Crab the answer was given wrt the 'simple accelerometer that is the 'balance ball' "you could look it up on google, or if it saves you the time it measures the direction element of the acceleration vector in the plane defined by the arc of the little glass tube, thereby indicating what proportion of the g experienced is lateral"
The distance can be measured by noting the position of the reference points (which I have answered many times now) wrt the back ground. So note the position of the nose wrt the background, then when the tail reaches that point wrt the background note the new position of the nose and repeat etc . There is no parallax involved because the position of the camera does not change, there is no issue with the pan, the straight lines from the camera to the backgraound are valid (because the camera is in the same position.
Do please try and find someone who agrees with your assertion that theQuote:Ultimate Thrust that a rotor disk is capable of is proportional to the Square of the Nr?I think you'll find Nick agrees, as do most academics. Anyway it is true that it is not exactly correct, but it is correct enough, and in a practical sense would be even more practically correct when the degree of induced flow is less important at speed (although that does bring other minor complications) it is still a valid first order phenomenon that should be interesting to folk interested in PoF.
The extent to which it is not exactly true should be quantified by dc/da so that we can see how relevant it is , I have asked him to do that several times.
It's like claiming that v=d/t is not true because of relativity, but it is true enough for our purposes
(hence the quip about throwing the baby out with the bath water, it is a shame that Nick has not addressed the point, probably because I did not convey it with sufficient clarity ('my bad')
Crab "- very logical and concise......" sarcasm again