A savings of 13+ minutes over 112miles seems like a lot.
Whither quicker? Macca’s Kestrel wind-tunnel test
By Jay Prasuhn
Chris McCormack, Kestrel’s longtime mainstay Talon SL rider, had oft wondered whether the seat-tubeless Airfoil Pro was faster than the aero-tubed Kestrel. So Kestrel gave him both bikes to test at the San Diego Wind Tunnel
February 10, 2006 -- On January 30, Australian Ironman powerhouse Chris McCormack paid a visit to the San Diego wind tunnel (http://www.lswt.com) to hone his position on the bike. Along to monitor the test was Kestrel’s Preston Sandusky, Profile Design’s Chris Travers and master bikefitter Craig Turner of Encinitas-based Nytro, one the country’s top tri shops.
Jay Prasuhn Nytro's Craig Turner, kneeling, helps to set up McCormack.
There were lots of micro-adjustments, such as hydration placement and head position, to Macca’s set-up on the carbon fiber Kestrel Talon SL Aero. Then Macca jumped on Kestrel’s Airfoil Pro (which was recently refined with a lighter carbon fiber lay-up) to see if he could squeeze any additional speed and efficiency out of his position atop a different rig.
The first test result came down from Dave Sanford and Dave King of San Diego Wind Tunnel: McCormack aboard the Airfoil Pro was 56 seconds faster per hour.
“Fifty six seconds?” McCormack said upon hearing the news. His gaze wheeled over to Sandusky. The decision was made. “Mate, I’m riding this bike in Hawaii next year.”
Once that baseline was established, Macca and the Airfoil Pro were tested in more realistic crosswind conditions as the team set bike and rider at a 10-degree yaw angle. This second test complemented the first and provided additional support for Macca’s earlier snap decision. With no seatpost to muddy the waters, cleaner air is able to pass through the rider’s legs and past the rear wheel, resulting in still greater aerodynamic advantage, according to the wind-tunnel results.
“The drag savings of the Airfoil Pro versus the . . . Talon SL in bike-to-bike testing just about doubled when tested at a 10-degree yaw angle versus a head-on wind,” Sandusky noted. “It would appear that the no-seat tube design of the Airfoil Pro is doing its job, allowing more, and cleaner, air to pass between the rider’s legs and past the rear aero wheel.”
Once on the Airfoil Pro, Macca gave Turner free reign to tweak his position – with the caveat that any changes would have to be sustainable for, and conducive to, 112 miles followed by a quick marathon.
“That’s what I like about dealing with Macca,” said Turner. “He had total confidence. And given that, I thought the gains would be pretty huge. I’d seen roadie-style [higher upper-body position combined with a slacker seat angle] triathletes for years, and no matter the level of athlete, [moving them] 5.5 cm forward and dropping the front [is] simply more aero.”
The numbers at the end of the day? A few things were kept under wraps, but here’re the findings for McCormack. “In round terms, it was almost a minute per hour [saved] going to the Airfoil Pro, and about two minutes per hour with position changes [for a total of three minutes per hour saved],” Turner said. “If he does a 112-mile bike, that’s a 13 and a half minutes of time savings in a 4:30 [bike split] for the same wattage output.
Which brought up an interesting question positioned by Turner. “What’s 13 and a half minutes in calories burned? If you don’t take the savings on the bike, how much is that in energy for the run? Of course, the strategy of the race determines everything.”
McCormack shook his head in near-disbelief at the final numbers. “It’s awesome,” he said. “I’ve always wanted to do it, seen all the bike riders do it. To be almost 14 minutes quicker by changing bike and position, it’s unreal. It’s a great tool, and this is a great place. I mean, Faris [Al-Sultan] was here, Michellie [Jones] was here, everyone’s been here. It’s one of those things you have to do to consider every part of your race.”
Photo by: Jay Prasuhn
Macca in the wind tunnel.
As for Turner, he was back at the wind tunnel just two days later with former Ironman Germany champ Katja Schumacher, who also underwent testing on her Airfoil Pro and a fit with Turner.
“I’m thrilled for Katja,” Turner said. “She did a long ride in the position we created for her, and she loved it. I’ll be curious to see if it translates for her this season in races.”
You can find more on Kestrel and the Airfoil Pro at http://www.kestrel-usa.com and more about Nytro at http://www.nytro.com.
