Kiwi Innovation Boosting Performance

Corey, the 2014 Sochi giant slalom silver medallist, is among the world’s finest sit skiers but keen to upgrade his equipment to gain a performance edge the Kiwi winter sports star approached Dr Paul McAlpine, the HSPNZ Performance and Technical Analyst and innovation lead for Snow Sports NZ, for solutions.

Identifying two “potential soft options” which were ripe for improvement, Paul kick-started work on the cutting-edge and collaborative project in July 2017 and was excited by the possibilities.

“We helped Corey gather some quantification on his sit ski shock absorbers,” he explains. “This was a data collection project to share greater information with the team who build Corey’s shock absorbers.

“The second area was to look at the shape of the sit ski in order to reduce drag and make it quicker on the snow.”

To improve the tuning of the sit ski suspension a greater knowledge was required for the pressure and extension rates of the springs of the shock absorbers when Corey skied in each of his various disciplines.

To identify more clarity with the numbers an engineering team led by Goldmine Director Kerry Spackman, who worked for many years in Formula One, ran tests in order maximum impact and a potential performance gain.

Robert Tang, an electronics/hardware engineer for Goldmine, explains “To use a car analogy you want the wheel to be on contact with the road as much as possible because as soon as the wheel lifts from the ground you have no grip. In the same way, we wanted the suspension to stay on the snow and offer as comfortable a ride as possible.

“We put some electronics on his sit ski to estimate the motion that the sit ski undergoes. “From this we turned that into numbers that Corey’s suspension company could use.”

Using this crucial data, the suspension adjustments were implemented by New Plymouth-based Kiwi Suspension Solutions, which has led to a smoother ride and more significantly a precious performance gain for the 34-year-old sit skier.

“The suspension acts like a knee and absorbs the terrain underneath me,” explains Corey. “The work done helps absorb the high and low speed bumps better. It gets quite technical, but the work on the suspension allows for the same travel speed, but feels much more controlled.”

The second element to the innovation process involved a re-design of the shape of the sit ski to reduce drag. To complete this piece of the puzzle Simon Briscoe, Head of Performance and Technical Analysis at HPSNZ, was brought into the project to design different shapes and sizes of the leg cover – which Corey sits in when racing.

The wind tunnel at the University of Auckland was then ramped up to identify the best combinations of drag reduction. Once determined HPSNZ went back to Christchurch-based Dynamic Composites to build the most aero dynamic leg cover design.

Once the freshly-designed leg cover was tested in the wind tunnel the results were enormously satisfying.

“After re-testing we found the new design has a one and a half percent decrease in drag,” explains Paul. “Compared to his old design this has brought about a tangible performance improvement. All of which means Corey knows he has a faster ski than last year.”

Besides the measurable scientific improvements, HPSNZ Innovation Manager Stafford Murray insists there is another benefit to the technical changes to the sit ski.

“There is a huge placebo effect because Corey knows he on the top of the slope he is in the best possible machine both from a structural perspective and in terms of aero dynamic positioning,” says Stafford. “This fills him with a lot of confidence.”

With the whole process of the “sit ski aero optimisation” project taking six months, Stafford is delighted at the results the team achieved in a relatively short period of time

“What I like about the project is that it has been a collaborative approach involving so many people,” adds Stafford. “We have pulled together all the multi-disciplinary teams and we are pleased with how quickly we managed to turn the project around. We were up against it but everyone pulled out their A games to make sure it happened.”