Helen Ethel Samuel, a retired D.C. public school educator, administrator and lobbyist, and one of the original group that organized the construction of Arlington Hospital in the mid-1930s, died Sunday at Fairfax Hospital following open-heart surgery.. She was 81.

An Arlington resident since 1925, Miss Samuel worked on behalf of Arlington Hospital for 43 years, first as a member of the citizens group that acquired the site of the hospital, and later as a fund-raiser. She was an original member of the hospital's board, then served on it for more than 40 years, and was the first woman to chair it.

She also was the first woman to head the Hospital Council of the National Capital Area.

During her 40-year career as an educator in D.C. public schools. she taught English and commercial mathematics at junior and night high schools. She was a principal of Western Night High School and an assistant principal at Gordon Junior High.

She wrote the first junior high school business curriculum for the D.C. public schools and served as chairman of the committee that wrote the first guidance course for the city's junior high schools.

After her retirement in 1960, she was an executive secretary and legislative consultant of the D.C. Teachers Association, lobbying for improved salaries and benefits for public school-teachers here. She also served as a member of the D.C. School Superintendent's Advisory Board and twice chaired the joint legislative council of the D.C. Public School Associations.

Miss Samuel was awarded the 1958 Agnes and Eugene Meyer Foundation Fellowship for her service to D.C. public schools. In 1970, she was named Service Club Woman of the Year by the Inter-Service Club Council of Arlington. A former president of the Arlington Business and Professional Women's Club, she received its Woman of Achievement Award in 1975.

Born in Nanticoke, Pa., she earned a bachelor's degree in English from Swarthmore College in Pennsylvania and a master's degree at George Washington University.She did graduate work at Harvard and American universities.

In adition to belonging to numerous professional organizations, Miss Samuel was a delegate to the White House Conference on Health and Protection of Children and to the Virginia State Conference on Youth. She was a former president of the Arlington County Reemployment Commission and a former member of the board of directors of the Washington chapter of the American Association of University Women.

There are no immediate survivors.