A Lofty Idyll : A new hobby is taking off over the Sepulveda Basin: flying remote-control model airplanes. Enthusiasts will get together on Sunday.

It’s a sunny spring morning at the Sepulveda Basin, and the model airplanes are flying, their tiny gasoline motors buzzing like mechanical hornets, powering the planes through climbs, dives, rolls and loops.

Restricted to a 200-foot ceiling, the airspace over the southeast corner of the basin is a narrow corridor of adventure for people whose passion is the growing sport of flying remote control models.

Although there are no figures on the number of remote control flyers in the country, the national membership of the Academy of Model Aeronautics, which sanctions local clubs and flying competitions, is 167,000 and growing.

Nearly all of the flyers are men, most of them well past middle age, many of them consumed by their miniature aircraft hobby.

“I’ve gotta write this check to you personally, not to the shop,” a gray-haired man says to Jay Replogle, proprietor of the Hobby House in Reseda. “I can’t have my wife see a check for another model plane.”

He already owns several model planes, which cost about $400 to $600 each, but he’s just seen another in the Hobby House that he must have. And he has to buy it on the sly, so his wife won’t know.

Replogle understands. He’s a remote control flyer himself, and he reserves two mornings a week for flight lessons at the Sepulveda Basin Model Airport.

The airport, part of the Los Angeles Department of Recreation and Parks, is home to the San Fernando Valley Flyers RC (remote control) Club, which has close to 300 members.

“The most important thing to do when you’re starting out,” says Replogle, “is to get an experienced flyer to help you. To try to learn on your own, you’ll probably destroy your aircraft in seconds--if you manage to get it off the ground.”

Replogle is a skilled flyer who enjoys the challenge of flying Giant Scale models--quarter-size replicas (with wingspans typically in the six- to eight-foot range) of Stearman biplanes, Pitts Special stunt planes, or World War I or World War II fighter planes.

A local get-together of Giant Scale remote control planes is scheduled for Sunday at the Sepulveda Model Airport, sponsored by the local Giant Scale Squadron.

“It takes a while to work your way up to flying them,” Replogle says. “You have to start out with the high-wing trainers that are designed for beginners.”

Matt Insley of Van Nuys loves building and flying the Giant Scale planes.

A model builder for seven years, Insley began flying two years ago. Now, he and his wife, Darlene, own 27 model planes.

“I love to build,” says Matt. “We have planes in every room of our house. Our project is to build a model B17--a four-engine World War II bomber--that will have a 10 1/2-foot wingspan. It’ll require two radios to operate, two pilots. One to fly it, the other to operate the bomb bays, the turrets, the landing gear.

“We want to get it right, down to the rivets,” says Darlene, who is learning to fly this year. “I’m trying very hard to learn,” she says. “It’s a lot easier to build than to fly them. But I want to be able to take a plane off and fly it.”

Dick Robinson, a tall, gray-haired, mustachioed man in his 50s, supports himself by building models for flyers who don’t have the time or the inclination to build their own, and flies as much as he can himself.

“If I don’t fly three or four times a month, I get hangar fever,” says Robinson, who lives in Westchester. “The large-scale planes I fly can go up in any weather, so, short of a hurricane or a tornado, I’m here.”

As Robinson speaks, a flyer is walking his plane to the takeoff strip, the small plane taxiing at walking speed, followed by its pilot-owner, who guides it like a man walking a mechanical dog. At the runway, he turns the model plane into the wind, gives it full power, zooms down the runway, and the plane lifts off.

The next takeoff attempt is less successful. Two men approach the flight line with a replica warplane--a twin-engine plane. A very, very difficult machine to fly by remote control.

“They’re gonna need a lot of luck to get that up in the air and keep it there,” Robinson says. The twin-engine fighter zooms impressively down the runway, lifts off, climbs sharply, then angles sideways, and abruptly crashes.

Robinson has experience in different aspects of remote control flying, which runs from recreational flying to stunt flying and competitive aerobatic flying and air racing, where cash prizes can run as high as $25,000.

“The planes for those levels of flying can run thousands of dollars,” says Robinson, “and there’s sponsorship involved.”

“I like the aerobatic planes,” says Robinson. “You’ve really gotta be on top of your game for that. You’ve really gotta fly the airplane. You really get intense on what you’re doing. And every now and then, a ground wave gets you.”

A ground wave means you crash.

“That’s one thing--crashing--that’s gonna happen to you plenty if you take up remote control flying,” says Replogle of Hobby House. “That’s why I prefer this over flying a real airplane, because these are crashes you can walk away from.”

Where and When What: San Fernando Valley Giant Scale Squadron Fly-In. Location: Sepulveda Basin Model Airport, off Woodley Avenue between Victory and Burbank boulevards. Hours: 9 a.m. Sunday. Price: Free for observers; $5 landing fee for flyers. Call: (818) 768-0855.