Quoting an old tech school lecturer 'LOP is the domain of old men and aeroclubs' ;-)
probably a good reason for that, those old men KNEW how to operate an engine. The SOP's for many airlines running big piston engines was precisely LOP and those things ran many thousands of hours between overhaul.
Too many old wives tales. There is such a thing as too lean, and its exactly the same place as too rich as well.
J
