slow and steady wins the race
2015 King of the Hammers
Full story @ weblog.spidertrax.com/2015/02/12/behind-the-lens-koh2015-ou… .
By Spidertrax on 2015-02-06 08:04:31
Deep in the Australian outback on a warm October morning, 14 MIT students and alums climbed out of their sleeping bags at six a.m. to get prepared for one more day of challenging driving, in convoy, down endless flat stretches of straight, hot, dusty roads. One particular vehicle took the lead to produce a buffer against other traffic, and a van brought up the rear to monitor the group’s progress.
In among these ordinary automobiles, a futuristic vehicle constructed by a tiny student-run team created its way more than three,000 kilometers, from Darwin to Adelaide, powered solely by the sun. Searching like one thing imported from a sci-fi fantasy, the low-slung single-seater was covered from stem to stern with shiny black photovoltaic panels–about 600 solar cells connected in six arrays. And inside, beneath a plastic bubble canopy reminiscent of a fighter jet, a driver tried to maintain an excellent speed calculated by the team in the chase vehicle on the basis of consistently updated estimates of how lengthy the battery power would final. In spite of the pressure–and temperatures as high as 110 °F–the drivers loved each and every minute of it.
“You have to hit oneself more than the head each and every night and say, ‘I’m in the middle of Australia racing a solar auto!’ ” says team member Maddie Hickman ’11. “You cannot comprehend how you ended up there.” The group passed flocks of emus (and mobs of kangaroos en route to the race), and each and every night the deep, quiet darkness of the remote desert was lit by unfamiliar stars.
The members of the MIT Solar Electric Vehicle Team (SEVT) had spent two years designing, creating, and testing to earn the correct to compete in the weeklong 2009 Globe Solar Challenge, the world’s longest race of solar cars. And on these isolated roads, their intimate familiarity with every single detail of their car–named Eleanor, following one in the film Gone in 60 Seconds–helped them make it to the finish line. More than half the teams did not.
The rules let teams drive only from eight a.m. to 5 p.m. But they could commence charging the batteries earlier, so every single team rose with the sun to set up the solar panels. “At 8 a.m., we’d jump in our automobiles and get off as fast as achievable,” says Hickman. And at five:00 p.m., they’d set up the arrays again to catch all the light they could before sundown.
The 1st day, every thing went smoothly for the MIT group. But on day two, when they pulled over for a routine switch of drivers, Eleanor hit a rock. One of the particular high-pressure tires right away went flat. And as they started to adjust it, a lug nut jammed.
VideoSlide Show”We pulled off the complete hub–something we had never practiced,” says team member Chris Pentacoff ’06, an iRobot engineer who was a driver for MIT in the 2003 and 2005 races. “But we had practiced taking almost everything apart, and we had spare parts of everything. We just swapped the hub and were back on the road in about MIT’s group is “normally 1 of the smallest teams, if not the smallest, in terms of number of people, and in the decrease tier in terms of the funding we get,” says Pentacoff. “But we’re generally regarded as the most resourceful.” That reputation was enhanced in 2005, when MIT’s vehicle suffered a rollover. “Most individuals believed we had been completely out of the operating,” he says, and however the team produced improvised repairs and completed the race in sixth location.
Final year, MIT’s team was 1 of only two that developed and constructed their personal electric controllers, the interface between the solar cells and the car’s array of batteries such as dell Latitude D800 battery, dell Inspiron 8500 battery, dell 8N544 battery, dell Inspiron 8600 battery, dell Inspiron 6400 battery, dell Inspiron E1505 battery, dell GD761 battery, dell KD476 battery, dell TD347 battery, dell Inspiron 1000 battery, dell Inspiron 2200 battery and dell 312-0292 battery. The amount of energy that solar cells capture varies with the time of day, the angle of the sun, and the quantity of cloud coverage. The controllers track the output of the cells and the level of charge in the batteries, maximizing the amount of energy stored in the batteries with out overcharging them. The custom-built units helped the vehicle capture solar energy a lot more effectively, says graduate student Robert Pilawa ’05, MEng ’07, who designed the controllers and oversaw the construction of 14 of them (six utilized in the auto, plus eight spares). The all round efficiency of the MIT controller is 98.five %, he says a normal industrial controller is significantly heavier and only 90 to 95 % efficient. Even though that does not sound like considerably of an improvement, the group calculated that its controllers shaved off 30 to 40 minutes overall–and in some years, even a couple of minutes would imply the difference between first and second location.
The custom controllers proved critical at the finish of the third day. “Our battery pack ran completely empty,” Pilawa says. There have been nonetheless about two hours of sunlight when the day’s racing was accomplished, but because the battery was so low, the relay that activated the controllers would not turn on, and they couldn’t begin charging. Once once again, they improvised: “One particular of the men and women who developed the battery pack and I had been able to literally hot-wire it to bypass the relay. It was sufficient to jump-start it, just for a handful of seconds.” A commercial controller may possibly not have survived the spike in power, he says, but theirs came through unscathed.
MIT’s SEVT, began by James Worden ’89 following he competed in the Swiss Tour de Sol in 1986, is believed to be the world’s oldest such group. (As a freshman, Worden commuted to campus from Arlington in an electric auto he’d constructed in high school he and his wife, Anita Rajan Worden ’90, went on to located a solar-car business known as Solectria.) It has competed in six of the 10 Planet Solar Challenge races in Australia, and this year’s functionality ranked amongst its very best ever: out of the 39 teams that registered, and the 32 teams that really raced, it was 1 of only 14 that completed, coming in second in its division (for automobiles making use of silicon solar panels) and sixth overall. With a shape that gives it a drag coefficient of just .11 (typical automobiles variety from .24 to .50), it can attain 90 miles per hour, though the group conserved power for the duration of the race by limiting speeds to an average of 55.
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