Dr. Ralph E. Gibson, 81, director emeritus of the Johns Hopkins University Applied Physics Laboratory and an authority on physical chemistry and biomedical engineering, died of a stroke Feb. 16 at his home in Chevy Chase.

Dr. Gibson was born in King's Lynn. Norfolk, England. He earned bachelor's and doctoral degrees at the University of Edinburgh. He came to this country in 1924 and joined the staff of the Geophysical Laboratory of the Carnegie Institution in Washington. He remained there until 1941.

During World War II, he worked for the government on the development of weapons. He was appointed director of the research at the Allegany Ballistics Laboratory near Cumberland, Md., in 1944. In 1946, he joined the Applied Physics Laboratory. He was made director in 1948 and retired as director emeritus in 1969. He then undertook research in the biomedical engineering program at Johns Hopkins University. He continued this until his death.

During the war years, Dr. Gibson was credited with making significant contributions to the development of solid propellant rocket technology. During his tenure as head of the APL, the facility gained a world reputation for its achievements in guided missiles, satellite navigation systems, space science and biomedical engineering.

Among the many honors Dr. Gibson received were an honorary doctorate in medicine from Johns Hopkins University. This was conferred in 1972 and was only the second honorary M.D. the university had ever granted. He also received the Hillebrand Prize from the Chemical Society of Washington, the Bureau of Naval Ordnance Development Award and the Capt. Robert Dexter Conrad Award from the Office of Naval Research.

In 1948, he received the Presidential Certificate of Merit for his war work.In 1958, he received the Navy Distinguished Public Service Award and in 1966 Queen Elizabeth II made him an honorary commander in the Order of the British Empire. Upon his retirement from the APL, the Defense Department gave him its highest civilian honor, the Medal for Distinguished Public Service.

Dr. Gibson was a former president of the Cosmos Club, the Chemical Society of Washington, the Philosophical Society and the Washington Academy of Sciences.

He also was a member of St. Columba's Episcopal Church and for 37 years was its organist and choir director.

Survivors include his wife, Elizabeth, of Chevy Chase; three children, Nancy Kumm of Severna Park, Md., John D.S., of Bellbrook, Ohio, and Air Force Col. Ronald M.E., of Tucson, Ariz.; a sister, Dorothy Lloyd of London, and eight grandchildren.