Thor, the reason the carburettor was placed on top of the supercharger in allied engines was that it increased the efficiency of the supercharger due to the cooling of the air due to vaporisation of the fuel. This was the main reason Rolls Royce chose the carb over fuel injection, because they considered it. On big radials the supercharger has the bonus of better distribution of the mixture to the cilinders.
Koivis, amazing find! I don't mind offtopic if it's about beautiful technology (and huge and absurdly complex engines
)
For fun you should see diagrams of the oil distribution system in big radials, it looks like spaghetti XD
Okay, here's a BIG ONE:
