Dorothy McFadden Hoover (1918–2000)
Dorothy M. Hoover was a pioneer in the field of aeronautical mathematics and research. The granddaughter of enslaved people, she overcame the significant obstacles facing African-American women in the twentieth century to earn advanced degrees in physics and mathematics. One of her greatest achievements in aeronautical research was her contribution to the development of the “thin sweptback tapered wing,” which revolutionized flight and became the aviation industry standard. Her life story was essentially unknown until she was briefly mentioned in the highly acclaimed book Hidden Figures: The American Dream and the Untold Story of the Black Women Mathematicians Who Helped Win the Space Race (2016), by Margot Lee Shetterly. Hidden Figures, which was made into a major motion picture in 2016, told the story for the first time of black women mathematicians, or “human computers,” who were key players in the space race.
Dorothy Estheryne McFadden was born in Hope (Hempstead County) on July 1, 1918, to William McFadden and Elizabeth Wilburn McFadden. She was the youngest of four children. She graduated from Henry Clay Yerger High School in Hope in 1934 at the age of fifteen. McFadden arrived at Arkansas Agricultural, Mechanical, and Normal College (AM&N) (now the University of Arkansas at Pine Bluff) as a sixteen-year-old in 1934 and graduated in 1938 with a BS in mathematics, two months shy of her twentieth birthday. There were only two math majors in her class of 135 students. In the 1938 class yearbook, The Lion, the quote associated with her picture was, “She handles big words as though she teethed on Webster’s dictionary.”
In a letter written to her mother, postmarked May 8, 1938, she requested that her mother try to arrange to come to graduation, since many of her classmates’ parents were coming. She also asked for “$6.50 which would cover the graduation fee that included $2.00 for a yearbook, $.55 for outstanding bookstore bill and $.09 each for 30 invitations.” She apologized for having to ask for money and mentioned she borrowed the $.03 stamp to send the letter.
Following graduation in May 1938, Dorothy taught mathematics, English, and science at Newport (Jackson County) from 1938 to 1939 and then rural Jesup, Georgia, from 1939 to 1941. The 1940 U.S. census shows she was teaching school in Jesup, living as a boarder earning $600 per year. From 1941 to 1942, she taught at Ft. Valley, Georgia. While there, she met Sylvanus Bowe Clarke. In 1942, they married, and he was inducted into the U.S. Army during World War II. In 1943, Dorothy Clarke earned her first master’s degree, an MS in mathematics, from Atlanta University (now Clark Atlanta University), the first institution in the country to award graduate degrees to African Americans. Her thesis, “Some Projectile Transformations and Their Applications,” served as a prelude to her future work in aeronautics. Her thesis advisor was renowned mathematics professor Claude B. Dansby (1897–1973).
As she was finishing her master’s program at Atlanta University, as a result of President Franklin D. Roosevelt’s prohibition of racial discrimination in the national defense industry, Langley Labs, NACA (National Advisory Committee for Aeronautics—later NASA) began hiring African-American female mathematicians. Clarke was one of the first of six African-American women hired as P-1 mathematicians at Langley, with a salary of $2,000 per year. She was immediately made one of the three section supervisors. She worked at Langley from 1943 to 1952, during which time she achieved several firsts in the field of aeronautical research. Her graduate-level work helped set her apart from her peers, and she was exceptionally fluent in abstract mathematical concepts and complex equations. For that reason, her white female supervisor, Margery Hannah, channeled to Clarke the rigorous mathematical assignments that came to the group from Langley engineer and chief of the Stability Analysis Division R. T. Jones, arguably the preeminent aerodynamicist of the twentieth century. In 1946, Jones selected Clarke to be his personal mathematician, replacing Doris Cohen, his new wife. Clarke was the first of the black human computers promoted to a line section, the Stability Analysis Section, and she thrived in this accomplished and highly competitive conclave.
In late 1946, Jones moved to the newly established Ames Laboratory in California, and Clarke began working for his successor, Frank S. Malvestuto Jr., a brilliant engineer and prolific researcher. Clarke was the primary mathematician for the Stability Analysis Section from 1946 to 1951. By 1951, she had earned the lofty title of Aeronautical Research Scientist, graded GS-9 in the government’s revamped rating system; the pay was nominally $5,400 per year. That same year, she was listed as co-author with Malvestuto on two significant research publications addressing “thin sweptback tapered wings” (or jet wings) on aircraft. Being listed as a co-author was a landmark accomplishment. She was the first African-American woman to be listed on a Langley engineering report; typically only white male engineers were listed.
The contributions made by Clarke and Malvestuto had real-world applications in the development of the aeronautical industry in the United States and around the world. This wing design allowed for stable flight at higher and higher speeds (“if it is not stable, it does not fly”). Today, every cargo or commercial jet aircraft utilizes the thin, tapered jet wing, which had become the aeronautical industry standard. It also supports the U.S. Air Force’s long-range B-52 bomber, its large C5 cargo plane, and its AWACS, a converted Boeing 707.
In 1947, Clarke had a daughter, Viola Clementine Clarke. Dorothy and Sylvanus divorced soon afterward. In 1950, she married Richard Allen Hoover; they had a son, Ricardo Allen Hoover. Ricardo died in 1967 at age seventeen; Viola died in 1969 at age twenty-two. Dorothy filed for divorce from Richard in May 1952, a few months before she started her graduate work in Arkansas.
