Thanks again Turbine D.
It's my understanding that a triple spool engine requires a higher volume of air to start than a twin spool engine.
A twin spool engine produces more power from two High Pressure Turbines (HPT) driving it's coupled High Pressure Compressor (HPC) than one HPT as in a triple spool engine driving it's respective HPC. That's the main reason that RR will be adding an extra HPT disk in it's XWB series engines for improved efficency. This will add quite a bit more extra weight to this engine series and one could say that they are copying some of the twin spool advantages in turbine architecture.
A330-300 Estimated Maximum Payload.http://www.airbus.com/fileadmin/medi...A330_Jan11.pdf
Chapter 2-1-1 - page 1 - Revision Jan 01/11
CF6-80E1 - 52,169 kgs.- 115,012 lbs.
Trent 700 - 52,069 kgs. - 114,792 lbs.
A330-300 Airbus Payload / Range graphs.http://www.airbus.com/fileadmin/medi...A330_Jan11.pdf
Chapter 3-2-1 pages 6 & 7 Rev. Jan 01/11
CF6-80E1 - 6,625 nm.
Trent 700 - 6,500 nm.