I really appreciate your thoughtful answer to my initial post.
However, I want to explore the issue of accuracy further.
I'm not a mechanical engineer, nor a watchmaker. But I figure that if the coaxial escapement decreases friction in the system, it must also increase isochronism by incrementally reducing dynamic and positional friction, and thus, irregularities in the movement of the anchor and balance amplitude.
It seems to me that Walt Odets is saying as much in his review of the coaxial escapement in the Horologium:
In small calibers like the Omega, the co-axial escapement is aimed much more at stability over time than "accuracy" per se. As delivered from the factory, the Omega Co-Axial appeared to provide consistent rate, and was adjusted about 15 seconds a day fast. Positional performance was essentially perfect. (Remember at the time of Mr Odet's review, the coaxial escapements manufactured by Omega were receiving too much lubrication, which may have deteriorated their performance).
Timer tapes for dial-up and crown-down positions are shown left after a rate adjustment (1) with the balance weights. Note, particularly, the extraordinary consistent amplitude between positions (2). We would normally expect a 20 to 40 degree difference. This consistency virtually eliminates anisochronistic effects in positions. Note also the (estimated) lift angle of 35 degrees (3).
I suspect that the short, equal-radius locking action, equal impulse to the balance in both directions, and, most importantly, the small lift angle of the co-axial escapement contribute to the remarkable positional performance of the Omega Co-Axial. In a conventional lever escapement, a steeper locking angle is normally used on the exit pallet than on the entry pallet. This difference may interact with gravitational influences in positions (e.g. with the exit pallet down). In the conventional lever escapement, differences in impulse to the balance running in different directions may, likewise, interact with gravitational effects in vertical positions.
I thought the very purpose of the Tourbillon was to eliminate anisochronistic effects in positions.
So, my question stands: which of the Tourbillon or the Coaxial escapement is the better technology, with regards to accuracy?
Thanks for your consideration.