Subsonic and Transonic: Ice - Term Paper Example

Subsonic and Transonic & Ice Snow Subsonic and Transonic & Ice Snow Introduction In aeronautical design and engineering, subsonic and transonic are concentrated terms. The terms are related to the speed of an aircraft, with respect to the speed of airflow being subjected towards it. Subsonic refers to a speed where the air flow is less than the speed of sound and transonic is similar to the concept, that the flight is about to reach the airflow which is near to the speed of sound. Specifically these are the indicators that show a “Mach number” “a constant number which sets the standard for a reasonable flight”. All subsonic and transonic aircrafts are below the Mach number 1, which is a standard for all the conventional aircrafts. 0.7 to 0.9 are right values and design a Mach number which is suitable for a transonic or subsonic airplane (Katz, 2001). During the flight, there are many factors that associate with an aircraft in altitude, like shock waves, compression, shear, density or wave drag. Such factors influence the flight and develop the environment in which the flight has to operate. In aviation the attempt is to minimize the excess limit of the drag in order to make the flight a transonic rather than a supersonic flight. This is to avoid the risk coming up from the excessive air pressure, shear and disruptive fluid dynamics, in order to avoid major accidents that can impart in such supersonic conditions. Likewise, excessive shear can interrupt the drag; shock waves restrain propulsion and establish over dense pattern. All these features are maintained in order to balance the flight environment and give a safe aircraft operation. According to aeronautical expertise, Mach number is a central value to estimate the flight environment. It is one indicator which tells that how and why the aerodynamics are changing and interrupting the flying field (Katz, 2001). The Design Features of Transonic Airplanes In a conventional flight, there are primarily some external and some internal influential factors. The internal factors are built-in while the external ones are adaptive, depending upon the environment in which the flight is operating. These factors stimulate the aerodynamics of the craft, “dynamics which associates with air flow, air pressure, compression and with internal air foil mechanism”. In transonic and subsonic conditions, aerodynamics is very important and plays a substantial role in adjusting the flight problems. But more importantly successful aerodynamics depends on successful aircraft design and engineering (Anderson, 1985). In transonic flights where the Mach number is close to 0.8 to 0.9, the main problem is of “wave drag.” During wave drag, there is an intense airflow compression, which is unwanted by the wings and hence making the jet to lose its original drag progression. This is due to shear created by the wave drag on denser wing cords. This problem can be avoided if the wings are with less denser equation and are potentially light weighted. Light wings carry light airfoil mechanism, which possibly do not allow any excessive airflow to sustain. This is to avoid interruption in drag and is very substantial in terms of flight control aeronautics (Katz, 2001). In the contrast, swept wings are of the same characteristics and are very responsive in terms of excessive wave aggression. A thinner airfoil section is adjusted with the swept wings, which balance the technical variations of the Mach number. With one swing forward and one in the backwards, control the rise of Mach number and delay the instant shock wave aggression. These are ideal features of swept wings which control problems in a transonic aircraft quite substantially (Anderson, 1985). Vortex generator is another design feature which takes part in delaying transonic flight problems. They are form of plates used to avoid flow separation and flight stalling. Vortex generators are mounted at the top of wings with a portion to trap a sufficient vortex on the surface. The generators play a crucial role in drag and in deduction of wave drag aggression. The low pressure areas are mounted with vortex generators in order to maintain a balance in the life and drag respectively (Mair & Birdsall, 1996). Ice and Snow on Aerodynamics Since from the beginning in aircraft design and operation, there have been many accidents reported due to ice and snow situations. It is one central factor which has always influenced the aircraft operation (Civil Aviation Athority, 2000). November 1987 reported the first crash in the south island of New Zealand, where the cause was intense icing. December 1989, another crash reported in Pasco Washington United States, killing four passengers along with two crew members. June 1997, Beechcraft BE 58 Baron crashed in North Island of New Zealand flying in high icing conditions (Civil Aviation Athority, 2000). With the aspect of time the accidents prevailed, and today icing is a big problem for flight operation and ground side navigation control. In safety, ice and snow is on higher node of consideration, which is to avoid further mishap in the near future (Civil Aviation Athority, 2000). Impact of Ice and Snow on Aerodynamics An extreme weather situation where temperature is below zero degree carries more risk than