Sun October 14, 2012
A Human-Powered Helicopter: Straight Up Difficult
Originally published on Mon October 15, 2012 10:00 am
"I grew up wanting to fly," says Graham Bowen-Davies. "I guess I just settled for being an engineer."
He's standing on an indoor track in southern Maryland, watching a giant helicopter take flight. At the end of each of its four spindly arms — arms he helped design and build — a giant rotor churns the air. In the cockpit sits the engine: a 0.7-horsepower, 135-pound graduate student named Kyle Gluesenkamp.
Gluesenkamp is pedaling like crazy to keep the rotors spinning and the craft aloft.
Bowen-Davies and dozens of his fellow students from the University of Maryland are chasing one of aviation's last milestones: the Sikorsky Prize. The American Helicopter Society (AHS) has promised $250,000 to the team that can build a human-powered helicopter. All it has to do is hover for a minute, reach a height of 3 meters (about 10 feet), and stay in a 10-meter box.
Turns out, that's harder than it sounds. The prize has been unclaimed for more than three decades.
The Flying Turtle
The University of Maryland joined the race in late 2008. Inderjit Chopra, director of the university's Rotorcraft Center, recruited a handful of graduate students and undergrads to take on the challenge. They named their helicopter Gamera after a flying turtle from a Japanese monster movie (U of M's mascot is a terrapin).
In the spring of 2011, after two years of work and 20 failed attempts, Gamera finally flew ... for four seconds.
"We went out for drinks," Bowen-Davies remembers.
Since then, about 75 students have worked on Gamera. They've slowly chiseled away at their own record. In June, Gluesenkamp flew for 49.9 seconds; another flight cleared 3 feet. Four long years of work, and not much altitude. That can get exhausting.
"At some point, you don't want to do it any more," Bowen-Davies says. "You've been going all week, and you're dirty and grimy and your fingers are cut up — but you have to do your part. You have a commitment to the team."
The Canadian Challengers
More than 300 miles north, near Tottenham, Ontario, another group of young engineers is also chasing the Sikorsky Prize. Their helicopter is named Atlas and their team is much smaller.
"It's only eight people, but it's equivalent to an army of a hundred," says Todd Reichert, leader of Team Atlas. Everyone, he says, wants "to challenge themselves and do something that other people have said is impossible."
Doing the impossible is a passion for Reichert. In 2010, he and his colleague Cameron Robertson built and flew the world's first human-powered ornithopter — an aircraft that flies by flapping.
Now Reichert and Robertson have cobbled together public donations and corporate sponsorship to finance Team Atlas.
"Honestly, what we're trying to accomplish here is nothing short of historic," Reichert told his team on the first day of construction, in May. "We need to both design and construct far better than any team has done before."
Light, Like The Wrights
The most famous pioneers of human flight, Wilbur and Orville Wright, had an easier task than these engineers. Their plane could use its forward momentum to climb a ramp of fresh air. Gamera and Atlas must rise through their own turbulence.
But the central problem is the same: "One of the big challenges for the Wright brothers was getting an engine strong enough to move them through the air, but light enough that they can actually get off the ground," Bowen-Davies says. "In that respect, we're no different — we've got the same problem. Our engine just happens to be a person."
Both teams use toothpick-thin carbon fiber tubes, Styrofoam and balsa wood. Though the finished helicopters are more than 100 feet across, they weigh less than 100 pounds.
Gamera is so light that the draft from an air-conditioning unit can swamp a flight. And on its way down, it tends to catch air like a falling piece of paper, drifting out of its 10-meter box and into a wall — or sometimes, into a spectator. No one has ever been hurt, but the structure has suffered some nasty breaks.
"That's when we learn — when things break, we know we have to make them stronger," Bowen-Davies says.
Don't Eat The Pizza
More people have walked on the moon than have successfully flown a human-powered helicopter. Just like their crafts, these pilots have to be light and strong.
Earlier this year, an Olympic cyclist called up Gamera's adviser, Chopra, and volunteered as a pilot. He offered to come out to Maryland once the games were over. Chopra turned him down: At 175 pounds, the Olympian was too heavy.
"I said, 'Don't waste your time,' " Chopra says.
"[Chopra] was looking for children — middle-school children — because they are so light and full of energy," says Elizabeth Weiner.
