They are out there somewhere now on that blue limitless prairie, these two would-be Lindberghs in a balloon, commending themselves to God and the wind. If all goes even reasonably as planned, two Colorado businessmen, Dewey Reinhard, 47, and Steve Stephenson, 44, will hit the good green earth of mother England sometimes this weekend, probably Sunday, after having confined them-selves for the better part of a week in a 7-by-15-foot basket suspended from a bag of helium. It doesn't make sense, but then the dreams of heroes and fools seldom do.

The two daredevils lifted off in "The Eagle" yesterday at 5:35 p.m., in a crush of huzzahs from comrades and family and the collected citizenry of Bar Harbor, pop, 3,800. Their launch site, not quite a Cape Canaveral, was a dewy meadow at the foot of serene Frenchman's Bay. The place is rung with fiery oaks and maples.

Norman Mailer wasn't there chronicling the vent for the ages, as he was for Apollo 11, though one did see the town constable and any number of old "Mainers" in thermal hunting jackets, baseball caps, and Mr. L.L. Bean's famous Maine Hunting Shoe. Somehow it all seemed in keeping with the art of ballooning, which is about two parts art and good faith, and about 98 parts blind stupid luck.

Depending on how you count, this is history's either 14th or 15th attempt across the Atlantic by free balloon. The recorded tries run the gamut - from pioneer aeronaut Thaddeus Lowe's attempt in 1859 (in a monstrous 200-foot-high affair appropriately named the City of New York) to millionaire Malcolm Forbes' aborted effort in 1975 (in a Dube Coldberal [WORD ILLEGIBLE] contraption of 13 individually filled ballonons).

Non one has even made it all the way though a year ago last week someone almost did. His name was Ed Yost and he got as far as 200 miles east of the Azores. That's where a German freighter found him floating in his gondola-turned-catamaran. He was seriously dehydrated, but he had set a distance record. He had been aloft 4 1/2 days.

Sometimes there is a thin, watery line between heroes and fools, between daredevils and the lunatic fringe. So a "single lonely boy," as his biographer called him, flying the mails between St. Louis and Chicago one night half a century ago, watching Peoria blink awake beneath him, feeling the rush of cold black air against his face and flying suit, has a sudden, wild, intoxicating thought. Listen:

New York to Paris - it sounds like a dream. And yet - if one could carry fuel enough . . . if the engine didn't stop . . . if one just held to the right course . . . The very thought makes me rise to contend again with the moon - sweeping over oceans and continents, looking down on farms and cities, letting the planet turn below.

- From "The Spirit of St. Louis"

The man, of course, is mad, a hopeless dreamer. Except that history thinks otherwise. Charles Lindbergh is the Lone Eagle. America's greatest hero, keeper of her boldest, most shining feat. Feat, mind you, not stunt. Stunts are performed by people trying to get into Ripley's Believe It or Not. (MAN FITS WATERMELON, LENGHWISE. IN MOUTH, LIVES TO TELL. (No, this is no stunt, this is an achievement, something to stir the soul.

Except what is the difference, finally, between a scared 25-year-old boring through dark and unknown skies across an uncharted ocean and say, someone who decides to jump off a New York City skyscrapper into a child's 12 1/2-inch wading pool - thereby [WORD ILLEGIBLE] paragraph in the [WORD ILLEGIBLE] of World [WORD ILLEGIBLE] between Lindbergh and someone who [WORD ILLEGIBLE] In 1974 [WORD ILLEGIBLE] the two towers of the World Trade Center in Lower Manhattan and cavorts on it for 30 minutes before calling it a day?

If Lindbergh is a hero, must Phillipe Petit be a fool?

Heroes and fools. The line blurs in this American cycles from Harry Houdini in 1902 to Evel Knievel in 1974, holding up a $6-million check and saying, "The greatest competitor in life is death," to a fellow named Dan Cameron Redhill in 1977, woebegone playwright leaping from the Brooklyn Bridge.

The jump was Rodill's final desperate ploy to gain attention for his unproduced work. In the process he nearly killed himself. When the police fished him out, all his ribs were broken and his lung was collapsed. But maybe it was worth it, because now Dan Cameron Rodill reports that at least three theaters around the country are interested in his play. That's not so unusual given the way Americans follow and even sometimes imitate the exploits of their daredevils. It gives us the rush of unreason, the fix of adventure, some of us need in an increasingly tame world.

"Abruptly, across America," wrote Lindbergh biographer Kenneth A. Davis, "it was as if 100 million minds had become one mind dominated by one emotion - and that almost a religious one. It focused on a single lonely boy . . . in a kind of passionate hope and yearning."

So where are 1977's passionate hopes and yearnings? With two balloonists named Reinhard and Stephenson, one supposes, who have spent the last 14 or so hours, while we were fast in our beds, tossing on the winds of heaven.

And where are they now? Well, the trajectory at takeoff last night was to proceed Northeast crossing the neck of Nova Scotia sometime between 8 and 10 a.m. this morning, then on toward Newfoundland, the last sight of land till who knows when.

It's anybody's guess how far these two sky sailors will soar, of course, but they launched yesterday with probably the most sophisticated balloon ever built. It was packed to the gunwales with marine radios, aircraft radios, emergency locator transmitters, a broadcast receiver, compasses, maps, barographs flares, survival suits - even a 30.30 rifle. There is a fishing kit on board, candles, a ladder, champagne, and food for 30 days.

