Hi EMIT
Well, I'm no expert but I was just thinking 'at which point would the straps preventing rearward movement of the load be under the greatest strain?'
I don't know the deck angle of the aircraft as rotation finished, but if they were doing a V2 (or V2+10 ) climb it might be 20-25 degrees. A 747 pilot might know, but I guess we dont know the TOW yet which is what will control it.
So, plain old 'inclined plane Newtonian mechanics', would, I think generate the largest rearwards moment for the tie downs to resist, rather than accel' on the rwy or during rotation.
So, once settled in the climb, the force acting to move the load rearward would probably be much greater than during the take off roll. Even a small rearward movement of part of the load might then lead to a larger deck angle, and then to even larger rearwards load on the remaining tie downs.
Just think of 5 25,000 vehicles parked on a 20-25 degree ramp and maybe getting a bit of a shaking.
So, I think they'd be ok until rotated into the climb. Gravity drags the load aft, both pilots grab and push the controls. Gear stays where it is.
Bigger deck angle causes gravity to pull harder on the load.....
