FOR 26 AREA KIDS, it's all downhill from here. On Saturday morning they'll hit speeds up to 32 miles per hour as they zoom homemade racers down a steep, 950-foot stretch of Eastern Avenue NE in the annual Washington Soap Box Derby.

Winners will go to the All-American Soap Box Derby in Akron, Ohio. Losers, although there'll be some tears, can still take great satisfaction and pride in the hours they've spent sawing, cutting, nailing, sanding, painting, buffing and waxing and, finally, readjusting the tiniest screw and redistributing lead weights to ready their model cars for the race.

"It gives them a goal to work for and knowledge for the future," says Sydnee M. Schwartz, director of the local event. "They learn how to use tools, but it's really a family kind of thing." Schwartz, who's been involved with the race since 1974, says all the preparation "requires a lot of time of the parents, but they get a positive end result. It gives them something to build on and forms a really strong bond. And if they have other children, the whole family gets involved."

The Hoover family of Fort Belvoir probably couldn't get more involved in racing. This year, 9-year-old Dustin has joined his brothers Donald, 14, and Douglas, 13, and sister Denise, 11, in the competition. He'll be driving in the junior division, while Denise enters the senior division. Last year she made it to Akron in the junior division and finished 16th in a field of 96 entries.

"It takes four months of steady work, especially when you're building four of them," says the kids' father, Donald. And the job of building four cars is even harder when the builders are "distracted by so many other things that seem to attract kids' attention, like baseball and fireworks on the Fourth of July."

David Burch, of Woodbridge, began helping his 11-year-old son, Justin, build a junior division car early this year. "It seems like two years ago. I can't remember not working on it," said the senior Burch recently after helping Justin put the final touches on the vehicle. Burch said that he and Jim Foreso, the service manager of M&M Pontiac in Springfield, Justin's sponsor, worked together helping the boy assemble his kit car and spent an average of two or three days a week. Derby officials say it should take about ten hours of work to assemble junior division cars, but, Burch said, "we put in at least 80."

"It was pretty fun," said the younger Burch recently as he climbed into his glossy red roadster for a trial run. "But it was a little more work than I expected."

That's often what it takes, though, if you want to do well in the competition. Racers compete in two age brackets: juniors from nine to 12 years; seniors 11 to 15 years. Rules require that senior cars weigh exactly 250 pounds including driver; the figure is 220 pounds for junior entries. The cars are sold in kits through the national derby office. The cost is $62 for the junior model, $65 for the senior kit, which doesn't include lumber, paint or wheels. The total cost generally runs $250 to $300. Kids must assemble the cars to exact derby specifications, but adults are allowed to instruct them in proper use of tools. Additional help is provided at clinics held throughout the spring by the race's main supporter, the Downtown Jaycees.

The Jaycees also provide people like Richard (Smitty) Smith, who works the bottom of the hill on race day, catching finishers if their rubber-tipped plunger brakes fail, or helping them in a hurry if there are any wrecks.

(Safety is one of the biggest concerns in soap box racing, and every precaution is taken. Drivers are required to wear helmets, and cars are closely inspected during the building stages. One week before race day, the cars are impounded to prevent last-minute changes that could make the vehicle unsafe or give it an unfair advantage. A 1973 cheating scandal nearly put the national race out of business when it was found that the winning car had an electromagnetic device that jolted the car foward when the starting block was lowered. The driver was disqualified.)

Even with all the family and volunteer help, kids often need financial help.

"Without sponsors it's just about impossible for kids to be able to afford to build cars," figures Donald Hoover. But sponsorship is a positive factor for the kids because "it teaches them how to sell themselves," says Hoover, adding that the derby involvement has also helped teach his kids how to repair their own bicycles, their neighbors' bicycles, the family lawnmower and how to deal with local merchants. They know how to order parts on the phone or get them at the store, and can often get a discount when they tell the merchants what they're doing, he says.

The Hoover kids have built nine cars over the past three years, and their father thinks it has taught them how to work together and how to compete. They've also learned to work out bugs in a design, and how to work against a deadline. Their dad acknowledges, however, that "they're always pushing it."

Saturday's entrants will race down the street in pairs, a trip that takes little more than 28 seconds. Each driver will have to lose at least two heats before being retired. The top two finishers in the Washington seniors division receive trophies and $250 and $150 savings bonds respectively; juniors also get trophies and savings bonds worth $150 and $100. The two division winners will travel to Akron's 20,000-seat Derby Downs for the 48th running of the All-American Soap Box Derby on August 10.

Senior winners in the national race also get trophies and scholarships of $5,000, $3,000 and $2,000. Power tools have traditionally been part of the junior division winner's package, but this year's prizes may include personal computers.

Washington entries at the national race may feel some additional pressure to win. The best a Washingtonian has done in Akron was in 1941 when Gene Bean raced to third place. OFF TO THE DERBY

Saturday's first heats begin at 10 a.m.; racing is expected to go on until 4. The race begins at the top of hilly Eastern Avenue NE, just above Varnum Street. Spectators are invited to bring picnics and watch from Barnard Hill Park which borders the route. Refreshments will be sold. The race is free. For more information, call Sydnee Schwartz, 301/229- 0118; or the Downtown Jaycees, 293-0480.

*If you'd like build a racer, kits are available by writing to: All-American Soap Box Derby Racing Products, International Soap Box Derby, P.O. Box 7233, Akron, Ohio 44306; 216/733-8723.