perfect storm, page-22

Wang
From the RR website, well of course they will say its the best !

More than 700 engines in service
Product details
The RB211-524 fleet has logged nearly 66 million flying hours, and almost 12.5 million flight cycles
First engine ever to achieve more than 27,500 hours on-wing
Selected by some of the world's leading airlines
Interchangeable between Boeing 747-400 and Boeing 767-300 (RB211-524H /-T)
Flexible rating selection
Lowest life cycle cost of ownership
Continuous improvement with Trent® technology
RB211-524G/H upgraded with the Trent HP system gives:
Lowest mature fuel burn
Best performance retention
Lowest maintenance costs
Compliance with all current and planned emissions legislation
Every 34 seconds an RB211-524 powered 747 takes off or lands
The RB211-524B4 currently operates on the Lockheed L1011 Tristar.
As a member of the RB211 family, the RB211-524 is built on sound fundamentals.

The three-shaft architecture, first introduced on the RB211-22B, allows an engine to have fewer stages giving a shorter, stiffer structure. This technology allows the rotors to run to their optimum speeds thereby reducing the need for compressor variable guide vanes.

The innovative wide-chord fan blades, allow a reduction in the number of fan blades, increasing efficiency, reducing noise and giving unrivalled protection against foreign object damage.

Through the Rolls-Royce concept of family designs, the RB211-524G/H was upgraded with 04 module HP (high pressure) technology developed on the Trent 700 engine family in 1997.

In the RB211-524G/H-T the HP turbine system is designed to operate at Trent 700 temperatures that are significantly higher than the RB211-524. As a result of this, the engine is able to better retain its performance characteristics throughout its service life.

The benefits of the -T on the Boeing 747-400 are:

2 per cent lower fuel burn.
longer lives on wing - through lower operating temperatures, increased margin and higher capability hardware in the core.
lower weight – over 200 lb per engine.
lower emissions – 40% lower NOx.
lowest maintenance cost - through longer lives and better capability hardware.
best performance retention.
The Trent style combustor reduces NOx emissions by 40 per cent, making the RB211-524G/H-T the engine with the lowest NOx emissions on the Boeing 747-400.

The RB211-524G/H-T was certified in 1997 with significant margin to all environmental emissions regulations and Chapter 3 noise limits on both the Boeing 747 and Boeing 767 aircraft.

The RB211-524G/H offers full commonality and engine changeability for a Boeing 747 and Boeing 767 mixed fleet. This results in lower spares holdings and the lowest possible cost of ownership. The RB211-524G/H-T was cleared for use on the Boeing 767 early in 2001.