Up, up and not quite away.

That’s the frustrating story of human-powered helicopters and the prize coveted by virtually everyone who has designed the cumbersome beasts and tried to get them aloft.

So far, nobody has come up with a muscle-driven machine capable of hovering for 1 minute and rising 3 meters — requirements for the Igor I. Sikorsky Prize, an honor the helicopter industry has dangled before aeronautics buffs for 32 years. The prize has been offered so long that the booty, initially $10,000, became embarrassingly small. Now it’s $250,000 and still unclaimed.

Despite the skeptics, Neal Saiki, a 45-year-old Santa Cruz engineer, chases the Sikorsky dream, building unlikely craft that are part bicycle, part super-sized pinwheel.

“We’re so interested in bigger and faster, we’re so used to going to the moon or looking at stars that are light years away that this goes against the grain,” he says. “But it’s one of the last aviation frontiers.”

The Sikorsky has gnawed at him since 1989, when he led a team at Cal Poly San Luis Obispo that built the first muscle-driven chopper to get off the ground. But the 7.1-second flight, which soared all of 8 inches off the floor of a Cal Poly gym, wasn’t nearly enough to take home the prize.

Still, it was a heady day. Onlookers cheered as Greg McNeil, a fellow engineering student and bike racer, pedaled furiously. Saiki, grasping a safety rope at the end of a 100-foot rotor, urged him on, twirling his hand over his head and yelling, “Up! Up! Up!” Clad in a white dinner jacket and black bow tie, Saiki looked as if he had sauntered in on his way to the prom. “If you’re setting a world’s record,” he explained in an interview decades later, “you might as well look good.”

But Saiki still didn’t have the Sikorsky, and it bugged him. After graduating from Cal Poly with a master’s degree in aeronautical engineering, he worked for NASA but soon turned entrepreneurial. He invented a hanging cot for climbers and designed high-end mountain bikes — but the Sikorsky was always churning in his imagination, just out of reach.

For a while, he tried his hand at creating another entry for the Sikorsky sweepstakes. In 1994, five years after the DaVinci III lifted off oh so briefly, his ongoing dream went up in smoke: A forest fire swept through his workshop near San Luis Obispo, destroying the Penguin, another human-powered chopper he’d been building with high hopes.

A trim man with a passion for rock climbing and samurai swords, Saiki sold his house in 2006 to start Zero Motorcycles, a pioneering manufacturer of electric cycles in Santa Cruz. In a management shake-up last year, he left Zero, saying he wanted to spend more time with his four children ages 1 to 11. He also announced — unsurprisingly, to those who knew him — that he intended to build a human-powered helicopter.

“I’ve always wanted to go back and have another try at it,” Saiki said. “Now I’ve got the time, and I don’t have the day-to-day financial pressures.”

So far, Saiki has spent more than $100,000 to create the craft he calls the Upturn. He works in his garage, has ultra-lightweight parts fabricated all over the country and runs tests at a friend’s private hangar, far from prying eyes. This summer, he hopes to make his bid in front of witnesses appointed by the American Helicopter Society International, the prize’s sponsor.

“We want to make sure we can win it before we do that,” Saiki said. “It’s a very large, very fragile aircraft and a million things can go wrong.”

A human-powered helicopter has no known use. According to conventional scientific wisdom, it would have to weigh less than a couple of checked bags but span a good-sized barn. Some experts doubt that such a craft can fly for a full minute, even with muscle power provided by an elite cyclist.

The fundamental challenge is daunting. Airplanes accelerate gradually, essentially lifting skyward on a ramp of air. Helicopters, however, shoot straight up — a feat that requires a jolt of energy so big that it is beyond the capability of most in-shape pedalers.

“Humans can only deliver so much,” said Matt Tarascio, a helicopter engineer who coordinates the contest and works for its chief funder, Sikorsky Aircraft Corp. “In industry, we’d just put in a bigger engine.”

Then there’s the problem of weight. To get off the ground, a helicopter must churn an immense volume of air. To do that with the measly power provided by a human, the chopper’s rotors must make up for their lack of speed with huge dimensions. But those big rotors — sometimes longer than the Wright brothers’ first flight of 120 feet — can be exceedingly floppy, and stiffening them adds more weight.

“Just getting off the ground is a significant achievement,” Tarascio said.

As time draws closer for Saiki’s shot at the prize, he’s raising money to remake key parts and shave 15 pounds off his craft. Every few weeks, he trucks it to the hangar in 17 pieces and, with a small crew, takes as long as six hours to assemble it. They grapple with high-tech puzzles of vibration and instability but also contend with low-tech problems, like looping a rope for a safety harness over a girder six stories off the ground. After trying a bow and arrow, Saiki managed it with a fishing rod.

Over the years, there have been about 20 attempts at the Sikorsky. The rules are strict: no batteries, no lighter-than-air gases, no parts jettisoned from midair, no drugs to amp up the pilot, no wind. Ground-based crew members may touch the craft to help keep it stable at takeoff and landing, but not during flight. It must hover over a 10-meter-by-10 meter square, an area roughly the size of eight compact parking spaces.

Besides Cal Poly’s DaVinci III, only two of the elaborate gizmos have lifted off. In 1994, students at Nihon University in Japan flew their Yuri I for 19.46 seconds, rising to 8 inches. Last May, the University of Maryland‘s Gamera, named for the huge, fire-breathing turtle of Japanese monster films, cleared the floor for 11.4 seconds.

In Santa Cruz, Saiki and his crew have run a few test flights at a local high school gym, barely large enough to accommodate the Upturn’s two delicate foam rotors. At one point, the 90-pound craft’s balsa wood seat flew off its titanium-and-carbon fiber frame like a piece of cheap scenery, dumping Greg McNeil, the bike racer who piloted the DaVinci III 23 years ago.

“It looked like we’d come off the ground, and once that happens there are all these funky loads pulling on the cables,” said the 44-year-old McNeil, who could be Saiki’s pilot once again. “Any weak points in the craft get stressed.”

McNeil said he’s just 3 or 4 pounds heavier than the 135 he weighed in college. He and some other Cal Poly pals, all engineers, are assisting Saiki, who is in touch with his former mentor, a now-retired Cal Poly engineering professor named William Patterson.

Patterson, a Vietnam War helicopter pilot who was shot down in Laos, was the driving force behind Cal Poly’s entry in the Sikorsky contest.

“My students figured it was something they could build in a couple of days,” he said.

It took eight years.

steve.chawkins@latimes.com