/sci/ - Science & Math

>Once the Germans came up with a good configuration for the V-2, they stuck with it. They proposed to use it anew in a two-stage missile that again sported fins that look excessively large to the modern eye, and that was to cross the Atlantic to strike New York.8 But there was no avoiding the need for a new round of wind-tunnel tests in studying the second stage of this intercontinental missile, the A-9, which was to fly with swept wings. As early as 1935 Adolf Busemann, another colleague of Prandtl, had proposed the use of such wings in supersonic flight.9 Walter Dornberger, director of V-2 development, describes witnessing a wind-tunnel test of a model’s stability.
>The model had “two knifelike, very thin, swept-back wings.” Mounted at its center of gravity, it “rotated at the slightest touch.” When the test began, a technician opened a valve to start the airflow. In Dornberger’s words,
>“The model moved abruptly, turning its nose into the oncoming airstream. After a few quickly damping oscillations of slight amplitude, it lay quiet and stable in the air that hissed past it at 4.4 times the speed of sound. At the nose, and at the edges of the wing supports and guide mechanism, the shock waves could be clearly seen as they traveled diagonally backward at a sharp angle. As the speed of the airflow fell off and the test ended, the model was no longer lying in a stable position. It made a few turns around its center of gravity, and then it came to a standstill with the nose pointing downward. The experiment Dr. Hermann had wished to show me had succeeded perfectly. This projectile, shaped like an airplane, had remained absolutely stable at a supersonic speed range of almost 3,500 mph.”