National Full-Scale Aerodynamics Complex The two largest wind tunnels in the world comprise the National Full-Scale Aerodynamics Complex (NFAC). The 40- by 80-Foot Wind Tunnel opened in 1944 and was the largest in the world until the 80- by 120-Foot Tunnel was added in the 1980's. The complex, located at Moffett Field, has enabled aerodynamic research in many diverse fields including rotorcraft, powered lift aircraft, aero-acoustics, turbine engine performance, decelerator systems, wind turbine technology, and NFAC ground vehicle aerodynamics. The six 40-foot-diameter fans, shown below, are each powered by a 22,500 horsepower motor. National Full-Scale Aerodynamics Complex

The National Full-Scale Aerodynamics Complex (NFAC) wind tunnel facility located at NASA's Ames Research Center in Moffett Field, California, is operated by the U.S. Air Force's Arnold Engineering Development Center, Arnold Air Force base, Tennessee. This facility is composed of two large test sections and a common, six-fan drive system. A wide range of available support systems combine with this unique facility to allow successful completion of aerodynamic and acoustic experiments that cannot be achieved anywhere else.

The 40 by 80 foot wind tunnel circuit was originally constructed in the 1940s and is now capable of providing test velocities up to 300 knots. The 80 by 120 foot open circuit leg was added and the new fan drive system was installed in the 1980s. The 80 by 120 foot test section is the world's largest wind tunnel and is capable of testing a full size Boeing 737 at velocities up to 100 knots.

A system of moveable vanes can be positioned so that air is either drawn through the 80 by 120 foot test section and exhausted into the atmosphere, or driven around the closed circuit through the 40 by 80 foot test section. A passive air exchange system is utilized in the 40 by 80 circuit to keep air temperatures below 125° Fahrenheit.

The current fan drive system is composed of six variable pitch fans, each 40 feet in diameter arranged in two rows of three. Each fan has 15 laminated wood blades and is powered by a 22,500 horsepower electric motor. The six fans rotate together at 180 rpm drawing 106 MW of electricity at full power while moving more than 60 tons of air per second.

Unique, test specific requirements are explored with each customer to guide the experiment design and new systems are integrated into the facility as needed. Utility support systems that have been used for testing powered vehicles and components include variable frequency electrical power, hydraulic power units, cooling water, 150 Hz electrical power, 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. Preparation Building NFAC Model Utilities External BalanceSystem Turntable Yaw Model SupportSystem Acoustic Lining Reynolds Number Test SectionDynamicPressure Test SectionVelocity Model Handling Test SectionDimensions Type specs Specifications High pressureair Variable frequency Cooling water Jet Fuelsupply Hydraulic system Shop air Line power 6 componentfloatingframe Nearly 360°,Test Dependent Sting mount Semispan mount Three strutsonturntable 42 indeep 3 millionperfoot 0 -262psf 0 -300knots 4 39 ftx7980 Closed Circuit addition ofsoundabsorbingmaterial. actually 39feetby79becauseofthe section ofthe40by80foottestareais circuit, singlereturnwindtunnel.Thecross The 40by80footWindTunnel isa 40 3000 psi,20gpmhydraulicsystem; 100psishopair 60 x100foothangarfloorspace; 0 s s s s s s s s / 5 tonbridgecrane    0  -AXIMUM -AXIMUM -AXIMUM -15

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Contact Person: NFAC Deputy Director Email: [email protected] National Full-Scale Aerodynamics Complex (NFAC) Phone: (650) 604-4711 Ames Research Center Mail Stop 221-9 AEDC Fact Sheet website: Moffett Field, CA 94035-1000 http://www.arnold.af.mil/library/factsheets