necessitating a high AOA is the most likely situation to cause a low-speed Mach buffet. The situation that increases, the angle of attack, the speed of the airflow over the wing, and chances of Mach buffet are (FAA, 2008):
Higher altitudes—the higher aircraft flies, leaner the air and the greater the angle of attack is necessary for producing the lift needed to preserve the flight level.
Heavy weights—the heavy aircraft, lead to greater lift from the wing and larger angle of attack.
Supersonic Design
Supersonic aircraft have a lot different structure, configuration and design. These differences are in term of the length of the fuselage, fuselage shape and wing shape; however, regardless of the differences it manages to break the sound barrier
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Delta Wing: advanced swept wing, it pulls the wings back and creating even less drag. The aspect of delta wing is that the aircraft has to fly fast in an enormous speed exceeds the speed of sound in order the wing to be effective. Delta wing only found and operates efficiently on supersonic aircraft to exceed the speed of sound. There are some supersonic aircraft that uses delta wing such as, space shutter and fighter jet. In the other hand, as for commercial the Russian TU-144 and Concorde both of which could cruise at supersonic speeds (NASA, 2010).
Sonic Booms
Supersonic aircraft are designed to fly at speed of sound. While they fly, the aircraft produce pressure waves or sounds. This sound generates a sonic boom, which is a loud sound produced by the pressure waves trailing behind the supersonic aircraft. There are three types of sonic booms can produced by supersonic speeds such as (PSU, 2015):
1- N-wave: the sonic boom is formed by aircraft flying straight and at constant speed.
2- U-waves: sonic boom is formed from maneuvering flights. In this stage, the sound is louder and more focused.
3- Secondary boom waves: It comes from sound firstly traveling away from the aircraft and then it’s reflected downward to far locations. Sound rumbles and can be quiet and difficult to
For as long as most of the world can remember aviation has played a major factor in how wars are fought. Starting in World War I the worlds fighting forces began using aircraft to conduct surveillance missions over enemy territory. While these aircraft were not the masters of stealth that todays aircraft are there was no technology to take down these planes at the time. Air-to-air combat was an event that rarely happened and was almost never effective.
...Another way to decrease the disturbance over the wings are to move the wings lower than the horizontal stabilizer or visa versa to allow the shock waves moving over each wing to miss each other. Most aircraft today do not have enough fuel to maintain the speed of sound for great distances. Engineers have designed a brand new aircraft known as the F-22, which has the ability to fly an entire mission at supersonic speeds. The speed of light is unattainable by aircraft due to drag. We have no materials that could with stand the heat caused by the friction of the air moving over its body, nor materials strong enough to be able to take the enormous drag. Today there is no thrust capability that would allow for the speed of light. Although aircraft has proved such things as time dilation it is still impossible for an aircraft to travel at 900,000 miles per second.
Major Ted Tolman’s F-105 Thud fighter/bomber streaked through the air at just under the speed of sound. His aircraft performed modestly at best, struggling to maintain its speed and altitude under the heavy load of ordinance and fuel it carried under its wings (Patrick).
If you put your finger gently on a loudspeaker you will feel it vibrate - if it is playing a low note loudly you can see it moving. When it moves forwards, it compresses the air next to it, which raises its pressure. Some of this air flows outwards, compressing the next layer of air. The disturbance in the air spreads out as a travelling sound wave. Ultimately this sound wave causes a very tiny vibration in your eardrum - but that's another story.
... force toward the rear that must be overcome by the forward thrust of the engines. As the angle of attack of an airplane is increased, the plane gains lift, but the lift is limited. As the angle is increased, air turbulence spreads over the wing. Then at a certain critical point (an angle of about 14 degrees in many airplanes), the wing loses lift and the plane stalls, nosing over into a dive.
Travelling at a speed twice that of sound might seem to be futuristic; however, this feat was already achieved almost 40 years ago by the world’s only supersonic passenger aircraft, the Concorde. Concorde brought a revolution in the aviation industry by operating transatlantic flights in less than four hours. The slick and elegant aircraft with one of the most sophisticated engineering was one of the most coveted aircraft of its time. However, this was all destined to end when Air France Flight 4590 was involved in a tragic disaster just outside the city of Paris on July 25, 2000. The crash killed 113 people, but more disastrous was its impact.
Ultrasound is sound waves that have a frequency above human audible. (Ultrasound Physics and Instrument 111). With a shorter wavelength than audible sound, these waves can be directed into a narrow beam that is used in imaging soft tissues. As with audible sound waves, ultrasound waves must have a medium in which to travel and are subject to interference. In addition, much like light rays, they can be reflected, refracted, and focused.
The most important factor in determining the lift generated by an airplane is the angle of attack. The angle of attack is the degree measure from the horizontal that a wing is elevated or declined. When the angle of attack is between 1 and 20 degrees, the most lift is generated. To find the lift generated by a particular area of wing in a standard airfoil shape, a teardrop with the fat end facing forward, the equation L=Cl 1/2 (pV2)S. Cl is the lift coeficent, which is determined by the shape of the airfoil and the angle of attack. P stands for the air mass density, V for the velocity of the air passing over the wing, and S for the area of the wing when viewed from above or below.
momentum transfer when air molecules collide. Our ‘subjective impression’ about the frequency of a sound is called pitch. High pitch has high vibration frequency, while low pitch has a low vibration frequency. A pure musical tone consists of a single pitch or frequency. However, most musical tones are “complex summations” of various pure frequencies - one characteristic frequency, called the fundamental, and a series of overtones or harmonics Younger people can usually hear pitches with frequencies from about 20 hertz (infrasonic) to 20,000 (ultrasonic) hertz. We can’t hear above 20,000 hertz or below 20 hertz (ultra and infrasonic waves).
Weather conditions- Sometimes the bad weather conditions become the huge problem for the aircrafts as they are not able to operate in bad conditions by which they get losses.
Flight uses four forces: lift, weight, thrust, and drag. In a nutshell; so to speak, an airplane must create enough lift to support its own weight. Secondly, the airplane must produce thrust to propel itself. Finally, the aircraft must overcome the drag or the force of resistance on the airplane that is moving through the air. All four of these forces are vital and necessary for an aircraft to move, takeoff, fly, and land.
" NASA's Supersonic Passenger Planes of the Future: Coming in 2025? N.p., 16 Nov. 2013. Web. The Web. The Web. 30 Nov. 2013.
Sound is essentially a wave produced by a vibrating source. This compression and rarefaction of matter will transfer to the surrounding particles, for instance air molecules. Rhythmic variations in air pressure are therefore created which are detected by the ear and perceived as sound. The frequency of a sound wave is the number of these oscillations that passes through a given point each second. It is the compression of the medium particles that actually constitute a sound wave, and which classifies it as longitudinal. As opposed to transverse waves (eg. light waves), in which case the particles move perpendicular to the direction of the wave movement, the medium particles are moving in the same or opposite direction as the wave (Russell, D. A., 1998).