The Flight of the Bird Men

The basics were easy: Put a double layer of parachute material between each arm and the torso, and between the legs. Give each wing a vent—in the armpits and in the groin—so that it can fill with air. Design the wings so that when they become rigid with air, they assume the classic wing profile, a shape that creates lift by redirecting the flow of air downward as it passes over the wing.




A critical determination was the angle the wing made between the torso and the arm. The larger that angle—the higher the arms can extend—the more the birdman's surface area increases and the greater the lift. At the same time, though, the larger the wing, the more strength needed to control it. At a certain point, it will get too large and overpower him in flight. Over the course of several generations of suits, Kuosma and Pecnik ultimately settled on an angle of 78 degrees for the arm wings (the arms are slightly lower than straight out to the side), and 35 degrees for the legs.




With no hard stays in the suit, Kuosma says, "everything you need to do to save your life, you can do with the wings on." A jumper can reach his main chute at the small of his back as well as the reserve chute handle on his chest. But if history taught one lesson, it was the importance of shedding the wings immediately in an emergency. So they designed two wing-cutaway systems. The first is a zipper that runs the length of each arm and frees it from the wing. During normal operations, skyfliers undo these zippers after they've pulled the parachute so they can reach overhead and steer with their toggles.




As a backup, Pecnik designed a novel secondary cutaway that works faster than a zipper. Interdigitated loops of strong nylon, alternately connected to the suit body and the wing, attach the wings to the torso. Running through those loops is a yellow cord, which ends in a small pillow on the side of the thigh. By yanking that pillow, the skyflier pulls out the cord and detaches the wing from the suit's body. "This system was the revolution that allowed us to market the wing suit," Kuosma says. "Because no matter what happens, you can cut away the wings and become just a regular jumper."




Of course, that's an assurance born of 1,300 wingsuit flights. On his very first flight in January 1999, Kuosma wasn't so confident. After five months of planning, drawing and sewing, Pecnik brought prototypes to DeLand, one for himself, one for Kuosma and one for Kuosma's then-girlfriend, a member of the Norwegian national skydiving team. Their mission: to test-pilot their own bodies from 13,500 feet.




What are your thoughts as the Twin Otter gains altitude and you're about to leap out wearing the sort of suit that has killed almost all of your predecessors? You wish you could test it somewhere safe. Vertical wind tunnels do exist, but they're only a few yards across; a birdman will bang into the walls. You have no choice but to test it from a plane—the higher the better because you'll have more time to react if something goes wrong. "I thought of the history," Kuosma says. "Of how Patrick—the god of this sport with 14,000 jumps—had died doing it. You're stepping into the complete unknown. You have to commit everything you ever knew or cared for. I gave myself a 50-50 chance."