by Nik Shulz/L-Dopa: Photo by Nik Shulz/L-Dopa

Dept.:You built what?!
Tech.: World´s fastest human-powered vehicle
Time: 200 hours
Cost: $15,000
Practical | | | | | PopcornIn October 2005, a dozen or so bicyclists will haul butt down a flat two-lane state highway near Battle Mountain, Nevada, reaching speeds of more than 60 mph. That's no typo. It's par for the five-mile course at the sixth annual World Human Powered Speed Challenge.

The favorite to go the fastest is Sam Whittingham, a compact Canadian who set the world record-a staggering 81 mph-on a streamlined recumbent called the Varna Diablo II that he rides lying down like a man in a bathtub. His bike, like those raced by most of his rivals, is more DIY than R&D. Its creator, Bulgarian migr George Georgiev, trained as a sculptor, not an engineer, and it shows in the Diablo's deceptively simple design. Georgiev fashioned the body purely by intuition, although subsequent wind-tunnel tests confirmed its remarkable aerodynamic efficiency. He literally built the bike around his 5'7" rider, arranging components to minimize its size and, therefore, the hole it punches in the air.

Whittingham's record has stood since 2002, but Georgiev remains convinced that the Diablo's speed-ometer can be pushed one more notch to claim the $23,000 .deciMach Prize, offered by a committee of human-powered-vehicle enthusiasts for the first HPV to exceed one tenth the speed of sound (82 mph for this race). If not, G
eorgiev will build Whittingham a new fully enclosed bike, and they'll try again.