In the middle of the Mojave Desert, 32 miles from the closest town, thousands of U.S. Army soldiers play "war games" each year with real tanks, targets and tactics. And almost a thousand civilians are brought in to pick up the pieces.

Maintenance of the 1,000-square-mile U.S. Army National Training Center at Fort Irwin near Barstow, Calif., is as tough as surviving one its simulated wars.

Tanks, helicopters, barracks, air fields, ranges and grounds must be kept in tip-top shape for each brigade of soldiers that comes to the fort for training the Army terms "the most realistic preparation for war."

Under an Army contract valued at $113 million over a four-year period, Dynalectron Corp. of McLean now has the job of picking up.

The contract, for the technical support and maintenance of the base, was awarded to Dynalectron's installation support and operation division last week. Boeing Co. had provided the services for the past five years. Dynalectron moves in July 28.

"We've been awarded two other major installation support contracts, but Fort Irwin is our big win," said Gaither Bray, vice president of the division. "This contract gives us the opportunity to gain the experience we need to bid on larger projects. If we do a good job at Fort Irwin, the division will take off."

Work on Army bases is a new front for Dynalectron, which provides engineering, aviation maintenance, construction and other services for both corporate and government customers.

The division was formed this January, two years after the company received its first contract from Fort Belvoir, Va. A second contract from Fort McClellan, Ala., was awarded in February.

According to Bray, Dynalectron followed its usual pattern in creating the new division. The company looks for a niche in the market and cautiously begins bidding. If the activity picks up, a division is formed and a staff added. Then, with money and marketing, the division is able to expand.

"We're small; only about 35 percent as big as our sister organizations [other divisions at Dynalectron]. But we're fast-growing, and there are unlimited opportunities to bid on business," Bray said. "This year, we have about $42 million in contracts, and if all goes well, we should have between $100 million and $150 million in two to four years," he said.

It is no secret that Dynalectron is after business. In 1985, the company reported $640 million in revenue, about $266 million of which was derived from U.S. government projects. According to Bray, his division is bidding on at least eight similar contracts across the country from Fort Carson, Colo., to Fort Lee, Va.

At Fort Irwin, the division will provide services ranging from the operation of a library, riding stable and recreation program to maintenance of 1,000 combat and tactile vehicles.

"It's like an oasis in the middle of a dry lake bed," Bray said.

It takes a lot to keep an oasis thriving; the division, among other things, will provide: food service facilities; mail and word processing services; equipment support and maintenance; housing assignments and upkeep; medical services; audiovisual training; actual field training; and maintenance of roads and grounds.

Approximately 1,000 people are employed to run the base. Dynalectron will have full operational responsibility starting Oct. 1.

Washington Federal, a federally insured thrift with 14 branches in the District, announced plans to expand operations to Virginia after the Federal Home Loan Bank Board ruled that District thrifts could branch into either Maryland or Virginia.

Washington Federal, with assets in excess of $850 million, is also a partner in First Washington Mortgage Corp. of McLean, which has offices in the mid-Atlantic region. The thrift plans to open branches in Herndon and McLean by the fall of 1987.

"Virginia was selected because of its high growth potential and because of our existing market share in Northern Virginia," said Bill Sinclair, chairman of the board.

Fairchild Republic of Farmingdale, N.Y., a subsidiary of Fairchild Industries, resumed test flights last week on a twin-engine jet that had been grounded for a month, said a company spokesman.

The T-46A trainer, built by Fairchild Republic under a U.S. Air Force contract, was grounded after an experimental wing control device caused the jet to flutter at low speeds. The jet completed a 1.7-hour test flight at Edwards Air Force Base, Calif., and reestablished a flutter clearance speed of 280 knots at 11,500 feet altitude. The trainer has completed 90 flights and 134 hours in the test program.

Fairchild Republic said the second prototype airplane, under the same contract, will be delivered to the Air Force in July.

The Bethesda CPA firm Stoy, Malone & Co. acquired the Baltimore accounting firm Tarr & Scholl P. A. for an undisclosed amount last week. Joseph A. Tarr and G. Richard Scholl, cofounders of Tarr & Scholl, will become partners of Stoy, Malone. Stoy, Malone operates offices in Bethesda, Baltimore and Columbia.

Stockholders of the Richmond advertising agency The Martin Agency Inc. voted to form Marketing Arts Corp., a parent company that will oversee activities of The Martin Agency Inc., The Stenrich Group Inc. and Marketing Solutions Corp.

The Martin Agency acquired the New York marketing company The Stenrich Group on April 1 and created Marketing Solutions last month to provide typesetting and photographic services.

Two Northern Virginia insurance agencies, Castiglia & Johnson Ltd. and Morrow & Brooks Ltd., merged to form Morrow & Brooks Ltd., a five-member insurance agency with offices in Burke, Va.

James V. Castiglia is chairman of the board and Jeffery M. Johnson is president of the new firm.

MCI International Corp., a division of MCI Communications Corp., signed an agreement last week with France Cables et Radio, a subsidiary of the French Postal Telegraph and Telecommunications Authority, to provide the first electronic mail service between the United States and France.

Under the agreement, more than 100,000 MCI Mail subscribers in the United States will be able to exchange electronic messages with subscribers of FRC's Missive Service in France.

The LINK software package, developed by MCI, was used to link the two noncompatible systems, and the agreement marks the first international application of the package.

Blakeslee-Lane Inc., a visual communications company with offices in Baltimore and Silver Spring, acquired the Baltimore video production company Encore Production for an undisclosed amount two weeks ago.

Blakeslee-Lane, a 60-member firm, bought out total assets of Encore Productions. The Encore staff will remain under the management of Blakeslee-Lane.

Systems Planning Corp. of Arlington received a $5.7 million contract from the Department of Defense to analyze how the Soviet Union might respond to the development of a "Star Wars" antimissile defense system, the Pentagon said last week.

Systems Planning received similiar contracts in connection with the development of Army defense systems against tactical missiles. This contract includes four annual renewal options that give it a potential value of $33.5 million, the Pentagon added.

The company will analyze the proposed Strategic Defense Initiative (the Star Wars program, which would use lasers and weapons to shoot down nuclear missles if they were fired at the United States or its allies) from a Soviet viewpoint. The effectiveness of the program against Soviet countermeasures also will be analyzed.

The Pentagon is spending $2.75 billion on such research this year and has asked Congress for an additional $4.8 billion in fiscal 1987.