Hi
I need to know from you how much runway lenght needs a 747 in order to play with runway lenghts.
harpsi
That's hard to flat out answer, as it depends on takeoff weight and outside temperature. Given the massive size of the 747, either of these can drastically change numbers.
From my charts, a 747 at MTOW, PACKS ON, anti-ICE OFF, standard altimeter, 15C OAT, 0 kts headwind, flaps 20 and a dry runwy without takeoff derate needs about 11,100' of runway for a takeoff. Note that this is not the length of the takeoff roll, but the full length needed for a takeoff with RTO at V1, but that's how necessary takeoff distance is calculated. Hence the reasons internationals almost always depart 32L full length at KORD.
A 747 at MLW, PACKS ON, anti-ICE off, standard altimeter, 15C OAT, flaps 30 manual approach, 0 kt headwind, autobrakes 4 and a dry runway needs 6,800' of runway for landing (plus 1000' displaced TD zone for most operations = 7,800').
I know you're doing this for AI which doesn't have nearly as many considerations, but I figured I'd give the worst case scenerios as something to work with. By comparison, an empty 747, but all other conditions the same, needs 4,400' for takeoff (50,000 lbs of fuel) and 4,600' for landing (with 24,000 lbs of fuel per FAR min. reserve fuel). As you can see, quite a difference. Technically, these numbers are also specific to O'Hare, as aiport elevation will change density altitude. Unless you're heading to some place like KDEN though, they won't change that much.