C. Dixon Smith, 69, a retired engineer and craftsman with the Johns Hopkins Applied Physics Laboratory in Howard County, died of a stroke Thursday in the Marion County Hospital near Yellville, Ark.

He had joined the laboratory in 1942 and retired in 1975. A specialist in plastics, adhesive chemicals, plating, and potting compounds, he had supervised the arts and crafts projects at APL for many years.

Mr. Smith's special knowledge of enxcapsulation of electronic assemblies contributed to the development of guided missile and space technology.

In 1946, he was a photographic specialists with an early laboratory scientific team that flew the first supersonic ramjet engine at Island Beach, N.J.

He was born in Judsonia, Ark., and received his early education in Little Rock. He attended the University of Arkansas and studied at art schools in Houston, and Chicago. He was a surveyor at Fort Leonard Wood, Mo., and a draftsman in Little Rock before coming to Washington in 1942. He worked briefly for the Carnegie Institution before joining the APL.

A resident of Silver Spring for many years, Mr. Smith moved to Yellville a year ago.

He is survived by his wife, Sigrid, of the home; two daughters, Margo Earley, of Hiram, Ohio, and Lynda McKee, of Frederick, Md.; a brother, Nicholas M., of Silver Spring, and five grandchildren.