BALTIMORE (AP) _ Sir Frank Whittle, the British engineer who developed the jet engine for his country at the same time a German was doing the same for his, has died at his suburban Baltimore home. He was 89.

Whittle was one of two onetime World War II enemies who independently developed the jet airplane engine in the 1930s and '40s. The German Hans J.P. von Ohain is also credited with the invention, and while Whittle was the first to hatch the concept, a German jet was the first to fly.

Whittle, who lived in suburban Columbia, died late Thursday, his son Ian said today. He said his father, a smoker until 1982, died of lung cancer.

Though the jet's invention was perfected too late to affect the course of World War II, it has revolutionized transportation since then. It earned Whittle a knighthood in 1948.

In 1991, Whittle and von Ohain _ who both had emigrated to the United States _ were jointly awarded the prestigious Charles Stark Draper Prize of the National Academy of Engineering.

``To imagine today's world without the jet engine is almost impossible, and to imagine the jet engine without Whittle and von Ohain certainly is,'' Robert M. White, academy president, said at the time. ``Few engineering achievements in history can compare to the work of these two men.''

Reached today at his home in Florida, von Ohain said he first met Whittle when they both got an award in 1966, and they had kept in touch.

``I admired him because he fought, under all circumstances, to get his ideas through, although he had enormous problems,'' von Ohain said. ``Although he was earlier than I with the idea, because he was 4 1/2 years older than I, he had to fight.''

Whittle applied for his first jet propulsion patent in 1930, after his ideas had been turned down by the British Air Ministry as too impractical to develop.

With the financial backing of friends, he founded Power Jets Limited in March 1936.

The first engine ran in 1937, but it was not until 1939 that the British government contracted for a flight engine. The first British experimental jet didn't take off until 1941. Later that year, plans for the engine were secretly taken to the United States, where the General Electric Co. worked on an American version.

Meanwhile, in Germany, von Ohain designed a jet engine and was hired by a manufacturer to do more research. By 1937, he had built and tested a laboratory model.

After that, work progressed rapidly and, on Aug. 27, 1939 _ days before the start of the war _ von Ohain's craft became the first jet-powered airplane to fly. It remain airborne for seven minutes.

By 1944, both Germany and Britain had limited numbers of jet aircraft in action.

Whittle emigrated to the United States in 1976, moving to Columbia, and working for a time as a research professor in the aerospace engineering department at the U.S. Naval Academy. Von Ohain, who came to the United States in 1947, did research for the U.S. Air Force and the University of Dayton in Ohio.

Born in Coventry, England, in 1907, Whittle began his engineering career in his father's shop, won a scholarship to attend Leamington College and left at 16 to join the Royal Air Force as an apprentice.

Besides his son Ian, Whittle is survived by his second wife, Lady Hazel Whittle, and another son, David.