If you have ever watched a movie featuring fighter jets, chances are that you may have witnessed or heard dialogue that references Mach 2 (Mach Two). Perhaps you know about Chuck Yeager breaking the sound barrier during one of his test flights on his Bell XS-1 aircraft.
The Mach number system was devised by Austrian physicist Ernst Mach, an influential scientist renowned for his contributions in various areas such as optics and cosmology. It measures variations in sound speed depending on the medium.
What is a Mach number?
Mach numbers measure an object’s speed in relation to local sound speeds, named for Austrian physicist Ernst Mach. When an aircraft travels faster, its Mach number increases; Chuck Yeager was the first pilot ever to break through the sound barrier manned flight back in 1947, and commercial jetliners usually cruise below Mach 1. Military aircraft may even travel at even faster speeds, up to hypersonic speeds.
A device known as a “machmeter,” often found in high-speed aircraft cockpits, can help determine an aircraft’s speed. The machmeter measures airspeed based on velocity and other environmental factors; additionally, it displays this figure in knots – one nautical mile per hour is 1 knot.
As an aircraft speeds up, a shockwave forms around it that compresses air particles in front of it, increasing temperature, pressure, and density. This change in conditions is known as the sound barrier; when broken, it produces the well-known “sound boom.”
Mach numbers depend on an aircraft’s surrounding environment and can change with altitude and temperature changes. Mach numbers are defined as the ratio between the local speed of an aircraft relative to sound speed in its environment and thus determine how fast an aircraft moves at any one moment in time. As such, their actual rates will differ depending on the circumstances in each domain in which an aircraft operates.
Mach number is typically reported for airplane speeds; knots may also be reported. An aircraft’s actual speed depends on altitude and temperature fluctuations in its surroundings; therefore, manufacturers must always provide accurate information. Due to air resistance and turbulence factors, in most instances, the actual aircraft speed exceeds what appears on a meter’s display.
What is the speed of sound?
The speed of sound is an objective measure of how fast something travels through an airborne medium such as air. This speed may differ depending on factors like temperature, pressure, and humidity of its environment; liquids travel faster than gases, while solids take longer. Altitude also plays a factor in its travel speeds: slower altitude travel results in slower sound travel speeds.
The science of sound is pretty straightforward. Sound waves are created when mechanical disturbances pass through layers of air – from an orchestral drummer hitting their drumhead against a stick to your cat meowing for food – making waves of pressure that move through the surrounding atmosphere until reaching your ear and creating ripples that continue their journey towards creating noise in your ear canal. Each movement pushes against other air molecules, which vibrate, which in turn makes against more molecules, which vibrate even further, ultimately reaching you and producing noise noises from within.
Although there have been various manmade objects capable of traveling faster than the speed of sound since 1947 when a four-engine Boeing B-29 Superfortress took off from Muroc Air Force Base (now Edwards Air Force Base) near Los Angeles, California and piloted by Major Robert L. Cardenas as Bell XS-1 it successfully broke through the sound barrier and reached speeds near Mach 1.
One of the biggest misconceptions surrounding Mach 1 is that it refers to an absolute speed, such as 761 miles per hour. Unfortunately, however, sound wave speeds depend on conditions in their path through various media and, therefore, may vary significantly between instances of Mach 1.
No universally applicable Mach 1 number covers all aircraft and types of air. To ascertain an aircraft’s Mach number, engineers and scientists use mathematical models of Earth or Mars’ atmosphere that account for variations in density with altitude; engineers also utilize these models to calculate maximum speeds on jets such as F-18, SR-71A, and B-747 jets.
What is the speed of an aircraft at Mach 1?
Mach 1 aircraft are rare as traveling at speeds above the speed of sound can produce shock waves, which can damage aircraft and any objects nearby while creating an audible noise known as sonic boom. These shockwaves also make loud noises known as sonic booms that can be heard for miles around.
Pilots and aeronautics experts prefer using Mach to describe an aircraft’s speed instead of giving its actual velocity in miles per hour or kilometers per hour (mph or km/h). Mach is defined as the ratio between true airspeed and the local speed of sound – which varies based on atmospheric conditions, air temperature, and density – with sea-level air having around 760 miles-per-hour of sound speed while at higher altitudes where jets usually operate, this figure drops down to about 660 mph.
So when a pilot or other aeronautical expert refers to flying at Mach 1, this means they are traveling precisely at the speed of sound in that environment. If they exceed it further, this would be considered hypersonic travel or supersonic flight.
On October 14, 1947, Chuck Yeager piloted the Bell X-1 research aircraft through the sound barrier for the first time. At that time, its velocity of one Mach (760mph) was considered the speed of sound; military aircraft can attain up to Mach 5 speeds; however, this technology is yet to become commercially available in commercial aviation.
There are currently several companies, like Hermeus and Radian Aerospace, working on technologies that enable commercial aircraft to achieve hypersonic speeds. Unfortunately, however, they face various difficulties, including that the air at such speeds is significantly hotter than what we are used to breathing on earth, changing aerodynamics drastically and making it hard to design aircraft that look attractive while traveling at these speeds.
What is the speed of a missile at Mach 1?
Mach 1 missiles travel at an astounding 760 miles per hour – fast enough to circumnavigate Earth in just under three hours! Various companies are working on bringing back supersonic jets into service; Hermeus, in particular, is making strides to achieve this goal with its ambitious project of developing aircraft that can reach Mach 5 speeds. Watch This Iteration22 Video featuring Skyler Shuford from Hermeus to learn more.
Radian Aerospace, working on a spacecraft capable of reaching Mach 10, is another exciting company. Watch the This Is Iteration22 video featuring Livingston Holder, co-founder and CTO at Radian Aerospace, to learn more.
At Mach 1, the speed of a missile depends on both temperature and density. Sound speed varies based on which medium is being traversed – air, water, or various gases all play an integral role – so when someone mentions speedy movement, you need to know which medium it’s happening in. To accurately understand its velocity.
At higher speeds, more energy is typically required to accelerate due to increasing air pressure pressing against your craft’s body. Therefore, having a powerful engine and lightweight skills are both key when traveling at such high speeds.
Be mindful that sound speed varies with altitude and temperature; fast military jets typically cannot exceed Mach 2 due to this factor; supersonic vehicles have blunted noses and large tailplanes in order to deal with the increased turbulence caused by traveling at supersonic speeds and can produce loud sonic booms that can be disturbing for human ears.
