"I never grew up," says Ed Headrick, 52, a Costa Mesa, Calif. engineer with nine patents, the latest of which is a game called "Disc Golf." It is played on a 9- or 18-hole course with a Frisbee.

Headrick worked for 13 years at Wham-O and helped to perfect the ubiquitous Frisbee by suggesting the grooves that make it sail better. He is still a consultant to the company, and his business card is a miniature Frisbee. "We develop toys we like as adults," he says, "and, grudgingly, we let children play with them."

Headrick will lay out an 18-hole course, which requires at least seven acres, and provide the metal baskets for $6,000. For playgrounds or backyards, a $250 scaled-down version (one hole with nine tees) is available. Disc Golf rules are similar to those of regular golf.

Headrick, who is separated and has four grown children, now devotes full time to Disc Golf. (He's at right with his oldest son and business partner, Ken, 26.) Three free courses in Southern California are drawing thousands of players each week. "We find there is very little vandalism," he says, "because potential vandals seem to relate to the game." Twenty more layouts are being installed nationwide. And on Memorial Day the first World Disc Golf Championship (with a $1,500 purse) will be played in Newfoundland, N.J.

"If it's 2 a.m. and I sit bolt upright in bed," says Dick Reed, 42, of Phoenix, Ariz., "my wife knows I've thought up something new." His newest something, Camp-A-Float, is for the outdoorsman who has ever dreamed of turning his camper into a houseboat.

A raft-like structure with twin steel pontoons, the Camp-A-Float carries vehicles up to 31 feet long, weighing as much as 10,000 pounds. It can cruise at 12 miles an hour and has a self-contained waste disposal unit as well as a separate fresh water system. "It's virtually unsinkable," claims Reed, whose company, CAF Inc., rents the five-ton floats for $40-a-day at Lake Ouachita in Arkansas, Lake Hartwell in Georgia and Lake Havasu in Arizona.

Reed is an inventor by heredity. His father Ray holds some 100 patents, including one for the Toni home permanent. "Dad taught me perserverance," says Reed, who holds an electrical engineering degree from the University of Illinois. "I had the idea for Camp-A-Float rattling around in my head for years. After all, why camp near the water when you can camp on it?"

Jack Hutchinson, 24, built his first hang-glider in 1971, the year after he got out of high school in Orlando, Fla. Two years ago he added a motor. "It lets you take off from anywhere and go where you want," he says, "and in case you start to lose altitude, you can just start the motor" (with a kick pedal).

Hutchinson (right, with his helmeted partner, Gregg Bryant, 23) is now selling motorized models from $1,450 to $1,850. One, with a 30-foot wingspan, accommodates a 150-pound passenger, while the 32-foot model can carry 200 pounds. (It is seen at right above with Bryant at the controls.) Both are made of Dacron stretched over an aluminum frame and powered by a two-cycle Chrysler go-kart motor.

A flying buff even in childhood, Hutchinson won the 1965 Florida science fair with a design for achieving weightlessness on a monorail. He put in a couple of years at a Georgia military college, earned a pilot's license and worked for the Orlando Fire Department until last year. In his spare time, he flew delta-wing hang-gliders in the Walt Disney World water show.

"It's the ultimate in flight," Hutchinson says of hang-gliding. "You're completely free from the bonds of earth."