AEDC’s Tunnel 9 team implements major facility upgrade during busy year Published Feb. 17, 2012 By Philip Lorenz III AEDC/PA ARNOLD AIR FORCE BASE, Tenn. -- A short break during a busy time at the Hypervelocity Wind Tunnel 9 facility at White Oak, Md., has provided an opportunity to replace the facility's 30-year-old transformer. "After a successful test series for missile defense and in advance of a multi-year test campaign for the Conventional Prompt Global Strike (CPGS) capability, we've shifted gears to an all-out effort to make a much needed improvement to our power transformer," said Jeff Waldo, chief engineer at Tunnel 9. "Our transformer is literally the heart of this facility. Replacing it is crucial and presents a tremendous challenge considering what a busy year we've had with an even higher test load scheduled for this year. "This transformer is a massive device, much like a Lionel train controller, that will ultimately provide clean power to our 1.5 megawatt heater. As Dan Marren, our site director has said, 'failure here is not an option.'" Marren said, "This upgrade is overdue. We need to guarantee our facility's reliability and performance now to tackle the next few years of record testing for a high priority DOD customer." To make sure everything gets done, including the record workload, teams at Tunnel 9 are wasting no time. Ground work on the transformer upgrade, including pouring concrete and erecting fencing, has already begun. Marren said the upgrade has been a team effort on a project that began three years ago. "Jeff Waldo, our chief engineer at Tunnel 9, was the winner of the William M. Dunne People's Choice Award for the first quarter 2010, and for good reasons," Marren said. "Waldo was recognized for finding creative ways to maintain mission effectiveness. He stepped in and has led the contracting effort for delivering the upgraded control room and redesign of the Tunnel 9 power transformer. "Jeff is also frequently called to operate systems critical to the facility operation while maintaining his daily tasks." Steve Grant, the electrical systems engineer at Tunnel 9, said to appreciate the importance of the upgrade, it helps to understand what a power transformer does. "The unit that's being replaced was built about 1965 by General Electric. It's known as an Inductrol and effectively was like a big variable transformer," he said. "It converts 13,800 volts AC (alternating current) down to [approximately] 150 volts AC - we're talking about a lot of power - in the neighborhood of a megawatt and a half. "That power is applied to our nitrogen process heater that is used to heat up the nitrogen in a storage vessel. Then the nitrogen is brought up slowly in our heater cycle to the proper pressure and temperatures as high as 3,400 degrees Fahrenheit and 22,000 psi (pounds per square inch), so that gives the fluid to the proper conditions so that when we blow the tunnel, we can reach the conditions that will allow us to test up to Mach 14 or whatever particular requirements are for that test." Grant explained why the upgrade is overdue. "The Inductrol is essentially a large variable transformer with lots of moving parts such as rotating windings that are turned by a DC motor," he said. "It is also filled with oil to keep the windings cool. Over the past few years, testing of the cooling oil has revealed high levels of dissolved combustible gases that occur when electric arcing is happening. "The electrical arcing inside the transformer could lead to a catastrophic failure which would end Tunnel 9's testing capability until another system could be brought on line. Unfortunately, repairing the unit was not an option as the know-how and ability to work on such a unique piece of equipment has been retired for some time. Also, similar power sized units are just no longer made." Grant said it helps to understand why Tunnel 9 is such an important national asset. "We've tested all kinds of different systems here for mainly DOD, but also for industry and NASA, including the Mars Science Laboratory and [more recently] the Orion capsule," he said. "We've done some recent testing on the hypersonic test vehicle, Missile Defense Targets and other critical systems that have gone to flight." Marren added, "NASA can test in their facilities and did, but for what we provided them, they could not get anywhere else. This involves mainly large core flow so they can do high angle of attack. Also we were able to provide uniquely an environment that replicates the state of physics near the body (boundary layer) naturally." Regarding the new transformer, Grant said, "We are now about three years into the project to replace the Inductrol. During 2009 we put together a technical specification and contract package for a power supply replacement design. In May 2010, after having been awarded the contract, Rapid Power Corp. in Burlington, Vermont, delivered our new power supply." Marren said support from AEDC in middle Tennessee was critical to the success in finding a solution to a complex challenge. "We also asked Karen Buckner and Nick Hibdon for insight into contracting and civil engineering support from long distance," he said. "Challenges there are also monumental and these folks are top rate. Those two are essential to a successful program and I consider them part of my 'A' team." Hibdon, a project manager with AEDC's program section, said supporting Tunnel 9's upgrade project can be a daunting task, but one that is rewarding. "Our job is to oversee a project from beginning to end," he said. "It requires constant communication with the [outside] contractor and our contracting office, who in this case, was Karen Bucker. The challenge is making sure all the players are on the same page within the project even though separated by several hundred miles. Dan and his team are our eyes and ears; Karen is our contracting officer. "My job, normally being a mediator, has been very pleasant during this project. Dan and his team, specifically Jeff Waldo, Greg Wannenwetsch, Stephen Grant and Larry Resch, have done a great job keeping all of us up to date and in the loop. "Tunnel 9 provides a very unique service and this project is about keeping that capability available."