Engineering & Technology

Flügge-Lotz, Irmgard | Discontinuous Automatic Control

  • First edition, first printing of this important work by applied mathematician and engineer Irmgard Flügge-Lotz (1903-1974).

    Flügge-Lotz studied mathematics at the University of Hanover with the intention of applying it to engineering problems, and was the only woman out of a class of one thousand students. After earning her doctorate in engineering in 1927 she first worked at the Aerodynamisch Versuchsanstalt, a research institute in Göttingen, where “she solved the integro-differential equation that had been formulated by Ludwig Prandtl for the spanwise lift distribution of an airplane wing” (Ogilvie, Biographical Dictionary of Women in Science, p. 456). After the war she and her husband joined the French National Office for Aeronautical Research, where she served as chief of a research group in theoretical aerodynamics. In 1948 the couple relocated to Stanford, and though Flügge-Lotz taught, conducted research, and advised graduate students, she was not appointed full professor until 1960, when she became the first woman to hold that title in Stanford’s engineering department.

    “Flügge-Lotz’s international reputation was based on her mathematical contributions to aerodynamics and automatic control theory. her first publication with the AVA in Göttingen, on the method fro the calculation of the spanwise lift distribution on wings, was important enough to be called the ‘Lotz method’”. She continued to contribute to aerodynamic theory. However, her contributions from 1948, when she arrived at Stanford, to her retirement in 1968, were very important. She worked in fluid mechanics and developed numerical methods for solving problems in compressible boundary-layer theory” (Ogilvie). Flügge-Lotz wrote two books, published over fifty papers, and served on the advisory boards of several journals. She was the first woman elected to the American Institute of Aeronautics and Astronautics, and the first to give that organisation’s prestigious Kármán lecture, in 1971.

    Discontinuous automatic control systems were increasing in importance during the mid-century, particularly for applications such as guided missiles. As the jacket blurb for this volume explains, “Discontinuously working elements (on-off controls) are widely used in automatic control systems. From an engineering point of view they are attractive because they are nearly always simpler, more rugged, and cheaper to build than continuous controls. But prediction of their effects in the controlled system is sometimes so complicated. Owing to mathematical difficulties... engineers have frequently avoided discontinuous control in systems where it wold have been preferable... This book, with its 102 diagrams, will be welcome to engineers who prefer visual presentation to formal mathematical development".

  • Princeton, NJ: Princeton University Press, 1953.

    Octavo. Original red cloth, title to spine in silver. With the dust jacket. Diagrams throughout the text. Ownership inscription to the front free endpaper dated 1959, and a small pencilled mark to the front jacket flap. A very good copy, the cloth and contents fresh, in the dust jacket with a little rubbing and toning along the edges and spine panel, a small uneven tear to the upper panel, a one inch partially closed and creased tear to the lower panel, and a few nicks and short splits.