THE PTEROXYLES look as though they love their work. Flying is, after all, work.

Here's one whose bony elbows are crooked, sinews taut, wrestling with the air. Another has just taken off, liberating itself from the ground, its fluid curves singing in the moment of release.

Pteroxyle means winged wood, and these sculptures by Thach Nguyen in a high-quality July show at the Art Barn are literally winged, with gossamer webs of stretched silk. But they are not simply wings, they are complex organic figures that get across the reality of flight, not just the dream. Athletic effort shows in the tensed limbs of elegantly laminated walnut and oak.

"I'm trying to give the impression of being in tension," Thach said, "like the tension at the moment of takeoff. You see these thin cables here, and the silk itself, everything is in tension. Also, the whole thing is cantilevered from the base as if it were perched there, and the base is an angular tube of steel to express the physical constraint that is being overcome."

The figures are pared down to a minimum of struts and tendons, suggesting, evoking, rather than stating.

Thach, 25, has dreamed of flying as long as he can remember. His father is an aeronautical engineer for Pan Am, who brought his family here from Vietnam seven years ago.

"I made kites when I was a kid, of course. Rice paper and bamboo. Now I design model gliders. I also play around with radio-controlled models."

He planned to make some stretched-silk kites for children at the Art Barn, which is having classes and demonstrations in Rock Creek Park every weekend this month as part of the show. There will be calligraphy, stone carving, woodblock and potato printing, painting and photo manipulation for both children and adults.

Thach, educated in a French lyce'e in Saigon, studied printmaking at Northern Virginia Community College before entering George Washington University. He is now a year away from his MFA degree. A university fellow, he helps beginning sculpture students there.

"When I was doing graphics I used to get impatient with the illusions of the two dimensions, though I made the drawings as realistic as I could. I discovered sculpture when my father was stationed in Zaire for a year. This work is a new phase for me; I've been doing wings for about three years. Before that, I would draw structures."

His earlier sculptures can be seen at the Dimock Gallery. They are smaller. He worries about his work getting so big that he loses control over it. In fact, control is the message in these lean, sinuous pieces. They are not about the fantasy of flight, but about the reality, the effort, the sweat that goes into any creation of beauty from a swan dive to an aria.

Nine other young area artists are featured in this show of "Directions in Surface Design." Many of them are graduate students at local universities.