Instead of getting angry, the parents of Fort Hunt High School have gotten experts.

Alarmed that the school, damaged last month by arson, might be closed permanently, they have signed up demographers, budget analysts, PhD. educators, lawyers and construction and public relations specialists to convince the Fairfax County School Board that Fort Hunt is too valuable to lose.

The experts were easy to find. In an area with a high percentage of government, military and industrial technocrats, the parents simply asked each other to help out.

"We have nationally recognized experts who can produce better results than the county's staff on this matter," said John T. O'Neill, chairman of the newly named Fort Hunt Coalition's ways and means committee, which will try to raise money for the fight.

County school administrators, asked yesterday about the Fort Hunt experts, said the more sophisticated the argument made against closing the school, the more the school board will listen.

The arguments that can be made by the coalition, considering its membership, may well be worth listening to.

Richard Irwin, a parent and a Department of Commerce demographer, has become chairman of the committee on research and statistics. The panel will review the county's projections of declining enrollment for the southeastern part of Fairfax, where Fort Hunt is located, and will remind the county force fully that such projecttions are "very chancy."

Frank Fede, also a parent and a budget analyst with experience at the Office of Management and Budget and in international finance, has become chairman of the coalition's committee for budget analysis. It will review the county's estimates that money could be saved by closing Fort Hunt.

The county school board has said it will decide on Feb. 1 whether to close the school for good. Official projections for enrollment at the school show a steady decline through 1984, from 1,750 students to 1,480. Other high schools in the Mount Vernon area could easily absorb Fort Hunt, administrators contend.

According to coalition chairman Peter H. Brinitzer, an operations manager at the Defense Department, there would be nothing easy about closing Fort Hunt.

"Our community is debilitated, our children are demoralized. We cannot and we will not believe that school planning is going to be based on the disgusting acts of a couple of vandals," Brinitzer said in a press conference called by the coalition.

Two 18-year-old Fort Hunt seniors and a 19-year-old graduate of the school have been charged in connection with the arson, which caused an estimated $4.5 million worth of damage. Fort Hunt students now are attending nearby Groveton High School.

The press conference, which the coalition managed to have listed on the same United Press International Day Book that lists presidential press conferences, was run by Wilbur Jones, a former advance man for Gerald Ford and now head of public relations for the U.S. Chamber of Commerce.

At the session, the chairmen of seven coalition committees presented impressive credentials and there was frequent mention of how Fort Hunt was the "fulcrum" of the community.

The coalition plans to remain silent unless the board decides to close Fort Hunt, Brinitzer said. If that happens, the coalition will marshal its resources, including the members of the legal committee, to persuade the board by all "reasonable and legal" methods to change its decision.

School spokesman George Hamel said yesterday the school board will seek public opinion before making its final decision.