AEDC team runs final TACS systems checkout for VKF wind tunnels

  • Published
  • By Philip Lorenz III
  • AEDC/PA
ARNOLD AIR FORCE BASE, Tenn. --  A test team at AEDC recently concluded a successful operational checkout of the new Test Article Control System (TACS) at the von Kármán Gas Dynamics Facility's (VKF) Tunnel B.

According to Simon Choi, AEDC's project manager for the effort, the objective of this test project was to validate the facility modifications for the VKF Tunnel B TACS while the tunnel was operating at maximum pressure and temperature levels.

Brandon Allen, an ATA test systems engineer and the manager of VKF Tunnel B, said the timing for this upgrade project enabled the team to accomplish two goals.

"With the down time for the Tunnel B TACS (upgrade) being scheduled, we saw a good opportunity for us to be able to take our system and rebuild it because the mechanical inject mechanism will not be in use while the control system is being upgraded," he said. "So it was a very opportune time for us to kill two birds with one stone."

Choi said the new system "gives a tester a better handling of testing and allows improved efficiency in doing aerodynamic and hypersonic testing, especially Mach 6 and 8."

Doug Hamilton, ATA investment manager on the project, said, "There were a number of individual control systems that were combined - the advantage being that an operator in one [facility] can see familiar screens and if you can operate one, you have a much higher ability to step in and operate another tunnel."

Paul Jalbert, an ATA test project engineer who has been assisting with the project provided some background information on the checkout work.

"We've been doing offline checks for several months now, after the TACS system was installed," Jalbert said. "There's been a series of three or four different checkout plans that have been conducted to make sure that the TACS functions as it was designed."

Jalbert said the recently completed system checkout was the culmination of a considerable upgrade project that included earlier checkouts of the TACS in VKF Tunnels A and C.

"TACS is the software that controls the facility operations and the attitude of the model and does health monitoring of various systems and tells us when things get out of specifications," he said, adding that another objective was met as well. "When they improved the TACS, they [also] took the opportunity to change out an encoder that measures the pitch attitude of the model in the tunnel to something that's more modern and easier to use than the old one used to be.

"So, the cooling system that maintains that pitch encoder at a low temperature during the high temperature tunnel operation has been replaced."

Terry Rayfield and Barry McCann, ATA control systems design engineers, took the lead with a team to design the TACS for the upgrade project.

"The [VKF Tunnels] A, B and C TACS designs were leveraged from the Propulsion Wind Tunnel (PWT) Facility TACS designs so that commonality between PWT and VKF test modeling positioning systems would be maintained," Rayfield explained. "At VKF, a TACS system resides in each one of the test units. Each system consolidated several control systems that were utilized to control the model in the test cell and other test customer parameters, such as mass flow control.

"This consolidation reduces the number of test operations personnel will be required to operate and perform maintenance on the test unit. The greatest enhancement for VKF is the ability to operate the system from each respective tank area, which was not possible with any of the existing control systems. This feature alone has improved efficiency in test buildup and maintenance activities immensely."

Rayfield went on to explain how and what the system upgrade can accomplish.

"Each TACS is a multi-processor control system that provides real-time, closed-loop control for the respective test article support mechanisms associated with each test facility and test user's test peculiar control hardware," he said. "The system also provides the controls and monitoring of model support systems associated with each test unit.

"The system provides the means to safely operate these mechanical model positioning and model support systems and provides system diagnostics that allow the operators and system engineers to interrogate these systems and the associated system hardware to determine system problems; thus, greatly minimizing lost test time. The TACS are a highly versatile control system that allows great flexibility in meeting test customer requirements when they are outside the normal operating envelope of the respective test unit."

Rayfield added, "Furthermore, the TACS systems have all been designed using common system architect and system hardware, thus, simplifying the maintainability and supportability of the systems."