Taking the heat

Craig Wilsey

Even for an engineering manager who sees a lot of impressive technology, the engine exhaust nozzle made of ceramic matrix composite (CMC) material is a remarkable feat of engineering.

“The nozzle center body -- the tapered part at the aft end of the engine -- is nearly 8 feet tall. The outer nozzle that wraps around it is 5 feet in diameter. At the start of the program, before the CMC team fabricated this nozzle, the largest ceramic composite part fabricated was about the size of a notebook,” says Craig Wilsey, leader of Boeing’s CLEEN program.

“To produce the two largest ceramic composite objects on Earth, following specs that make it perform correctly on a jet engine, is a great team accomplishment.”

CLEEN, or Continuous Lower Energy Emissions and Noise, is a five-year joint research-and-development effort with the Federal Aviation Administration. Its purpose is to accelerate the development of new technology that will lead to cleaner and quieter aircraft.

The ceramic matrix composite nozzle is one of the technologies selected to be tested onboard the next ecoDemonstrator flight, scheduled for late 2013. Wilsey said the advanced nozzle can play a big role in the next generation of more fuel-efficient engines.

“To be at peak efficiency, engines need to run extremely hot in their core -- as much as 3,600 degrees Fahrenheit. The exhaust reaches over 1,200 degrees. Very few materials can stand up to that harsh environment. Ceramic composites can do the job, and thereby be a key enabler to better, more fuel-efficient engines,” Wilsey says.

For the CMC team, the chance to test the nozzle onboard the ecoDemonstrator is a unique opportunity they didn’t want to miss. “We are true believers in technology demonstration projects, like the ecoDemonstrator. You have the chance to learn so much more about your technology when it’s integrated onboard a real airplane in a flight test. It greatly improves its chances for a successful transition,” he says.

Wilsey sees the CLEEN program’s focus on environmentally progressive technology as another big opportunity for Boeing. “What personally appealed to me about this program was the chance to make a real, tangible impact on our products through technologies that reduce fuel burn, emissions and community noise,” Wilsey says.