I don't think so, lomapaseo. Moving mass at a steady state with less energy is the definition of higher efficiency, no? (from barit1).... The aero efficiency increases, due to increased latitude with design/material, so more work is done with less expenditure of energy. RPM is erm......rate, not NET? The gaspath thrust past LPT is not neglected, the number of stages and their respective capture rate leave a remainder. This does not moot their number; it is a ratio that gets selected based on core power, as TurbineD says. In this engine, the exhaust is ten percent of the power available. Actually, with a bypass ratio of 9/1 more like 11.13 per cent?
I think some credit for the success of this engine and its airfoils should be shared. The use of welded compressor disc/blade rotors, Titanium alloys in high temp areas, and coatings are not inconsequential.
Rgds
Last edited by Lyman; 10th November 2012 at 14:42.