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Henry Enerson, a University of Maryland freshman who runs track, is both lightweight and strong, which makes him an ideal powerplant for Gamera II. (Earl Zubkoff)

Pedal Power

University of Maryland students close in on the human-powered helicopter prize.

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(Continued from page 1)

In May 2011, after thousands of student hours and months of construction, Wexler muscled the giant fledgling into the air for the first time. It was a close call, both aerodynamically and logistically. To set up, assemble, and hope nothing went terribly wrong, the team had acquired permission to use the gymnasium for only a few days. The flight happened in the closing hours of their last day.

In July, the team got an opening to fly at the university’s armory building, and experienced their first crash. One of the transmission lines slipped off its pulley, a rotor lost lift, and Wexler came down—hard. She was fine, but Gamera’s trusses were mangled. A crew worked through the night to repair the vehicle. The next day, July 13, Wexler smashed her own record, going 11.4 seconds. As in May, an official observer from the National Aeronautic Association was present. Gamera officially became the human-powered helicopter world record-holder (Yuri I had had no official observer).

As satisfying as the recognition was, the real lesson was in the crash, and the team’s ability to respond. “The first time we crashed, we were heartbroken,” says Will Staruk, a lead student engineer. “The last time, no one cared, because we’ve never been stopped by something like that.” The students were gaining experience in what most aeronautical engineers dream of doing: flight testing.

In the small but energized world of human-powered vehicles, word of Gamera spread quickly. At that point, the team decided to publicize their efforts, posting videos on YouTube and inviting the media to their tests. None of it was lost on Cameron Robertson and Todd Reichert in Ontario, Canada. In 2010, they’d realized their own graduate student ambitions by creating and flying a human-powered ornithopter. In January, they established a group called AeroVelo to further explore the possibilities of human-powered vehicles. Inspired by Gamera and enticed by the prize, the two tackled a human-powered helicopter. Reichert would be the co-designer/engineer and the pilot. Based on their experience with the ornithopter, they were able to compress their development of a human-powered helicopter to five months.

As the Gamera team reviewed every aspect of their own design, they decided to build a whole new helicopter, with better transmission, more efficient rotors, and a lighter structure. They also learned that Neal Saiki, the first successful human-powered helicopter pilot, had begun his own pursuit of the Sikorsky Prize. His experience focused his approach: “It’s not so much the getting off the ground—it’s the stability,” says Saiki. His new ship was named Upturn. The race was on.

Gamera had taught its creators all it could, and the vehicle was set aside. After witnessing that first flight, I began working with the team to create an exhibit about the 2011 flights and the engineering challenge of a human-powered helicopter for the College Park Aviation Museum. The star of the exhibit is one of Gamera’s rotors, suspended from the ceiling. The helicopter had become a museum piece, and the students were fine with that. Its successor was well under way.

Gamera II came to life as computers crunched design and performance parameters, and the team made some big changes. They simplified the structure and slashed weight by using far more “baby” trusses, which had formed only part of the first Gamera’s structure. To provide more lift, they designed longer, tapered rotors with stiffer spars. And they added a flywheel to synchronize and smooth the formerly jerky pedaling done by the pilot’s hands and feet.

Up in Ontario, the AeroVelo team (populated mostly by volunteer students from the University of Toronto) christened their project Atlas and forged their own way. Also adopting the quad-rotor design, they incorporated the lightest known bicycle frame on the market. But to catch Gamera II, Atlas would have to hurry. As the summer of 2012 approached, the Atlas team began working around the clock, racing to get their first flights in before the end of August. Gamera II was already completed, with plenty of spare parts.

By now, the Gamera team had experienced a considerable ebb and flow: Older students departed, and younger ones joined. The team’s goal for its next flights was clear. “They had no intention of going for the prize,” says Pines. “None. Zip. Zero. They were just going to go for the [60-second] time.”

The new vehicle did not disappoint. Compared to its predecessor, Gamera II leapt into the air. In late June 2012, with an official observer from the National Aeronautic Association on hand, it turned in a series of record-destroying duration flights: 20, 35, 40, then 49.9 seconds (the last flown by Kyle Glusenkamp, and another official world record). Yuri-I’s 18-year reign was over; the 60-second mark was in view. A set of unofficial flights, some tethered, began to explore altitude, and Gamera II began to climb past three, then four feet.

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