Shawn
TORRE Consulting Services, LLC
http://www.TORREcs.com
Whither quicker? Macca’s Kestrel wind-tunnel test
By Jay Prasuhn
Chris McCormack, Kestrel’s longtime mainstay Talon SL rider, had oft wondered whether the seat-tubeless Airfoil Pro was faster than the aero-tubed Kestrel. So Kestrel gave him both bikes to test at the San Diego Wind Tunnel
February 10, 2006 -- On January 30, Australian Ironman powerhouse Chris McCormack paid a visit to the San Diego wind tunnel (http://www.lswt.com) to hone his position on the bike. Along to monitor the test was Kestrel’s Preston Sandusky, Profile Design’s Chris Travers and master bikefitter Craig Turner of Encinitas-based Nytro, one the country’s top tri shops.
There were lots of micro-adjustments, such as hydration placement and head position, to Macca’s set-up on the carbon fiber Kestrel Talon SL Aero. Then Macca jumped on Kestrel’s Airfoil Pro (which was recently refined with a lighter carbon fiber lay-up) to see if he could squeeze any additional speed and efficiency out of his position atop a different rig.
The first test result came down from Dave Sanford and Dave King of San Diego Wind Tunnel: McCormack aboard the Airfoil Pro was 56 seconds faster per hour.
“Fifty six seconds?” McCormack said upon hearing the news. His gaze wheeled over to Sandusky. The decision was made. “Mate, I’m riding this bike in Hawaii next year.”
Once that baseline was established, Macca and the Airfoil Pro were tested in more realistic crosswind conditions as the team set bike and rider at a 10-degree yaw angle. This second test complemented the first and provided additional support for Macca’s earlier snap decision. With no seatpost to muddy the waters, cleaner air is able to pass through the rider’s legs and past the rear wheel, resulting in still greater aerodynamic advantage, according to the wind-tunnel results.
“The drag savings of the Airfoil Pro versus the . . . Talon SL in bike-to-bike testing just about doubled when tested at a 10-degree yaw angle versus a head-on wind,” Sandusky noted. “It would appear that the no-seat tube design of the Airfoil Pro is doing its job, allowing more, and cleaner, air to pass between the rider’s legs and past the rear aero wheel.”
Once on the Airfoil Pro, Macca gave Turner free reign to tweak his position – with the caveat that any changes would have to be sustainable for, and conducive to, 112 miles followed by a quick marathon.
“That’s what I like about dealing with Macca,” said Turner. “He had total confidence. And given that, I thought the gains would be pretty huge. I’d seen roadie-style [higher upper-body position combined with a slacker seat angle] triathletes for years, and no matter the level of athlete, [moving them] 5.5 cm forward and dropping the front [is] simply more aero.”
The numbers at the end of the day? A few things were kept under wraps, but here’re the findings for McCormack. “In round terms, it was almost a minute per hour [saved] going to the Airfoil Pro, and about two minutes per hour with position changes [for a total of three minutes per hour saved],” Turner said. “If he does a 112-mile bike, that’s a 13 and a half minutes of time savings in a 4:30 [bike split] for the same wattage output.
Which brought up an interesting question positioned by Turner. “What’s 13 and a half minutes in calories burned? If you don’t take the savings on the bike, how much is that in energy for the run? Of course, the strategy of the race determines everything.”
McCormack shook his head in near-disbelief at the final numbers. “It’s awesome,” he said. “I’ve always wanted to do it, seen all the bike riders do it. To be almost 14 minutes quicker by changing bike and position, it’s unreal. It’s a great tool, and this is a great place. I mean, Faris [Al-Sultan] was here, Michellie [Jones] was here, everyone’s been here. It’s one of those things you have to do to consider every part of your race.”
Photo by: Jay Prasuhn
Macca in the wind tunnel.
As for Turner, he was back at the wind tunnel just two days later with former Ironman Germany champ Katja Schumacher, who also underwent testing on her Airfoil Pro and a fit with Turner.
“I’m thrilled for Katja,” Turner said. “She did a long ride in the position we created for her, and she loved it. I’ll be curious to see if it translates for her this season in races.”
You can find more on Kestrel and the Airfoil Pro at http://www.kestrel-usa.com and more about Nytro at http://www.nytro.com.
Shawn
TORRE Consulting Services, LLC
http://www.TORREcs.com
