The field of human-powered flight achieved an unlikely milestone yesterday when, for the first time, two independent teams went head-to-head in an attempt to win the Sikorsky Prize. Unclaimed after 22 years, the Prize?a human-powered hover of 60 seconds and an altitude of three meters altitude while remaining within a three-meter square box?has long been believed by many aeronautists to be flatly impossible to attain. But recent achievements have convinced most observers that not only will the prize fall, but it will fall soon.
Before this year, attempts were few and far between, with only three machines ever managing to leave the ground. In 1989, a craft built by students at Cal Poly San Luis Obispo stayed airborne for 7.1 seconds. Five years later, Yuri I, built by students at Nihon University in Japan, flew for 19.5 seconds. After a dormant long period, the prize was reinvigorated in 2009 when the Sikorsky Aircraft Corporation bumped the prize amount up from $25,000 to its present quarter million. Last year, a team from the University of Maryland?s A.J. Clark School of Engineering achieved 11.4 seconds with a machine dubbed Gamera.
Given all those anemic results, it?s no wonder skepticism remained rife. But this summer the Gamera team fielded a larger, lighter-weight version of its earlier machine, this one called Gamera II, that quickly racked up a string of stunning achievements. This past June, the team upped their best time to an astounding 50 seconds, then in early August improved that to 70 seconds. The duration requirement was in their grasp, but could they pull off the altitude? A three-day visit by an official from the National Aeronautic Association, who could certify a bid for the Sikorsky Prize, was scheduled for Tuesday, August 28 to Thursday, August 30.
Meanwhile, 300 miles to the north, a secretive insurgent campaign was underway. Canadian aeronautical engineers Todd Reichert and Cameron Robertson, both of whom had recently earned degrees from the University of Toronto, put together a Kickstarter campaign this spring and raised $30,000 to fund their craft, Atlas. Like Gamera, it?s a quad-rotor design, with four pairs of twin composite rotors connected by carbon-fiber trusses, with a pilot?s seat suspended in the center. Last weekend they assembled their craft for the first time at an indoor soccer stadium in Toronto and began preparing for an officially certified Sikorsky run from Wednesday to Friday.
During trial runs on Wednesday at an indoor track near Washington, D.C., Gamera consistently managed to achieve heights of five, six, and seven feet, but encountered significant difficulty in staying within the horizontal confines mandated by the prize?s rules. (See above video)
The Atlas team, meanwhile, managed to get off the ground for a few seconds on Tuesday, but things came undone early Wednesday when one of the rotor blades hit the ground and snapped. Repairs took all day and into the next morning. Finally, after lunch on Thursday, Atlas team was ready to start flying. While a team member nervously checked the Gamera team?s numerous Twitter feeds, project manager and chief pilot Todd Reichert climbed onto the bicycle frame suspended by thin cords from Atlas? cruciform truss, causing the craft to sag and sway. Pedaling with a brisk but measured pace, he managed to raise one of the rotors off the ground for a few seconds before settling back down. The assemblage of carbon-fiber tubes, polymer cords and balsa-and-foam wings were not yet in proper trim, and the team hustled to make adjustments.
Meanwhile, the Maryland team got off to a slow start, too. Thursday was the second day of class at the university, and many team members could not show up until after lunch. By mid-afternoon, though, their Twitter feeds were humming. ?Just did a trim flight with [pilot] Colin [Gore], should be going for it within 30 min!? one member tweeted at 2.46pm.
The Atlas team hurried to get their craft ready for another run. By 4.30pm, they were ready for a second run. Reichert hopped from the stationary bike, where he?d been pedaling to stay warm, and climbed into the Atlas frame. With a soft clanking and whirring, the eight blades began to spin.
Three of the four rotors rose briefly above the artificial turf, but the trim was still not right, and after a few seconds Reichert set the machine back down again. Their time was up; they had just half an hour to break down the machine and stow it inside a semi-trailer parked outside, because at 5pm league soccer players would descend and begin kicking balls around the turf where the fragile craft now lay.
The Maryland students, meanwhile, pressed on, galvanized by a string of successful flights that edged them stepwise closer to their goal. Each run began with the sounding of a chime, after which the other team members released the rotor tips that they?d been holding and the student in the pilot?s chair began furiously pedaling. Accompanied by the sound of whirring bicycle chain and a periodic clanking, the eight blades rotated slowly, each making only 20 rotations per minute, so that the huge craft (which at 76 pounds weighs a bit more than half as much as its 135-pound pilot) seemed to levitate by sheer force of will.
As the pilot?s seat neared the height of a student?s head standing alongside, the craft hovered for a moment, then began to ease groundward, sliding sideways with increasingly velocity as it descended. After each attempt, the team analyzed data on a laptop computer and reviewed videos of the flight, trying to figure out how to remedy the drifting problem.
At 7 pm, they achieved a best-ever altitude of 8.5 feet, in a flight that lasted 31 seconds, all while managing to stay within the prescribed box. The Sikorsky Prize seemed poised to fall. And then, at 9pm, disaster: a hard landing snapped a truss and left Gamera grounded. ?#gonnabealongdaytomorrow,? one member tweeted.
The day had ended with the Sikorsky still standing, at least for the time being. With the NAA official leaving the Gamera team, and the Atlas team still struggling to optimize its rigging, it seems unlikely the Sikorsky prize money will be claimed in the immediate future. But in the weeks to come, both teams will continue to tweak and modify, trying to steal a march on the other.
And another dark horse lurks: California entrepreneur Neal Saiki, former leader of the Cal Poly project, has secretively launched his own bid with a craft called Upturn. In June, he publicly demonstrated a flight of 10 seconds, then retreated into secrecy. No one knows how much progress he?s made?but if he?s going to step forward and claim the prize, everyone agrees, he?d better do it soon.
Jeff Wise is a contributing editor for Popular Mechanics and the author of Extreme Fear: The Science of Your Mind in Danger. For a daily dose of extreme fear, check out his blog.
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