In ancient Greece, Daedalus the inventor and intellectual flew -- on handmade wings and under muscle power alone -- from captivity in Crete to freedom on the Greek mainland. The myth is one of the strongest symbols to persist across the ages.
After 3 1/2 millennia, MIT engineers, Yale classical scholars, physiologists and meteorologists, with a gaggle of graduate students, have determined to draw the Daedalus flight out of mythology and into the plastic, metal and wire reality of a human-powered craft that might make the mythical flight.
The group announced yesterday that it is ready to build the prototype of the Daedalus craft, test it this summer and make the flight across 69 miles of Mediterranean Sea next spring.
However easily the mythical flight was accomplished with feathers, wax and string, the real thing is so difficult that it will press the pilot-engine to the limits of human physical effort and give the field of medicine new information on what athletes can do.
The mission also has pressed aeronautical engineers to make wings that will have the least drag of any aircraft wing in existence. It also will be the lightest and strongest human-powered craft yet designed.
The statistics are striking: The craft will have a 102-foot wingspan and a 35-foot fuselage but will weigh only 68 pounds, including instruments and an automatic-pilot device. It will have three times the range, 30 percent more speed, 50 percent more strength in the frame, yet will call for 15 percent less power than the Gossamer Albatross, the human-powered craft that flew the English Channel to gain the world distance record of about 22 miles.
The pilot has not been chosen, but "since we use one person as pilot and engine, that person must be an endurance-trained athlete . . . of national or world-class level," said Steven Bussolari, human-factors specialist on the Daedalus team.
The plane's power plant is a pair of bicycle pedals attached to rods that turn the 20-foot propeller. The pilot will have to pedal with an effort matching that of a runner at moderate speed -- but a marathon takes just over two hours for a world-class runner, and the flight will take more than four hours.
One of two athletes who tried to simulate the flight in a lab was forced to quit because of dehydration. The second, a young femaletriathlete, pedaled at the required speed for the full four hours.
"This is an unknown area in human physiology," said Ethal Nadel, professor of physiology at Yale University and a member of the Daedalus team. When marathon runners' muscles run out of carbohydrates to burn and their legs collapse, it is called "hitting the wall." The flight will be pressing that limit and will require special diet and preparation to prevent a crash from exhaustion, dehydration or overheating.
The plane will fly at about 17 mph and 10 to 20 feet above the water to take advantage of the calm surface air. (That avoids the flaw fatal to Daedalus' son Icarus, who soared so high that the sun melted his wax wings.)
Three takeoff points are being considered: an airstrip that will add 12 miles to the trip, a beach that will add a bit less to a straight-line flight and a thousand-foot cliff that is the closest point on Crete to the Greek mainland.
The Daedalus is the most recent in a new generation of human-powered aircraft that began with the building of the Gossamer Condor by engineer Paul MacCready. His group solved the initial problem with muscle-powered flight, determining that a very large, very light wing was essential to translate the low level of human power into flight.
The MIT group, led by John S. Langford, also has built two muscle-powered planes, one of which held the world speed record in 1984.
The Daedalus project is expected to cost $74,000 for the initial year's study, paid for by the Smithsonian Institution and MIT; $99,000 for the prototype and tests, donated by Anheuser Busch, and $195,000 to build and fly the finished craft. Sponsors for the final phase are being sought.
The craft's skin will be tissue-thin Mylar plastic, an extremely tough material that will cover the 700 square feet of the craft with only a couple of pounds of material. Its bones will be tubes made of graphite threads and epoxy, having the strength of metal poles but weighing only about 40 pounds, which will support the wings and fuselage.