Yes dc/da !!!
that is very close to exactly what I am saying, the points of difference are not worth getting into at this stage, you are the first person (other than perhaps AC) who seems to be getting it. If we can keep this constructive then I think we could make a difference.
I still think to have the difference would be interesting
If you have a think about it it would be a curve (i suspect fairly subtle, practically irrelevant) of how UCA changes with Nr, to go with the function that is dUCA/rho (straight line?)
I think it would be fair for YOU to elucidate the difference to UCA that the departure from Nr^2 would give. can you quantify it ?
After all I accepted your challenge to derive some maths and did so within the assumptions that I made, (including addressing points you LATER made wrt twist etc) Anyway don't bother if you don't feel like it, I might do it if I get the chance.
[Crab ONLY - do we really have to waste our time arguing about an irrelevant point that you are disingeuously abusing to try and demean me?
Especially when you are not even right. [i]I was assuming that the camera was stationary as far as is relevant whilst panning. If we allow for your (ridiculous) supposition that it moves laterally as it pans, and we take the MOST EXTREME example of moving the camera whilst panning, we say the holder of the camera has 3 ft arms, we assume the ratio of distance to the helicopter to distance from helicopter to background is about 1:25 seems reasonable we find that it makes no difference within the tolerance of the measurments 1 part per 250 is not relevant {{{EDIT INSERT, that is 1 in 250 of the measured path length, NOT the distance of the helicopter or background which is completely unimportant}}} and I most definately don't claim such an irrelevant degree of accuracy.
and in any case the measurments I never claimed were particularly accurate. The only accurancy I was going for at that stage were to see if the EXPERT OPINION was anywhere near correct , which it WAS NOT (20-30kts, ridiculous !!! ). please don't come back to me on this parallex w.o.t. please try and understand what dc/da has said, he's really close, and I think you would enjoy the point if you 'got it'. try it you'll like it ]