Ralph B. Williams, 61, a former lumber company executive and a retired real estate developer, died of a heart ailment Aug. 9 at Georgetown University Hospital. He lived in Potomac.

Mr. Williams was a native of Richmond. He was a 1941 graduate of North Carolina State University, where he earned a degree in chemical engineering.

During World War II, he served in the Mediterranean with the Army Air Forces. He flew P-47 (Thunderbolt) fighter planes. His decorations included the Distinguished Flying Cross and Purple Heart Medal. He was a life member of the P-47 Thunderbolt Pilots Association.

Mr. Williams worked for the old Ewing Lumber Co. in Beltsville for 18 years before leaving as its executive vice president in 1971. He then became affiliated with Weaver Brothers and worked on land development projects until retiring in January of this year.

He was a director of Greater Washington Investors Inc. and a member of the University Club, the Congressional Country Club, the Friends of the Great Falls Tavern and St. Francis Episcopal Church in Potomac.

Survivors include his wife, Margaret Halliburton Williams of Potomac; a son, Spotswood H., and a daughter, Kate Cox, both of Baltimore; his mother, Elizabeth G. Williams, and a brother, Arthur J., both of Warrenton, Va.; a sister, Jean Hamilton of Hermosa Beach, Calif., and two grandchildren.