Good Morning, Oppo, and happy Friday.
No, this is not a giant container of beer being brought to you on a flatbed rail car, though it might be nice, since it’s Friday of a week that feels like it was about nine days long. It’s actually the Variable Density Tunnel, or VDT.
Researchers had been using wind tunnels to test scale models of aircraft for years. In fact, the whole idea of a wind tunnel dates back to Leonardo da Vinci (he was a pretty smart dude). However, those tunnels could only produce results in the ambient air pressure where the test was taking place. The VDT, installed at the Langley Memorial Laboratory in 1922, was a quantum leap forward in the development of aircraft because it allowed for the density of the air inside to be altered to more accurately predict how air would flow over an object in real life and at different altitudes.
Now, this gets into all sorts of things like viscosity and density and Reynolds numbers, things that I don’t even pretend to understand. I’ll put some links below if you want to learn more. Ultimately, the VDT catapulted the National Advisory Committee for Aeronautics (NACA, predecessor to NASA) to the forefront of pre-WWII aviation research.