Last week, we brought you a photo gallery on the Langley Full Scale Tunnel, a historic wind tunnel that NASA took out of operation in September after nine decades of distinguished research. As it turns out, the Langley Research Center has long been a cornucopia of wind tunnels large, small, and often specialized. In the early 1990s, NASA said that the Hampton, Va., facility had 23 major wind tunnels, along with an unspecified number of other wind tunnels. (We haven't been able to come up with a more recent count.)
At Langley Laboratory, the forerunner to the LRC, the first major U.S. government wind tunnel went into operation in June 1920. Pictured here, it was a replica of a 10-year-old British design, according to NASA.
This is the open-circuit air intake for that first Langley wind tunnel, which, NASA says, ensured a steady, nonturbulent flow of air to the test section of the structure. NASA wouldn't be around till almost four decades later, of course--the Langley facility was put into operation by the space agency's predecessor, the National Advisory Committee for Aeronautics, or NACA.
The very first wind tunnels date back to the 1870s as folks of an engineering bent sought to understand the physics of powered flight. The Wright Brothers, too, used a small wind tunnel to study the aerodynamics of their first flyers in the first decade of the 20th century.
Behold the control room of NACA Tunnel No. 1. The opening in the side of the wind tunnel, which had a 5-foot diameter, shows a model of a Curtiss "Jenny" aircraft. "Both a real JN4H and a highly accurate model were put through identical tests," NASA says. "The NACA engineers used this data to make the necessary corrections to the wind tunnel."
In 1923, engineers at Langley began to use the Variable Density Tunnel, which is said to have been the world's first high-pressure tunnel. This photo from March 1929 shows NACA staff as they use the tunnel to test the aerodynamics of airfoils (structures such as wings and propellers). Pictured from left to right are Eastman Jacobs, Shorty Defoe, Malvern Powell, and Harold Turner.
Some decades later, the Variable Density Tunnel, the Full Scale Tunnel, and the 8-Foot High-Speed Tunnel were declared National Historic Landmarks.
The 7x10-Foot Atmospheric Wind Tunnel went into operation at Langley Laboratory in early 1931, the year that this picture was taken. It was an all-purpose tunnel, though with a focus on studying stability and control problems, and it was one of two tunnels that replaced the original one. The other was...
Remember the Variable Density Tunnel? This is the exterior of the building that houses it, and compressed air from that facility was used to induce air from the atmosphere into the structure in the foreground, the 24-Inch High Speed Tunnel. In the test section of the 24-Inch HST, seen here in 1934, air velocity could reach almost the speed of sound, roughly 760 miles per hour.
This grim-looking series of concrete structures is the 8-Foot High-Speed Wind Tunnel, where the air could move at a simulated speed of 500 mph, NASA says. The facility was large enough to accommodate some sizable aircraft models and some full-scale components. (The photo is from 1936.)
The 12-Foot Free-Flight Tunnel, built in 1939 (and seen here in December 1940), allowed researchers to test the stability and control of dynamic scale models. The tunnel operator could adjust the air speed and the tunnel angle, as well as the power to the model aircraft. Three 35-millimeter movie cameras recorded the model's motion. Pictured in the tunnel is a 1/12th scale model of an SBN-1 aircraft.
The principles of aerodynamics may be constant, but telephones and electronic meters aren't what they used to be. This picture from 1946 shows the control desk of Langley's 9-Inch Supersonic Tunnel in the foreground and the test section in the background.
In October 1947, a Bell X-1 piloted by Chuck Yeager became the first aircraft to fly faster than the speed of sound. This photo from March 1951 shows a model of the X-1 in the 16-Foot High-Speed Tunnel at Langley.
Gone are the windows to the outside world of the earlier wind tunnel facilities; here to stay are the fluorescent lights of the modern workplace. These are the control panels of the Unitary Plan Wind Tunnel, "a closed-circuit, continuous-flow, variable-density supersonic tunnel with two 4x4x7-foot test sections," according to NASA. The photo is from 1956.
This looks like a set for a cheesy 1950s movie about aliens from outer space, but it's actually Langley's Transonic Dynamics Tunnel. (The photo is from 1962.) "Transonic" refers to air speeds that range from just below to just above the speed of sound. The test section of the TDT featured slotted walls and measured 16 feet by 16 feet; it was a renovation of the earlier, circular 19-foot Pressure Tunnel. The TDT allowed researchers to use controlled gusts of air to see how the aircraft models responded to being buffeted.
Now we come to the cheesy 1960s movie set--or rather, the 9x6-Foot Thermal Structures Tunnel, where the application of high temperatures offered insights into how materials would react to high-speed re-entry into the Earth's atmosphere. Of course, with a name like "Project Fire," maybe the 1962 NASA research effort wasn't all that far removed from Hollywood brainstorms after all.
This aerial view from 1968 shows the construction of the 14x22-Foot Wind Tunnel, along with a number of other, unspecified wind tunnels at the Langley Research Center. "Both powered and unpowered models of various fixed- and rotary-wing aircraft are tested in this facility," NASA writes, "which can be operated as a closed test section with slotted walls or as one or more open configurations when the sidewalls and ceiling are removed to allow extra test capabilities, such as flow visualization and acoustics testing."
Like many of the ever-newer Langley facilities, it replaced (and was built on the site of) an earlier one, in this case the 7x10-foot 300 mph tunnel.
In 1993, a 19-foot model of a proposed 300-passenger supersonic commercial aircraft gets checked out in the 14x22-Foot Subsonic Tunnel. The aerodynamic tests were simulating takeoff and landing conditions. Plans for the "Reference H" design by Boeing called for the plane to fly at about Mach 2.4, or roughly 1,600 mph.
This is a 0.021-scale model of the X-38, a proposed rescue vehicle intended for emergency evacuation of astronauts from the International Space Station. Seen here in 1997, it was being readied for testing in the 31-Inch Mach 10 Tunnel. Other tunnels being used in the project included the 20-Inch Mach 6 Air Tunnel, the 20-Inch Mach 6 CF4 Tunnel, the 22-Inch Mach 20 Helium Tunnel, the Unitary Plan Wind Tunnel, and the 16-Foot Transonic Tunnel.
This undated photo shows a model of the X-43A hypersonic research aircraft undergoing tests in the 8-Foot High-Temperature Tunnel. The X-43A and its scramjet engine were key parts of the $250 million Hyper-X program, which dated to the mid-1990s, to evaluate alternate propulsion technologies.
A scramjet engine has few or no moving parts and starts at supersonic speeds; it scoops oxygen from the air and uses the incredibly high rate of speed to compress air and propel itself. ("Hypersonic" means five times the speed of sound.)
In 2004, NASA says, an X-43A scramjet flew at Mach 9.6, or nearly 7,000 mph.