ORIGINAL: Chris H
ORIGINAL: Uamaga
There is no die roll involved here: at the moment you gathered 100 prototypes for given a/c its availability date is bumped by one month unconditionally(of course sometimes it can be effectively less then a month - when the "100" is reached just a few days before the original avail date is to come). No random factor at that point. Point. [:)]
This brings me back to my origina question. Why do they arrive anytime during the month when they automatically arrive on the 1st otherwise. The only way this can happen is that a die is rolled everyday duing the month.
Nop. No die roll, sorry. [:)]
Internally it goes more or less like this: every day when R&D factory produces new prototype(s) (it's rare case that single factory create more then one prototype in a day) the (hidden, non visible in game interface) prototype total is increased and when it finally reaches value >= 100 then avail-date is adjusted and prototype total reduced by 100 and then the acumulation cycle restarts.
So why sometimes a/c are entering production in the middle of the month? Easy... Using as example my current game:
I've got Tojos in production (about) 8. June (their original avail-date was 1 July). This happens every time when the last 100 of prototypes is reached in less then a month before a/c avail-date. In my case Tojos apparently reached 100 8th (or rather 7th) of June - at that moment avail-date was moved from 1st July to 1st June (and proto-totals reduced to zero) and next day game found out that Tojos avail-date <= today so Tojo factories went productioin path delivering first machines to IJAF which badly needed them.
In the same game I got Tonys exactly a month earlier (original avail-date 1st Aug, moved to 1st July). it was because I managed to accumulate the 100 of Tojo prototypes more then month before avail-date: I noticed avail-date bump on Replacement Screen around 15th June in this case. There was only about 15 days left which was clearly not enough to gather new 100 of prototypes and get another month of speed bump which would make Tony case looking like Tojo above.

