Engineering, where he remained until his retirement in 1989. He also taught for periods at other universities he visited, including Delft Technical University in Holland. What was important about his teaching in Holland was that he learned Dutch and gave his lectures in Dutch. A number of Wally’s friends who lectured at Delft after he did were upset with him because they were all asked why they could not give their lectures in Dutch like Wally did.
In a series of papers beginning with his Ph.D. thesis, “Linearized Supersonic Flow,” submitted to the California Institute of Technology and defended on New Year’s Day 1947, he developed the concepts of transonic and supersonic area rules. Although the world-famous aerodynamicist Theodore von Karman was Wally’s thesis supervisor, he had never seen his work until Wally turned in his thesis, at which point he discussed the results with him. The rules define how an airplane’s cross section should be designed to minimize the drag that results from shock waves that develop locally when a plane flies at speeds below but close to the speed of sound and the shock waves that develop about the airplane above the speed of sound. Credit for the transonic area rule was not accorded Wally but rather given to Richard Whitcomb, who independently but some five years after Wally’s presentation of it discovered it while working at the National Advisory Committee for Aeronautics, which later became the National Aeronautics and Space Administration. This work resulted in the “Coke-bottle” aircraft design in which the airplane’s fuselage was indented from the wings inward by an amount related to the area occupied by the wings from the fuselage to the wingtips.
Wally has been given full credit for the related supersonic area rule. The design concepts of his theoretical work were applied to the Convair B-58 bomber, the world’s first operational supersonic jet bomber, which went into production in 1959, and to the Concorde airliner, which went into service about 10 years later along with other supersonic aircraft of the period. All supersonic aircraft incorporate the area rule considerations in their design.