Six months after dedicating their first wind tunnel on June 11, 1920, the researchers at America’s first government-funded aeronautics laboratory reached what many saw as a foregone conclusion.
Though the new equipment based on a 10-year-old British design had helped the inexperienced Langley team get its feet wet in an arcane and still largely unexplored field, it was so outdated they could not produce any meaningful new research.
Compounding their struggle with obsolescence was a still more crippling dilemma that had stymied even the most experienced minds at the most advanced aeronautics labs in Europe.
Like their counterparts abroad, the researchers could not correlate the data gathered from scale model tests in their tunnel with the real-world behavior of full-size airplanes flying through the atmosphere.
Even as they butted heads against this apparent dead end, a cutting-edge solution was emerging in the Washington, D.C., offices of the Hampton lab’s parent agency, the NACA.
There, a newly hired young theoretician from the famed German aeronautics research center at the University of Göttingen already had applied his brilliant, if difficult, mind to the seemingly insoluble puzzle.
Soon Max Munk was overseeing the development of a visionary wind tunnel unlike any other on the planet.
By October 1922 the new facility started to generate test results seen around the world as a landmark breakthrough in aerodynamics.
“They’re getting results that no one else could get — and people all over the world are picking up on what they’re doing,” Hansen says.
“The Variable Density Tunnel was a revolution in aerodynamic research — and it put Langley on the map. It helped create the Langley brand.”
Pioneering tool
Hemmed in by the so-called “scale effect,” the Langley researchers first tried the route taken by everyone else, “scaling up” the data they’d obtained from small, one-twentieth scale models in order to approximate the performance of full-size aircraft.
But the resulting numbers fell short in so many areas that they soon determined this widely accepted method was unreliable, Hansen says.
Increasing the size of the models, the speed of the airflow or the density or viscosity of the air were widely known theoretical ways to overcome the failings of the tunnel test data.
But not until Munk suggested building a wind tunnel inside a sealed, airtight chamber and compressing the air did the NACA and its Langley lab move past the realm of theory — and the rest of the world — to construct a practical, pioneering solution.
“It was the arrival of Munk that turned Langley around,” Hansen says.
“He was a tough, tough bird — and really difficult to get along with. But he brought ideas and experience from Germany that none of these young guys had.”
The emerging culture of the American lab played an important role, too, providing an immigrant who had been no more than a talented assistant in Germany with a freedom and authority that enabled his genius to flourish, Hansen adds.
Within eight months after the first wind tunnel opened, Munk had received permission to proceed with his innovative design.
Funding came in 1921, and after getting the tunnel underway at Newport News Shipbuilding that same year, construction finished in February 1922.
“Langley was not only starting to ask big, smart questions in a pretty primitive field but also building the new tools needed to answer them,” said the Smithsonian’s Crouch.
“And when they got the Variable Density Tunnel up and running, it was the first time anybody had data they could bring to the bank.”
Breakout tests
Munk’s contributions might not have happened without MIT aeronautics program founder Hunsaker — a future head of the NACA — who spotted him during a 1913 visit to Göttingen, then recommended that the agency employ him when he sought to immigrate to the United States.
President Woodrow Wilson played a crucial role, too, signing a presidential order that allowed a former enemy to enter the country, then issuing a second order enabling him to work for the government.
Despite the rare and subtle theories for which he was so highly valued, Munk’s VDT was a brute-looking monster.
Measuring 34.5 feet long and 15 feet across, the giant, bomb-shaped tank was riveted together by Newport News shipbuilders from 2-inch-thick steel boiler plate and weighed 85 tons.
So heavy and ponderous was the immense shell that it had to be moved to a James River wharf by rail car, then by barge to the lab site on the Back River.
Soon after it began operating in October 1922, the VDT focused on airfoil design and performance, which previously had been largely the domain of cut-and-try experiments rather than a scientific undertaking, Crouch says.
Even when empirical methods had been used, the scale effect had led to basic misinformation about the performance of various sizes and shapes, resulting in a widely accepted but mistaken belief in the superiority of long thin wings, Hansen adds.
Within three years, however, the Langley researchers not only had brushed this longtime misconception aside but also formulated a catalog of 27 different airfoil forms that designers could choose from depending on the kind of performance they wanted.
By 1933, they’d added dozens more, making “Technical Report No. 460” an aeronautical design bible — and the source for the wings on such revolutionary planes as the Douglas DC-3 transport, the Lockheed P-38 Lightning fighter and the Boeing B-17 Flying Fortress bomber.
“They put together the first systematic database — and that suddenly made everything a lot easier for aircraft designers,” says Hoilman. “And the amazing thing about it is that it wasn’t proprietary information. You didn’t have to buy it. You didn’t have to license it. It was there for anyone who wanted to use it.”
Even before the initial 1925 report, aircraft designers around the world were incorporating Langley’s airfoils in new planes.
Aviation enthusiasts flocked to Hampton to see the VDT at work, and engineer after engineer came to study and then copy Munk’s miracle. These guests included some famous names.
In the fall of 1928, Amelia Earhart dropped in. She was wearing a knee-length raccoon fur coat that at one point got sucked into the fan of a much smaller high-speed wind tunnel. Both Earhart and the coat recovered in time to pose for photos.
On May 23, 1934, Langley hosted the ninth annual Aircraft Engineering Research Conference for the NACA’s advisory committee. The chairman of that committee? Orville Wright. Another committee member was Charles Lindbergh, seven years after his famous trans-Atlantic flight.
Lindbergh also would come to Langley on occasion to run tests with engineer Fred E. Weick, a pioneer in the field of propeller design.
Even Howard Hughes, the early aviation pioneer who would go on to become a legendary billionaire, would make the trip to Langley to check out the wind tunnel.
And make no mistake: These celebrities were not making promotional appearances in Hampton. They came to Langley to learn.
As NACA staff member Abe Leiss told historian Parke Rouse in a 1992 Daily Press article: “It was never a matter of NACA going out to find what other researchers were doing. It was a matter of other people trying to find out what we were doing.”
“What started out as a very rocky enterprise — to say the least — was transformed into a magnificent venture almost overnight,” says aviation historian Yarsinske. “All great names of the day went to Langley after they got their footing. It became the center of aviation research in the United States and led the way for the rest of the world.”
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