Transonic Dynamic Tunnel (TDT)

Test facilities at NASA-LaRC provide information essential to the advancement of atmospheric and space flight. Over forty wind tunnels, with test sections ranging from 6" in diameter to 30'x60', are used to supply invaluable information to the aerospace industry. Langley sponsored studies contribute much of the research data needed to ensure continued U.S. preeminence in aerospace science.

One test facility, the Transonic Dynamics Tunnel (TDT) is dedicated specifically to aeroelastic testing. This unique national resource is staffed by skilled professionals carrying out research which is unparalleled in the free world. Since 1960 the TDT has tested just about every type of American high-performance civil and military airplane by conducting research in dynamics and aeroelasticity. About 50% of testing is carried out for in-house research, while the remainder supports Department of Defense and commercial activities.

Through specially designed, dynamically scaled models, both vibrational and aerodynamic characteristics are simulated in the TDT. At this test facility, studies are conducted on aeroelastic problems in such areas as flutter, divergence, buffet, active controls, gust response, rotorcraft dynamics and aeroelasticity, launch vehicle ground wind loads, and unsteady aerodynamics. Researchers at the TDT need very sophisticated monitoring and measurement capabilities to investigate active and passive control of aeroelastic response, develop means for reducing rotorcraft vibrations, and verify computational fluid dynamics for unsteady air loads. Aeroelastic problems encountered by high-speed aircraft and launch vehicles most often arise in the transonic speed range (flight velocities just below and above the speed of sound- 760 mph at sea level), the very range where aerodynamics theory is least accurate. Designers and researchers therefore, must place heavy reliance on wind tunnel models to aid in clearing new designs for safety from flutter and buffet, evaluating solutions to other aeroelastic problems, and studying new aeroelastic phenomena.

Stringent test conditions coupled with a multiplicity of testing models for varying government and commercial purposes places a requirement on the TDT for collecting voluminous amounts of data, therefore requiring a leading-edge data acquisition, display, and control system. The TDT computer system must be able to handle the flight configuration of a complete vehicle, acquire continuous real-time response data, and perform real-time data analysis for display to the test engineers. To meet this demand, NASA-LaRC-TDT selected MODCOMP's high-performance 32-bit CLASSIC real-time superminicomputers.

The MODCOMP computer systems is today making a reality state-of-the-art testing of aerospace systems. Through this unique partnership, NASA-LaRC-TDT and MODCOMP are conducting aeroelasticity testing to ensure that the world's most sophisticated aerospace systems are unhindered from aeroelastic instabilities. And at the same time, aeroelastic testing promotes increased understanding and knowledge of aeroelasticity for future aircraft and spacecraft. The NASA-LaRC-TDT is a resource to be commended for its efforts in providing advanced aircraft testing for both civil and military purposes, and MODCOMP is honored for its longtime association with NASA.