27-08-2005, 11:30 PM
SWAFO certainly know best about mach and knots (at least from his F18 era 
) but switching from knots to mach won't allow you to fly
faster.
The mach scale vary with altitude, because the speed of sound vary with temperature. If you are very high (and the air is colder), the
sound travel slower than at sea level (where the temperature is higher). You don't have to travel as fast at 45 000 to break the sound
barrier.
Between 30 000 and 60 000 feet, the speed of sound is about 570 knots, and at sea level it's about 660 knots.
So mach and knots are different scale, mesuring two separate thing. If you fly at mach 0.8, your speed is about 80% of the sound's
speed. It won't allow you to know your "true speed".
Pagir
Look at: http://en.wikipedia.org/wiki/Speed_of_sound
) but switching from knots to mach won't allow you to fly faster.
The mach scale vary with altitude, because the speed of sound vary with temperature. If you are very high (and the air is colder), the
sound travel slower than at sea level (where the temperature is higher). You don't have to travel as fast at 45 000 to break the sound
barrier.
Between 30 000 and 60 000 feet, the speed of sound is about 570 knots, and at sea level it's about 660 knots.
So mach and knots are different scale, mesuring two separate thing. If you fly at mach 0.8, your speed is about 80% of the sound's
speed. It won't allow you to know your "true speed".
Pagir
Look at: http://en.wikipedia.org/wiki/Speed_of_sound
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