Tunnel 9 heater system expert passing along knowledge
By Bradley Hicks, AEDC/PA
/ Published June 17, 2019
ARNOLD AIR FORCE BASE, Tenn. -- Mike Metzger holds a unique position in the world.
A system engineer at AEDC Hypervelocity Wind Tunnel 9 in White Oak, Maryland, he is among a handful of people familiar with the Tunnel 9 heater system and the only system engineer ever assigned to it. The system is used to store and heat the nitrogen gas needed for testing operations at the facility.
This, however, is soon to change. Metzger, who recently celebrated his 40-year service anniversary at the White Oak facility, is in the process of instilling his knowledge of the heater system in the individual who will serve as his backup in the near-term and his eventual successor.
Metzger has worked at Tunnel 9 for all but around four years of its operational existence. The tunnel became operational in 1976 as part of the Naval Surface Weapons Center. It became an Air Force facility in 1997 after the Base Realignment and Closure commission closed much of the Navy’s White Oak site.
Early in his career Metzger was involved in efforts to develop a high-pressure, high-Reynolds Mach 10 capability. These test conditions increased the aero loads Tunnel 9 produced, causing the heating elements in Tunnel 9 to break during testing. As testing pace picked up in the wake of then-President Ronald Reagan’s Strategic Defense Initiative, also known as the “Star Wars” program, heater element failures were becoming frequent and placing pressure on the Tunnel 9 run rate and schedule.
“Around 1986, I was tasked with solving this problem and was sent back to my old Structures Branch to do some forensics and stress analysis to get at what was causing the element failures,” Metzger said. “This was my introduction to the T-9 heating system.”
This led to a successful redesign of the heater elements, just one of the projects with which Metzger has been involved over the years to improve the heating system technology, reliability and safety.
“It is most satisfying knowing that we’ve solved a technical challenge by adding a significant new test capability and, as important, completing an upgrade or an improvement to the system that enhances reliability and/or safety of the system, of which there have been many,” he said.
Metzger is currently in the process of passing on his knowledge of the heater system to Tunnel 9 system engineer Parth Kathrotiya. Kathrotiya will serve as Metzger’s heater system backup for now and his replacement when he retires.
“He has been slowly learning about the heating system while spending a lot of time on his own related system which has similar high-heat and high-pressure issues that the heating system has,” Metzger said.
Several of Metzger’s colleagues heaped praise upon him. Tunnel 9 Site Director Dan Marren, who has known Metzger since arriving at the facility in the early 1980s, said Metzger’s education, training and experience make him one of the top people in the country to “make Tunnel 9 work properly.” Marren went on to describe Metzger as the detail-minded “quiet genius” who has helped Tunnel 9 become a world-renowned capability critical to every acquisition hypersonic program.
“He is a talented engineer, critical staff member and wonderful person who is as reliable as they come,” Marren said. “He is directly responsible for training many of the engineers and technicians onsite today.
“I can safely say that if not for the innovations and persistence of Mike Metzger, Tunnel 9 may not even be here today.”
Tunnel 9 Engineer/Technician William Betz first met Metzger while the latter was developing a vacuum-packed heater liner process for the Tunnel 9 heater system. After some trial and error, they succeeded, and the technical breakthrough earned several folks at White Oak a quarterly Technical Achievement Award in 1998.
“Mike has always been very generous and appreciative of all the technicians he has worked with,” Betz said. “In my 40-plus years in the research and development field, I can honestly say – and I have told Mike to his face – he is without equal; the very best mechanical engineer that I had ever worked with. The innovations Mike has brought forward for the Tunnel 9 heater system has, in my opinion, been responsible for the success of the development of hypersonics.
“He approaches the technical challenges with an uncanny ability to break the problem down and come up with a surefire fix. He listens to whomever has a suggestion and gives credit for all the contributions.
“I hope we have many more years of Mike Metzger here at White Oak. He is truly one of our greatest assets, and I am proud to have him as a friend.”
Kathrotiya said Metzger has served as a “great mentor and source of knowledge” since he started at Tunnel 9 in 2013 as an undergraduate researcher.
“Over his 40-year career between the Navy and Air Force, he has become a holder of a lot of history and engineering understanding of our tunnel,” Kathrotiya said. “This probably comes from the various engineering functions he has served over the years, ranging from test model designer, diaphragm area engineer and heater system engineer. His engineering knowledge is also vast and deep-ranging from structural analysis, heat transfer analysis, fracture and fatigue analysis, and much more. These tools he has cultivated allow him to be a great designer for the complex engineering systems at Tunnel 9.”
Kathrotiya said the plan is for him to serve as Metzger’s backup on the heater system as needed, possibly transitioning fully to the heater system depending on future facility and personnel needs.
Metzger said it is a “privilege” to help equip warfighters with the tools and technologies needed to keep them safe. He used the same word to describe his experience working alongside what he referred to as “the best technical professionals on the planet.”
“For me, it’s the unique and talented individuals I have worked with and continue to work with which is most memorable,” Metzger said. “Early in my career, I was on a steep learning curve and, in some ways, still am as there’s always something new to learn or tackle here. But I learned from the skilled people working here, first as a Navy facility and later as AEDC.
“In this business, it seems everything is unprecedented, and there are a vast array of technologies and processes involved in pulling off the testing we do. Throughout my career here, our team has constantly evolved T-9 to meet the latest needs of the aerospace community.”