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The subsonic speed range is that range of speeds within which, all of the airflow over an aircraft is less than Mach 1. The critical Mach number (Mcrit) is lowest free stream Mach number at which airflow over any part of the aircraft first reaches Mach 1. So the subsonic speed range includes all speeds that are less than Mcrit. Transonic: 0.8–1.2
Transonic (or transsonic) flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. [1] The exact range of speeds depends on the object's critical Mach number, but transonic flow is seen at flight speeds close to the speed of sound (343 m/s at sea level), typically between Mach 0.8 and 1.2.
Mach number is more useful, and most high-speed aircraft are limited to a maximum operating Mach number, also known as M MO. For example, if the M MO is Mach 0.83, then at 9,100 m (30,000 ft) where the speed of sound under standard conditions is 1,093 kilometres per hour (590 kn), the true airspeed at M MO is 906 kilometres per hour (489 kn).
For example, consider that at Mach 1.3 the angle of the Mach cone generated by the nose of the aircraft will be at an angle μ = arcsin(1/M) = 50.3° (where μ is the angle of the Mach cone, also known as Mach angle, and M is the Mach number). In this case the "perfect shape" is biased rearward; therefore, aircraft designed for lower wave drag ...
A subsonic aircraft is an aircraft with a maximum speed less than the speed of sound (Mach 1). The term technically describes an aircraft that flies below its critical Mach number, typically around Mach 0.8.
For jet aircraft operating in the stratosphere (altitude approximately between 11 and 20 km), the speed of sound is approximately constant, hence flying at a fixed angle of attack and constant Mach number requires the aircraft to climb (as weight decreases due to fuel burn), without changing the value of the local speed of sound.
So the regime of flight from Mcrit up to Mach 1.3 is called the transonic range. [citation needed] Northrop X-4 Bantam (Mach 0.9) — Supersonic [1.2–5) 921–3,836 mph (1,482–6,173 km/h; 412–1,715 m/s) The supersonic speed range is that range of speeds within which all of the airflow over an aircraft is supersonic (more than Mach 1).
In many nose cone designs, the greatest concern is flight performance in the transonic region from Mach 0.8 to Mach 1.2. Although data are not available for many shapes in the transonic region, the table clearly suggests that either the Von Kármán shape, or power series shape with n = 1/2 , would be preferable to the popular conical or ogive ...