Cerberonics Inc., a Bailey's Crossroads company that provides engineering and logistics services for the armed forces, nearly doubled its profits in the quarter ended April 2. Net earnings were $365,938 (29 cents per share), up from $185,918 (20 cents) during the same period the year before.

Revenue soared to $10.1 million from $3.7 million, thanks in large part to the C-9 contract with the Navy for services and material support which has potential five-year revenue in excess of $60 million, according to Cerberonics' executives.

The company's working capital increased dramatically to $8.8 million from $333,400 a year earlier as the result of a public stock offering in January. Almost half a million new shares were sold by the company for $20.50 each.

Ethyl Corp. of Richmond reported a 12 percent increase in net income to $18.4 million (21 cents) on revenue of $395.8 million during the first quarter of 1983 compared with earnings of $16.4 million (19 cents) on revenue of $402.7 million during the same period last year.

Management said the dip in sales was caused primarily by lower prices for its industrial chemicals and lower shipments of lead antiknock compounds. About $2.1 million of Ethyl's first-quarter profits came from First Colony Life Insurance Co., which it acquired a year ago. First Colony revenue jumped 40 percent, reflecting sharply higher sales of single premium annuities, investment income and slightly higher premiums from ordinary life insurance policies.

Washington Homes Inc., a residential construction company in Waldorf, Md., ended the quarter with a profit of $308,027 (25 cents) on sales of $9.4 million. That compares with a first quarter 1982 loss of $348,262 (29 cents) on sales of just over $2 million.

Net income was $916,088 for the past nine months following annual losses for three years in a row. That gain included a tax benefit from loss carry-forward of $240,000. Sales increased to $22 million from $8 million during the period.

Allied Capital Corp. of Washington, a publicly traded venture capital company, announced a 23 percent gain in earnings for the year ended March 31, 1983, and a five-for-four stock split. Net income rose to $3.1 million ($2.37 per share), up from $2.6 million ($1.97) one year earlier. Investment income declined to $5.6 million from $6.1 million due to a drop in interest rates.