Soaring pterosaur

With a mechanical brain, a pterosaur replica soars

February 10, 2012 at 12:15 pm

May 4, 1985 | Vol. 127 | No. 18

Soaring pterosaur!

Next spring, for the first time in more than 65 million years, the flapping shadow of a giant prehistoric flying reptile will be cast on the ground. No, scientists have not cloned the genes of the pterosaur Quetzalcoatlus northropi. Instead, the Smithsonian’s Air and Space Museum in Washington, D.C., has secured funding to build a full-scale, radio-controlled flying replica of the largest animal ever to fly.

According to the plans, the replica, with about a 36-foot wingspan, will fly realistically, propelling itself by wing flapping. It will be built by AeroVironment, Inc., of Monrovia, Calif., an innovative-aircraft design company. AeroVironment is directed by Paul MacCready, who has developed such human-powered aircraft as the Gossamer Condor and the Gossamer Albatross, which flew across the English Channel, and the solar-powered Gossamer Penguin and Solar Challenger (SN: 6/14/80, p. 373). The major funding for the $400,000 pterosaur project will come from Johnson Wax of Racine, Wis. The museum plans to fly the replica in Washington, beginning in spring 1986, to call attention to a new film about flight. The museum says it “hopes the project will make a significant contribution to the fields of aerodynamics and paleontology.”

UPDATE | February 25, 2012

Flight lessons from extinct flapper

A Quetzalcoatlus model soars above its builder Paul MacCready (left) and Tray MacCready in 1999 at the Museum of Flying in Santa Monica, Calif.

Think of a great blue heron with a 40-foot wingspan, and you’ll get an idea of what Quetzalcoatlus northropi was like 65 million years ago, says evolutionary biologist Kevin Padian of the University of California, Berkeley. Now think of the front half of a Cessna 172 trying to stay aloft by flapping its wings, and you’ll realize the enormous challenge undertaken by Paul MacCready when he decided to construct a life-size, flying, radio-controlled replica of the pterosaur.

From the beginning, one of the biggest engineering puzzles was how to stabilize the model: Quetzalcoatlus lacked the tail and rudder that typical flying machines use to control pitch and yaw. Keeping the version true to life required some extra thought, but it also offered a powerful insight into the evolution of flight.

“Through time, flying things have become less stable and more maneuverable,” Padian says. Quetzalcoatlus and its peers sacrificed the tails donned by earlier pterosaurs to make way for faster, more flexible flight. This evolutionary change meant the brain had to become more sophisticated to take on the stability task. Likewise, the Quetzalcoatlus replica had a special autopilot to serve as a “brain,” controlling the head to maintain stability.

“The problems the engineers went through were, I think, simulating the challenges that animals go through when they evolve flight,” Padian says.

In the end, MacCready settled on a half-size pterosaur replica. The model successfully flew during filming, but the project ended with a crash at Andrews Air Force Base in May 1986. —Elizabeth Quill

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