Monday June 30, 2008 – NASA Glenn Research Center – Cleveland, OH
Our tour of the 10 x 10 began by watching a video describing the features of the wind tunnel. Jim Roeder, a mechanical engineer, explained to us that the 10 ft x 10 ft Supersonic Wind Tunnel was brought to life in 1956, under the direction of Dr. Abe Silverstein and Eugene Wasliewski. This tunnel can reach various altitudes and aero speeds from 1400 to 2500 mph which is 2-3.5 times the speed of sound. Mach 3.5 is produced using two engines to produce 250,000 horsepower which is 200 million watts per hour. The test section has movable, 1 and 3/8 inch, continuous, stainless steel walls which can move inward up to 4 feet. The walls are moved inward through the use of multiple of hydraulic actuators along the outside of the walls. The walls of the tunnel are less than 2 inches thick, 10 ft high and 78 ft long. The rest of the tunnel is made of carbon steel.
The tunnel, dedicated to Dr. Abe Silverstein in 1994, can simulate speeds about 10 to 30 ft above Earth with a maximum temperature of 680°F. Within the Wind Tunnel facility, there is a machine shop which produces supersonic inlets and nozzles for the tunnel. The purpose of the wind tunnel is to test propulsion capabilities in ever-changing environments. Due to the complex open-loop system present at Glenn, which we saw in the wind tunnel, one can test burning engine models. In fact, the test facility has the capability of providing Liquid Oxygen and Hydrogen to the test section. Most of the million-dollar models from the test runs in the wind tunnel are taken back with the company who ordered the test or are stored at the Plum Brook station. One of the tests done in the 10×10 was a Scaled Space Shuttle tests, done in 1988, to test the system flight dynamics in the event that one of the engines on the orbiter did not fire.
The test section of the 10 x 10 wind tunnel can be adjusted given the plates in the ceiling and floor for variable struts. The angle of attack can also be varied at the mounting locations in the test section. Extremely polished glass windows allow cameras to see into the test section. Before running a test in the wind tunnel, it is inspected for people and everyone is accounted for. If not, the test will not be run until everyone’s whereabouts are known for safety assurance purposes. When we moved into the 10 x 10 control room, we learned that two operators must be on duty when a test is performed: one to operate and another to perform shutdown procedures properly. In addition, the test facility provides the capability of monitoring data from a given test on a real-time basis from remote locations by other researchers.
The tests are run mostly on third shift to save money. The electric engines use 200 million watts per hour to run a test and the electric company will cut NASA a break if a run is done during third shift. Costs to run a test in the wind tunnel depend upon occupancy time in the tunnel itself, despite a run of only a few seconds. The 10 x 10 Supersonic Wind Tunnel runs about 3 to 4 tests a year lasting about 2 to 6 weeks per test.