Editing Mach number (section)

==Etymology==
The Mach number is named after the physicist and philosopher [[Ernst Mach]],<ref>{{cite encyclopedia|title=Ernst Mach|encyclopedia=[[Encyclopædia Britannica]]|url=https://www.britannica.com/biography/Ernst-Mach|year=2016|access-date=January 6, 2016}}</ref> in honour of his achievements, according to a proposal by the aeronautical engineer [[Jakob Ackeret]] in 1929.<ref>Jakob Ackeret: Der Luftwiderstand bei sehr großen Geschwindigkeiten. Schweizerische Bauzeitung 94 (Oktober 1929), pp. 179–183. See also: N. Rott: Jakob Ackert and the History of the Mach Number. Annual Review of Fluid Mechanics 17 (1985), pp. 1–9.</ref> The word Mach is always capitalized since it derives from a proper name, and since the Mach number is a dimensionless quantity rather than a [[International System of Units#Unit names|unit of measure]], the number comes after the word Mach. It was also known as ''Mach's number'' by Lockheed when reporting the effects of compressibility on the P-38 aircraft in 1942.<ref>Bodie, Warren M., ''The Lockheed P-38 Lightning'', Widewing Publications {{ISBN|0-9629359-0-5}}.</ref>