Sphere drag at Mach numbers from 0·3 to 2·0 at Reynolds numbers approaching 10⁷

Abstract

Our analysis of 18th and 19th century cannon firings shows that knowledge of sphere drag can be substantially extended into the region of 0·3 ≤ M ∞ ≤ 2·0 and Re ∞d up to 10 7 . Bashforth’s chronographic measurements (1868) are of a quality comparable to modern measurements. The data of Mayevski (chronograph, 1868), Hutton (ballistic pendulum, 1787-1791), and Didion (ballistic pendulum, 1839-1840) are of lesser accuracy but in agreement with Bashforth’s. These cannon data are combined with modern data to provide the most extensive curves available of C D vs. Re ∞d in this region. Interesting features of these curves for M ∞ ≤ 1·0 are briefly described.