The first-ever Supersonic aircraft was the Bell X-1, an experimental rocket-powered plane. Planes that move at Supersonic speeds must also be designed with aerodynamic heating in mind. Continuous shockwaves will be generated by planes moving at Supersonic speeds, necessitating their slick design. The compression effect of sound comes into consideration around Mach 1, and because of the high drag that is created by the compression Transonic aircraft typically have swept wings to deal with the drag.įrom 1.3 Mach to 5.0 Mach exists the Supersonic range of speed, air behaves quite differently above Mach 1, so planes that fly at Supersonic speeds must be extremely aerodynamic with sharp edges and moveable canards. This covers craft moving at 0.8 to 1.3 Mach. While anything below Mach 1 is considered to be Subsonic, aircraft that fly at approximately Mach 1 are considered to be Transonic craft. “Most pilots learn, when they pin on their wings and go out and get in a fighter, especially, that the one thing you don’t do, you don’t believe anything anybody tells you about an airplane.” - Chuck Yeager The Mach numbers can be split into Transonic, Supersonic, Hypersonic, and High-Hypersonic categories. In terms of the various Mach numbers, they fall into a few different categories. In general, the Mach number of an aircraft can be determined by dividing the velocity of the craft by the speed of sound at the given altitude of the craft. Remember that like Mach 1 these other Mach speeds are relative, they reflect two or three times the speed of sound in those specific conditions. Mache 3 means an aircraft is traveling three times the speed of sound, and so on. That covers Mach 1, but what about the other Mach numbers? Put simply, Mach 2 means that an aircraft is traveling twice the speed of sound. Note that the figures given here reflect the speed of sound at sea level, and at higher altitudes, the speed of sound gets incrementally slower. In general, sound can travel faster in warmer air, so when the temperature is at 20 degrees Celsius (or 68 degrees Fahrenheit) the speed of sound is at 343 meters (or 1127 feet) a second. What is the exact speed of sound? That question is more difficult to answer than you would think, as the exact speed of sound is dependent upon a variety of variables, like the current temperature and air pressure of the air the sound is passing through.Īs a general rule though, at an air temperature of 0 degrees Celsius (32 degrees Fahrenheit), the speed of sound is approximately 331 meters per second (1,087 feet per second). Mach 1 refers to the point at which an aircraft exceeds the speed of sound, creating a sonic boom. This is the mechanism that creates sonic booms.Ī Mach number is calculated by dividing an object’s speed by the speed of sound. As the aircraft passes an area, all the accumulated sound is released at once as the cone of sound expands rapidly. This causes the sound waves to pile up and accumulate in a cone of sound which forms directly behind the aircraft. Mach noted that when objects accelerate faster than the speed of sound, an interesting phenomenon occurs.Īs an airplane approaches the speed of sound, the sound waves that are emitted by the plane itself cannot get ahead of the plane. While Mach contributed much to the fields of cosmology and optics, he was the one to first describe the speed of sound, as well as what happens when an object exceeds the speed of sound. Mach numbers were created thanks to the work of Ernst Mach, an Austrian physicist. However, the speed of sound isn’t constant and can actually fluctuate greatly depending on things like the atmospheric conditions observed at a particular place and a particular time.
Ultimately, Mach numbers are defined by their relationship to the speed of sound. Yet while pilots in these movies will routinely talk about planes traveling at Mach 2 or 3, what does that mean in reality? As it turns out, Mach numbers don’t indicate a set speed, and two different planes can actually be at the same Mach number while moving at different speeds.
#Speed of sound feet per second movie#
If you’ve ever watched a movie with fighter jets in it, chances are you’ve heard them talk about Mach numbers. For normal and dry conditions and temperature of 68 degrees F, this is 768 mph, 343 m/s, 1,125 ft/s, 667 knots, or 1,235 km/h. Mach Speed is when an object moves faster than the speed of sound.