Dr. Thaddeus G. Csaky, 79, who retired last year as a mechanical engineer with the Naval Ship Research and Development Center at Carderock, Md., died of a heart ailment Jan. 10 at Anne Arundel General Hospital in Annapolis.

Dr. Csaky, who lived in Annapolis, moved to the Washington area in the mid-1960s to work for the Navy. In the course of his career here, he did research on propulsion systems for naval vessels, including hydrofoils and air-cushioned craft.

He was born in Hungary. He graduated from the Technical University in Warsaw. Early in World War II, he moved to Britain where he served as a major in the Royal Air Force. After the war, he earned a doctorate in mechanical engineering at the University of London and also taught there.

He came to this country in the mid-1950s and helped found the department of mechanical engineering at the University of Mississippi. He was department chairman there before moving here to work for the government.

Dr. Csaky was a member of the American Society of Mechanical Engineers, the British Hovercraft Society and the British Institution of Mechanical Engineering.

Survivors include his wife, Sophie, of Annapolis, and a son, A.S. Csaky of Washington.