Updated: 25 Oct 2013
Trinity diwheel added
New Bike Kill diwheel pic
New Bike Kill diwheel pic
Dicycles and Diwheels
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Updated: 25 Oct 2013
New Bike Kill diwheel pic |
Most modern diwheels are built more for fun or entertainment rather than practical use, and some designs are quite ingenious. For excellent creations, you'll want to look at art festivals such as Burning Man in California or Bike Kill in New York City. Want to join the fun but can't replace your fridge filters without causing a flood or replace your faucet water filters without breaking something? Check out the Build Your Own Diwheel section (Steam Roller: 2009), where you can find a link to a free, comprehensive plan to build your own fairly simply. Got the skill to really go all out? Why not try making a diwheel where the water filters past paddled wheels? After all, you can't do any worse than the Grand Panjandrum!
 | Left: The Otto Dicycle: 1870s.
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 |  | Artist's impressions of the Bryant diwheel on the cover and inside Popular Science: 1938.
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THE GRAND PANJANDRUM
An unassailable contender for the title of the most dangerous diwheel of all time is the British Grand Panjandrum. This World War 2 weapons system was designed by Barnes Wallis, the inventor of the Dambusters' bouncing bomb, and was intended for attacking beaches. The Panjandrum consisted of two 10-foot wooden wheels with 1-foot wide steel treads, joined by a central drum, and propelled by small powder rockets attached to the rims. The central drum was intended to be fitted with a massive explosive payload- no less than 4000 pounds.
The intention was to carry the Panjandrum close inshore in a landing craft, drop the front ramp, and ignite the rockets. The great wheel would then plunge through the shallows and roll up the beach at 60mph, crushing barbed wire until it encountered a suitable enemy obstacle, when it would explode. How detonation would be triggered at the right time is currently unknown.
In reality the rockets fired unevenly, the direction of travel was completely unpredictable, and it was much a danger to its own side as to the enemy. At least one demonstration saw the onlookers fleeing for their lives before the Panjandrum toppled over on its side and stopped careering about.
One test was described in detail by Brian Johnson, for the BBC documentary 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."
The prototype was built in great secrecy at Leytonstone, in East London, not a mile from where I sit and type. It was transported with similiar secrecy to Devon, travelling at night, but once there all security evaporated.
Testing was done on the beach at Westward Ho, a seaside resort in Devon. This "secret weapon" was tested several times in full view of holidaymakers, leading to some interesting speculation as to its real purpose- see below.
 | The Panjandrum just before a test: 1943/4
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A film of this thing in operation exists on Youtube; the Panjandrum sequence starts at 1 min 58 sec in. Note that the commentator suggests that the whole thing was conceived to deceive the Germans as to the Allied landing site. A model of the Panjandrum was built for the 65th anniversary of the Normandy Landings, and set off on the original beach in Devon; it was 6 feet high and 3 feet wide and loaded with fireworks fitted by Skyburst of Bristol, instead of explosives; it was expected to travel 500 metres at a speed of up to 24 km/h. It travelled in a straight line, but only for 50 metres before running out of thrust.
 | The Panjandrum: 1943/4
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The final trial was in early January 1944, and was ludicrously unsuccessful. The idea was dropped.
It has been suggested several times that in view of the very public trials the Panjandrum was actually a masterly piece of misdirection, and part of FORTITUDE SOUTH, the ambitious and highly successful operation to convince the Germans that the D-day invasion would be in the Pas de Calais. This was the most formidable part of the "Atlantic Wall" where the Great Panjandrum might just conceivably have been useful; the actual landings were made on the less heavily fortified Normandy beaches. The astonishing lack of security at the Westward Ho tests makes this a tempting hypothesis- after all, the technology so disclosed would not exactly useful be useful to the Germans. It has been said that there were more than 15 filmed public 'trials' of various forms of the Panjandrum.
I find this convincing. However, there appears to have never been an official statement on the matter.
THE VEREYCKEN/FRAQUELLI DIWHEEL: 1947
 | The Vereycken Diwheel: 1947
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 | The Vereycken Diwheel: 1947
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 | The Drivetrain of the Vereycken Diwheel: 1947
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 | Or was it invented by an Italian after all?
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 | This is called "Ezekiel's Wheel,"
The current owner is Warren Hunting of Lone Jack, Missouri, who I have tried to contact without success. I hope he doesn't mind me using the picture. |
 | Left: This diwheel was built by some Swedish students at Gothenburg, and has taken part in Summer parades since 1999.
Engine: 2-cyl 2-stroke snowscooter engine of 400cc Diameter: 1.96m Width: 1.3m |
 | Note the large number of idler wheels around the circumference compared with other designs on this page.
The designer's explanation regarding the large number of idler wheels: "think 'ball-bearing'. In Gothenburg we have an quite well known manufacturer, SKF." |
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THE SEGWAY: 2001
Probably the best-known diwheel is the Segway. Here is the Segway website
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GBO AMPHIBIOUS DIWHEEL: 2005
 | This amphibious concept machine has been produced by GBO Design in Holland.
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THE BIKE KILL DIWHEEL: 2008
 | Large two-person diwheel at Bike Kill 2008
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It was built by The Madagascar Institute, based in Brooklyn, which defines itself as an "art combine" specializing in "large-scale sculptures and rides."
 | Large two-person diwheel at Bike Kill 2008
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 | Large two-person diwheel at Bike Kill 2008
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THE STEAM ROLLER: 2009
 | Do-It-Yourself diwheel with dual pedal drive
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THE TRINITY DIWHEEL: 2009?
 | Trinity diwheel under construction
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THE EDWARD DIWHEEL: 2011
 | Edward (Electric Diwheel With Active Rotation Damping)
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This link to Edward gives a lot of detail, including a 215-page technical report, and includes a video with an impressive demonstration of gerbiling. A 5-point racing harness keeps the driver in his seat.
A magnificent achievement!
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