BY ELAINE LAFAY
Daily Staff Reporter
Published November 9, 2008
In late October, a University of Michigan student group zoomed into the world record book for launching the longest flight by a fuel cell-powered airplane.
The group, called SolarBubbles, flew the airplane in a field in Milan, Mich., for 10 hours, 15 minutes and four seconds, whizzing past the old record of a little over nine hours held by a California-based engineering company.
The group, composed mostly of aerospace engineering undergraduates, had been working on the plane, named Endurance, for six months.
These small planes, called unmanned aerial vehicles, are often used by the military, which sends them to collect data in places unfit for human access. UAVs can be used for mapping territories, testing chemicals, exploring the environment or delivering medical supplies.
The fuel cells used were manufactured by Adaptive Materials Inc., an Ann Arbor-based company that approached SolarBubbles about working on the project. Nick Schoeps, a University alum and fuel cell engineer for the company, said SolarBubbles was a good way to test out some of the company’s products.
“We have some other military contracts we’re testing it with, but we thought this would be a great opportunity to collaborate with the University and bring some students into the mix and see what we can accomplish,” he said.
SolarBubbles chair Nick Rooney, a College of Engineering senior, said the group agreed to help with the project because he wanted to help break ground in the alternative energy field.
“It’s important because it shows that there are alternative forms of energy out there that can be used for powering these types of vehicles,” he said.
The 11.7-pound plane, which was controlled by radio waves and had an eight-foot wingspan, zoomed off the ground like a commercial plane.
Fuel cells take a fuel — in this case, propane — and convert it into energy. Because of their small size, UAVs, which usually run on batteries, can only carry enough battery power to last between one and two hours, but fuel cells can last between 10 and 12 hours.
Rooney said fuel cells are only good for smaller objects like UAVs and robots because large machines, like commercial planes, are run by more efficient interior combustion engines.
Schoeps said UAVs are the ideal testing ground for fuel cells because after the flight, engineers have a clear idea on how well the fuel cells worked.
“It’s a very unforgiving environment,” he said. “If you don’t have enough power, the plane falls out of the air — there’s no question to how it’s performing.”
Not counting the fuel cells that AMI developed, the plane cost around $2,500 to build. AMI funded the project.
Rooney said the group’s ultimate goal is to build a UAV that can be powered for 24 hours on fuel cells, a project scheduled for completion in the spring. He said the fuel cells could have powered their world record run for about five more hours, but because daylight was ending they had to bring the plane down.
In order for the plane to fly at night, the group needs to develop a night-power system, which includes a way of having the plane constantly visible and able to navigate in the dark.
“It’s hard to tell where the UAV is, figuring out what the orientation is, which ways it’s flying, how it’s turning — since you can’t see anything, it’s really hard to look at,” Rooney said. Of the night-power system, Rooney also said that it’s really “just a matter of connecting all the systems and making it work.”
An original version of this story wrongly stated how the far the place traveled. It traveled a total of 99 miles in its flight.
The story said fuel cell systems last between 10 and 12 hours. They last until they run out of fuel.
The story incorrectly said fuel cell systems are only good for smaller objects. There are fuel cell-powered car prototypes currently operating.
The story also mistakenly said internal combustion engines are more efficient than fuel cell systems.