The Arabs have announced the price of their oil will be up 14 1/2 percent before the year ends. Car manufacturers are building smaller and lighter.

In the Department of Energy lies the nation's emergency standby gasoline rationing program, shrouded in dread and fear.

And what is American buying?

Not tents and not backpacks. Americans aren't going wild over bowling balls or tennis togs. They aren't burning up their paychecks on jogging shoes and they aren't standing in line to buy sailboats.

American is buying RVs. That's recreational vehicles, sports fans, the highway gas-gulpers that carry campers to a rustic destination, then couch them in nylon-pile luxury for the duration of the stay.

RVs are supposed to be dead. Five years ago the bottom fell out of the industry with the oil-producing nations cutting off the tap. Recreational vehicle production dropped from 528,800 units that year to less than 300,000 in 1974.

Winnebago, whose name was almost synonymous with motor home, had to close its factory.

Good riddance, said a lot of outdoors people who had pitched their tents in some leafy glade. only to wake up next morning to the clatter of an RV generator and the chatter of the TV on the pad next door.

The hiatus didn't last. RVs are back where they left off, with production of 526,300 last year.

That year Americans spent about $16 billion on recreational pursuits, including everything from boats and fishing rods to basketballs, bicycles, golf clubs, scuba tanks, backpacks and tents.

According to the Natonal Sporting Goods Association, which keeps tabs, more than $4 billion, one-quarter of that amount, was spent on RVs. "It's the biggest single chunk of recreational money spent on any one category, by far," said Robert Goodwin, NSGA assistnat executive director.

The RVs are in Washington this week, hundreds of them crammed nose to tail across the width and breadth of two floors of the D.C. Armory at the 14th annual RV show.

The people file in daily, paying $3.75 apiece to hear the sales pitches and cruise through exhibit after exhibit of shag-rugged, stereo-equipped, porta-pottied homes away from home.

What motivates modern American man to covet a cumbersome vehicle. that is unlikely to get more than 6 or 8 miles to a gallon of gasoline in these troubled times?

Louis Mitchell, an RV salesman for Holly Acre in Woodbridge, says "big motor homes" are for people who don't know what to do with their money. You look see them sitting there. People can't afford to drive them.

"I think the man, when he looks at it, he wants to drive it -- like a fire truck. It's big and powerful. He wants a toy. You know. You went through it too."

It behooves Mitchell to be blunt because he sells truck campers and trailers, which compete directly with the big motor homes.

Impartial observers are more evenhanded. Anderson Flues, who publishes an annual camping guide from his home in McLean, thinks RVs can provide real savings to families on vacation.

"Take a family of six and try to stay at motels and eat in restaurants for a vacation and see what you get," he said. "The same family can spend $15,000 on a minimotorhome and stay in campgrounds for $5 or $8 a night. They'll save money and get more enjoyment out of it."

Flues recognizes that the 35-foot, four-ton monster RVs can't last forever. "Amercians traditionally have felt that if you don't like it here, put it on wheels and move it down the highway. But that's going to have to change."

Flues and others have found a happy compromise in "minis" -- motor homes built on the chassis of a van, but expanded to sleep five or six in modest luxury.

Flues has a mini and he claims he can use it as a second car when he isn't camping, and that it gets up to 13 miles per gallon of gas on the highway.

Minis are grabbing a bigger share of the motor home market. Production jumped from 76,400 units in 1977 to 91,100 last year, and the RV Industry Association expects another increase to 111,300 this year.

By contrast, production of travel trailers declined last year, and fullsize motor home production increased only slightly.

By even bigger contrast, the nation each year strays further from simple tents for its camping gear. Only 1.3 million tents were sold in 1977, compared to 2.3 million four years earlier.

And camping trailers, the pop-up trailer-tents that are the bottom rung of the RV ladder, are showing no great inclination to boom, although everyone in the industry expects that.

"The manufacturers have been very aggressive in scaling down weights to match up with the lighter, smaller cars," Flues said. But American doesn't respond.

"Some things are happening," he says, "that just don't make sense."

The RV show opened last weekend and runs through Sunday. Hours are 5 to 10 p.m. tonight, noon to 10 Saturday and noon to 6 Sunday. Admission is $3.75 for adults, $1.50 for children. There is a $1 rebate available on adult tickets to Metro riders who present transfer tickets from their ride to the Armory stop.