A 28-year-old accountant, who had said that what he most wanted out of life just now was a "top-of-the-line" motorcycle helmet, won the grand prize last night in the third D.C. instant-millionaire drawing--$50,000 a year for the next 20 years.

"I've been called a lot of things, but never a millionaire," said Kim E. Davenport, grinning widely and looking somewhat dazed in his dark blue, three-piece suit after the drawing at the D.C. Convention Center.

During the drawing, 19 other finalists--each of whom had won $100 in the city's "Loose Change" instant-winner game last spring--received prizes ranging from $100,000 to $1,000.

"I didn't even want to think about winning because I didn't want to be disappointed," said Davenport, who lives in Arlington and works for the National Council of Senior Citizens in the District.

Seconds later, his father, John Davenport, a retired Air Force pilot, rushed up and kissed his son. "Remember your daddy. The one who gave you your allowance," he said as Davenport's mother and six of his nine brothers and sisters hugged and kissed each other excitedly.

"Ask him if he still honors his father and mother," the senior Davenport joked to reporters.

Davenport, one of 3,448 original $100 winners, said he bought his ticket at Readers' World newsstand at 1006 Vermont Ave. NW. His was the last of 20 names called during last night's ceremonies, which began with drawings for $1,000 awards for 15 each of finalists.

"This is one of those times you don't want to hear your named called," D.C. Lottery Board member Lillian Wiggins said as she teased the audience of several hundred persons, mostly friends and relatives of the finalists and city government workers.

Other top winners were:

Algia Small, a personal care aide at D.C. General Hospital who has six children and eight grandchildren. She received $100,000.

Earl Burgess, an employe for ITT Continental Bakery, who won $25,000 despite prolonged shouts of "Million Dollar Earl" from friends in the audience throughout the program.

Mary Wilson, owner of a cleaning business, who won $10,000.

The "Lucky 13" group, a partnership of 13 Internal Revenue Service employes who pooled their resources and planned to split the million dollar prize, ended up winning $1,000. They were going against tough odds. Local and national lottery officials said they knew of no group that had won any millionaire drawings in the country.

All of last night's winners received their prize checks on the spot--with 20 percent deducted to cover federal and local income taxes, according to a lottery official.

The long evening began at 8 p.m. and continued beyond 11:30 p.m. as the anxious finalists and crowd sat through two modern dances, songs peformed by a local lounge singer and long pauses on stage.

After the drawings, the finalists joined Mayor Marion Barry--who had announced the top prize winners--and lottery board officials for a private reception.

"After the reception I'm going out for a beer and a cigarette," said new millionaire Davenport, who had shifted his lanky frame nervously on stage as competitors for the top prize were eliminated one by one.

When only two were left, and Barry announced Small's name for the $100,000 prize, it took Davenport a moment to realize he had won.

"Did I win?" he asked weakly. Told he had, indeed, he leaped from his chair and jammed his fist jubilantly into the air. CAPTION: Picture, Kim C. Davenport savors his D.C. lottery prize--$50,000 a year for 20 years.