At the height of the fall hawk migration, I'm soaring like a raptor in a 40-year-old sailplane, silently corkscrewing through the sky 4,000 feet above the Sunset Highway just west of North Plains.

There's no throbbing engine to shout over--no noise at all, really, other than the wind whistling through a broken seal in the plexiglass canopy. Laird Smith, a retired high-school biology teacher and flight instructor, is at the controls, wearing a floppy fishing hat, scanning the horizon through thick eyeglasses. He's just cut us loose from our tow plane, and now he's trolling for thermals. I can tell he's not having much luck: The variometer, the dial that indicates lift, keeps going negative.

The view, though stunning, isn't very promising, either. Above and all around, there's nothing but seamless cobalt blue. No stratocumulus, the puffy white clouds that crown thermals, pistons of rising hot air we desperately need to find if we're going to stay aloft much longer.

"This is a mountaintop experience," says Smith, as one volcanic peak after another appears then disappears on the twisting horizon. "When a person climbs to the top of a mountain and looks down, there's an exhilaration, a euphoric high. Here we are on a mountain of air looking down on the patterns of fields, on people in their homes, in their cars, with things laid out like a map. It's an entirely different world up here. We see things that most people never see."

Like, for instance, the eyes of a bloodthirsty hawk when he's diving at your canopy in full cry, talons bared, ready to fight because he thinks you're a bird invading his airspace. Or the summit of Mount Hood filling your entire field of vision, moments before you leap right over it, riding "the wave," a vortex of air that sucks you up--from 11,000 feet to 29,000 feet--and pulls you over in a matter of seconds.

Suddenly, the old glider shudders. The variometer needle jumps, and my stomach falls. We've hopped aboard a thermal rising directly out of the crotch of the Sunset and Highway 30. "This is exactly what raptors do," says Smith. "Nobody knows how they find thermal columns, if they can sense the difference in air pressure, or feel the bounce like we just did." The plane shudders again. "Unfortunately, that was an 'out' bounce." The variometer confirms that we are no longer riding a thermal. Again, we spiral down, this time for good.

Our flight ends at the North Plains Gliderport. Gary Boggs, another pilot, sits at a picnic table with a radio.

He's pointing at a redtail. It's hovering, suspended on a column of air, directly above our heads.

The Willamette Valley Soaring Club offers sailplane rides at the North Plains Gliderport (on the north side of Highway 26, at Dersham Road) from 10 am until dusk every Wednesday, Saturday and Sunday, weather permitting. After Halloween, the club moves to the Hood River Airport. Longer drive, sweeter soar. Rides start at $59, , 241-9237.

An "out" bounce is the turbulence a sailplane encounters as it exits a thermal.