Rear Adm. Lloyd Harrison, retired, 84, a former assistant chief of the bureau of aeronautics in the Navy Department who became a vice president of the McDonnell Aircraft Corp., died May 5 at Georgetown University Hospital after a heart attack.

Adm. Harrison, who lived in Washington, was born in Takoma Park. He graduated from Central High School here and attended the Oregon Agricultural College before he was appointed to the U.S. Naval Academy at Annapolis.

During World War I, he served aboard the battleship Arizona in the Atlantic. He graduated from the Naval Academy in 1919, ranking second in a class of 467. He later studied naval architecture at the Postgraduate School at Annapolis and earned a master's degree at the Massachusetts Institute of Technology.

Virtually all of Adm. Harrison's naval career was devoted to the design and production of aircraft. His assignments included the Naval Aircraft Factory in Philadelphia, the bureau of aeronautics in Washington and the Naval Air Station at Pensacola, Fla., where he qualified as a pilot in 1936.

During World War II, he was at the Naval Aircraft Factory, where he became manager and rose to the rank of rear admiral. During the Korean conflict, he was the material officer on the staff of the commander of the air forces of the Pacific Fleet. He then returned to the bureau of aeronautics, where he retired in 1955.

His military decorations included the Legion of Merit and the Navy Commendation Ribbon.

Immediately after leaving the service, Adm. Harrison went to work for McDonnell Aircraft as vice president in charge of procurement. He retired in 1962 and spent the next two years as the receiver of the Howard Foundry in Evanston, Ill., a company that produced materials necessary to the nation's space effort.

Adm. Harrison was a member of the Army Navy Country Club, and the Army & Navy Club, the Society of Colonial Wars, The Fossils and the Chevy Chase Presbyterian Church.

Survivors include his wife, Elizabeth Sanford Harrison of Washington; three children, Polly Wilson and Dr. William S., both of Annapolis, and Cmdr. Lloyd Jr. of Bethesda, and 11 grandchildren.