Within months, Kremer had offered a prize of about $213,000 for the first human-powered flight across the English Channel.
MacCready immediately began improving the Condor. What emerged was the Gossamer Albatross, which he described as a "next-step clone." The biggest difference was its stronger, lighter frame, made of carbon fiber tubing instead of aluminum.
On June 12, 1979, with Allen at the pedals, the Albatross took off from Folkestone, England, and headed east. Fighting head winds and turbulence for the better part of three hours, Allen overcame cramps and exhaustion to land successfully on the beach at Cap Gris-Nez, France.
Kremer called it a "splendid achievement" and handed over the prize money.
Six months later, MacCready's ultralight Gossamer Penguin, powered by a 2.75-horsepower motor that ran on electricity generated by solar panels atop the fuselage, skimmed over the Arizona desert in the first climbing flight powered by sunlight.
In 1981, a similar plane, MacCready's Solar Challenger, flew 180 miles from Paris, France, to Kent, England. A few years later, another of his human-powered aircraft, the Bionic Bat, won two more Kremer prizes.
In one of his greatest flights of fancy, MacCready then enlisted the help of engineer Henry Jax to create and fly a wing-flapping, radio-controlled, half-scale replica of a pterodactyl, a creature with a 36-foot wingspan that last soared over Mesozoic landscapes more than 60 million years ago.
"If you can make something that moves around but gives you the feeling of a prehistoric creature, then people experience it; they feel it much better," MacCready said in a magazine interview.
In 1987, his GM Sunraycer, a streamlined vehicle the size of a soapbox derby entry, easily won a 1,867-mile race in Australia against other, larger, solar-powered cars.
Some of his later creations were big, like the Helios, an unmanned, solar-powered plane with 14 electric motors and a 200-foot wingspan that climbed to more than 96,000 feet. It was the highest altitude ever achieved by a propeller-driven aircraft.
Some were small, like his surveillance planes, the size of a man's hand, that carried tiny television cameras.
Some didn't work, like a little plane powered by a hamster.
"Hamsters are lazy," he lamented.
The son of a prosperous physician, Paul Beattie MacCready was born in New Haven, Conn., on Sept. 29, 1925.
