Thanks for that information, Steve.
I was specifically thinking of my Easy Star where a 2200kv inrunner seems a popular upgrade choice. Some guys seem to run it on 2S and some on 3S, but in both cases with a 6x4 prop. Invariably they fly about half-throttle with power to spare.
Returning to the original question - with same motor/ same prop and 2S or 3S batteries supplying the same power, what is the difference with the 2S where the prop is (presumably) turning slower?
Can I ask an additional question - some inrunners are an exact fit in the EZ. Do they run any hotter than the standard brushed motor or is some additional cooling needed?