But for all their gear, the aeronauts seem an unlikely pair. Reinhard is an amateur pilot and appliance-repair tycoon (shops in Colorado Springs and Albuquerque) who got into hot-air ballooning four years ago. He has never flown over water and he has almost zero experience in helium craft. It doesn't matter says the self-possessed adventurer. "Thermal conditions over land are trickier anyway."

Stephenson/ He's a crack pilo all right with 24 years of flight n his logbook. Only thing, he's never piloted a balloon in his life, and has only been in one a couple of times. That doesn't matter either, says Reinhard Stephenson's along for his navigation skills.

Then why are these innocents going abroad? "Well, I guess it's because I'm egotistical enough to want to get in on aviation history," said Reinhard. "When you think about it, it's one of the last challenges left."

"See the thing that interests me." said Bill Snider, a documentary film-maker and close friend of Reinhard's the other day, as the tension began to hover over Bar Harbor, "is that you've got all this advanced tech equipment - even a beacon for satellite tracking to the Goddard Space Center - hand-in-hand with, well, the idea that these guys don't really have a bloody chance, that it's all just one big shot in the dark."

There have been other shots in the dark.

Consider George Willig, the "human fly." Willig, once obscure toy designer from Queens, is the man who last May gained a measure of immortality when he walked to the north-east base of the World Trade Center, unpacked some specially-rigged mountaineering equipment, and proceeded for the next three hours to scale the shear aluminium face of the world's tallest building.

And what happens then? Well, the next day the mayor of New York calls a press conference to congratulate George Willig "for a courageous act." Never mind that immediately after his climb. Willig is slapped with a $250,000-lawsuit by the city and charged with disorderly conduct, reckless endangerment, criminal trespass and - best of all - climbing a building without a permit.

The disposition, of course, is that the suit is dropped with Willig agreeing to a $1.10-fine - a penny for each story climbed.

In the days after his stunt (feat?), George Willig becomes a "folk hero," the rosiest media apple of the Big Apple's eye. There is talk of a movie, commercial endorsements, maybe a Human Fly toy from the Ideal Toy Corp., where Willig works.

All of that was this past summer. Now, in the autumn of his gathering discontent. George Willig wonders why there should have been such national to-do over him in the first place. To try and sort it out, he has taken a leave from Ideal Toy. He has turned down offers to do commercials (liquor, cigarettes), and though he won't readily admit to it. Willig's father volunteers that his son is "pretty desperate for money right now."

"I just did it for the experience." Willig said on the phone the other afternoon, quietly reflective. "You see, the goal was in the act, not necessarily in the achievement. It didn't matter that there were thousands down there cheering me on. It's sort of like being alive - it's the day-to-day part that's as important as reaching summits - you know? Besides, you can't hold on to the top forever. It's been four months."

George Willig and Phillipe Petit aren't the only latterday daredevils who have had a mystical moment with New York's World Trade Center. On July 22, 1975 at 4 o'clock in the afternoon, a dockworker from Long Island, a man who had helped lay the foundation for the building, faked his way past security guards to the roof, pulled out a parachute, said a prayer, gave himself shove, and went sailing out over New York City in what might have been the world's most starting sky dive.

"For the first half of the ride," says Owen Quinn, 36 who sounds entirely sane, "people on each floor must have thought I was a suicide. All they saw was this body hurtling past their window. And then when I pulled the chute and began floating down, like a feather riding the wind. I kept getting these even weirder looks from each floor. I mean, it's not something you expect to see every day. I landed right where King Kong landed in the remake of the movie. The only difference was, I made it."

But why did he do it? "I've thought about that a lot," he says. "Superficially I guess I'm attracted to it because it's fun. But you can't ever remove the element of danger, having to deal with certain fears inside you. Also, I wanted to draw attention to the problem of starving kids around the world. I used the publicity as a forum.

And then Owen Quinn says a funny thing: "You know. I was reading this column by Dr. Joyce Brothers. She said people who do this stuff are people who are always moving around, always on the go. Well, that's me. And you know what else? I think there's some kind of kinship, something spiritual, between us all - all of us daredevils. I mean, that little Frenchman, Phillipe Petit, I really love what he did, balancing on a wire like that. It was a magic thing. And that George Willig, he had his bug in him. I could just feel something the morning he made his climb. Yep. I think we're all on the same vibration . . ."

It isn't known whether Dewey Reinhard and Steve Stephenson feel the vibrations just now of family and fellow daredevils. Home must seem very far away. Last week, Reinhard's oldest son speculated on what his feelings might be once his father got under way. Steve Reinhard is a bulky, sad-faced 20-year-old.

"See, nobody in the family wanted him to do it - but then he didn't ask anybody either. Once we saw he had his mind made up, we had no choice but to dig in and help. I have his living presence with me now, and even if I never see him again. I'll be able to remember. I hope, what he always stood for, which has something to do with courage, but mostly with adventure."

And then maybe, just maybe, there is a small, significant clue in the gold medal Reinhard is wearing around his neck, a gift from his wife, Jeanie. The medal's inscription reads: "If I ride the morning winds to the furthest ocean, even there your hand will guide me, your strength will support me."