“Where does the idea come from?” I ask Chris as Andy nips back to his kitchen to brew up.
“We were thinking how we could make the countdown to the lights switch-on more of an event,” he says. “Something special.”
Chris Squire from Impossible Arts has collaborated with HeckmondLIGHT for the last couple of years. This year he and festival organiser Simon Thirkill are using an Arts Council grant to create a showpiece light sculpture that will kick off this year’s event on Saturday, 26th November.
“So the Momentum Wheel was born?” I say.
“Exactly. Essentially it’s a giant Catherine wheel that’s triggered to spin as the fizzing blue touchpaper reaches it. It will appear to be powered by pyrotechnics but actually it’s powered by this hand-cranking system.”
We’re at the Hebden Bridge workshop of mechanical sculptor Andy Plant, high above the Upper Calder Valley, just metres from the Pennine Way.
Andy’s workshop has all the wizardry of a fabricating shop – a milling machine, band saw, welders – plus all the bizarre paraphernalia – segments of clock faces, bundles of willow, bits of drum kit – of an artist’s studio.
This afternoon, as the light fades, the giant wheel is being tested. With all its sprockets and chains, magnets and LED lights, it’s a mixture of traditional and contemporary technologies all of which have to work together.
“Do you take sugar?” asks Andy holding out a welcome tray of steaming tea and chocolate biscuits.
Dave Chadwick from the fire and pyrotechnic specialists pa-BOOM is here too, to discuss the firework element of the Momentum Wheel.
“It’s a bit smoke and mirrors really,” he says when I ask him if this project is particularly challenging, “we can’t have lots of wires dangling everywhere because the wheel is spinning, so we’ll be using remote firing boxes instead. The challenge is to find the right combination of pyrotechnics.”
“If we could tip it on its back it might be easier,” says Andy as they manhandle the structure onto its stand at the front of the workshop. “For the event I’ll weld some runners on so we can drag it along the floor. That will make a huge difference.”
The three men successfully assemble the five-metre metal Catherine wheel and Andy and Chris stand at its base turning the handles that rotate windmill-like arms above.
“On the outside the pyro effects will look as if its rocketing around,” explains Chris, happy that everything works. “In the middle is a digital image. As the wheel spins the LEDs show different parts of the picture. Once it’s at the right speed your brain is fooled into thinking it can see the whole image.”
“Very clever.” I say.
With Andy still cranking, Chris taps his mobile phone and a faint magenta image appears in the centre of the wheel. “Can you tell what it is yet?” He taps again. “How about that?”
“It needs to get a bit darker yet,” says Andy.
“The touchpaper should fizz,” says Chris, “and the wheel should start to move: SCHUMPH! SCHUMPH! SCHUMPH!”
“And then the fire cans go off…” says Andy. “PER-TOOPH! PER-TOOPH!”
“And the firecrackers… PER-CHEW! PER-CHEW!” says Dave, waving his arms.
“And then, for the finale,” says Andy, “maybe some loud firework from the very top of the structure. POW!”
“The bang could be the cue to switch on the lights,” says Chris.
“Absolutely,” says Dave “And I have some flamey things that would work well.”
“Flame would be good,” agrees Chris.
“Flamey things?” I ask, making notes. “Is that a technical term?”