Keith Williams,
Hmm. Having started from the position:
The important thing to note in all of this is the fact that the thrust was not actually produced by the acceleration of the exhaust gas. It happens because the air is not sufficiently stiff...
...the road is stiff enough to prevent it form being accelerated [whilst] the exhaust gas is not sufficiently stiff to resist being accelerated
of late you have said:
I have never argued that there is a direct relationship between the stiffness of a material and the acceleration produced
And now:
[blah blah Fairey Gannet blah]... For all of this to be possible it was necessary for the gearbox structure to be sufficiently stiff to resist the two opposing torque reactions without being destroyed. Had the designers simply looked at the equations of motion and not beyond them, they would simply have said “we’re stuffed”, and gone home.
Now I said many posts back;
"stiffness of the road is irrelevant except insofar as it transfers force to something with more inertia. Stiffness is for structures. In terms of propulsive efficiency it is nothing more than a distraction." Having spent literally thousands of words arguing you are clearly coming round to what I managed to say with about 30 words in my second post.