RB 211 r.p.m.
I'm not connected with the industry at all (only by enthusiasm, if that counts).
I've just been to New York from Manchester and return, courtesy B.A. (excellent service, I might add, even for us in Steerage), and whilst we were gently wafting our way back across the Atlantic, listening to the 211's thrumming away outside, the thought occurred - Whilst at cruise, given "Average" everything, weather, weight, altittude, W.H.Y?, what r.p.m. are the engines turning at?