Volume 2 : 3 ratio of the volumes of the sphere and cylinder is credited to Archimedes. The volume of a sphere is the integral of an infinite number of infinitesimally small circular disks of thickness "dx". The calculation for the volume of a sphere with center 0 and radius "r" is as follows. The surface area of the circular disk is formula_10. The radius of the circular disks, defined such that the x-axis cuts perpendicularly through them, is or where y or z can be taken to represent the radius of a disk at a particular x value. Using y
Northrop X-4 Bantam dragged on until February 1950, before both aircraft were turned over to the Air Force and the NACA. The first X-4 never flew again, used as spare parts for the second aircraft. The NACA instrumented the second X-4 to conduct a short series of flights with Air Force pilots. These included Chuck Yeager, Frank Kendall Everest, Jr., Al Boyd, Richard Johnson, Fred Ascani, Arthur Murray and Jack Ridley. The flights were made in August and September 1950. The first flight by an NACA pilot was made by John H. Griffith on September 28, 1950. The initial NACA X-4 flights, which