I had nothing to do so decided to calculate what would be the real height size of Fortress maximus.
http://www.youtube.com/watch?v=vj_43GB2tVg
In this clip you can clearly see spike in his binary bound suit and he's not bigger even in the suit. So let's says he's 6 foot.
Since I have a fortMax now I can mesure that the spike figure is 5 cm.
I can also mesure that fortMax is 56 cm total in robot mode.
So if I take 56 * 6 / 5 it give's me 67.2.
So FortMax in real life would be 67.2 foot high.
He's not THAT big :P Just to give you an idea this gundam is 60 foot tall.
http://www.japannewbie.com/wp-conten...yo-gundam2.jpg