Test Support and Tunnel 9 teams to complete first remote installation of original AEDC data system

October marks the 20th anniversary of the Hypervelocity Wind Tunnel 9 as an Air Force facility. Tunnel 9, located at White Oak, Maryland near Silver Spring, became operational in 1976. The facility provides aerodynamic simulation critical to the development of hypersonic systems, including critical altitude regimes associated with strategic missile systems and advanced defensive interceptor systems, and hypersonic vehicle technologies. (AEDC file photo)

Tunnel 9, located at White Oak, Maryland near Silver Spring, became operational in 1976. The facility provides aerodynamic simulation critical to the development of hypersonic systems, including critical altitude regimes associated with strategic missile systems and advanced defensive interceptor systems, and hypersonic vehicle technologies. (AEDC file photo)

ARNOLD AIR FORCE BASE, TENN. -- A team effort between personnel at AEDC Hypervelocity Wind Tunnel 9 in White Oak, Maryland, and Arnold Air Force Base recently facilitated the replacement of the 20-year-old Tunnel 9 system used to record, process and display test data.

Last month, Tunnel 9 completed the final installation and necessary sign-offs for its new Enterprise Data Acquisition and Processing System (EDAPS). EDAPS replaces the Legacy Data Acquisition and Recording Equipment (DARE) IX system used previously at Tunnel 9 and marks the first installation of EDAPS outside of Tennessee.


EDAPS, which was fully designed and developed at Arnold, provides capabilities for acquiring, processing, displaying, and recording test article measurements. Both the EDAPS and DARE IX systems collect data via Digital Voltage input signals from pressure and temperature transducers and store the raw data output.

“The primary difference between EDAPS and other data systems is its modular plug-&-play architecture,” said Ashley Campbell, Arnold Hypersonics Instrumentation, Data & Control Systems engineer. “Each test unit has different requirements so each test cell’s configuration has just the modular components necessary to meet its requirement. Each test cell configuration is defined in a configuration database. That database defines which modules are present and where each software application will run.”

Tunnel 9 Data Systems and Instrumentation Engineer Joel Barr said the upgrade was necessary due to the age of the DARE IX system.

“The current DARE IX system had reached the end of its life cycle and replacement parts were no longer being supported by the manufacturer,” Barr said. “Further, the EDAPS System is an Arnold proprietary system that has been installed in multiple other tunnels in Tennessee. This group provides software development services and improvements instigated by one tunnel [and] gets propagated across multiple testing areas.”

When it came time to replace the DARE IX system, Tunnel 9 initially explored the development of a DARE X system utilizing onsite personnel and sourcing equipment from Precision Filters Inc. to include improvements over the prior legacy system including a higher speed data acquisition capability.

Before beginning this work, the Tunnel 9 team opted to first explore outside sources to see if the needs could be met.

“The DARE IX system was beginning to have issues with supportability and adaptability to meet future test needs; therefore, Tunnel 9 had released an Request For Information to industry looking for potential solutions,” Campbell said. “AEDC Contracting Execution Directorate contacted my office to let us know about the request, and after looking into the requirements, we saw there was not much of a gap between what they needed and what we were already able to provide with EDAPS.”

EDAPS to Tunnel 9

Discussions of bringing EDAPS to Tunnel 9 began in the latter part of the 2014 fiscal year. Early in the 2015 fiscal year, the Test & Communications Branch presented a plan to Col. Timothy West, chief of Test Operations Division at Arnold, and Tunnel 9 Director Dan Marren detailing the intention to expand EDAPS capabilities to meet the needs of Tunnel 9 while reducing the total lifecycle cost of data acquisition there. West and Marren accepted the proposal which initiated the development and installation project.

“It was determined that Arnold had been developing EDAPS over the years and applying it to multiple Testing sites, and it was fundamentally decided that the system could be modified for use at Tunnel 9,” Barr said.

Although new to Tunnel 9, EDAPS has been in place for several years at numerous test facilities across Arnold AFB. The first EDAPS was installed in the Engine Test Facility T11 Test Cell in 1996. The system is also currently installed in the Aerodynamic and Propulsion Test Unit; the Arc Heaters; multiple Engine Test Facility test cells; and the J-6 Large Rocket Test Facility.

