The America’s Cup-winning Emirates Team New Zealand (ETNZ) is to use its knowledge of yacht design and technology to inform an attempt to break the wind-powered land speed record.
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The independently funded project will attempt to beat the existing record of 202.9 km/h, set in 2009 by Richard Jenkins in Greenbird. ETNZ skipper Glenn Ashby paid tribute to Jenkins. ‘In doing our research and digging deeper and deeper into the intricacies of the design challenges, it became very apparent that Richard really did an incredible job with his world record design,’ he said. ‘As a team, we explored some pretty creative and innovative conceptual ideas in the quest for more speed; however, in the end, our design and performance principles evolved into a concept reasonably similar in basic layout to the existing record holder, which really emphasised to us what a huge challenge this will be.’
According to Ashby, any gains will come down to small improvements and refinements. ‘Like the America’s Cup, we just need to be doing it better across the board by utilising our experience, skills and tools gained as a team to date,’ he explained. ‘And then, like sailing, there is always the weather gods and doing everything we can to be ready when the right conditions are presented at the location.’
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‘This project is a really compelling one for all of us involved,’ said naval architect Guillaume Verdier. ‘There are a lot of similarities to what we do with fast sail boats in terms of the aerodynamics and structural forces, construction methods, materials and so on, so we are well placed in many respects. But without doubt, no boat we ever design will go anywhere near as fast as we need our land yacht to go. So, with the increase in speed comes increased complexities, but we are sure these are complexities that we can learn from so we can make our next AC75 [yacht] go faster.’
According to the designers, tyre technology and the dynamic forces associated with tyres on the ground, as opposed to hydrodynamic forces on foils in the water, offer some of their biggest challenges. ‘This is the big unknown for us,’ explained ETNZ mechanical engineer Tim Meldrum. ‘Tyres on a flat salt surface going at more than 200 km/h is a whole lot different to foils in the water at more than 50 knots.
‘Our craft, when compared to a speed-record motorised car, has a lot of differences,’ he continued. ‘First, our “motor”, a wing in our case, really delivers a small thrust force compared to a racing combustion engine. So, anything working against that thrust, such as wheel rolling resistance and aerodynamic drag, has been a high priority to reduce if we want to hit high speeds. Second, our wing creates a lot of side load over the main back wheels – so we need to provide grip to keep it tracking straight. A downforce aerodynamic wing like those used in F1 to assist cornering grip would rob us of too much speed, so we have opted to add variable ballast weight to allow us to tune our grip level. Extra weight mainly affects our acceleration time, but does not compromise aerodynamic drag. The trade-off is we can go faster but we end up using more runway to get to our top speed.’
The craft is currently under construction at the ETNZ build facility on Auckland’s North Shore and the team hopes to be ready for a record attempt in July or early August, possibly on either Lake Gairdner in South Australia or Lake Lefroy in Western Australia.
‘Obviously, the objective is to design a craft that becomes the fastest wind-powered land yacht ever,’ said Ashby. ‘And no-one would have ever been that fast in a wind-powered craft on or off the water. So that’s a pretty bloody exciting thing to try to become.’
