In Person: Fecke says AEDC leads the way in turbine engine testing

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  Theodore Fecke, the senior leader for the Propulsion, Engineering Directorate for Aeronautical Systems Center at Wright-Patterson AFB, Ohio, is no stranger to Arnold Engineering Development Center.

"I started coming here in 1979," said Fecke, who was recently on base for a test and evaluation meeting hosted at the University of Tennessee Space Institute. "We ran the Aeropropulsion Systems Test Facility through its paces when they first built it, as well as running the development engine through its paces. So, I've been coming here for many years."

When he first came to AEDC, Fecke had recently been an engineering student working a co-op job for a power plant in Dayton, Ohio.

"You'd think I would have understood big things - even at that point," he said, "but when I came here I was just overwhelmed. It's just the physical size and complexity of things that you really can't appreciate until you're here. When you start thinking, well that's the compressor building and there are the exhausters and they're almost a half a mile away... it's just the size of everything that really caught my attention."

After all these years, Fecke said he is still impressed with AEDC, but it is for what the work force is able to accomplish with the world-class complex of ground testing facilities.

"I deal with a lot of test communities," he said. "There are a lot of organizations that are big and have a complex infrastructure, but I would say it's what AEDC as an organization can pull off that is something they deserve a big pat on the back for - that and their professionalism."

Fecke gave an example of AEDC's level of commitment to the mission beyond their gate.

"We had a problem when I had to send an [aircraft] engine to NASA Lewis Research Center," he recalled. "NASA hasn't tested a lot of afterburning engines. We did some damage to their test cell, an acoustics problem. AEDC, since they run those engines all the time, went up and helped NASA fix that problem.

"They could have said no, it's not my problem, but from a national perspective, they said we need to make sure that NASA has the capability to do testing in the future in case something happened here."

Fecke credited former center Commander Brig. Gen. David Stringer and the current AEDC Commander, Col. Art Huber, with helping to ensure AEDC is the center of excellence in ground testing by sharing these skills.

"They understand what we need to do to get as much of this knowledge as possible to those we do business with throughout the country," Fecke said.

Synthetic Fuels
Fecke said AEDC is a key player in helping the Air Force to achieve a goal of certifying the 50/50 Fischer-Tropsch and JP-8 blend for their entire fleet. He also emphasized that this goal's success depends on the collaborative effort between the program offices working through the Fuels Certification Office and Air Force Research Laboratory with the Test Community at Edwards AFB, Fla. and AEDC.

"We are actually ahead of schedule," he said. "So, we are making great progress - we've had three of the engines come through AEDC. At this rate, by the end of fiscal year 2010, all Air Force systems will be certified to operate on the 50/50 mixture."

Bio-Fuels
Fecke said the Air Force is also looking at bio-fuels as alternatives to petroleum-based fuel sources for the fleet.

"The focus is to also go to these bio-fuels," he said. "These can be derived from a whole spectrum of sources, from chicken fat, to saw grass to algae. With bio, there are a lot of ideas; it's trying to figure out which one can provide a large quantity of fuel. The challenge is two-fold, meet the requirements, what are these processes, and which ones can generate three or four hundred million gallons of fuel a year?"

National Asset
Fecke said AEDC is an outstanding national asset, including in his area of expertise, turbine engine ground testing.

"This is the only place in the world - certainly in the U.S. - that has full capabilities for us to take an engine and 'fly' the entire envelope," he said. "When you've got single-engine fighters, taking unnecessary risks really becomes unacceptable. With a development program, 20 percent of the cost is in testing. AEDC is an important player in pulling that off."

Component Improvement
From a sustainment point of view, 50 percent of our Component Improvement Program each year goes to testing. The reason is that as we fix issues, we've got to validate them, and the most effective way to do that is to come to AEDC where you can run an engine at any altitude condition and get that high level of confidence in its operability.

If the engine requires it, then you do flight testing, but many parts can be tested on the ground and verified."

Critical to Success
Fecke said, "AEDC is critical to the success of the Air Force."

"In 1973, we had 14 engine-related losses of aircraft," he said." In 2008, we had zero. I think a large part of that is due to the strong interaction of the propulsion community, but a critical piece of that is the testing that goes on here at AEDC."

He said a less dramatic, but no less important part of the picture, falls on the side of aircraft maintenance fighter engine.

"In 1970, a maintenance interval, that's when you have to pull the engine out of the aircraft, tear down all of its parts and clean and reassemble them, was at 1,000 hours or 2,000 TAC ," he explained. "TAC is a form of life measurement that major engine components are tracked against. Now, we do that at 4,000 TACs or 2,000 hours, and we are moving that to 6,000 total accumulated cycles. This is a big deal with cost."

"So, if I can keep that engine out there longer, it's a major issue," he continued.

Fecke said, "It sometimes helps to think of an aircraft engine in automotive terms."

"If a NASCAR team could say, that engine is going to stay in that car for two years, everybody on the team, from the driver, engine manufacturer, the pit crew to the sponsors, would know they have a winning combination. The bottom line is the safety record will go up and costs will come down."

Computational Modeling
Fecke said, "AEDC is leading the way on another front as well, the integration of computational modeling and traditional ground testing."

"When we first started down this path of modeling versus testing, people thought that modeling was the Holy Grail, and the future was no testing," he said. "We've come back to reality and now what we're doing what was probably the right focus all along, the integration of modeling and testing."

Non-intrusive Measurement Systems
Fecke explained an important part of this integration of modeling and testing is the use of the newest generation of non-intrusive measurement systems.

An example of an intrusive measurement system would be a strain gauge and associated wiring installed inside an engine to assess turbine blade and vibration. The physical presence of the gauge can contribute errors into the data because it physically can alter the flow of air through the engine turbine's blades. With a NSMS, two or more offset optical probes mounted on the engine casing can unobtrusively and accurately determine the arrival of a blade tip and specific case location.

"Where the non-intrusive method becomes critical is when you look at an engine and you take global or local measurements of temperature, pressure or vibration," he explained. "You get better fidelity with a very focused local measurement."

Fecke said, "Arnold has taken the lead with NSMS, computational modeling and working with the tools in tandem."

"AEDC has the most advanced system called NSMS Generation 4, and they're moving to Generation 5," he said. "It is very critical in its non-intrusive capability - it allows every blade to be monitored and allows us to take high fidelity measurements and remove the boundary condition of a strain gauge. NSMS still gets that deflection and allows us to better correlate our advanced modeling, and what we're really doing on modeling is integrating computational fluid dynamics with finite elements. Those things are now kind of merging together."

Fecke, like other senior members of the Air Force and avionics engineering industry nationwide, realizes a need exists to bring bright and motivated young people into the sciences and the organizations that support the war fighter.

"I know Colonel Huber is focused on re-energizing the engineering output of the facility, not just a matter of taking a test article and running tests on it, but to provide engineering insight and guidance at all levels," he said.

Aging Workforce
"I think the biggest issue with replacing our aging workforce - and I'm in that group - is giving the new folks coming in the excitement to want to come and work in a facility like this. However, they have to be challenged engineering-wise; this can't just be a cookbook kind of approach," Fecke added. "The new folks coming in have to realize, 'You know, I'm going to have to grow and I'm going to be challenged to do things differently. How do I integrate this CFD model and predict the roughly 2,000 chemical constituents and then measure those in an engine test?'

So, we have to challenge them and that can be achieved by us providing further insight into the acquisition community and the war fighter."