Each is a high technology engine that offers significant benefits in fuel economy, noise and environmental performance. The major difference is that Pratt & Whitney uses a gear, enabling the fan to turn at a different speed than the core, while the LEAP-X builds on technology from the successful wide-body GE-90 and GENx engines with a conventional single speed design.
How do these new engines compare? Based on published data from CFM and Pratt & Whitney, the following table summarizes performance characteristics.
The LEAP-X is currently on two programs, the C919 and NEO, with a 2015 scheduled entry into service. The GTF is on the Bombardier CSeries, Mitsubishi RJ, Irkut MS-21 and NEO, with initial entry into service in 2013 for the CSeries. Advantage PW
Initial fuel economy is similar for both – 15% for the LEAP-X and 16% for the GTF. As the technology matures, PW promise a 30% improvement for the GTF, and while no estimate is provided for the LEAP-X, we would expect 20% as the engine matures. Advantage PW
Maintenance costs are a significant element of engine economics. The LEAP-X promises costs comparable to today’s CFM-56, or no change. The PW GTF, which eliminates low pressure turbine sections through the improved efficiency of the fan, promises a 20% reduction in maintenance costs. Advantage PW
Noise is a key factor for airports, and each of the new technology engines promises quieter performance. The LEAP-X projects a 15 dB reduction, making it 3 times as quiet as today’s engines. The GTF promises a 20 dB reduction, making it 4 times as quiet as today’s engines on the logarithmic decibel scale, where every 10 dB doubles the volume. Advantage PW
Nitrous Oxide emissions are a critical element in improving air quality, and each engine provides a 50% reduction when compared with today’s levels, and easily meets the CAEP/6 standards. Advantage: Tie
When directly comparing published information on the NEO engine alternatives, it appears Pratt & Whitney has returned to the narrow-body market that it once dominated, and then lost, with a vengeance. The GTF has the lead in virtually every category, and has potential to be a game changing engine. Of the two offerings, it appears that the GTF is the more desirable alternative.