A view from the world’s largest wind tunnel

  • Published
  • By Scott Waltermire
  • AEDC/National Full-Scale Aerodynamics Complex

AEDC’s expertise in low-speed aerodynamic testing resides at the National Full-Scale Aerodynamics Complex, or NFAC, a geographically separated unit located on the NASA Ames Research Center campus in Mountain View, Calif.

The NFAC is primarily used for determining the aerodynamic characteristics of large-scale and full-scale fixed wing, rotorcraft and powered-lift vertical and short take-off and landing aircraft.

One thing that makes the NFAC particularly unique is the enormous size of the test sections. The available space enables nontraditional types of experimentation that could never be done in a ‘normal’ wind tunnel. These nontraditional tests include flying refueling systems in the tunnel, demonstrating active flow control over aircraft surfaces, shooting mortars in the tunnel to simulate planetary decelerator parachute deployments, spraying water on a test article to test improvements to pilot visibility in heavy weather, and operating rotor and tiltrotor testbeds at speeds never before accomplished anywhere on earth.

Very cool stuff!

However, while doing cool stuff may be the reason many of us continue to work at the NFAC, it is not the reason our nation needs and resources the Subsonic Aerodynamic Ground Test and Evaluation capability. The NFAC facility and the dedicated team that operates and maintains it are a critical part of the larger AEDC suite of test and analysis capabilities used to develop the tools needed by our services to deter if possible, or defeat if necessary, any potential adversary.

As an engineer, it is very satisfying knowing that so many of the military aircraft currently fielded and flying in support of our national defense were, in some small part, developed in the same place we go to work every day. The entire NFAC team takes pride in the amazing history of the facility, knowing that the success of the F-35 Lightning II, P-8 Posiedon, V-22 Osprey, F-18 Hornet, and UH-60 Blackhawk aircraft, to name just a few, was dependent on the work of our predecessors. But, it is not only these legacy systems that will ensure the future security of the nation, to paraphrase Gen. Henry “Hap” Arnold, “we must think in terms of tomorrow.”

As the National Defense Strategy drives a realignment of U.S. security focus to great power competition, the NFAC team will remain a critical node in the development of next generation aerospace systems.

The recently adopted AEDC mission statement demands every member of the Complex support the effort to “prove the superiority of systems re¬quired to meet the demands of the National Defense Strategy.” No matter the system under test, the AEDC subsonic aero test capability team likely has the ability to meet this high standard of “proving superiority.”

Unique, even strange, test requests are relatively common at the NFAC, and the facility contains various support systems that can be utilized to develop solutions. Both test sections are designed as anechoic chambers for acoustic testing. Powered vehicles and components make use of the available variable frequency (150 and 400 Hz) electrical power, hydraulic power units, cooling water and jet fuel systems. Rotor test beds incorporating electric motors and rotor balance systems are available for testing complete rotor and hub systems independent of the flight vehicle. Safe and effective test operations in the NFAC requires the entire team creatively working together to conduct the right experiment, meticulously designed to produce the necessary data, which is then expertly analyzed to provide the proof needed by the customer.

The majority of the DOD test and analysis conducted at the site supports the Future Vertical Lift program management offices. These programs will eventually field a replacement aircraft for every helicopter and tiltrotor used by every service; and every one of these new aircraft will be tested at the NFAC using the only rotor and prop-rotor testbeds in the DOD inventory. In direct alignment with the AEDC mission statement, the NFAC team is well positioned and will leverage every available resource within the test enterprise to prove the superiority of these systems.

AEDC’s ability to provide controlled environments on the ground to simulate flight conditions is unsurpassed. Collectively, we can test at speed regimes ranging from takeoff through hypersonic, and at altitudes ranging from ground level to space – a truly remarkable capability set which enables our nation to maintain an enormous aerospace engineering development advantage. This ability to work together across the en¬tire AEDC enterprise, bringing the entire suite of test, computational and analysis capabilities to bear against the most difficult problems will ensure continued proof of the superiority of our defense systems.