: "For other uses see Supersonic".The term supersonic is used to define a speed that is over the
speed of sound(Mach 1). At a typical temperature like 21 °C (70 °F), the threshold value required for an object to be traveling at a supersonic speed is approximately 344 m/s, (1,129 ft/s, 770 mph or 1,238 km/h). Speeds greater than 5 times the speed of sound are often referred to as hypersonic. Speeds where only some parts of the air around an object (such as the ends of rotor blades) reach supersonic speeds are labeled transonic(typically somewhere between Mach 0.8 and Mach 1.2).
Sounds are travelling vibrations (pressure waves) in an elastic medium. In gases sound travels longitudinally at different speeds, mostly depending on the
molecular massand temperatureof the gas; ( pressurehas little effect). Since air temperature and composition varies significantly with altitude, Mach numbers for aircraft can change without airspeed varying. In water at room temperaturesupersonic can be considered as any speed greater than 1,440 m/s (4,724 ft/s). In solids, sound waves can be longitudinal or transverse and have even higher velocities. Supersonic fractureis crack motion faster than the speed of sound in a brittlematerial.
fighter aircraftare supersonic, but Concordeand the Tupolev Tu-144were the only supersonic passenger aircraft. An aircraft that can still sustain supersonic flight without using an afterburneris called a supercruiseaircraft. Due to its ability to supercruise for several hours and the relatively high frequency of flight over several decades, Concorde spent more time flying supersonically than all other aircraft put together by a considerable margin. Since Concorde's final retirement flight on November 26 2003, there are no supersonic passenger aircraft left in service. Some large bombers, such as the Tupolev Tu-160and Rockwell/ Boeing B-1Bare also supersonic-capable.
firearm munitions are supersonic, with rifle projectilesoften travelling at speeds approaching Mach 3.
spacecraft, most notably the Space Shuttleare supersonic at least during portions of their reentry, though the effects on the spacecraft are reduced by low air pressures. During ascent, launch vehicles generally avoid going supersonic below 30 km (~98,400 feet) to reduce air drag.
Note that the speed of sound decreases somewhat with altitude, due to lower temperatures found there (typically up to 25 km). At even higher altitudes the temperature starts increasing, with the corresponding increase in the speed of sound. [ [http://bpesoft.com/s/wleizero/xhac/?M=s eXtreme High Altitude Conditions Calculator] ]
wavetraveling through a bull whipis also capable of achieving supersonic speeds. [ [http://www.hypography.com/article.cfm?id=32479 Hypography - Science for everyone - Whip Cracking Mystery Explained ] ]
Breaking the sound barrier
aerodynamics, the sound barrier usually refers to the point at which an aircraftmoves from transonicto supersonicspeed. The term came into use during World War IIwhen a number of aircraft started to encounter the effects of compressibility, a grab-bag of unrelated aerodynamic effects. The term fell out of use in the 1950s when aircraft started to routinely "break" the sound barrier. Refer to the speed of soundfor the science behind the velocity referred to as the sound barrier, and to sonic boomfor information on the sound associated with supersonic flight. Chuck Yeagerwas the first man to achieve super sonic flight.
aerodynamicsare simpler than subsonic because the airsheets at different points along the plane often can't affect each other. Supersonic jets and rocket vehicles require several times greater thrust to push through the extra drag experienced within the transonicregion (around Mach 0.85-1.2). At these speeds Aerospace engineers can gently guide air around the fuselageof the aircraft without producing new shock waves but any change in cross sectional area further down the vehicle leads to shock waves along the body. Designers use the Supersonic area ruleand the Whitcomb area ruleto minimize sudden changes in size.
It should be kept in mind, however, that the aerodynamic principles behind a supersonic aircraft are often more complex than described above because such an aircraft must be efficient and stable at supersonic, transonic "and" subsonic flight.
At high speeds
aerodynamic heatingcan occur, so an aircraft must be designed to operate and function under very high temperatures. For example, the SR-71 Blackbirdjet could fly continuously at Mach 3.1 while some parts were above 315°C (600°F).
* Supersonic aerodynamics
De Laval nozzle
* Jet engine intake design
Jet engine nozzle
Rocket engine nozzles
* the Right Stuff a movie about early supersonic pilots
Supersonic area rule
Whitcomb area rule
Other flow regimes
* Subsonic flows.
* [http://www.mathpages.com/home/kmath109/kmath109.htm MathPages - The Speed of Sound]
* [http://online.cctt.org/physicslab/content/phy1/lessonnotes/Sound/lessonsound.asp Sound]
* [http://www.makeitlouder.com/Decibel%20Level%20Chart.txt Supersonic sound pressure levels]
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