Sunday, January 7, 2018

'Pants on Pants': Engineer designing new airplane for Cirrus Aircraft, creates new snow pants design

Jeffrey Xu, an engineer who moved to Duluth from Shanghai to design a new airplane for Cirrus, describes how his dislike of the cold weather drove him to design his own easy-on, easy-off snow pants he calls "Pants on Pants." 


Experiencing his first winter after moving from Shanghai to Duluth, Jeffrey Xu wondered why Minnesotans put on jackets, but then leave their legs vulnerable to the elements when they're out and about.

"I knew it's cold. But until you feel the cold ..." Xu said with a laugh. He explained, "It's something that really puzzles me. People here, they have the attitude that they just want to tough it out."

Exiting a building and getting into a frigid car is the coldest moment, he said. It's like his body goes into cold shock, he said, showing in a chair how he keeps his body raised off the cold car seat until the seat warmers kick in.

"That takes, like, three minutes and that's a — every time — very long, long three minutes," he said.

Xu, an engineer designing a new airplane for Cirrus Aircraft, asked his coworkers how to keep his legs warm while he's going to and from work or running errands. Their response was to "walk fast."

He found long johns to be too warm while he's inside at work and snow pants were too cumbersome to wear going to and from work. He wanted something that could be a "jacket for the legs," where he could just put it on and zip it up while standing, without having to sit down and slide it over his shoes. But he couldn't find anything on the market that exactly matched what he was looking for.

Instead of just dealing with the cold, Xu set out to find a solution. He designed a pair of snow pants that he can put on as quickly as a jacket when he's walking out the door. An engineer with two master's degrees and a doctorate from Stanford University, he approached the idea like an engineer and spent more than a year designing, testing and retesting the pants until every detail worked to his satisfaction.

"To make this into a product, it's a huge decision. ... I'd do all kinds of fatigue tests, so on the Velcros, I would just hand pull them on and off and on. What can they withstand? Four-hundred times or 1,000 times? And those snaps, how long are they going to last? But it's a lot of fun," he said, laughing.


Jeffrey Xu demonstrates how to put on his "Warmthology" snow pants invention, also known as "pants on pants."


The end result was a pair of snow pants he calls "Warmthology," although he noticed that the nickname "pants on pants" is more popular. The pants wrap around the waist and zip up the legs, while zippers on the front and back provide access to a wallet and keys in your pockets underneath, he explained. In under a minute, he put the snow pants on while balancing on one foot and raising his other foot, which was in a cast, injured in his recent first attempt at sledding.

He began a Kickstarter campaign, and it's not only Americans buying into the pants — he's had inquiries from Iceland and Norway.

Duluth resident Nancy Knezevich said she was intrigued when she heard about the pants and now owns a pair of them. She enjoys being outside, but gets cold easily due to a medical condition and she said the pants work well to keep her warm. She used them Sunday to walk the half-mile to and from church and they're useful when she doesn't have a chair to sit down on to put on snow pants over her shoes, she said.

The best part of the pants "is staying warm," she said. "Very ingenious, very intrigued and very impressed. Quite impressed with them."

Winter in Duluth

Xu arrived in Duluth in November 2015 to design a new airplane for Cirrus. The airplane industry is small and it's not often that a chance like that comes around, he said.

"You can start a design from a clean sheet of paper. In the general aviation industry, it's a very rare opportunity that you can do something like that," he said. "Cirrus asked me to join and I said OK, it's a rare opportunity and I would like to come here."

He grew up in an area of China where the daily weather is more like the weather in Miami. In Shanghai, where he lived before Duluth, it snows once every few years and melts within an hour, he said. The San Francisco area was also warm while he was attending Stanford.

Designing a pair of pants was new to him, but he said he's someone who likes to research and try new things. He's still exploring what to do with his new pants design — whether to have someone handle the sales or license the design to sell it to a company. He also has other innovations he'd like to focus on, he said. He doesn't like to scrape frost off his car windows in Duluth and, not liking the existing windshield covers on the market, he created a cover that goes over his car's windows and mirrors to keep the frost off. He said he has found dealing with Duluth's cold weather to be inspiring for his creativity.

"They said 'necessity is the model for innovation.' For me to survive here, I use my creative power to control the weather," he said, laughing.

Steps to completion

He said he began his snow pants project by first defining "convenience" as putting on pants while keeping both feet on the ground. He then started drawing and testing the drawings by creating each design.

"That's the good thing about being an engineer. Engineers know how to test new ideas cheaply," he said.

He created his first design out of a pair of pajama pants, learning that the placement of the zippers didn't work, he said, adding, "I learned a lot with the first pair." Subsequent designs tested different zipper placements, styles and different materials to ensure that the pants were convenient, warm, light and flexible. He started adding in zippers for pocket access and powder skirts around the pants' bottom to keep snow out.

He went through 20 versions of the pants before deciding on the completed pair he has on Kickstarter, he said.

Meanwhile, his coworkers were asking about the invention and he realized there's a market for a pair of snow pants like he was designing.

"It's not just me. Everybody feels cold and I think this is physiological, but its universal," he said.

Story, video and photos ➤ http://www.duluthnewstribune.com

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