In 1952, at what seemed the pinnacle of her career, Hoover took a four-year leave from the world of engineering to pursue her interests in theoretical mathematics. In 1954, as a single parent of two small children, she earned her second master’s degree, this one in physics at the University of Arkansas (UA) in Fayetteville (Washington County). (Fayetteville at this time was a highly segregated community.) A portion of her 1954 master’s thesis, “Estimates of Error in Numerical Integration,” was included in the Journal of the Arkansas Academy of Science the following year.
Hoover was one of only fifteen African-American graduate students at UA at this time; she was likely the only hard-science graduate student. She was the first African-American woman to earn a master’s in physics from UA and is believed to be the second African-American woman in the country to earn two technical master’s degrees. She also belonged to Pi Mu Epsilon and the physics honor society, Sigma Pi Sigma.
In 1954, Hoover was awarded a John Hay Whitney Foundation Opportunity Fellowship, a competitive grant aimed at candidates with “evidence of special ability” and “exceptional promise” who did not have “full opportunity to develop [their] talents because of arbitrary barriers, such as racial or cultural background or region of residence.” At this time, only three African-American women had earned PhDs in mathematics.
She then entered the PhD program in mathematics at the University of Michigan, serving as a teaching fellow and as an instructor of “school algebra” and trigonometry. She completed the typical coursework during her first three semesters, taking classes in algebra, analysis, geometry, and topology. She also passed language exams in French and German. For reasons unknown, however, she resigned as a teaching fellow in 1956 and subsequently left the PhD program before completing her preliminary (qualifying) examinations.
Hoover returned to the Washington DC area, where she served in a variety of government positions. From 1956 to 1959, she was a mathematician at the Joint Numerical Weather Prediction Unit, a collaborative effort between the U.S. Weather Bureau, the U.S. Army, and the U.S. Navy, where meteorologists, mathematicians, and other scientists used atmospheric data to make real-time weather forecasts, a significant achievement at that time.
In 1959, she entered space research, working at NASA’s Goddard Space Flight Center, where she was one of the few female mathematicians. After Vice President Lyndon B. Johnson released a report on minority employment in federal service, Hoover was promoted to GS grade 13 (one of the first African-American women to achieve this pay scale), making about $11,000 per year. While at Goddard, Hoover teamed up with Dr. Aaron Temkin, who later became one of NASA’s preeminent atomic physicists, to coauthor a chapter titled “Nonseparable Theory of Electron-Hydrogen Scattering” for the 1963 book Methods in Computational Physics.
While continuing her mathematics research in Goddard’s Theoretical Division, Hoover began writing a book, A Layman Looks with Love at Her Church, that chronicles the history of the African Methodist Episcopal (AME) Church. This book allowed her to reflect on her childhood in Arkansas and the influence of her churchgoing parents. The preface was dated November 22, 1966, and the book was published in 1970, two years after she began working as an operations research analyst at the Defense Communications Agency (now the Defense Information System Agency), where she also served as a program officer. In 1968, she received her twenty-year federal service award.
She was an active member of the Campbell AME Church, located in the Anacostia DC area. She lived in Temple Hills, Maryland, a growing black middle-class community in southern Prince George’s County.
Hoover died on February 7, 2000, in Washington DC of complications from congestive heart failure.
For additional information:
Frazier, Lisa. “Searching for Dorothy.” Washington Post, May 7, 2000. Online at https://www.washingtonpost.com/archive/lifestyle/2000/05/07/searching-for-dorothy/b565fa48-6a5d-44c7-9267-453a33d492c6/?utm_term=.fc2a353317a7 (accessed March 15, 2021).
Hoover, Dorothy M. “Estimates of Error in Numerical Integration.” Journal of the Arkansas Academy of Science 8 (1955): 204–207. Online at https://scholarworks.uark.edu/jaas/vol8/iss1/23/ (accessed March 15, 2021).
Khadjavi, Lily, Tanya Moore, Kimberly Weems, and Ulrica Wilson. “Shining a Light on a Hidden Figure: Dorothy Hoover.” Notes of the American Mathematical Society 67 (March 2020): 368–372. Online at https://www.ams.org/journals/notices/202003/rnoti-p368.pdf (accessed March 15, 2021).
Malvestuto, Frank S., Jr., and Dorothy M. Hoover. “Lift and Pitching Derivatives of Thin Sweptback Tapered Wings w/Stream Wise Tips and Subsonic Leading Edges at Supersonic Speeds.” National Advisory Committee for Aeronautics, Technical Note 2294. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930082953.pdf (accessed March 15, 2021).
———. “Supersonic Lift and Pitching Movement of Thin Sweptback Tapered Wings Produced by Constant Vertical Acceleration subsonic Leading Edges and Supersonic Trailing Edges.” National Advisory Committee for Aeronautics, Technical Note 2315. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930082993.pdf (accessed March 15, 2021).
Shetterly, Margot Lee. Hidden Figures: The American Dream and the Untold Story of the Black Women Mathematicians Who Helped Win the Space Race. New York: William Morrow, 2016.
Stewart, Shea. “Hope’s ‘Hidden Figure.’” Arkansas Democrat-Gazette, May 14, 2017, pp. 1E, 6E.
“They Chart the Course for the Astronauts.” Jackson Advocate, July 6, 1963, pp. 1, 8.
Richard D. Sallee
Oklahoma City, Oklahoma
Last Updated: 03/31/2021