WAUKEGAN, Ill. – On any other weeknight, Teresa Hansen and her staff at The Field House Sports & Fitness Center clear out the building at 9 p.m., turn off the lights and lock up the shop.

But on Friday nights during this ongoing winter, the six courts in the 40,000-square-foot gymnasium have found a late-night tenant: The members of the Lake County Radio Control Club and their flying machines.

“I look forward to getting the basketball guys off the floor so I can watch them,” said Hansen on a recent Friday night, as a small squadron of plastic or wire or Styrofoam aircraft hummed above her head.

“The first week, there were like 10 guys here, and it’s grown by word-of-mouth,” she added. “You get young guys, older guys, kids who come to watch … My son started out watching them (because) he has aspirations to be a pilot, and now he’s flying with them.”

According to club president Dave Taylor, who collects $10 a session from any Academy of Model Aeronautics member as they come in from the cold, the Field House bridges a giant gap between fall and spring for hobbyists who normally practice their craft in the Van Patten Woods Forest Preserve.

“This is designed for us to not go stir crazy during the winter,” he said, “and it keeps our fingers limber for the outdoor season.”

The club dates back to 1973, when a handful of local “RC” buffs gathered on private property on Kilbourne Road near Wadsworth. Steve Yeaton of Lindenhurst, who joined that first year, recalled that “when we started, there were around 15 members, and we had a limit of 25 because we didn’t want (the field) to get too crowded.”

The models seen inside the Field House – including airplanes, helicopters and at least one Starship Enterprise – bear little resemblance to what is seen during the warmer months. Outdoor models can have 100cc gas engines, 100-inch wingspans and weigh 20 to 25 pounds. Taylor said Waukegan Park District officials needed to be assured that nothing that heavy-duty would be involved.

“I was just driving by here one night, and it looked big enough to do what we wanted to do,” the Beach Park resident said. “So I came inside and talked to them, and the main thing they wanted to know was if it was going to cause damage to the floor.”

Fortunately for the club, indoor models use battery-operated engines and can weigh barely more than your basic paper airplane. Jayson Sovsky of Antioch, who heads the Chain O’ Lakes Eagles RC club, said the indoor craft aren’t known for their power.

“It can go as slow as you can walk, or as fast as you can run. And it can go as far and as high as you can see,” said Sovsky, though he added that the Field House roof has its limiting factors, from girders to basketball hoops to volleyball nets.

Jim Spice of Beach Park agreed. “The soccer nets are the biggest challenge. We usually end up with one up there a night,” he said, testing out a SIG 1909 Demoiselle, which weighs about 10 ounces. “And you have to watch out for the air vents. You go under that and it’s like a tornado coming down.”