Supersonic Flight - Report Example

Supersonic Flight Name Name of Institution Supersonic Flight Introduction It is an accepted fact that aviation plays a pivotal role in today’s world. Most of the cultures in the world have at some time experimented with devices that are intended to travel through the air. The modern aviation began with hot air balloons and progressed rapidly as a result of the two World Wars. The role of aircraft became increasingly important components in the transportation of people and cargo over increasingly longer distances. Supersonic flight is an area of aviation that has fascinated the world as a whole. The purpose of this report will be to describe supersonic flight and to explain how it differs from subsonic flight. This will be followed by examining issues such as the transonic region, supersonic aircraft designs, power plant limitations, commercial applications, and the history of supersonic flight. The paper will conclude with a discussion on the future outlook of supersonic flight. Meaning of Supersonic Flight and How It Differs From Subsonic Flight Supersonic flight defines a flight that goes beyond the speed of sound. It is worth noting that the speed of sound at sea level is approximately 768 miles per hour. Additionally, supersonic flight occurs in the range between Mach 1 to Mach 5. The Mach number denotes the speed of an object relative to the speed of sound in the same medium (NASA 2015). Therefore, the supersonic flight range covers speeds between around 768 miles per hour to 3840 miles per hour at sea level. An important point to note is that supersonic flights can be achieved at much slower speeds when an airplane is traveling at high altitude. This is because of the lower temperatures at high altitudes that reduce the speed of sound, meaning that an aircraft can achieve supersonic flight at just 653 miles per hour at 40,000 – 90,000 feet (NASA, 2015). Supersonic flight is achievable using specially designed aircraft that can manage these levels of speed. This is because supersonic flights introduce conditions that make flight more difficult. The flights that go beyond Mach 5 are referred to as hypersonic flight, but current technology has not yet produced prolonged flights at hypersonic speeds. Supersonic flight differs from subsonic flight that occur at speeds that are below Mach 0.8. Subsonic aircraft can use propeller-driven piston engines, high bypass turbofan engines, or turboprop engines while supersonic aircraft use low-bypass turbofan engines (Anderson, 2015). Other differences can be found in the wing designs and the construction materials. Finally, current supersonic aircraft serve military purposes while subsonic flights power global travel and transport aviation. Transonic Region and its Effect on Controls The transonic speed refers to the speed range that is slightly below Mach 1 and slightly above Mach 1 (Anderson, 2015). This range can be approximated to lie between 600 and 900 miles per hour, and it is a transition stage that all supersonic flights have to go through. Part of the challenge of going past the transonic range is its effects on controls. The airflow over a plane traveling at these speeds is responsible for the erratic behavior of aircrafts flying in the transonic range. Part of the airflow is supersonic while other parts are subsonic leading to instability. However, there has been considerable research that has allowed many modern jets to operate at the transonic range (Anderson, 2015). The figure below shows airflow at speeds that are slightly below (a) and slightly above (b) the speed of sound and the shock wave that negatively impacts control. Figure 1. Airflow slight below and slightly above the speed of sound (Anderson, 2015) Supersonic Aircraft Designs As stated, airplanes that achieve supersonic speeds face significant technical challenges that come with the air flow. Additionally, drag increases in a dramatic manner as the flight approaches the speed of sound. Drag, in this case, defines air resistance to the aircraft’s forward motion. The implication is that supersonic aircraft have to be designed with airframes that are streamlined and engines that can overcome the increase in drag (Stanford, 2015). The wings of supersonic aircraft have to have limited spans that can minimize drag at the higher speeds while supporting landing and takeoff speeds. Examples of wing designs are the delta-wing design, sweepback wing, swept forward wing, short, thin wing, and the variable geometry wings (Anderson, 2015). Figure 2 below provides an example of a typical design with the delta wing and streamlined airframe. Figure 2: Supersonic aircraft design (Stanford 2015) An additional problem facing supersonic aircraft is high temperature. The supersonic airflow over the aircraft body creates a lot of friction leading to very high temperatures. For this reason, supersonic aircrafts have to be made out of materials that can withstand the high temperatures while retaining their structural integrity. Aluminum allows can serve this purpose, but they limit the aircraft speed to the mid-range of supersonic speeds. When it comes to engines, the low bypass turbofans fitted with afterburners are the preferred option. Power Plant Limitations While in Supersonic Region As stated, the supersonic region results in a considerable increase in drag. For this reason, the power plant needs to generate considerable power in order to overcome the drag. The ability to produce sufficient power was one of the early limitations of power plants. A related limitation is low fuel efficiency. This is a significant limitation as fuel efficiency plays a major role in determining whether an aircraft can operate profitably. Additionally, low fuel efficiency has an impact on a range of an aircraft and might make longer, profitable routes more difficult to serve. Sonic Booms As stated, supersonic flight involves an aircraft