That whoosh you just heard and the breeze you felt weren't illusions. They were the sound and feel of Richard Nolan and John Cavanaugh getting out of town.

Nolan of Minnesota and Cavanaugh of Nebraska are congressional oddities; they quit just when their legislative careers were reaching cruise speed.

Most of what you read in coming weeks will be about a new congressional class moving in, throbbing to save the world and reshape government. Time will set them straight.

So this is about two bright, young, effective, upward-bound Democrats whose own vision of the truth convinced them the brass ring of Washington may be more like fool's gold.

Nolan, 37, and Cavanaugh, 35, differ, too, in that most of the 29 other House and Senate voluntary retirees this year were veterans, well into their middle or late years, tired of the chase and hassle of public office.

Nolan, father of four, is going back to the rural area of Minnesota he represented to take up farming and remake a life upset by a divorce spurred in part by politics.

Cavanaugh is returning to Omaha to practice law and to be a full-time father to five small children he suddenly realized he didn't know as well as he thought.

Their reasons for early retirement are similar, but their views on the political system and how it drains are strikingly different.

Nolan, for example, was elected in 1974, devoted to the idea that the Vietnam war had to be ended. He was one of the congressional newcomers whose pressure played a role in U.S. withdrawal from Vietnam.

"After the war ended I felt my mission was accomplished," Nolan said recently. "But I was never enamored with the thought of being a congressman. rMy experience here only reinforced that feeling."

A former teacher and state legislator, Nolan fits the pattern of the liberal idealist unhappily turned wiser and more realistic. He believed an individual could make a difference. Ironically, he did have an impact on the system as a congressman, yet he drew little comfort from that.

"Congress is relatively impotent to make the changes the country needs: mandatory wage and price controls, drastic tax reform, national health insurance, arms cutbacks, new directions in energy, mandatory conservation, a redirection of agriculture. But there is no political will in Congress; no will in the outgoing or incoming administrations," he said.

"Being here, I've become more liberal and radicalized . . . I just think that for people of my mind and philosophy during the next few years, we will be the loyal opposition. And I'm impressed with things happening outside of government -- oftentimes inspite of government. I feel I can do a lot more good outside than I can here."

For the nonce, Nolan is going to take up farming and emphasize specialty crops such as berries, broccoli and asparagus -- no idea gleaned from his Agriculture Committee work -- and start a small export management company for agriculture in developing countries.

In three terms here, Nolan left an imprint.He pushed the legislation that created a presidential commission on world hunger, on which he later served. He also chaired a rural development subcommittee and was stunned to see how governmental policies promote bigness at the expense of small farmers.

Cavanaugh's view of Congress is not quite so bleak, but he found the demands of politics as disturbing as Nolan -- time away from family, constant fund-raising, special-interest pressure, no time for thought.

"No question, I experienced disappointment and frustration, but I expected that," he said. "That's why you participate. I'm pretty optimistic on the whole and I also think the system works . . . I think we will find new directions."

"If I'd stayed here longer, I might have gone flat. I needed to go back to the country and reflect on what I've done. Here you are in constant motion and combat. You find yourself defending things you didn't feel could be defended."

Cavanaugh, like Nolan, left something of a mark on public policy, even with only two terms here. His work on the Banking Committee drew notice for his activism on international monetary issues and regional development banking, for pushing Congress and the Carter administration toward Third World development questions.

There was "exhilaration" in that, Cavanaugh said, but he worried more about what it would ultimately do to him.

"The greatest malady of the system is defined as Potomac Fever. Good people come here and lose their integrity before they lose their virtue. They become mired in the system, lose their vitality and then become devoted solely to reelection. You see an awful lot of unhappy people here. The system squeezed it out of them and that's pathetic. That is what I feared: that I would become a hollow shell," Cavanaugh said.

The real problem, though, was the children -- a side of life that few officeholders allow to intrude. Wives, as long as they remain wives, often are the only parent in the political family.

"For me," Cavanaugh said, "the distance and time away from my family became very painful. It was a choice between stable family life and an active political life. To pick the latter, you have to draw a line where family becomes secondary. I was unhappy drawing that line."

Cavanaugh drew his line and announced the decision last January, after only three years here. To ignore children and wife until after the next election, he told his constituents, "is an endless road traveled sadly by too many men too deeply captivated by public life."