News Column

MAX Engine Lifts Boeing... and Airbus

Dec. 7, 2012

Seattle Times Business Staff

Boeing 737
MAX engines reportedly will power Boeing's newest generation of 737s.

In the heated sales battle between Boeing's 737 MAX and Airbus' A320 neo, one neutral arbiter can blow some cool air on the claims of superior performance by both sides.

For this next generation of narrowbody airplanes, it's all about the engines.

CFM International, a joint venture between GE and Snecma of France, makes an engine that powers today's 737s and A320s. It also is developing a new, super-efficient engine -- called the LEAP -- for both the MAX and the neo.

In a briefing in Seattle this week, LEAP program managers Gareth Richards and Francois Bastin outlined their technology.

They also offered a calmer take on how the two airplanes may stack up than Airbus did in recent trade- press ads showing the 737 MAX with a Pinocchio nose.

The engine-makers' assessment? "The relative improvement over today's product is the same in both cases," Richards said.

With the Boeing plane lighter than the Airbus, the MAX version of the LEAP is much smaller than the neo version -- 69 inches vs. 78 inches in diameter.

Yet, CFM is contractually guaranteeing that the MAX and the neo engines will each be 15 percent more fuel-efficient than current models.

That sounds like a recipe for maintaining today's status quo, in which Airbus and Boeing split the narrowbody market roughly evenly.

Yet there is risk. Improving today's already breathtaking engine technology entails some big ... leaps.

Snecma is making the LEAP's fan from advanced composites instead of metal ? each of the fan's 18 hollow blades is woven from miles of carbon fiber.

The shroud around the fan is made from a ceramic composite, strengthened with metallic threads ? just thousandths of an inch away from the fast-spinning blades.

Both components expand and contract with heat, so a flow of cooling air, precisely adjusted on the fly, must be used to tweak the temperature and maintain the tight clearance.

The total weight saving from using composites in the fan system alone is 500 pounds.

GE's expertise is in the hot, high-pressure core of the engine, where the air is squeezed until its volume is reduced by a factor of 22 ? twice the compression ratio in today's 737 engine.

As the compressed air flows into a combustion chamber that can reach a temperature of more than 3,000 degrees F, only a separate streaming layer of cool air prevents the metal from melting.

With so much that's new, can the LEAP be as reliable as CFM's current engines?

That's a tough standard. Earlier this year, an engine on a 737 flown by German charter carrier TUIFly passed the record milestone of nine years on the wing: more than 50,000 flight hours without coming off for maintenance.

Bastin said the LEAP's new elements have been developed and tested over years. "It's an evolutionary approach to introduce revolutionary technology," he said.

Both executives said CFM is on schedule to test the first complete LEAP engine for the neo next year and fly it in 2014, with the MAX version after about a year later.

"We are right where we want to be," Richards said.



Distributed by MCT Information Services



Source: (c) 2012 The Seattle Times


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