'Manta' being readied for solar race


The MIT Solar Electric Vehicle Team is readying a new car called Manta for Sunrayce 95, an 1,100-mile race from Indianapolis to Denver that takes place next month.

The vehicle, whose profile resembles that of a manta ray, will compete against 39 other collegiate teams in a race from Indianapolis to Denver from June 20-29. The event, the third since its inception in 1990, is sponsored by the Department of Energy and managed by the National Renewable Energy Laboratory.

Constructed with a chromoly space frame inside an extremely light shell made of carbon fiber with a Nomex honeycomb core, Manta is 14 feet by 6.5 feet and weighs 620 pounds without the driver. It's driven by an 8-hp electric motor run by off-the-shelf lead-acid batteries as required by race rules, which account for half the vehicle's weight. The rules also stipulate that entrants must be university-affiliated and that the vehicles' solar array must cost no more than $10 per watt.

"You can't win this thing by throwing money at it," said technical instructor Kathleen Allen, who is managing the team's efforts. "It really is an engineering race, which is nice."

The competition begins with inspections and a 50-mile qualifying run which must be completed within two hours. Manta and its competitors will start with fully charged batteries, but they cannot use any additional power except that from the sun once they begin. The course, which is run on public roads (vehicles have lead and chase cars), is also uphill and upwind for most of the way. Consequently, teams have to take sun forecasts and terrain into careful account when deciding how fast to run each day.

In past races, cars have averaged about 35 miles an hour, though Manta is capable of much higher speeds. "Speed is not the real challenge in cross-country solar car races," said Wandy Sae-Tan, a sophomore in computer science and engineering, team treasurer and a member of the electronics group. "If we drain the batteries completely on the first day by running 100 miles an hour and can't charge the batteries all the way full by sunset, we're in for a lot of trouble on the second day. This is why most teams use extensive strategy planning and keep the speed relatively low, because budgeting battery energy for over 10 days is so difficult with unknown weather and other potential problems."

Other key members are Goro Tamai, a graduate student in mechanical engineering and team engineer; Milton Wong, a junior in mechanical engineering and team president; and Ivano Gregoratto, a sophomore in chemical engineering and head of the team's composites group working on the car body.

MIT's $100,000 effort has received support from the President's Office and the Office of the Dean of Engineering, as well as sponsorship from companies including 3M, Canon, Ciba, Draper Laboratories, Gerber Electronics, Intel, Instron, Michelin and Nissan, which is lending a chase car. However, the team (which is spending less than one-fifth of the University of Michigan in 1993) is still short of funds for members' accommodations and trucking Manta. Anyone who wishes to make a contribution can contact Ms. Allen at x3-1963 or .

A version of this article appeared in MIT Tech Talk on May 3, 1995.


Topics: Energy, Contests and academic competitions

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