The Arlington County Board meeting was entering its ninth hour on a recent rainy Saturday afternoon when Walter L. Frankland Jr., presiding over his second meeting as chairman, cast the deciding vote for a small housing development.

A county resident, an Army lieutenant colonel's insignia pinned to the collar of his fatigues, strode to the microphone to personally thank the chairman for his vote.

"Always did have faith in a good ole boy from Tennessee," drawled the colonel.

Frankland, a retired lieutenant colonel and son of one of the most prominent families of Jackson, Tenn., grinned appreciatively.

In the seven weeks since he became head of the ostensibly nonpartisan five-member county board, Frankland has shown that he intends to be as outspoken and as contoversial as he was when he was first elected in 1975. His election that year sent shocks through the Democratic coalition known as Arlingtonians for Better County (ABC), who had run the county for nearly 25 years.

Today, with Frankland and two other Republican-backed board members firmly in control, he is out to prove that he is not a political accident; that his brand of fiscal conservatism and back-to-basics education have a place in a county that has long been regarded as one of the most liberal in Virginia.

Frankland, says a prominent Arlington lawyer, "is the right man at the right time" for a county that was becoming disillusioned with rising property taxes and ABC.

"I am part of the team that torpedoed their ship of government," Frankland boasted gleefully in a recent interview. "They had a nice little love boat going on out there and they just ran the government the way they wanted."

"Now it's our turn," said the silver-haired, immaculately groomed 55-year-old Frankland, whose sharp attacks on Metro financing plans and Arlington public schools already have made him one of suburban Washington's better known conservatives. It also has made him one of the most devisive figures in the area, his critics say.

Former Fairfax County Supervisor John Shacochis, a fellow Republican who served on regional boards with Fra nkland, calls him "arrogant and stubborn," refusing to back down on many stands. "Frankland is very vocal. I just wish he were better informed," Shacochis complained in an interview.

To critics who say he persists in asking the same questions, Frankland replies that his perserverance is merely an attempt to get answers to tough problems. "I'm just trying to get the issues out on the front burners, he said. "In Arlington we have a county staff that has been living under the ABC reign for 25 years. We have to . . . turn that train around."

Although his job is officially parttime, and pays only $10,000-a-year, Frankland has served notice on county workers that he intends to become as much a fixture at the courthouse as County Manager W. Vernon Ford, Arlington's full-time county executive. a

He installed a private unlisted telephone line in his county office (at a cost of about $200) saying the existing six lines didn't afford him the privacy he needed.

More significant, say his critics, was his hiring of a retired school administrator as his personal assistant at a salary of $13,340 a year, filling a position that had gone vacant since 1976. His aide, Howard Bovee, also has a 100-day, $280-a-day consulting contract with the Arlington schools.

Yet for all his willingness to do battle with the county bureaucracy, Frankland freely acknowledges that he is something of a political novice. He was unknown, outside of a small high school group where he had challenged the transfer of a principal, when he ran for office in 1975.

"I just never dreamed of running for office," he said in an interview in his small office on K Street NW where he works as a registered lobbyist. He is vice president of the Silver Users Association, a trade organization of 400 companies, including Eastman Kodak and Reed and Barton which are major silver consumers.

"I had a very different time selling Walter to some people in the Republican Party in 1975," recalled Herbert Morgan, president of Arlington's Real Title Co. and a chief fund-raiser for Frankland. "He was an unknown and nobody really knew what he stood for. Now, everybody in the party loves him."

But there are persistent indications that everybody in the party does not love Frankland and that his partnership with Dorothy T. Grotos, his running mate, resembles a bad political marriage.

Since Republicans gained majority control of the board two years ago the two have squabbled over who should be board chairman and who should be Arlington's delegate to the regional Metro Transit board.

