Precession in Turbofans
Must remember that that there are precession effects in turbofans. Much of the precession effects may be negated by having HP and LP Spools that rotate in opposite directions. Examples of engine that do so are the RR Trent, the GE90 and the Engine Alliance GP7200 ( which is based on the GE90).
EDIT: - Whoops I see awblain has already answered with my point. My apologies.
Last edited by hval; 8th August 2011 at 15:41.