Largest engine undergoing testing at AEDC's C-2 test cell

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  A test recently conducted in AEDC's Aeropropulsion Systems Test Facility C2 test cell on a Rolls-Royce Trent XWB (Extra Wide Body) engine set a new record at the world's largest and most advanced flight simulation facilities located in middle Tennessee.

According to Rolls-Royce officials and those conducting the test, the Trent XWB is not only the largest engine under development to date by the company, but it is also one of the largest engines tested at AEDC.

Tom Schmidt, ATA project manager on the test, said, "I believe this is the largest commercial engine that we've tested, with a fan diameter of 118 inches."

The Rolls-Royce Trent XWB, a developmental engine, was at AEDC for simulated altitude performance and operability testing. Once certified as operational, the massive engine will power the Airbus A350 XWB, a "family" of long-range, wide-body jet airliners.

The XWB designation specifically describes the aircraft family's wide fuselage and not the engine.

Andrew Fist, AEDC Turbine Engine Ground Test Complex project manager on the test, said, "We're performing a full suite of performance and operability testing, and helping Rolls-Royce prepare for certification testing for this engine family.

"AEDC offers an opportunity for the commercial aviation industry to evaluate their engines in an environment that's very different from flight test. You can put more instrumentation on an engine when you're doing a simulated altitude test. You can vary the conditions with more control than when you do a flight test.

"One of the other challenges in flight testing is that it's very difficult to measure in-flight thrust, whereas we have a methodology and facilities that provide that high accuracy for the customer."

Fist said that commercial aviation customers are keenly focused on thrust and specific fuel consumption data, which is "the heart of performance testing, and is critical in this extremely competitive industry."

He said the primary focus of operability testing on the Rolls-Royce Trent XWB engine is to evaluate the limits of safe operation of the engine under a variety of stressing flight and engine conditions.

Fist acknowledged that the ongoing project has been challenging, particularly the operational phase of testing.

"We've excelled at being dynamic with changing conditions in the plant or the engine," he said. "Every test that we do out here relies on a lot of moving pieces and both Aerospace Testing Alliance (ATA) and the customer, Rolls-Royce, have been extremely dynamic in making those determinations on how to move forward."

ATA is the support contractor at AEDC.

Fist drew a contrast between the two types of engine test facilities available at AEDC and the difference in challenges presented.

"When you perform a test at a sea level facility, the primary focus is just the engine," he said. "There's not a large amount of infrastructure around the engine that you have to be concerned about.

"When you're testing an engine at an altitude test facility, there's a lot of unique issues that need to be addressed. For instance, when we calculate thrust, the values in the scale on a thrust stand are just one part of the total equation. We're also producing pressures in front of and behind the engine that need to be factored into our calculations.

"Overall, I think our project team has done a great job in preparing for this test. Rolls- Royce's engineers have a good sense for what to expect and what is different."

Fist spoke about how Rolls-Royce will use the data derived from the engine testing.

"In the near-term, this engine family is currently going through its development program, so they're looking at the performance of this engine versus the other engines in that initial fleet of test articles," he said. "Looking down the road, they'll use this data to calibrate performance models and that gives them a more accurate picture of the product that they're ultimately selling to an airframe manufacturer. They'll be able to predict fuel efficiency the engine will have as it gets more and more use. And that's something that we've looked at very carefully in our testing here."

Fist said data derived from the ground testing at AEDC will be used to help validate mathematical models of the engine and to guide the power plant's continued development.

Overall, this process takes several years and will lead to flight testing, certification and production.

"This is a very special engine to Rolls-Royce and they expect it to continued performance testing back in Derby at a later time," Fist said. "Completing the development of a new engine requires a lot of testing in a number of facilities, and I'm really proud that AEDC and the project team are able to provide these services to the industry."

Schmidt added, "AEDC and Rolls-Royce have a very long and strong relationship. I've been involved with testing two other members of the Trent family of engines at AEDC (Trent 900 and Trent 1000) and it's always been a pleasure working with Rolls-Royce. In every instance, we've worked well as a team on every level to achieve a common goal."