moving at a speed that is above the speed of sound. As the plane travels through the air, it creates pressure waves on its front and rear, but the high speeds prevent these pressure waves from getting away from each other. The result is the creation of one bigger shock wave that travels at the speed of sound. The sonic boom occurs as a result of a sudden change of pressure that occurs due to an abrupt fall and increase in pressure (U.S. Centennial of Flight Commission, 2015). The sonic boom travels along the ground and its width can often approach the 50 mile mark. Any person or building that is within this fifty-mile area along the path of the airline will hear a loud boom as the shock passes. This can be an annoying experience for people and can have negative consequences for buildings that are along the paths of supersonic aircraft. It is evident that sonic booms present a major problem that needs to be solved before supersonic aircraft can fly above populated areas without major inconveniences. Commercial Applications As any other cutting age innovation, supersonic flight has had commercial implications. There has been considerable interest in supersonic transport (SST) as it holds the promise of shortening travel times by up to half the previous durations. However, the attempts at commercial application have faced challenges that include the sonic boom, safety, and low passenger capacities. The first successful application of supersonic flight came through the Concorde, an aircraft designed through the cooperation of British and French firms. The plane was a passenger aircraft that could reach Mach 2 and higher speeds (U.S. Centennial of Flight Commission, 2015). The planes development took a considerable time, but it managed to operate with relative success for approximately 30 years. However, an accident in Paris and environmental concerns led to the stoppage of the Concorde service. The then Soviet Union also developed and introduced a supersonic passenger aircraft, but technical difficulties led to the stoppage of the program (U.S. Centennial of Flight Commission, 2015). Figure 3 below shows the Concorde. Figure 3: Concorde History of Supersonic Flights Charles Yeager made what is considered as the first supersonic flight in October 1947 (Hallion, 2011). This happened after considerable research that sought to minimize the influence of the transonic range. It is worth mentioning that Yeager’s flight was launched from a jet and propelled by a jet to an altitude of 43,000 feet. The maximum speed achieved in the first supersonic flight by the Bell XS-1 rocket was Mach 1.06 which corresponded to a speed of 700 miles per hour at that altitude (Hallion, 2011). This first flight proved that what was considered to be the sound barrier could be broken. Subsequently, there was increased international effort that led to the development of many supersonic aircraft. Most of these aircraft were designed to serve military purposes, but their development provided the scientific knowledge that would facilitate the development of commercial aircrafts like the Concorde. Future Outlook At present, there are several aircraft that have the ability to undertake supersonic flight. However, there are limitations that restrict these flights to relatively short durations. For instance, military jets enter supersonic flight when attacking a target or fleeing from another aircraft and resort to subsonic flight. The reasons behind this strategy are the enormous stresses that planes have to undergo as well as the increased fuel consumption. When it comes to commercial applications, the Concorde produced a loud sonic boom that led to flight path restrictions. Additionally, the streamlined body reduced the number of passengers, and the combination of this factor and high maintenance costs meant that airlines found it a challenge to generate profits. Based on this facts, it can be argued that supersonic flight has a challenging future. However, this is not the case. The rapid technological development of the last decade implies that there can be solutions to some of the problems facing supersonic flight. For instance, a corporation between NASA and Lockheed Martin promises the production of aircraft that are up to 100 times quieter than the Concorde (Lipsey, 2014). This should lower the sonic boom to levels that will not affect people living along the plane’s flight path. On the other hand, Aerion is concentrating on trans-Atlantic and trans-pacific flights. It is evident that sonic booms will not be an issue on these flight paths, meaning that research has concentrated on increasing fuel efficiency and drag (Lipsey, 2014). Supersonic flight holds considerable promise as it can reduce travel times by half. The future of these flights relies on aviation’s ability to come up with aircraft that can overcome the limitations of previous supersonic aircraft. References Additional Considerations for Supersonic Aircraft. (2015). Stanford. Retrieved 15 March 2015 http://adg.stanford.edu/aa241/AircraftDesign.html Anderson, J.D. (2015). Research in supersonic flight and breaking the sound barrier. NASA. Retrieved 15 March 2015 http://history.nasa.gov/SP-4219/Chapter3.html Hallion, R. (2011). Supersonic Revolution. History Net. Retrieved 15 March 2015 http://www.historynet.com/supersonic-revolution.htm High speed transport in commercial aviation. (2015). U.S. Centennial of Flight Commission. Retrieved 15 March 2015 http://www.centennialofflight.net/essay/Commercial_Aviation/High_Speed/Tran11.htm Lipsey, S. (2014). Concorde comeback? Two new jets plan to take air passenger supersonic again. Yahoo News. Retrieved 15 March 2015 https://www.yahoo.com/travel/concorde-comeback-two-new-jets-plan-to-take-air-104077884877.html What is supersonic flight? (2015). NASA. Retrieved 15 March 2015 http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-supersonic-flight-k4.html#.VQSV1-GKv_g Read More

