To correct the instability was the next priority. But how could this be achieved? It was decided to try fitting a third, central wheel. It is fairly obvious that, on even slightly rough terrain, this would add to the instability rather than correcting it. The test that followed proved the point. The huge contraption ran a little way up the beach, powered by a total of 70 rockets instead of the original 18. It lurched to one side, then turned back on itself, ran back into the sea and fell on its side, the rockets boiling the water around. Other rockets became detached and flew off low across the sands. Clearly, the middle third wheel was not an improvement. It was found to have been bent and buckled after this test run, and was abandoned.
During the month of October 1943 further trials were arranged in which heavy cables were attached to each end of the hub and secured to two winches which could, it was hoped, steer the contraption safely up the beach. Of course, when the test was run the clouds of smoke and flame from the combustion of the rocket fuel obscured the direction of travel from the controllers manning the winches, and the increased drag from the cables was itself an added disadvantage.
There was yet another practical problem in the design that began to emerge. The breaking-up of the rocket units was clearly very dangerous, yet it was obvious that the rockets might disintegrate. They were designed, as rockets always are, to produce a steady backwards thrust and by being fixed to the periphery of the Panjandrum wheels they were being submitted to centrifugal forces for which they were never intended. These acted laterally against the casings and the force would become considerable when we consider the dimensions involved. A 20lb (9kg) rocket whirling on the edge of a large wheel moving at speed is clearly subject to lateral forces of considerable magnitude and the break-up of some of the rockets was clearly probable. Yet this hazard was also ignored, and was omitted from the design calculations.
A further test took place over an uneven surface. The wet sand was specially cratered for this trial run. After a distance of only 140 yards (about 130m) the wheels of the Panjandrum buckled, the winches seized and the cables became entangled; its trajectory this time had been a wild zigzag pathway across the sand, ending up with the giant device lying pitifully on its side, spent rockets still smoking. If any further evidence of the impracticality of this absurd contraption were needed, this surely was it. But no — development work continued, in spite of all the accumulated evidence. Two new prototype Panjandrums were constructed. They were ready early in the New Year and an official demonstration was arranged in January 1944. A number of senior government officials came to witness this latest test run and several senior members of the Armed Forces were also in attendance. It was to be an auspicious occasion.
The rockets on the first Panjandrum were successfully ignited and the monster began to roll forward. But within a short distance, the first rocket exploded violently and disintegrated, soon to be followed by others. The great wheel, as it gathered speed, began to weave dangerously from side to side and then erratically to change direction. It was completely out of control, and began to head straight towards a group of terrified photographers. The VIPs leapt behind a sand-dune and fell into a tangle of barbed wire. The roaring device turned again, headed down the beach back towards the sea, then in a cloud of smoke and a series of explosions it crashed heavily on its side. Rockets broke away and screamed across the beach in all directions, at least one being vainly pursued by a holidaymaker’s dog. All that remained of the secret weapon was a scorched and twisted hunk of metal beneath a lingering cloud of black smoke.
So, at last, the project was terminated. All the scientific and engineering data should have shown that it could not work. Even a cursory examination of the elementary physics involved would have shown that it was doomed from the start. The cost of the project is unknown, but was clearly considerable, and the wastage of time was immense. At the time, a financial saving, or the release of a few thousand man-hours, would have been of the greatest value to the war effort. Householders were giving up their kitchen saucepans in order to supply light alloy to the aircraft industry and railings were being torn up and melted down to make steel sheet for weapons manufacture. To have these resources diverted to the Panjandrum project was unjustifiable.
This was not the last we heard of the wasteful Panjandrum fiasco, however. It has re-emerged in more recent times. A lightweight reconstruction featured in the BBC’s wartime comedy series Dad’s Army, first broadcast on 22 December 1972. This episode featured the many problems that befell the device, and paralleled the original trials in some ways. The only time a Panjandrum ran successfully was in 2009 when a 6ft (1.8m) diameter replica was constructed to mark the 65th anniversary of D-Day. Like their wartime predecessors, these designers also envisaged that it would speed along the beach, heedless of the problems caused by the question of torque and the backward pointing rockets. It was ignited in a ceremony for the Appledore Book Festival in Devon, and ran down a small ramp. Although it worked to a fashion, the model trundled for several yards, mostly moving at walking pace, before it slowed to a halt and its rockets burned out.
And so attention turned to designing an explosive landing craft. It was planned that this could deliver a load of explosives to breach a protective Atlantic Wall of concrete and allow the Allied troops through to the plains of France. It was being argued privately, that — even if the Panjandrum had delivered its load of explosives — they would not have exerted the desired effect. To give full benefit, an explosive charge would have to be clamped firmly against the wall. The blast would otherwise be dispersed and dissipated as it produced a huge crater in the sand. The proposed landing craft were designed with hydraulic rams which would provide the desired result — they would extend to force the explosive charge firmly against a concrete wall, maximizing its effect.
The vehicles chosen were Alligator landing craft made in the United States. They were based on the amphibious DUKWs vehicles but had caterpillar tracks instead of conventional wheels. Attached to the tracks were spoon-shaped paddles which propelled the craft through the choppy seas until it came to land, when it would rise from the water and proceed up the beach like a conventional tracked vehicle. The Directorate planned to fit each craft with a 1-ton bank of high explosive mounted on a mattress base; this — on contact with the concrete wall — would be firmly clamped in position by the hydraulic rams and automatically detonated.
The Alligator itself was a formidable device. Each was 26ft (10m) long overall and more than 10ft (3m) wide, weighing about 11 tons. But once in the water they were cumbersome and slow, and under sea trials they ran into repeated problems of instability that are reminiscent of the Panjandrum tests. On one occasion the hydraulic ram mechanism was actuated while the craft was still at sea. Its 1-ton mattress of explosive, ballasted with sand, tilted the whole contraption upwards at a crazy angle and a serious accident was narrowly averted. The Alligator took with it more casualties than its fiery predecessor had done as it spiralled up the beach.