3-D View of the New Captive Trajectory System in 4T

The image above is a three-dimensional cutaway view of the Captive Trajectory System (CTS) recently installed in AEDC’s 4-foot Transonic wind tunnel (4T). The new CTS, used for weapons integration testing, has improved performance capacities over the original system. It is designed to carry higher loads and achieve higher angles with more accurate positioning capacities and improved reliability. The design approach took advantage of AEDC experience, as well as technology developed in the robotics industry. This new CTS will allow AEDC to perform separation testing over an expanded 4T test envelope. Several of AEDC’s test teams assisted in the design and installation of the new CTS. The CTS and enclosure was designed by the Test Systems Design Group, instrumentation and controls were designed and fabricated by the Information and Technology Group, the fabrication and assembly was accomplished by the Model Shop and installation was accomplished by the Model Shop and the 4T test crew. The complete effort was coordinated and managed by the Investments Group.

AEDC tunnel back online after $33 million upgrade

Published Feb. 4, 2015
By Kathy Gattis
AEDC/PA

ARNOLD AIR FORCE BASE, TENN. -- The AEDC wind tunnel 4T, known for store separation testing as well as conventional sting-mounted force and pressure model testing, is now back online after a $33 million facility upgrade effort. The work was funded by the Test Investment Planning and Programming (TIPP) and the Direct Budget Authority (DBA) programs.

The upgrade to the tunnel extends the range of testing capability for store separation testing to above 1000 psf (up to ~2000 psf), provides the ability for improved operational flexibility and control of the nozzle, and the new data system is now common to the Von Karman Facility tunnels at AEDC with post-processing capabilities both on- and off-line, according to Ozey Young, Air Force program manager and Jon Seely, ATA program manager.

The facility was down for two years as part of the upgrade and the tunnel was stripped down, new systems were installed, and extensive system and tunnel air-on checks were accomplished. New systems installed included nozzle controls/actuators, Automatic Model Attitude Positioning System Roll mechanism, a replacement for the floor seal flaps, a new Captive Trajectory Support (CTS) System, and a new Data Acquisition System.

Mike Mills, ATA tunnel senior engineer, says customers can be assured the high quality tunnel data that AEDC is known for is still there, but even better. "Part of our work included an extensive calibration effort," he said. "F-15 model data was compared with a historical data set; the typical centerline pipe tunnel calibration was expanded beyond what has been done in the past to further characterize the tunnel flow quality; a second tunnel calibration using the centerline pipe was accomplished using a DoE (Design of Experiments) approach; a cone probe survey was accomplished for flow-angularity characterization; and a humidity-effects study was conducted."

The majority of the work for the 4T upgrade was accomplished with AEDC personnel from concept, design, manufacturing, installation and testing and check outs. The planning and execution took seven years.

The renovation will prepare AEDC to support the Department of Defense in the years ahead. The tunnel operates between Mach .05 and Mach 2.5.

Testing in 4T resumed immediately after the upgrade.