Pentagon leaders denied vehemently yesterday that advancement of President Carter's political fortunes was their motive in publicizing formerly top-secret "Stealth" technology for making planes invisible to radar. As Republican standard-bearer Ronald Reagan was leveling that charge yesterday in Jacksonville, Fla., members of the House Armed Service Committee were also assailing Defense Secretary Harold Brown and Pentagon research director William J. P for ripping the secrecy veil off Stealth in a nationally televised news conference on Aug. 22.

Critics got an assist from Gen. Richard H. Ellis, commander of the Strategic Air Command, who said the Pentagon should have stuck with a "no comment" response to questions about Stealth even after the secret had been broken in several press accounts.

Ellis followed Brown and Perry to the witness table in the House committee's cavernous hearing room. Retired Army Lt. Gen. Edward Rowny, military adviser to Reagan, stood along the back wall watching.

Chairman Samuel S. Stratton (D-N.Y.) of the House Armed Services investigating subcommittee demanded last week that Brown and Perry testify to explain why they were "yielding up territory to the enemy" by discussing Stealth publicly. t

In yesterday's explanations, which White House spokesman Jody Powell said would constitute Carter's response to Reagan as well as the committee, Brown and Perry said press disclosures made it impossible to keep the existence of the Stealth program secret and longer.

"A 'no comment' in the face of a spectacular news story by a reputable reporter in a major newspaper is tantamount to confirmation," said Brown in discussing why he decided against going that route in response to a Washington Post story on Aug. 14 describing Stealth as a "key breakthrough."

A no comment. Brown told the subcommittee, would hve resulted in a rash of competitive reporting and a cascade of new leaks, some of them containing much more damaging information about the technical details.

"A second suggested option," Brown continued, "was to try to discredit the story" -- an option SAC commander Ellis seemed to favor, judging from a telegram he sent Pentagon superiors.

"Today's Washington Post story on the possible development of an advanced technology bomber brought the hair up on the back of my neck." Ellis said in the telegram, released yesterday.

"I don't have to tell addresses that giving the Soviets [deleted] years advance warning of a new technology system they must counter is to sound the death knell of that system.

"As the current commander of the combatant command that would eventually operate such a system, I ask that you take immediate action at the necessary levels to discredit the story and otherwise defuse the situation."

(Ellis said later in yesterday's hearing that he was not recommending that the government lie, simply that it refuse to confirm or deny Stealth's existence.)

Brown said "I rejected any effort to deceive the press and the public as both wrong and not feasible. As the nation learned to its bitter regret in the Watergate era, a policy of deceiving the public undermines the basic link of trust between the government and the people."

The defense secretary added that such publications as The Washington Post and Aviation Week & Space Technology Magazine, which also had written about Stealth, "are read closely in the Soviet Embassy and are viewed as authoritative publications.

"In those circumstances," Brown told the subcommittee. $ i decided that the only truthful and effective course of action would be to acknowledge what had already been disclosed to the Soviets in the leaks and to lay down strict new security guidelines to prevent any further disclosures.

"By so doing," Brown contended, "we have in effect created a firebreak to prevent the spread of the technical details which, because they are at the heart of operational effectiveness, must remain highly classified."

Stratton scoffed at the "firebreak" theory, declaring: "You are simply whistling 'Dixie.' The first line of defense didn't work" because Stealth leaked into the press. He said he had "no confidence the second line will work."

The Brown rationale for the press conference, Stratton contended, amounted to believing that "by giving out more information you're giving the Soviets less."

Pentagon research chief Perry said it was he who had recommended to Brown that a limited amount of information be disclosed about Stealth in hopes of keeping the press from digging out the deeper but less newsworthy technical secrets.

The basic idea of Stealth technology is to keep enemy radar beams from bouncing directly off the airplane and back down to an antenna on the ground. This requires reshaping the airplane and perfecting a number of other radar-foiling techniques. Stealth already has been proved out in flight tests, according to brown.

Although Perry acknowledged that the trade publication Aerospace Daily had discussed Stealth back in 1976 when the program was just starting up, he said those and other reports did not threaten to blow off the secrecy lid. They quickly sank from sight, he said.

But in June 1978, Perry said, Benjamin Schemmer of the Armed Forces Journal showed him a story on Stealth that he intended to publish. "I would not confirm or deny the story, but urged him not to publish it on national security grounds," Perry said. Schemmer withheld publication.

"The first published security break," Perry continued, came on June 28, 1980, when the Washington Post disclosed that the Air Force had a bomber on the drawing board that "could be made invisible to enemy radar through highly secret gadgety."

The disclosure was part of a story on congressional frustration with Pentagon procurement policies through the years. It was based on interviews with defense specialists in Congress and the Carter administration.

Perry said he told Brown that "we should not respond to the 28 June leak, but that I did not believe that we would be able to conceal the existence of the program much longer."

With Brown's approval, Perry said he started drawing up new guidelines for what Defense Department officials could say about Stealth. While those guidelines were being drafted, Perry continued, Aviation Week on Aug. 11 and The Washington Post and ABC News on Aug. 14 gave "increasingly greater detail" about Stealth.

The major security break occurred on 14 August in The Washington Post article," Perry told the subcommittee, "and irretrievably compromised the existence of the program. But this only accelerated by a few months what I had already considered inevitable.My major concern was that there was an imminent danger of having really damaging information come out . . .

"What had been revealed," the defense research director said, "in no way threatened the very great, indeed the revolutionary value, of the program to our national security."

But to draw a new security line, Perry said, Brown on Aug. 16 signed off on rules which would allow the Pentagon to confirm the existence of the Stealth program. Arrangements for a Pentagon press conference and congressional briefings on Stealth were begun at that time, Perry said.

Because Schemmer had agreed to hold the Stealth story, Perry believed he owed it to him to answer questions on Stealth under the liberalized secrecy rules.

Perry said he met with Schemmer on Aug. 18, with the understanding that any resulting story would be embargoed until Aug. 21 -- the day before the Pentagon's press conference. Schemmer wrote a Stealth story and distributed galleys of it to news organizations on Aug. 20.

The following week he told the House subcommittee under oath that it was his "opinion that this information was directed to be made public for political purposes," testimony that Reagan alluded to yesterday.

Rep. Robin Beard (R-Tenn.), as part of the Republican attack on the administration's disclosures, told Perry he was "befuddled" about why it was necessary to hold a "full blown press conference" on Stealth right after the Democrat's presidential nominating convention, given the fact that press leaks had been going on for years.