Retired Col. Leslie A. Skinner, 78, a pioneer in the development of American military rockets including the baookaz, died Thursday in a hospital in Clearwater, Fla. He suffered from a heart condition.

Most of his military service was with the Army Ornance Corps. He later spent two years on active duty with the Air Force.

Although he had set up three Army rocket projects prior to our entry into World War II, Col. Skinner became the "almost forgotten Army rocket man," Leo A. Codd, editor of Ordnance Magazine, wrote in 1959.

Codd noted that the projects involved a 4 1/2-inch aircraft rocket, a 3 1/2-inch aircraft rocket and a shoulder-launched rocket, fired from what became known as the bazooka. All three weapons were standardized by the Army and produced in quantity during World War II.

Col. Skinner had been assigned to the office of the chief of ordnance in 1940 and was detailed to work with Dr. Clarence N. Hickman of the National Defense Research Committee at a laboratory at the Naval Powder Factory at Indian Head.

Despite the indifference of Congress and other government officials to rocket research and handicapped by a lack of funds, they and others working with them developed the bazooka. It became one of the most effective antitank weapons in the war.

Col. Skinner received little formal recognition for his pioneering work, according to an article in Army Magazine in 1973. Toward the end of the war, he was sent first to the California Institute of Technology to establish an ordnance suboffice there. He also was sent on an assignment to the Pacific.

He was on the staff of the Command and General Staff School at Ft. Leavenworth, Kan. when he retired in 1948. At that time the Army gave him the Legion of Merit. Later the American Rocket Society honored him with its Hickman Award for this contributions to weapons and solid-fuel rocket propulsion.

Col. Skinner was born in San Francisco, the son of an Army surgeon. His interest in armaments and rockets began when he was a child. he graduated from the Military Academy at West Point in 1924.

During the 1930s, while he was stationed at the Aberdeen Proving Grounds, he used his own time and his own money to work on rocket experiments.

After his retirement, he was with the Aerojet Engineering Co. in California. During the Korean conflict, he was on active duty with the Air Force helping to plan the air armament test center at Eglin Air Force Base in Florida. He retired for a second time in 1951.

He had worked with private industry and as an independent consultant for some years after that. He had lived in belair Bluffs, Fla. for the last eight years.

He is survived by his wife, Margaret, of the home; a son, George, of Novato, Calif.; a daughter, Leslie Jagiello, of Silver Spring; two sisters, Mary Anne King, of Asheville, N.C.; and Lucille Lincoln, of Las Vegas; eight grandchildren and two great-grandchildren.