787 fuel burn, GEnx and how it relates to LEAP-1B
787 fuel burn: Aviation Week has this story about the early fuel burn results for the Boeing 787 beating expectations (which admittedly were tamped down because of the program difficulties). Some of this has been reported before. What caught our eye was the detail about the GEnx engine. Why? Because the CFM LEAP-1B derives much of its technology from the GEnx, including the higher temperatures fleetingly referenced in the AvWeek piece.
CFM is relying on high temperatures to achieve the fuel burn required by Boeing’s 737 MAX. This is hotly debated (pun intended) between CFM and Pratt & Whitney in the competition between the LEAP and the PW GTF.
CFM advocates that its hotter-running engine, equipped with advanced technology ceramics and other advanced materials, gives it the advantage over PW’s Geared Turbo Fan technology. PW argues that the hotter CFM engine will require more maintenance. Engineers that we ask generally agree that the hotter temperature approach will be a challenge for long-term maintenance but fall back on CFM’s sterling reputation of reliability as a measure of comfort. At the same time, these same engineers–who have no connection to either CFM or PW–like the GTF technology but want to see it proved in service.
Steven Udvar-Hazy said it best. It will be five to seven years after the engines are in service before the industry knows the reliability and performance of either engine’s advanced technology.