Physics freaks: Multicell vs. Sectoral?

[gearfreak]

...example, the original little horn on the Altec 604 and 604B (multicell) vs. later incarnations.Anyone have any better links?

Not to contaminate the original post question, but of course eventually many (UREI, JBL/PAS, latter Altec) went to non-vaned / non-sectoral HF for duplexes.
Point being, I believe there is some discussion here on the board already about the newer GPA coaxials, and whether they are exponential or tractrix (?) or hybrid of some sort.
It might shed some light, working backwards.