Just an interesting observation on the takeoff roll lengths of my past 2 747 flights last week.
1. LAX-ICN on OZ 744. Flight time: 12:50 for about a 6,000 mile journey
I was seated in the F cabin so I had a great view of the runway. We hear all the time that the 747 is a dog on long heavy flights, but I was amazed that we lifted off Runway 24L at the "3" marker, which means we had about 3,000 ft of runway left. By doing the math, we only needed about 7,200 ft to take off on this fairly long flight.
2. SYD-LAX on UA 744. Flight Time: 12:48 for about a 7,500 mile journey
Surprisingly, this flight took much more room and at rotation only had about 2,500 ft of runway left on Runway 34L, which is 13,000 ft long.
Now both flights had roughly the same flight time length, load factor, elevation, temperature at takeoff and winds were less than 10 mph on both segments.
Now I know a lot of variables can go into takeoff calculations and whatnot, but I just thought it was an interesting observation that one flight used so much more runway than the other given many similar variables. Granted I do not know anything about the cargo loads. I'm 99% both flights used a de-rated takeoff as well.
Just my observation for my trip. Great flights on both though