A graduate student, Weiner helps build Gamera's rotor blades and coaches its pilots. She tests their power outfit, gives them instructions during flight tests and yells at them when she sees them eating pizza.
"It's more of a joke," Weiner says, "but a little bit serious as well."
This summer, Weiner has been busy training newcomer Henry Enerson, a freshman at Maryland and former middle-distance runner. He weighs just 120 pounds and can produce 0.6 horsepower for a full minute.
An Impossible Challenge
When you add up all the late nights, cut fingers and crashes involved in building a human-powered helicopter that can get only a few feet off the ground, it makes you wonder: What's the point?
"It's an engineering challenge," Weiner says. "Nobody's ever done it before."
Sure, pursuing the Sikorsky Prize might inspire innovations in ultralight composite materials. Sure, the project has provided a hands-on learning opportunity for scores of students. But that's not what keeps them engaged.
"It's really an opportunity to inspire people and change the way they think about what's possible and what's impossible," says Reichert of Team Atlas.
Up, Up and Away
At the end of August, the Gamera and Atlas teams both schedule a week of test flights — Gamera at an indoor track, Atlas at an indoor soccer field.
The Canadians hope the week will bring Atlas's first takeoff. They're eager to test their design innovation: steering controls that minimize the drift problems that plague Gamera.
The Maryland team seems less enthusiastic. The students are weary, and there's talk that this will be Gamera's last round of flights. After four years, they're nowhere near the Sikorsky Prize's height requirement.
"We're probably not going to hit 10 feet," Weiner says. "We're going to really try, but it's going to be difficult."
Just in case, Weiner transforms herself into a human yardstick, decorating her shirt and pants with colorful tape at 1-foot intervals. Bowen-Davies tells Enerson he'll be ecstatic if the pilot reaches 5 feet — a respectable foot-and-a-half higher than the team's record.
Enerson hops in the cockpit, clips in his shoes and starts pedaling. He easily sails past the previous record, hits 5 feet, then keeps going. Weiner, standing on tip-toe with her hand stretched upward, can't reach the craft. They make it to 8 feet before drifting back down.
"That's really flying!" Bowen-Davies exclaims. "We wanted it to happen, but we thought, 'Maybe it's not going to be us.' But now, there's no reason we can't do it."
For the first time, the Sikorsky Prize seems within reach.
Back in Ontario, on the same day, Team Atlas has a triumph of its own: getting off the ground for the first time.
But it faces an extra challenge. The team can rent the field only during the day, so every night, it dismantles the craft, and the next morning, rebuilds it. It's difficult to make the adjustments Atlas needs.
Meanwhile, in Maryland, Gamera reaches 9 feet, then 9.4 — then a crash ends the week of test flights. Atlas meets a similar fate, breaking two spars.
Both teams are already redesigning and rebuilding. There is no talk of quitting now. They still have their eyes on the Sikorsky Prize.
In September, Reichert and Robertson took a break from chasing the Sikorsky Prize to race superlight bikes at Battle Mountain (Reichert holds the collegiate human-powered land speed record) and then to appear on Mythbusters. They say they'll be back working on Atlas soon. The University of Maryland's Team Gamera headed back to the drawing board as school started; it's gearing up for another round of flight tests this winter.
RACHEL MARTIN, HOST:
So, we humans have been able to fly with the help of motors for more than a century, and yet we cannot seem to let go of the dream of soaring like birds on our own power. NPR's Adam Cole brings us this story of some young engineers who are racing to build a person-powered helicopter.
ADAM COLE, BYLINE: A few feet above the floor of an enormous gymnasium in southern Maryland, Colin Gore is flying.
ELIZABETH WEINER: You're climbing, good. Keep going up. Push it. Go, Colin, go.
COLE: He's gritting his teeth and pedaling furiously as his teammate, Elizabeth Weiner, watches from the ground.
WEINER: Keep going. Keep pushing it.
COLE: Gore is suspended below an enormous skeletal flying machine that's more than 100 feet across. He's pedaling with his feet and his hands to spin the four enormous rotors that keep his fragile craft in the air. But he's getting tired and begins to drift down towards a wall.
WEINER: Back down, back down, back down. Are you OK?
COLIN GORE: I'm OK.
WEINER: Oh, man.
