More than 30 stunt pilots will perform extreme aeronautical maneuvers Saturday, Aug. 23 - all without leaving the ground.

Instead, these members of the Chattanooga Radio Control Club will send their large-scale aerobatic models through the skies on high-flying tricks that outshine what can be seen at a full-scale air show or the Red Bull racing events, says spokesman Paul J. Wright. They call it a 3-D Jam, "3-D" a reference to maneuvers beyond basic rolls and loops.

Now in its 13th outing, the event has become a perennial favorite for spectators. Wright believes one reason for its popularity, beyond the gravity-defying stunts, is the size of the models at play. In layman's terms, these are "really, really BIG airplanes," he says, most with wingspans exceeding 10 feet.

The most common aircraft replicated for 3-D flying are the Edge 540, Extra 300, Cap 232 and the Russian aerobats built by Yak and Sukhoi. These aircraft, ranging from 35 percent to 45 percent of their full-scale counterparts, take advantage of space-age composite materials to create high-strength but low-weight air frames, Wright explains. When coupled with large, lightweight engines designed and built exclusively for this type of model, their power may be as much as twice their weight.

"This is key to flying 3-D maneuvers, in which the aircraft is performing extreme aerobatic maneuvers while the plane is actually in a stalled condition," he says. "It would fall out of the sky but for the powerful engine and the skill of an experienced pilot. The art of flying 3-D is using this seemingly disastrous situation to make an airplane do stunts that it otherwise could not do."

Pilots will fly a continuous display of 3-D aerobatics during the Jam. Concessions will be available, and several hundred dollars worth of hobby goods will be offered as door prizes. Seating is limited, so spectators may wish to bring their own folding chairs.