Straight Up Difficult It's difficult to build a working four-rotor helicopter that spans 100 feet and only weighs 80 pounds. It's even harder when your engine is a 0.7-horsepower person. But two teams of young engineers hope to do just that.

A Human-Powered Helicopter: Straight Up Difficult

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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?


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.


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.


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.


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.


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,


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.

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