Francis Edward Butler, 80, a weapons engineer for the Navy Department, died Oct. 7 of colon cancer at his home in Washington.

Mr. Butler worked as a civilian engineer for the former Naval Ordnance Laboratory in Silver Spring and its successor groups for 30 years.

A native of Washington, he graduated from Armstrong High School in 1942 and served in the Navy during World War II. He received a bachelor's degree in mechanical engineering from Howard University in 1950. He also did graduate work at Pennsylvania State University, the University of Michigan and Rensselaer Polytechnic Institute in Troy, N.Y.

He joined the laboratory in 1951 as a design engineer and later spent 10 years as a senior project engineer. For 13 years, he was a senior manager, directing research and development programs at six Navy laboratories and three universities. He was a Navy representative at NATO meetings from 1967 to 1971 and also served in the Navy's Office of Legislative Affairs.

He was granted several patents during his tenure with the Navy's research laboratories. He received many official commendations for his work.

After retiring from the Navy Department in 1981, Mr. Butler joined Presearch Inc., a defense contractor based in Fairfax, for which he served as a foreign liaison specialist in research and development.

In 1987 and 1988, he was a consultant and expert witness for Squire, Sanders & Dempsey, an international law firm with offices in Washington.

From 1961 to 1966, Mr. Butler was a member of the board of examiners for the U.S. Civil Service. He served on the board of science education for the D.C. public schools from 1956 to 1968.

A photography enthusiast, Mr. Butler was a member of the FotoCraft photography club in Washington. His photographs received many awards and were shown in several major exhibits, including one in Beijing in 1967. Two of his prints are on display at the John F. Kennedy Library in Boston.

He also enjoyed swimming and won several medals in senior competitions.

Mr. Butler was a lifelong member of Nineteenth Street Baptist Church of Washington and sang baritone in its choirs for 60 years.

He was a member of the Omega Psi Phi fraternity, the American Society of Mechanical Engineers, the National Society of Professional Engineers and the National Technical Association.

His son, Karl Butler, died in 1994.

Survivors include his wife of 54 years, Alberta J. Butler of Washington; a daughter, Mira Shanks of Bowie; a brother, Clayton Butler of Washington; two sisters, Mirian Alexander of Columbia and Barbara Butler of Washington; and a grandson.

Francis E. Butler also was a D.C. public schools volunteer and a photography enthusiast.