The Wharfedale MACH The Wharfedale MACH The Wharfedale MACH series of loudspeakers consists of the MACH 3, 5, 7, and 9. This is an informational page devoted to owners and users of these loudspeakers and those interested in history and construction of electronic sound reproduction. These loudspeakers were manufactured at Rank Hi-Fi, Wharfedale Works in West Yorkshire by Wharfedale Loudspeakers in England (UK). They were featured in the Gramophone magazine in July 1982. This range of high-efficiency (hi-fi) loudspeakers were released to replace their "E" Series of loudspeakers. They were originally launched with prices from £200 to £430 per pair. The drive units
Drag divergence Mach number Drag divergence Mach number The drag divergence Mach number (not to be confused with critical Mach number) is the Mach number at which the aerodynamic drag on an airfoil or airframe begins to increase rapidly as the Mach number continues to increase. This increase can cause the drag coefficient to rise to more than ten times its low speed value. The value of the drag divergence Mach number is typically greater than 0.6; therefore it is a transonic effect. The drag divergence Mach number is usually close to, and always greater than, the critical Mach number. Generally, the drag coefficient