The massive structure at NASA Ames Research Center is hard to miss from the Stevens Creek Trail, where its larger-than-a-football-field mouth sucks up air from across the bay and spits it out with such force that planes are not allowed to fly overhead. Its six massive fans can generate 115 mile per hour winds while consuming the electrical load of a city of 225,000 people.
Inside, everything from Mars rover parachutes to jet planes have been blasted while keen eyes observe the laws of physics in action and read data collected by sensors hidden under the floor, and attached to aircraft through struts.
The National Full Scale Aerodynamics Complex is home to the world's largest wind tunnel, and having been built in 1987, it celebrates a quarter century of existence on Dec. 11. In celebration, NASA Ames has organized a Dec. 11 talk by Dr. William Warmbrodt, who has worked in Ames' wind tunnels since 1978 and is chief of the aeromechanics branch at Ames.
"When we turn on this facility, it's like introducing a city of 225,000 people onto the utility grid," Warmbrodt said, referring to the six, 18,000 horsepower fans which can draw a total of 104 megawatts. "It's surprising the lights don't dim at my house in Mountain View."
The National facility is used mostly by private aircraft companies, NASA and the military, but is used to test the aerodynamics of more than just airplanes and spacecraft. Its 80-by-120 foot section, the largest anywhere, was used to test the parachute that helped the Curiosity rover land on Mars, has helped develop innovative helicopter designs, more efficient rotors on wind power generators and even aerodynamic semi truck designs for the Department of Transportation. A smaller, 40-by-80 foot test section at the NFAC, built in 1944, can generate 345 mile per hour winds and has been used to test a one-third scale model of the Space Shuttle and a replica of the Wright Brothers plane. Warmbrodt says one of the two sections is in use at any given time.
Suffice to say, it's not safe to stand inside when the fans are on full blast. But parachute engineers often want to be up close to see how their parachutes open at lower wind speeds.
"Parachute engineers love walking out into cold, windy test sections," Warmbrodt said. "They are crazy."
Warmbrodt said the NFAC gets calls from weathermen who want to have themselves filmed standing in hurricane force winds. Warmbrodt says the NFAC doesn't allow that, but says there is a wind tunnel facility on the East Coast that does.
The use of supercomputers at Ames to analyze aircraft design has not rendered NFAC obsolete, Warmbrodt said.
"The increase in our computer capability has allowed us to refine and reduce the amount of wind tunnel testing necessary, yet the ability to capture all physics of a complicated aircraft or rotor craft can and does require full scale wind tunnel testing." Warmbrodt said.
While there will not be public tours of the wind tunnel on Dec. 11, Warmbrodt will show and operate a 1/50 scale model that was used to develop the tunnel, complete with working fans.
"It's amazing, it's bigger than your living room," Warmbrodt said of the model. "I'm going to operate it during the talk. I'm going to blow people away," he chuckled.
To get a free ticket to the 250-seat, 7 p.m event, visit the NASA Ames event page at tinyurl.com/NFAC25th.