The Wharfedale MACH 9) Some competing loudspeakers sold at the time were the Bose 901 Series IV and V, Bose 201 Series I, Bose Series 601 Series II, JBL Delta, Cerwin Vega D series, JBL Radiance, JBL Sigma, and Acoustic Research AR-58B. 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
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