During one particularly heated discussion, Grotos pointedly told Frankland that she had received more votes than he and deserved one of the jobs, which are filled annually by the board. Two days before he assumed the board chairmanship Frankland unexpectedly resigned from the Metro board, allowing Grotos to take his seat there.

"I think it's hard for a lot of people to accept that he came in on my coattails," said Grotos, who is acknowledged by leaders of both parties to be a particularly skillful politician popular with civic and conservation groups. "I don't think he [Frankland] realizes it. The question in last year's election was, was I going to pull him through or was he going to pull me down?"

Frankland minimizes the schism and insists he and Grotos get along well. "In my training in the military, you're always out to be the best, to be a leader. It was natural I would want both jobs," Frankland said.

Along with his Tennessee roots, Frankland's West Point education and Army background have influenced his political style. And while critics variously describe his attacks on the school system as "warped," "irrational" and a personal vendetta against school superintendent Larry Cuban, his supporters suggest a different motive.

"Walter thinks Arlington's schools should teach things like grammar and diagramming sentences, the way we learned in Jackson in seventh grade from Miss Bennett," said Morgan, a childhood friend and political adviser. "The schools haven't been doing their job and Walter is just trying to change that."

Frankland himself says that Arlington's clubby, small town atmosphere reminds him of Jackson, the west Tennessee city of 18,000 where his family settled in 1900 and opened a carriage company and string of other businesses.

The elder of two sons of a retired Army colonel and nephew of a brigadier general in the Tennessee National Guard, Frankland left Jackson in 1943 to enter West Point. After graduating 511th in his class of 875, he returned home briefly to marry the girl he had met in the third grade. He spent the next 20 years as an Army public affairs officer stationed in Japan, Paris and the Pentagon, retiring from the Army in 1966.

"If you spend a lot of time in the military, you get the view that things will be done simply because the regs [regulations] say they will," said ABC county board member John Purdy. "A military background doesn't give you the experience of accomodating other views or reaching a consensus."

"Walter reflects that experience," Purdy continued. "He can be personally very pleasant, but politically he's volatile narrow-minded, thin-skinned and conservative."

Shacochis, the former Fairfax board member and Frankland's colleague on the Metro board, agreed.

"He had these fixed ideas and it cost Metro a helluva lot of money to produce reports on ridership that never even confirmed his position. "He wasted a lot of the board's time," said Shacochis, who claimed to be especially annoyed by Frankland's repeated requests for data that would support a limited 60 mile -- rather than the already approved 101-mile -- subway system. In 1978 Frankland, who insists that he supports Metro, was the only county member to vote against financial plans for the 101-mile system. t

"I don't believe I'm overly endowed with the mental capability of some other people so I have to work harder," Frankland said.

One of the areas on which Frankland is concentrating -- and the one where he may have the most influence -- is in the county schools. On July 1 the Republican-backed county board majority will have the chance to make two school board appointments, giving the GOP a majority on the five-member school board which has the power to hire and fire the superintendent.

Because Cuban has been the object of Frankland's wrath for the last five years, he is expected to leave Arlington before his contract expires in 1981 .

Although board member Stephen Detwiller has recently aligned himself with Franklan's school criticism, Grotos has disassociated herself from it. "I think our schools have tightened up and are doing a lot of things better," she said.

Frankland holds Cuban personally responsible for what he says is the decline in discipline and academic standards. His statements have angered school officials who counter that Arlington's college board test scores are the highest in the metropolitan area.

"It just proves that Walter Frankland doesn't know what's going on," said school board chairman Ann C. Broder. "I think one of the big surprises is going to be that no matter who the Republicans appoint, they're not going to be able to make any revolutionary changes. The problems are going to be the same -- declining enrollment, increasing ethnic diversity and a whole bag of urban problems."

Others argue that Frankland's criticism is destructive. "How can we attract families to Arlington when the chairman of the county board says the schools are deterioting?" asked school board member Mary Margaret Whipple, who ran against Frankland last year. "He's in a position where people believe what he says."