Figure 1. Airflow slight below and slightly above the speed of sound (Anderson, 2015) Supersonic Aircraft Designs As stated, airplanes that achieve supersonic speeds face significant technical challenges that come with the air flow. Additionally, drag increases in a dramatic manner as the flight approaches the speed of sound. Drag, in this case, defines air resistance to the aircraft’s forward motion. The implication is that supersonic aircraft have to be designed with airframes that are streamlined and engines that can overcome the increase in drag (Stanford, 2015).

The wings of supersonic aircraft have to have limited spans that can minimize drag at the higher speeds while supporting landing and takeoff speeds. Examples of wing designs are the delta-wing design, sweepback wing, swept forward wing, short, thin wing, and the variable geometry wings (Anderson, 2015). Figure 2 below provides an example of a typical design with the delta wing and streamlined airframe. Figure 2: Supersonic aircraft design (Stanford 2015) An additional problem facing supersonic aircraft is high temperature.

The supersonic airflow over the aircraft body creates a lot of friction leading to very high temperatures. For this reason, supersonic aircrafts have to be made out of materials that can withstand the high temperatures while retaining their structural integrity. Aluminum allows can serve this purpose, but they limit the aircraft speed to the mid-range of supersonic speeds. When it comes to engines, the low bypass turbofans fitted with afterburners are the preferred option. Power Plant Limitations While in Supersonic Region As stated, the supersonic region results in a considerable increase in drag.

For this reason, the power plant needs to generate considerable power in order to overcome the drag. The ability to produce sufficient power was one of the early limitations of power plants. A related limitation is low fuel efficiency. This is a significant limitation as fuel efficiency plays a major role in determining whether an aircraft can operate profitably. Additionally, low fuel efficiency has an impact on a range of an aircraft and might make longer, profitable routes more difficult to serve.

Sonic Booms As stated, supersonic flight involves an aircraft moving at a speed that is above the speed of sound. As the plane travels through the air, it creates pressure waves on its front and rear, but the high speeds prevent these pressure waves from getting away from each other. The result is the creation of one bigger shock wave that travels at the speed of sound. The sonic boom occurs as a result of a sudden change of pressure that occurs due to an abrupt fall and increase in pressure (U.S. Centennial of Flight Commission, 2015).

The sonic boom travels along the ground and its width can often approach the 50 mile mark. Any person or building that is within this fifty-mile area along the path of the airline will hear a loud boom as the shock passes. This can be an annoying experience for people and can have negative consequences for buildings that are along the paths of supersonic aircraft. It is evident that sonic booms present a major problem that needs to be solved before supersonic aircraft can fly above populated areas without major inconveniences.

Commercial Applications As any other cutting age innovation, supersonic flight has had commercial implications. There has been considerable interest in supersonic transport (SST) as it holds the promise of shortening travel times by up to half the previous durations. However, the attempts at commercial application have faced challenges that include the sonic boom, safety, and low passenger capacities. The first successful application of supersonic flight came through the Concorde, an aircraft designed through the cooperation of British and French firms.

The plane was a passenger aircraft that could reach Mach 2 and higher speeds (U.S. Centennial of Flight Commission, 2015). The planes development took a considerable time, but it managed to operate with relative success for approximately 30 years.

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