“Each test unit has an acquisition subsystem for each of its measurement sources,” Campbell said. “The acquisition subsystems distribute the data they acquire to the data consumers via the Primary Data Network. The consumers include the real-time displays, external systems, and the data recorders. The recording subsystem archives all data and provides it to other external computers for further processing and analysis.

“EDAPS is totally composed of software developed at Arnold. The system is composed of Commercial Off the Shelf hardware. In the rare instances where there is no COTS hardware available, special hardware solutions are developed by Arnold personnel.”

Design of the Tunnel 9 EDAPS began in June 2015. The assembled system was put under test in the EDAPS lab at Arnold to be validated before the complete system was shipped to Tunnel 9 in September 2016.

Throughout development, personnel at Arnold and Tunnel 9 worked together to develop detailed requirements, discuss design and review the system for acceptance.

“The teamwork involved is a testament to AEDC’s ability to reach across organizations and many miles to efficiently and effectively meet current and future test needs,” Campbell said.

New Features

The Tunnel 9 EDAPS required the development of several new features. One such feature was having an aggregate data rate of 13.5 million samples per second, which is higher than the approximately 3 million samples per second EDAPS was capable of prior to March 2016.

“The EDAPS System was modified to include sampling rates into the 100 kHz range and provide for customizable digital filtering on board,” Barr said. “Other modifications include a high performance buffer that can hold up to four hours of continuous data at maximum streaming rates across all channels. This is an improvement over the legacy system as the buffer could only hold individual triggered points. This new design allows us to recreate data points from stored data and allows analysis during tunnel buildup times.”

According to Barr, EDAPS not only acquires data at a quicker rate but offers its users greater flexibility.

“Further improvements include customizable user panels which allows live streaming of data-of-interest during buildup to runs and during run cycles, as well as coding features which allow in-process data analysis,” Barr said.

EDAPS also includes balance completion bricks used for providing controlled excitation voltages at high accuracy rates and the recording of voltage outputs from Wheatstone Balance Bridges.

EDAPS Validation

The installation of the EDAPS at Tunnel 9 began around a year ago. To prevent impact on customer testing, the EDAPS system was tested in parallel with the existing DARE IX system. Barr said the EDAPS has been appropriately vetted and its testing is complete.

“For this particular system, both the legacy data system and EDAPS were installed in parallel and used during testing,” Barr said. “The data was then compared to verify that data was acquired as expected. After about a year of testing if the system continues to operate as expected, the legacy system is uninstalled and final verification occurs.”

“After the system was installed, Tunnel 9 personnel assisted us with completing testing and validation to ensure that all requirements were met,” Campbell said. “During the parallel testing, Tunnel 9 and Arnold worked closely to track and close out any issues as they arose.”

Now that the EDAPS at Tunnel 9 has successfully completed its Functional Configuration Audit, the system is now operational. EDAPS will be used as the primary data acquisition system at Tunnel 9 and used on all test programs. The legacy system there will either be eventually excessed or repurposed as a data system in the onsite student Tunnel.

Marren noted his observations about the effort that brought EDAPS to Tunnel 9.

“This amazingly successful effort is another great example of what AEDC is capable of,” he said. “Implementing EDAPS here was not a simple task and came with significant challenges. Even though the final result was more expensive than a one-to-one replacement would have been, the savings in the lifecycle costs along with the skills developed by the team were an investment in all of AEDC and will benefit the implementation teams and future installations.”

Future of EDAPS

Those who have been involved with EDAPS over the years and assisted with the Tunnel 9 effort intend to use what they have learned in the development of a future data acquisition system.

“The EDAPS architecture is now 20 years old,” Campbell said. “Maintenance budgets have supported numerous upgrades to EDAPS over the years allowing it to remain adaptive with ever-changing test requirements. The Enterprise System for Test Data Acquisition Recording and Redistribution project, currently under design, has been using the knowledge gained in development and sustainment of EDAPS and other AEDC data acquisition capabilities to create a single data acquisition system which meets the needs of all AEDC test facilities for the next generation of test articles and their associated data acquisition requirements.”