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Conversion Formula:
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Mach number is a dimensionless quantity representing the ratio of an object's speed to the speed of sound in the surrounding medium. At sea level under standard conditions, the speed of sound is approximately 661.478 knots.
The conversion formula is:
Where:
Explanation: This conversion assumes standard atmospheric conditions at sea level (15°C, 101.325 kPa). The speed of sound varies with altitude and temperature.
Details: Mach number is critical in aviation and aerodynamics for classifying flight regimes: subsonic (Mach < 0.8), transonic (0.8-1.2), supersonic (1.2-5.0), and hypersonic (Mach > 5.0).
Tips: Enter speed in knots. The calculator will convert to Mach number based on sea level standard conditions. Valid values are positive numbers greater than 0.
Q1: Why is the conversion factor 661.478?
A: This represents the speed of sound in knots at sea level under standard atmospheric conditions (15°C, 101.325 kPa).
Q2: Does Mach number change with altitude?
A: Yes, the speed of sound decreases with altitude due to lower temperatures, so the same indicated airspeed corresponds to a higher Mach number at higher altitudes.
Q3: What is the difference between indicated airspeed and true airspeed?
A: Indicated airspeed is what the aircraft instruments show, while true airspeed is the actual speed through the air mass. Mach number is based on true airspeed.
Q4: When is Mach number most important in aviation?
A: Crucial for high-speed aircraft, especially when approaching or exceeding the speed of sound, as aerodynamic characteristics change significantly near Mach 1.
Q5: Can this calculator be used for different altitudes?
A: This calculator uses sea level standard conditions. For accurate conversions at different altitudes, temperature-specific speed of sound values should be used.