A fine example of very low-tech British engineering in today’s weird wikipedia article, unearthed by the Wikiworm…

Panjandrum, also known as The Great Panjandrum, was a massive, rocket-propelled, explosive-laden cart designed by the British military during World War II. It was one of a number of highly experimental projects, including Hajile and the Hedgehog, that were developed by the Admiralty’s Directorate of Miscellaneous Weapons Development (DMWD) in the final years of the war. The Panjandrum was never used in battle.

The DMWD had been asked to come up with a device capable of penetrating the 10-foot-high (3.0 m), 7-foot-thick (2.1 m) concrete defences that made up part of the Atlantic Wall. It was further specified that the device should be capable of being launched from landing craft since it was highly likely that the beaches in front of the defences would act as a killing ground for anyone attempting to deliver the device by hand. Sub-Lieutenant Nevil Shute calculated that over 1 long ton (1,016 kg) of explosives would be needed in order to create a tank-sized breach in such a wall. The delivery method for such a quantity of explosives posed a significant problem, and one of the concepts discussed ultimately resulted in the construction of the prototype “Great Panjandrum”. The proposed device was composed of two wooden wheels, ten feet in diameter with steel treads a foot wide, joined by a central drum fitted with the explosive payload. It was to be propelled by sets of cordite rockets attached to each wheel. It was predicted that when deployed with a full 4,000-pound (1,800 kg) load, Panjandrum would achieve speeds of around 60 mph (97 km/h), simply crashing through any obstacles to reach its target. The name “Great Panjandrum” was chosen by Shute as a reference to Samuel Foote’s famous extempore nonsense paragraph (though Foote’s term was actually “the grand Panjandrum”), and in particular to its closing line “till the gunpowder ran out at the heels of their boots”.

The prototype was secretly constructed at Leytonstone and transported by night to the testing grounds at Westward Ho! in Devon. However, once there the secrecy surrounding the project broke down, as the beach chosen as a test site was also a popular destination for holidaymakers and from the first test on 7 September 1943 onwards, every trial was witnessed by large citizen audiences despite the DMWD’s warnings concerning the safety of the weapon. Since nothing remotely resembling the Panjandrum had ever been constructed before, the trials began with a good degree of trepidation — only a handful of cordite rockets were attached to the wheels, and the payload was simulated by an equivalent weight of sand. When Shute gave the signal, the rockets were ignited and the Panjandrum catapulted itself forward, out of the landing craft used as a launchpad, and a fair distance up the beach before a number of the rockets on the right wheel failed and the weapon careened off course. Several further attempts were made with more and more rockets, but on every occasion the Panjandrum lost control before reaching the end of the beach.

After tinkering with the project for a further three weeks, the Department returned to the beach. Panjandrum was now equipped with over seventy cordite rockets and a stabilising third wheel. When launched, it hurtled towards the coast, skimming the beach before turning back out to sea. A number of the 20 lb (9.1 kg) rockets detached and whipped wildly above the heads of the gathered audience or exploded underwater. Despite these failures, Shute and his team persevered, removing the third wheel and attaching steel cables to the remaining two wheels as a basic form of steering. Panjandrum proved to be too powerful however, snapping the cables and whipping them back across the beach when they were used. More weeks were spent testing every conceivable variable from thicker cables to heavier rocket-clamps without success before the DMWD received notification that the weapon was only required to be consistently able to travel in the general direction of the enemy. With some degree of confidence, a final trial was scheduled to be performed in January 1944, in front of a number of Navy officials and scientists, as well as an official photographer.

The day of the test was described in detail by Brian Johnson, for the 1977 BBC documentary The Secret War:

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 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.

Given the results of the trial, it is perhaps not surprising that the project was scrapped almost immediately over safety concerns. However, it has since been suggested that the entire project was a hoax devised as part of Operation Fortitude, to convince the Germans that plans were being developed to attack the heavily fortified defences surrounding the Pas-de-Calais rather than the less-defended Normandy coastline.

Although not named as Panjandrum, a similar device was the focus of an episode of the comedy Dad’s Army, “Round and Round Went the Great Big Wheel”. The device malfunctions in a similar way to the original, although it was operated by remote control and for comic purposes it is more manoeuvrable and remains active far longer.

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About Author Profile: Worm

In between dealing with all things technological in the Dabbler engine room, Worm writes the weekly Wikiworm column every Saturday and our monthly Book Club newsletters.