по оборотам и визуально видно, вообще-то. две позиции шага винта - не переменный, что ли? постоянный?

знатоков английского и читателей википедии развелось немеряно.


Air Publication AP1530B Blenheim MKIV Pilots notes

Section 2 Handling and Flying notes for the pilot. Introductory notes


(iv) Variable Pitch Airscrews - The airscrews are of the two pitch type i.e. Fine and Coarse. Fine pitch is always used for take off, for climbing on one engine and when approaching to land. Coarse pitch is used for all other conditions of flight, except when throttled well back when fine pitch may give smoother running