The 1950s brought about significant developments and commercialization of cross-flow fans, and Coester [6] developed the first simple vortex model for the fan internal flow. Perhaps the most noteworthy early developer and researcher of cross-flow fans is Bruno Eck, and his comprehensive book [1] describes their fluid mechanics and controlling parameters, including the predominant eccentric vortex region which he discovered. Eck also outlines the wide range of possible vortex wall designs and their influence on fan performance. Progress and utilization of cross-flow fans thereafter has been considerable, based primarily on experimental development, seeking means for stabilizing the vortex and fan performance (e.g. [1], [7] and [8]). Simplified models of the fan were developed using potential flow and mean-line analysis (e.g. [9], [10] and [11]), but limited capability was achieved with those techniques.