As expected, Lockheed Martin Corp. yesterday posted a loss for the second quarter, as the Bethesda-based defense company struggled with delayed space launches, postponed deliveries of a key military airplane and troubles in its satellite business.

The country's largest weapons maker said it lost $41 million on revenue of $6.2 billion, compared with earnings of $289 million (76 cents a share) on revenue of $6.5 billion in the same period a year earlier. The loss was equal to 11 cents a share, within the 10 to 15 cents per share loss that Lockheed had warned investors to expect back in April.

For the first six months of the year, Lockheed lost $128 million on revenue of $12.4 billion, compared with a profit of $558 million ($1.47) on revenue of $12.7 billion in the same period in 1998.

Lockheed's stock, which has been underperforming the market much of the year, closed yesterday down 75 cents at $38 on the New York Stock Exchange.

General Dynamics Corp. of Falls Church yesterday said second-quarter earnings rose 14 percent, aided by acquisitions and a strong performance in its core nuclear submarine business.

The defense contractor said its profit in the period ended July 4 was $105 million (81 cents a share), compared with $92 million (72 cents) in the same period a year earlier. Revenue rose 17 percent, to $1.38 billion.

For the first six months, General Dynamics' earnings rose almost 13 percent, to $370 million ($2.87), compared with $174 million ($1.37) in the same period last year. Earnings were helped by a research and development tax credit worth $165 million after taxes, or $1.29 a share, that was recognized in the first quarter. Revenue in the period increased 18 percent, to $2.8 billion.

Shares of General Dynamics closed yesterday down 37 1/2 cents at $66.06 1/4 in trading on the NYSE.

Reynolds Metals Co., the nation's third-largest aluminum producer best known for its aluminum foil and plastic wrap brands, reported $35 million (55 cents a share) in net income for the second quarter, compared with a loss of $126 million for the same period last year.

But the Richmond company attributed lower aluminum prices and the loss of income from the sale of some operations for the dip in second-quarter revenue to $1.2 billion, compared with $1.6 billion for the same period last year.

For the first six months, Reynolds posted sales of $2.2 billion, compared with $3.1 billion for the first half of 1998. Net income for the first six months was $25 million (40 cents a share), compared with a loss of $91 million for the same period last year.

The company said it offset a significant portion of the shortfall with increased sales volume in the prices it pays for base materials and its packaging and consumer businesses.

Reynolds stock closed yesterday at $58.81 1/4, down 18 3/4 cents, on the NYSE.

Saga Systems Inc., the parent company of Reston-based Saga Software Inc., reported lower earnings in the second quarter, attributing the decrease to higher research and development costs as well as lower income from software licensing fees.

Saga said its net income was $5.1 million (16 cents a share), compared with $6.1 million (19 cents) a year earlier. Revenue dropped to $55.9 million, from $60.4 million in the same quarter last year.

The company said its second-quarter results reflect its customers' concerns over Y2K priorities because it has seen a decrease in software licensing fees from the prior year's quarter of $7.4 million.

For the first half of the year, Saga posted net income of $10.5 million (33 cents) down from $11.5 million (36 cents) last year.

Saga shares yesterday closed at $12.75 a share, down 62 1/2 cents, in trading on the NYSE.

RWD Technologies Inc. of Columbia yesterday said its net income for the second quarter dropped to $2.3 million (15 cents a share) from $3.2 million (20 cents) during the same period the year before.

Revenue for the second quarter was $32.4 million, compared with $27.4 million in 1998.

RWD's net income for the first six months was $6.1 million (39 cents), flat from $6.1 million (38 cents) during the same period last year.

The company's revenue for the first half of 1999 was $65.7 million, compared with $53.6 million in 1998.

RWD also announced a 750,000 share repurchase program for its common stock.

Robert W. Deutsch, chief executive of RWD, attributed the lower profits and revenue to a slower-than-expected demand for some of the company's technology services it sells to Fortune 500 companies.

RWD stock closed down 18 3/4 cents at $9.87 1/2 in trading on the Nasdaq Stock Market.

Transaction Network Services Inc., a Reston-based data communications firm, reported net income of $3.1 million (23 cents a share) for its second quarter, up from $2.2 million (17 cents) for the same period last year. The latest figures include a charge of $919,000 related to intangible assets associated with an earlier acquisition.

TNS earned $4.2 million (30 cents) in the first six months, compared with $3.7 million (29 cents) in the same period a year ago.

Second-quarter revenue jumped 109 percent, from $20.4 million to $42.7 million. For the six-month period, TNS's revenue was $80.8 million, compared with $38.5 million in the year-ago period.