Circular Aerodyne Tests from the 1930s in the U.S.
Thought some of you might be interested in two non-classified documents I came across recently from the 1930s. They are official NACA (which name was later changed to NASA) technical reports about the testing of circular airfoils (round flying thingies!). Here are NACA TN 539 and NACA TR 431.
Tags: NASA, UFOs, US military
