No one had done it before. And it's doubtful that even Orville and Wilbur Wright, the first successful engineers of a motorized aircraft, could foresee what those inaugural 12 seconds in the air above Kitty Hawk, N.C., would mean for the world.

On Saturday, a traveling national exhibit celebrating a century of powered air travel comes to the Museum of Flight in Tukwila. "Countdown to Kitty Hawk" includes a reproduction of the Wright Flyer that, in December, will re-create the historic voyage, 100 years to the minute after Orville Wright took to the air for the first time.

The Wrights were Dayton, Ohio, siblings whose inclinations to fix and build things came from their mother, the daughter of a wheelwright and wagon maker.

It was on Dec. 17, 1903, that the Wrights launched their makeshift plane into the air. There were only four flights, the longest just shy of 900 feet. But if it was one small flight for man, it was a rocket blast for mankind.

"In a little over 60 years, we went from the Wright brothers flying 120 feet to man landing on the moon," says Randal Dietrich, executive director of the traveling exhibit, sponsored by the Experimental Aircraft Association in Oshkosh, Wis. "It really did change the world as we know it."

The exhibit also features flight simulators echoing the Wright Flyer experience that have thrilled amateur pilots and spectators alike at tour stops throughout the Midwest and East Coast. (The Museum of Flight is its only West Coast visit.)

And there is Wright brothers material compiled from family archives, the Library of Congress and Smithsonian Institution, including correspondence with relatives and auto pioneer Henry Ford. Another display commemorates the top flying innovations of the past century.

But the centerpiece is the copy of the brothers' original plane. The aircraft is a reproduction as opposed to a replica, meaning its creators have aimed to adhere to historical accuracy.

"A hundred years' hindsight is a valuable thing," Dietrich says. "But our commitment has been to do exactly what the Wright brothers did, even if in the present day we know better."

That meant building the plane with steel, wool and muslin instead of modern-day materials such as titanium and aluminum, commonly used in replicas.

Construction was led by the Wright Experience organization in Warrenton, Va., which spent a decade researching the craft, mostly via century-old photographs. "Thank goodness they were photographers before they were aeronautical engineers and pilots," says Ken Hyde, Wright Experience president. "They took very-good-quality photographs."

Hyde and his crew also gleaned details from letters the brothers wrote to family and friends. Construction took about 2½ years, and the detectivelike tale of research and fabrication is detailed in a Discovery Channel documentary tentatively set for next month. The flight simulators, which replicate the Flyer experience for museum visitors, were produced by Microsoft and the Experimental Aircraft Association. The simulators let amateur pilots feel what it was like to operate the experimental craft above the North Carolina sand dunes chosen by the brothers for privacy and wind quality.

Participants lie on their bellies, using a "hip cradle" to control pitch and yaw. A shove of the hips in one direction, and the wings turn. The technique particularly baffles trained pilots.

"They basically have to go against everything they've learned," says simulator publicist Rebecca Holmes. "It's really fun to watch people's expressions as they get off. They're like, 'How did anybody ever fly this thing?' "

On the other hand, kids ace the challenge. "They don't have any preconceived notions about how it's supposed to work," she says. "For them it's a game."

Many can beat the 12 seconds achieved by Orville Wright on that historic virgin flight, Holmes says; one guy with the Wright stuff lasted nearly two minutes.

While the simulators have attracted lines of people 30 deep, they've been equally popular with spectators, who gather to cheer on participants. "You'll hear this group laughter, or clapping, and you'll know that someone flying was able to pull off a few more seconds (in the air)," Dietrich says.

Two flights are planned for December's 100th-anniversary re-creation at Kitty Hawk, one at 10:35 a.m. — the time of the historic trip — and another at 2 p.m.

After its commemorative voyage, the reproduced Wright Flyer will retire to Greenfield Village, next to the Henry Ford Museum in Dearborn, Mich.

The reproduction will, in a way, fulfill a failed effort by Ford, a friend of the Wrights', to bring the original plane to Dearborn, where he'd persuaded the brothers to move their bicycle shop and boyhood home.

The original plane remains at the Smithsonian's National Air and Space Museum in Washington, D.C.