COLE: Weiner and her teammates, all engineering students from the University of Maryland, are chasing one of aviation's last prizes, the Sikorsky Prize. The American Helicopter Society has put up a purse of $250,000, hoping to inspire young engineers and spur innovations in lightweight technology. To win, the Maryland team has to build a human-powered helicopter that can reach a height of 10 feet and hover above the ground for a minute without drifting. They have been trying since 2008.
GRAHAM BOWEN-DAVIES: At that stage, I didn't know how hard a helicopter was. I've learned how hard it is. I know how hard it is now.
COLE: Ph.D. student Graham Bowen-Davies says it took two years of frenzied work before they could coax their helicopter into the air. They named the craft Gamera after a flying turtle from a Japanese monster movie. Gamera's first flight was only four seconds long and just a few inches high. That was early last year. Now, more than 75 students have helped with the project and they still haven't reached their goal.
BOWEN-DAVIES: That's when we learn. We know when something breaks that we need to make it stronger.
COLE: Their failure isn't that surprising. Engineers all over the world have been after the Sikorsky Prize for three decades and they haven't even come close. Rising straight up into the air and staying there requires an incredible amount of power. Flapping your arms isn't going to work. To generate enough lift, you need enormous wings, or in the case of a helicopter, enormous rotors, to convert human power to flying power. And at the same time, Bowen-Davies says you want everything to weigh as little as possible.
BOWEN-DAVIES: That's something we're constantly balancing, trying to see how light can we make it but still be strong enough that we can safely take off and carry our pilot off the ground.
COLE: They built Gamera of super-light materials, mostly toothpick-thin carbon fiber tubes and Styrofoam. And the pilots who fly this thing, they have to be super-light too.
(SOUNDBITE OF BEEPING)
COLE: Gamera's newest pilot, Henry Enerson, is training on a hand and foot cycling machine. In high school, he was a middle distance runner and he has that build.
HENRY ENERSON: I was like 115 during track.
COLE: Now, he's closer to 125.
ENERSON: So, kind of got fat after I graduated but, you know.
COLE: To practice generating the power he'll need to fly - about seven-tenths of a horsepower for a full minute - Enerson has to pedal along with a clicking metronome at 90 RPM. It's tough.
WEINER: Looks good, looks good, 92, 89, 86. OK.
(SOUNDBITE OF HEAVY BREATHING)
COLE: In late August, after months of tinkering, shaving the grams off their pilots and their helicopter, Team Gamera rented a huge indoor track for a new round of flight tests. But they were weary, and expectations weren't high.
WEINER: We're probably not going to hit 10 feet. We're going to really try but it's going to be difficult.
COLE: There was talks that the project had reached its end. This would be Gamera's last round of flights.
(SOUNDBITE OF BELL RINGING)
UNIDENTIFIED MAN: Blocks away. You're clean. Go.
COLE: But then with Henry Enerson in the cockpit, Team Gamera did what they thought was impossible: they shattered their own record.
WEINER: We were all kind of like what is he doing? Hold on, hold on, hold on, keep flying, keep flying.
BOWEN-DAVIES: But after we got to that eight feet, that was the most amazing feeling in the world because, I mean, that's really flying. We wanted it to happen but realistically we were like maybe it'll happen one day but it's not going to be us. But now there's no reason why we can't do it.
COLE: Two days later, they reached 9.4 feet, just a few inches short of Sikorsky Prize height. And then they crashed again. This round of flight tests is over, but Team Gamera isn't talking about quitting anymore. They're already planning repairs. As engineers like to say:
BOWEN-DAVIES: It's not a problem. It's a challenge.
COLE: And the Sikorsky Prize is still there, hovering just out of reach.
(SOUNDBITE OF MUSIC)
COLE: Adam Cole, NPR News.
MARTIN: This human-powered helicopter really does look as cool and strange as it sounds. And you can watch it fly - and you can watch it crash - on our website, npr.org.
(SOUNDBITE OF SONG, "DON'T STOP ME NOW")
QUEEN: (Singing) Can't stop me, 'cause I'm having a good time, having a good time. Shooting star leaping through the sky like a tiger defying the laws of gravity. I'm a racing car passing by like Lady Godiva. I'm gonna go, go, go, there's no stopping me...
MARTIN: You're listening to WEEKEND EDITION from NPR News. Transcript provided by NPR, Copyright NPR.