Re: T. Rex mechanics

["James R. Cunningham" <jrccea@bellsouth.net>]

> Thus, when the rex straightened its tail back to in-line with its torso
> after executing the turn, it would have found itself pointing in exactly the
> same direction as before the turn.  So tail bending would not have helped
> alleviate the foot torque problem at all.

Try bending the tail inboard when only one foot is on the ground. 
Straighten it when both feet are on the ground to create a larger
resisting moment, and take a longer time for straightening to reduce
peak instantaneous loads.

> Move the center of gravity even
> further off to the side, and you have a rex that is falling over.

  All walking, turning, and running seem to me to be acts of controlled
falling.


> There is nothing about the act of banking into a turn per se
> which will help a body rotate in the direction of that turn.  It still comes
> back to torque transmitted through the ground contact(s).

When you drop a cat upside down, how does it flip over prior to ground
contact?   This isn't an old wives' tale.  I've owned a number of cats,
and they do.  My point being that ground contact isn't required.


> only small and barely noticeable quantities of torque are needed to start and
> stop us rotating, so foot torque is more than ample to the task.  Is it
> actually obvious to most people that leaning over in a turn does not have
> the effect of rotating the body into that turn, or should I explain this
> further?

I don't claim to be much of an athelete, but I had a tennis scholarship
in college, and at the time, I found that in some circumstances, massive
amounts of torque were required to start and stop turning, and that
several techniques combined with leaning over served to minimise them. 
None of the above is intended to imply that I think a T Rex was
particularly agile.  In fact, I've not thought enough about them to have
an opinion on the subject.

                                                All the best,
                                                Jim Cunningham
                                                Cunningham Engineering Assoc.