Since the ICAO data for the previously mentioned engines indicates that the RR hogs more fuel in take-off, climb, descent and idle, she sure ain't going to burn less in cruise than the competition.
I hinted at it in a previous post, but I guess I'll have to spell it out - untreated SLS testbed values of sfc. are NOT a valid comparison of installed cruise sfc unless the bypass ratios of the two engines are identical.
Basic engine thermodynamics says that the ratio of SLS to cruise sfc depends on the Bypass Ratio and the cruise Mach Number. The higher the BPR the worse is the ratio (i.e. the worse the cruise sfc for a given SLS sfc.) Comparing engines simply on SLS sfc therefore introduces a systematic bias in favour of the high bypass engine.
In addition, the high BPR engine will have more wetted area (drag) so the installed sfc will be relatively higher and the powerplant will be heavier.
I take the point that one has to be careful about comparing apples with apples, and the engine weights given in the FAA certification fact sheets (which one might have thought free of bias even though one of their functions is to further US civil aviation
) do not seem to be consistent definitions from one manufacturer to another. In addition, there is usually a factor of 1.6 or more between the bare dry weight of the engine and the installed powerplant weight, and this factor will obviously depend on what is included in the datum engine weight. For this reason I would prefer to use differences between installed engines derived from the aircraft manufacturers MWE values. For the A330, taking the RR version as datum, the GE aircraft weighed just over 600 lb more and the PW version a whopping 1800 lb more.
To the best of my knowledge, the GE engines have higher BPR than the Trent equivalents, which is probably why the net gain on the A330 was only 1% over the Trent and PW4000 versions rather than the value suggested by ICAO emissions data which is based on SLS measurements.
Don't get me wrong; I hold no brief for one engine manufacturer against another, but I hate to see dodgy comparisons
