#mach number

[moonwatchuniverse]

55 years ago... Rolex at max speed ! October 3, 1967 test pilot William "Pete" Knight wore his personal Rolex GMT-master Pepsi 1675 during X-15 flight 188 taking the hypersonic rocket aircraft to a speed of 7232 Km/hr (Mach 6.7). On October 17 he would take an X-15 to an altitude over 85 kilometers, high enough for USAF astronaut wings. Several photos show William Pete Knight wearing his Rolex GMT-master pilot watch between October 1966 and December 1988. Since 1963, the Rolex GMT-master pilot watch remains the sole timepiece strictly chosen on a personal preference basis by both Russian cosmonauts and International & American astronauts ! (Photos: USAF/NASA)

[moonwatchuniverse]

December 7, 2020 ... remembering USAF General Charles Yeager Testpilot Charles “Chuck” Yeager was the first to break the sound barrier, flying at a speed of 1240 km/h on October 14, 1947... Although retired since 1975, Brig General Yeager remained a USAF consulting testpilot and always broke the sound barrier on October 14, be it in modern day jets… Yeager the first pilot to fly supersonic ! Charles Yeager was a watchlover with a keen interest in Rolex pilot watches, which he wore since the 1940s… 75 years with a preference for the GMT-master true pilotwatches! Charles Yeager surely was the greatest pilot we ever saw… RIP  ! (Photo: USAF/AP)

[moonwatchuniverse]

October 4, 1967  record breaking Mach 6.7 flight... USAF test pilot William “Pete” Knight walks away from the white X-15A2 hypersonic research rocket aircraft after setting a record-breaking Mach 6.7 flight. In fact the ablative coating had a light pink color and protected the aircraft against high temperatures during hypersonic, above Mach 5, flight. Note Knight had his personal Rolex GMT-master 1675 Pepsi pilot wristwatch strapped over his left forearm. On October 17, 1967 Pete Knight took another X-15 rocket plane up to an altitude of 280500 feet (85 kilometers) earning him USAF astronaut wings... again wearing his Rolex GMT-master. Pete Knight made 16 flights in the X-15. (Photo: USAF/NASA)

[moonwatchuniverse]

60 years ago... USAF B-58 New York to Paris record flight ! The USAF aircrew of the Mach 2 strategic bomber Convair B-58 Hustler, nicknamed “The Firefly”, pose at the Paris Airport apron near the plaque that commemorates the landing spot of Charles Lindbergh’s first solo trans-Atlantic flight in May 1927. Left-to-right: Major William R. Payne, Aircraft Commander, Captain William L. Polhemus, Navigator, and Captain Raymond R. Wagener, Defensive Systems Officer, won the Harmon and Mackay Aviation Trophies for this flight. While Lindbergh’s flight took 33 hours 33 minutes, the B-58 Hustler only needed 3 hours 19 minutes... an average of 1755 Km/Hour for the very first supersonic transatlantic crossing ! Note the Rolex GMT-master Pepsi pilot watch at Captain Polhemus’ wrist, a favorite wristwatch among many pilots, civil and military alike! (Photo: USAF) (Scan: MoonwatchUniverse collection)

[biology-geology-beaches-india]

The Scientific Research Notes Of S. Sunkavally (years: 2002-2011).

3568-3570.

[bhagatkapil]

Ernst Mach

[secondfreak]

Mach Number

Mach number ( Ma ) merupakan salah satu bilangan tak berdimensi dalam ilmu mekanika fluida. Mach number ditemukan oleh Ernst Mach (1838-1916), seorang ahli fisika dan filsafat kelahiran Austria. Mach number didapatkan dari kecepatan ( v ) dibagi dengan  kecepatan suara dalam fluida ( c ).

Mach number diartikan sebagai ratio gaya inersia terhadap gaya kemampu-mampatan.  Apabila Mach nuber suatu sistem dibawah 0,3 maka dapat dikatakan bahwa gaya inersia akibat gerakan fluida tidak akan membuat fluida tersebut perubahan kerapatan fluida. Dalam hal ini dapat dikatakan sifat kemampu-mampatan fluida diabaikan,

Selain Mach Number ada satu lagi besaran tak berdimensi yang mempunyai fungsi yang sama, yaitu Cauchy Number yang bernilai kuadrat dari Mach Number.