St. George is famous for slaying a dragon, but he’d have a real challenge on his hands if he showed up today in Furth im Wald, Germany. There he’d discover the streets of this town of 9,000 being stalked by an 11-ton fire-breathing dragon with a steel skeleton and a diesel engine for a heart. Built by Zollner Elektronik AG, the robotic monster is the star of Germany’s oldest folk play and, according to the 2014 edition of the Guinness World Records book, the world's largest four-legged walking robot.

The Drachenstich play, which translates as “Spearing the dragon,” has been performed in the town of Furth im Wald for the past 500 years. Set in the year 143, it relates the tale of a bloody war in which an army of knights launch a crusade against the Bohemian rebellion. All the killing and evil awakens a dragon, who lays waste to the countryside until a young lady and a knight defeat it.

If you’re going to create a play about a dragon, you naturally need a dragon. When it came time to reinvent the five-centuries old play, the producers decided to build a full-scale walking robot.

The result is Tradinno, a portmanteau name made out of tradition and innovation. It was begun by Zollner in 2007 and, unlike many stage dragons, isn’t a piece of puppetry. It’s a self-contained, self-powered four-legged walking robot 15.5 m long, 3.8 m wide and 4.5 m high (50 x 12.4 14.7 ft) that clocks in at 11 tons (24,000 lb).

When it spreads its wings, they come out to a span of 12 m. Its steel chassis is covered in polyurethane and fiberglass through which run “veins” carrying 80 l of stage purplish stage blood. And, of course, there’s 11 kg of natural gas for spewing fire.

A two-liter, 107 bhp (80 kW) turbo diesel engine supplies power to a hydraulic system comprised of 272 hydraulic valves and 65 animated axles. There's also 238 sensors for measuring length, rotation, and force; 1,300 m of electrical cables, and hundreds of meters of hydraulic and pneumatic lines.

All this adds up to a hugely impressive moving mechanical beast. Controlled by four radio remotes backed by complex processors, Tradinno has seven degrees of freedom in each leg and can walk at a speed of 1.8 km/h (1.1 mph) as well as go around corners and crab sideways. It can also wave its head with an suitable menacing air and snap its jaws at impudent knights. Since the Drachenstich is performed outdoors, Tradinno is suitable weatherproofed.

Being a star, Tradinno doesn't have to walk to and from the performance space. Instead, Zollner has also built a 4.3-ton transporter for driving it about. This is also radio controlled with all-wheel drive, all-wheel steering and a 2-liter, 4-cylinder turbo diesel putting out 138 bhp (103 kW). At the end of a hard evening, Tradinno can simply crouch on the transport, where four docking couplers will latch on to its torso before the transport whisks it away at a brisk 6 km/h (3.7 mph).

The video below shows the Tradinno dragon going through its paces.

Source: Zollner

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