A Chatham man makes them in 150 different designs. They all return.

CHATHAM — "If you can eat Jello with a spoon, you can throw one of these things," says Chatham's JohnCryderman.

These "things" are boomerangs. And Cryderman, crafter of hundreds of the wooden aircraft, can obviously eat Jcllo with a spoon.

He demonstrates the art of the throw: Grasp one end of the boomerang with thumb and forefinger, as if holding a pen. Then toss it overhand, from your shoulder, like a football quarterback.

Sure enough, it sails and spins and twirls, then hooks left and sails and spins and twirls some more as it returns to sender.

Of course it returns. It always returns.

KIDS ABOUND: Some days. entire platoons of kids encircle Cryderman on this field and compete for distance and time aloft and accuracy. "Doesn't matter what age the kid is, if they can talk, they know what a boomerang is," says Cryderman, whose full-time job is organizing craft and trade shows across the country. It's a hobby — an obsession, maybe — that began in earnest in 1984. "Curiosity through the years got the best of me and I just had to understand what made these funny sticks go out and come back to you," he says, almost apologetically.

His workshop includes 150-individual designs (both left-handed and right-handed) with names such as the Galaxie Probe Tri-blader, Omega Sunrise and the Incredible Hammer Hook. Some are designed for distance, others for flight time. He sells them for between $25 and $400 each.

Oh, he could go on about the seminars he has run, about his attempt to bring a world boomerang championship to Kent County.

He could show you books about the boomerangs found in King Tut's tomb in Egypt, and explain how they were used for recreation in Australia, not for hunting. He could talk about the pair of gold-and-silver inlaid boomerangs he made for Prince Charles a couple of years ago.

But all these he skips over lightly, as one of his creations dances on a breeze — his real passion is designing and tuning boomerangs, making them do what careful planning has intended them to do.

WOOD STRIPS: Each is made of eight or nine strips of wood (ash. walnut. cherry, tulip trees) that have been carefully cut, dried, formed, dried again, glued, clamped, cut again, con toured, sanded and laminated. That all can take more than a month.

Then its wings are "twist-tuned" with steam to ensure optimal balance, optimal lift, optimal flight.

If you buy a boomerang somewhere and it doesn't come back, it's probably not tuned properly, he says.

Or maybe it's too heavy: "In order for a boomerang to boomerang, it has to be light enough."

So if Cryderman speaks as a pilot might — with talk of aerodynamics. fuselage and fluid mechanics - - it's be- cause he has come to see these creations as aircraft in their own right. He long ago solved the mystery of how boomerangs work. But, in the end. all the physics principles that propel the craft become secondary to the sheer marvel of it all.

You can see it in his face as he wings another boomerang across a broad expanse of field and watches it return, gently and unerringly, to its source.

At Air Cryderman. you see. the flight's the thing.