Support from the Arnold Engineering Development Center’s Air Force Analysis Branch recently helped bring a successful conclusion to a “challenging” Accelerated Mission Test on an upgraded TF34 engine, the power source for the A-10 Thunderbolt II, which is nicknamed “Warthog.”
The AEDC is located at Arnold Air Force Base, Tenn.
Josh Hartman, AEDC Air Force test project manager, said ATA analysis engineers also contributed to the project and emphasized that the recent engine testing employed “a more blended team” than has usually been the case for previous AMT entries.
“Between our Air Force Analysis Branch and ATA we always had two people in the control room at SL-1 during the test,” he said. “Any time it was running they were performing data trending and logging. They’ve been monitoring critical engine and facility parameters.”
Regarding the Air Force Analysis Branch, he said, “They’ve been responsible for weekly data packages, uploading the data, trending it, as well as checking data repeatability for performance testing and cell correlation – they’ve done QLRs (quick look reports). Overall they have really done a lot for the test. They’ve been doing a really good job.”
The constant 24/5 monitoring of data from the TF34 AMT entry and offline data analysis on the project serves a two-fold function, according to Joshua Osborne, who, along with Reggie Floyd, conducts aeropropulsion analysis for the Air Force Analysis Branch.
The main benefit of this 24/5 monitoring approach is that it allowed Osborne and Floyd to focus on the in-depth “offline” data analysis.
Osborne said they have historical data from the engine that served as a baseline to compare the recently acquired data with to quantify any observed changes.
“From the historical TF34 data, you can look at [and compare] fuel flows and temperatures, which allows you to correlate how much thrust you get,” he said. “Changes in the engine’s performance are expected, but we specifically wanted to see how much the engine deteriorated over the test and how performance drops off, how much more fuel is it using and pressure changes.
“We’re looking at all the data. The information that we’re giving them [the customer] is engine performance parameters [including] pressures and temperatures around the compressor and turbines, engine speeds, vibrations, and fuel flow to name a few.”
Osborne said Derrick Daniel, Ed Wantland and other ATA analysis engineers have been extremely helpful in his learning of how to analyze engine test data.
“The people that have been helping out with the continual monitoring of the data are engineers from flight systems and space and missiles from our branch, TSTB personnel to include project managers, a lot of second lieutenants, and Mike Dent even stood in for a day,” Osborne said.
“There’ve been multiple instances where they’ve caught some issues with our data instrumentation, for instance a flow meter not reading correctly,” Osborne said. “Catching things like that allows us to go in there, schedule to get it fixed so they’re not constantly recording a bunch of bad data and more importantly ensure the safety of the engine.”
Osborne said the team effort paid off in terms of both efficiency and sharing valuable information.
Osborne acknowledged the AMT entry has provided him with some challenges.
“This was [my] first time and it’s been a learning curve – just kind of thrown in there without any previous engine testing background,” he said. “That was a difficult thing to start off with, but being in that situation you had to learn a lot [and] quickly, which ultimately I believe made me gain more knowledge for this test and makes me more valuable for future tests to come. I’ve also learned a lot because of Derrick Daniel, Ed Wantland and others.”
Hartman said the TF34 customer was pleased with the test result and for good reasons.
“If there’s one thing that AEDC doesn’t compromise on it’s the quality of their data,” he said.
Gus Kamphaus, Aeronautical Systems Center at Wright-Patterson AFB, Ohio, said there were many benefits of bringing the test to AEDC, including keeping within schedule and budgetary constraints.
“We also improved control of many AMT data quality drivers as a direct result of the TSTA’s analysis effort,” said Kamphaus, who is ASC’s lead engineer for the TF34 Boltless Rotor Upgrade Component Improvement Program. “For example, we were able to reduce the number of water washes during the AMT to mimic fleet maintenance practices. This enabled us to operate the BRU turbine blades at hotter cooling flow temperatures to simulate fleet operation of older engines.”