The idea of the GTF is one that has been around for a long time. Instead of having the fan and turbine spinning at the same speed, you could theoretically use gears which in turn would require less power for the entire engine, despite weighing more. This means the engine would be a fuel sipper. So why hasn't this happened?
A GTF is a very complex piece of machinery, and it's one that they've never been able to make reliable enough over the years to put it on the wing of a commercial airliner. But now, Pratt & Whitney thinks it has the answer, and it will be putting the GTF on the recently launched Bombardier C Series.
No other engine manufacturer has taken this route. Pratt is the only one that thinks this is the best way forward, but if it truly is reliable, then it can be a remarkable leap forward and one that will thrust Pratt & Whitney back to a position of leadership, instead of where it currently sits as a partner in a couple successful engines but little more.
So when will we know how successful this is? It will take some time. It's one thing to run tests on the engine in the lab or even on a testbed, but it's another to see how it holds up flying the line. Both the C Series and the Mitsubishi regional jet (which will also use the GTF) will enter service in 2013. If this engine has successful runs over time, then we can probably expect to see a larger version as a contender for the Airbus and Boeing narrowbody replacements that are still probably on deck for the 2020 timeframe.