When Robert R. (Bud) Spillane drove up yesterday to the Elks Lodge on Rte. 50 where he was to meet with about 150 principals of the Fairfax County school system he has been named to head, he found a special parking place.

"I see you left a parking space for me," he told the principals, "the 'Exalted Ruler' space. That was very nice, but you all can call me Bud."

That brought down the house and typified the tone for a day in which those who met Spillane, who has been superintendent of the Boston public schools for 3 1/2 years, professed to be impressed and even charmed.

Spillane, hired last week for $90,000 a year to run the Fairfax schools when Superintendent William J. Burkholder retires July 1, was on hand basically to say hello. In Boston he was nicknamed "the velvet hammer" for his ability to make tough, painful decisions and keep smiling.

In Fairfax County yesterday, his approach was all velvet. He sported a stylish burgundy handerchief, and about the only time he wasn't grinning was when he was laughing.

"He was very impressive . . . . He seems like a very open kind of guy," said William Bestimt, president of the county Chamber of Commerce.

"He seemed like a very affable gentleman. Hopefully, we'll get along real well," said John F. Herrity, chairman of the County Board of Supervisors.

Even the principals, frequently reticent about saying anything about their bosses, appeared won over after the meeting at the Elks Lodge at which each one got to shake Spillane's hand.

"He was very humorous; he seemed to be a very warm individual . . . . I think everybody was very excited," said Ed Ryan, principal of Falls Church High School.

"My first impression is outstanding . . . . He was very warm. He did say he was a strong supporter of school-based management, which is what we wanted to hear, of course," said Janie Smith, principal of Rocky Run Intermediate School.

At the end of the day, Spillane returned the enthusiasm of those he had met: "It has been terrific, I've enjoyed it very much, I've found everybody to be very gracious, it's been a warm welcome."

Spillane said he did not know when he would be back in Fairfax. Last week he said he would be spending several days a month here before he formally takes over in order to make the transition smoother.

Yesterday, he met the county supervisors before their meeting at 9:30 a.m., met the principals at 11, lunched with administrative staff in the school headquarters cafeteria, met with a group of community and union leaders at 2 and with those who will be his top deputies at 3 before heading for a plane back to Boston at 6.

Along the way, he started to learn some particular concerns of Fairfax residents.

"Just wait until it snows three flakes and someone says to him, 'Bud, you've got to close the schools,' " said one person after a meeting with Spillane. "Yeah," agreed another. "Someone should take him out and let him see the roads in Burke before that happens."

And Spillane learned a little about Fairfax hospitality. He said he had had "at least 10" offers to go sailing prompted by press reports that he loves to sail but doesn't own a boat.

"Wait until I tell them what kind of pasta I like," he said with a grin.