Factors influencing endurance
Looking at the figures for endurance/range in the C172M handbook, I see that it gives figures for various engine rpm values and altitudes, but assumes max gross weight for all. This led me to wonder how much influence weight has on endurance. I guess that there are a bunch of other factors too, obviously mixture setting is one, and I suppose that trim will have a significant influence on drag and thus range? How important are these factors? Is there any way to quantify them?