ordinary weather condition. The cold regions where snows are common have more proportion of ice and snow formation. The flights passing through such regions are opened to risk and can get influenced at any point of situation. So need is to understand how ice and snow appears and what are their factors of influencing (Mair & Birdsall, 1996). Critical Problem Clear Ice Clear ice is a type of rainy formation where the rain drops are made up of cold airframes. The cold air patterns collide with the clouds and then mix up with rain drops to form clear ice. This is a continuous process which sustains till the clear ice is there. It happens in zero degree centigrade or sometime below than this temperature (Thomson & Politovich, 1993). Clear ice is with obstinate characteristic, which is persistent in affecting airfoils. Once the airfoils are affected, the aerodynamics of the airplane starts to change too. Clear ice submerges with wings and indirectly influences the internal working of an aircraft. The ice affects the performance and the overall drag mechanics of the airplane. In higher altitudes clear ice proves to be very dangerous, because it traps the aircrafts and build an interrupting environment for drive and propulsion (Mair & Birdsall, 1996). Rime Ice Rime ice is another type of icing, which takes place from 0 degree to 10 degree C. Rime ices are thin and tiny ice patterns, which deposit with a little amount of air trap in its internal pattern. Rime ice deposits from cold airframe to a low temperature surface. Rime ice slows down the performance of airfoils, which is because the tiny deposits don’t spread, and stick with the surface to a longer period of time. For the long flight periods, rime ice is very distracting and deviate the foils in higher altitudes (Thomson & Politovich, 1993). Mixed Ice Mixed ice is a form of moisture, which is small in size but with a sustainable impact on the air jet. Both rime and clear ice forms the pattern of mixed ice and holds the properties of both intense ices. In cloudy ranges, mixed ice is a common phenomenon, where both effects of moisture and rain are travelled along with the flight. When subjected to mixed ice, the aerodynamics is quite distracted as the airfoils bear droplets plus a powerful freezing snow which can go in forceful long term deposits. When mixed ice ranges tails and wings, compressibility is much affected (Civil Aviation Athority, 2000). Frost Ice In intense cooling temperatures frost ice is a major problem in flight operation. Temperature below zero degree settles frost ice with the traveler. It is a mixture of moist air and water vapors. When moist air is merged with constant airframe it forms frost ice. It is a crucial problem for the flight operators, especially when the deposits are submitted on the opening window. Haziness of vision is a parallel affect of frost ice, which goes on until the deposits are split and cleared (Burke, 2005). Overcoming Problem When it comes to aeronautics and aviation, the much consideration is given to the risk and safety aspects. In conventional aircrafts and flights, there are many factors which develop risk in the airplane. No matter the planes are big or a conventional fighter plan, there are always hazards which are involved during the flight. Major crash accidents and flight failures are often due mis management of flight or unwanted flaws in the design phase. Taking preventive measures in a crashing plane is impossible, so engineers try to cover all safety measures right from the very first stage of inspection. Apart from design or prevention, the flight safety is another aspect to be covered in all flights. Pilots are given trainings and the crew is with intense technical orientation in order to minimize the spectrum of risk on the side. Maintaining safety is a continuous process in all the conventional flights and it is part of aviation risk and safety objective (Mair & Birdsall, 1996). Ice and snow is a natural problem and requires a human ability to deal with this sort of situation. In extreme weather situations, more emphasize should be on ground operations. People in the lower desk can play a more decisive role than people on the upper corner. Engineered monitoring with point to point navigation control is what is required over here. More accidents take place due to negligence in navigation control, if navigation is prudent there are very less chances of any mishap to happen. This is a modern objective of aviation experts and much concern is to provide deliberate human safety in all extreme situations (Stolzer et al., 2010). List of References Anderson, J., 1985, Fundamentals of Aerodynamics, New York: McGraw-Hill Education. Burke, R., 2005, Chapter 4 - Weight and balance and airplane performance, Viewed at: [Accessed 11 August 2012]. Civil Aviation Athority, 2000. Aircraft icing handbook, Research report. Lower Hutt: Civil Aviation Athority. Katz, J.P.A., 2001, Low Speed Aerodynamics, New York: Cambridge Univeristy Press. Mair, W. & Birdsall, D., 1996, Aircraft performance, Cambridge: Camrbridge University Press. Stolzer, A., Halford, C. & Goglia, J., 2010, Safety Management Systems In Aviation, Burlington: Ashgate Publishing. Thomson, G. & Politovich, M., 1993, Aircraft icing, Research Report, Boulder: National center for atmospheric research. Read More