I suppose most of you know the "zero G" aircraft like the NASA KC-135, the A300 and now the 727.
When Concorde stopped flying, it was suggested, tongue in cheek, they should keep one for zero-g flights because it would allow zero g for two to three times longer.
But then I was told by a NASA engineer (who actually flew on the NASA "Vomit Comet" KC-135) that somewhere the speed of the aircraft dropped out of the equation that defined the duration of the zero g: the speed didn't matter, just the availablity of a nice big cabin to work in.
I just now got involved in a discussion about this (I think that discussion was triggered originally by the zero-g dog video on YouTube you all must have seen.... never mind ....), and tried to re-do the maths.
And according to my maths, assuming the same procedure: pull-up to 45°, push-over at zero g, until pitch-down at 30° (or 45° for simplicity of the maths), the duration of the zero-g state is proportional to the speed of entry of the parabola at 45°.
I would like a second opinion
