, to attach all the drivers and get it in position on the beach," says Christie. "One of the things I wanted to try and simulate it as the landing craft pulled up they dropped down the front of it like a ramp, and it [the Panjandrum] was supposed to roll off. So we built a small ramp ourselves, and then we tied it up with what we call it 'black match', it's just like plastic-covered gunpowder rope.
"We fired it, and it fired the black match as well, which released it and let it go." Christie says Skyburst tried to make their miniaturised Panjandrum as faithful as possible to the original.
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"We got it about 50m (165ft)," he says. "It looked spectacular. I think it actually looked better than the originals did, with all the sparks snarling off it and stuff."
There is no doubt that this odd weapon was built – we have the pictures, footage and testimony of confused onlookers to corroborate it – but there remains a tantalising hint that the Panjandrum may have been an elaborate ploy to fool the German defenders that the Normandy landings were to take place far closer to one of the fortified ports. Was the Panjandrum ultimately an intelligence tool, rather than something that would have been used in anger?
"I think it was a trick, to be honest," says Christie. "They were very open about testing it. A lot of the other secret weapons that they built, nobody got to see what they were or knew anything about them. It was supposed to roll up the beach and hit certain defences. When you look at the Normandy beaches, there was barbed wire and things like that, but there wasn't anything for them to actually crash it into."
Perhaps the Panjandrum was not intended to be a secret weapon at all…
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