ok i got it perfectly:
Atomic weaponry is a new technology that has a prerequisite Heavy Bomber technology. Once you got HB you can research Atomic but it costs you 10 IPC per researcher. if you get a 6 result you then roll 2 D6 and modify this roll by the number of invested researchers.
Example: you got HB, then spend 30 IPC for Atomic… after the 3rd turn you roll at least one six, so you then roll another two dice (lets say you roll a 8)… then you subtract 3 ( for 3 researchers) yields number of turns till you can start buying Atomic bombs…
Then when that time comes you spend 10 IPC for this weapon and you can buy just one bomb per turn. Naturally the HB delivers this and NO AA gun fires ( the bomb was dropped from too high an altitude for AA to reach).
The effect: remove any AA gun and factory, PLUS permanent damage of what was rolled on D6.
I am not sure if you must declare how many turns before you start making the A-bomb, I like to have players declare it, but realistically it does not make sence. However, to make it fair i think it should be declared so the other side can do something.