Do Winglets Improve the Fuel Efficiency of an Airplane - Essay Example

Aerodynamics: Do Winglets improve the Fuel Efficiency of an Airplane? Table of Contents 3 Introduction 4 Diagram 6 Winglets do not improve the fuel efficiency of an airplane 7 Conclusion 8 References 9 Appendices 11 Abstract The paper aims at determining if the fuel saving abilities availed by the winglet design holds weight. The method of research was through searching for available internet sources on the winglet design. The searches were done using key words like winglets, advantages, and disadvantages of winglet, and use of winglets. The search results helped at obtaining information for and against the winglet design. The findings show that the winglet design helps in saving fuel, but only under some special conditions during flight. Hence, it means that an improvement can be made to ensure they save fuel during flight as a whole. However, they are not to be assumed in the current time where fuel is expensive. Aerodynamics: Do Winglets improve the Fuel Efficiency of an Airplane? Introduction The National Aeronautics and Space Administration (NASA) (2013) define aerodynamics as the manner in which air travels around things. It indicates that through the laws of aerodynamics, researchers have been able to expound on how aircrafts fly. Physics indicates that for an airplane to be able to travel through the air, there are force constituents that make up aerodynamics. These force constituents relate in such a way that an airplane is able to fly symmetrically. When flying symmetrically, two forces are in action. They are lift and drag. Drag is defined as the part of the aerodynamic force, which is parallel to the wind in action. It is said to impede on the forward movement of the airplane. If an airplane is travelling at a speed less than that of the speed of sound through air, it experiences induced and parasite drag (Dole & Lewis, 2000). On the other hand, lift is the sum of all aerodynamic forces that are acting on an airplane, which is after they are determined perpendicularly to the path of flight. It is the result from forces of pressure that act on the surface exposed to airflow. So, what design can save fuel? It is the paper’s aim to answer this question. Firstly, this paper will look at the arguments in support of the idea that winglets help in saving fuel. Secondly, it will examine the arguments against this idea. Thereafter, a conclusion shall be made on the fuel saving ability of winglets. Winglets Improve the Fuel Efficiency of an Airplane Lift is required to cover for mass forces and is approximately equal to the weight of the airplane (Torenbeek & Wittenberg, 2009). The wings and tail plane generate lift successfully when drag is at most minimum. Hence, there arises a lift to drag ratio (L/D) that is used to measure their efficacy. Minimum drag (D min) is obtained by: (W) ÷ (L/D) max. With these in mind, there has been questions around the best wing design that enables airplanes to cut on the costs of fuel, which have plagued the aviation industry for a long time. The idea of winglets was conceptualised in the 1970s by NASA’s research into ways to cut on fuel costs. It is from this research that it was hypothesised that vertically shaped wingtips could reduce induced drag. Minimal drag meant that there was a reduction in the amount of fuel used. According to the research by NASA, it was discovered that the winglet model was better than the normal wing allowances used in airplanes then. The normal extended airplane wings require more weight to strengthen them and make them longer. However, the winglets availed a solution to these limitations. The lead researcher, Richard Whitecomb, stated in his findings that the winglet designs were able to reduce induced drag by a fifth and enhance the L/D ratio by 6-9 % (National Aeronautic and Space Administration, n.d.). Based on this research, NASA partnered with Boeing and the U.S. military to develop a test flight program. Using a KC-135 test airplane, the results indicated that the induced drag was reduced by a fifth and the L/D ratio raised by 7 %. Since then, manufacturers began developing wings based on this design. For instance, Boeing developed the 747-400 airplane with the winglet designs. Over time, the winglet design has undergone makeovers to deal with interference drag. As Aviation Partners Boeing (APB) said “There is an aerodynamic phenomena called interference drag that occurs when two lifting surfaces intersect.” (National Aeronautic and Space Administration, n.d.). To deal with this shortcoming, Boeing and its partners developed the Blended Winglet. The design is produced in a way that the winglets are merged with the wings in an overturned curve facing up. The fused upturned curve enables the winglet design to build airflow separation. The design has been found to cut fuel usage by 4-6 %. Computing this percentage on an annual basis, the amount of fuel saved amounts to thousands of gallons (National Aeronautic and Space Administration, n.d.). Diagram The diagrams below illustrates the blended winglet design a. b. Diagram 1(a & b): Blended Winglet (Rajendran, 2012). The dimensions for a winglet are 4 feet in width and 8 feet in length. The tip is roughly two feet. When compared to the overall length of the wing, they constitute 5 feet of this length. The wight of each winglet is 132 pounds, In order to cater for the wiglet design, the center and internal parts of the wing are strengthened (Brady, 1999). Ning and Kroo (n.d.) note that, a drag benefit is realised from larger winglets. According to Boeing, the winglet design has enabled them to diversify. They are both rigid as the conventional wings. Hence, when it comes to saving fuel, the winglets decrease the cruise thrust. A reduction in the cruise thrust leads to a lessening in the amount of fuel consumed during cruise by around 6 percent. Doing so increases the range an aircraft can cover with a lesser amount of burnt fuel. Winglets do not improve the fuel efficiency of an airplane With the success story behind winglets in the past, there do arise concerns around the so called fuel saving capabilities associated with the winglet designs. These concerns have emanated from doubts expressed by various aviation stakeholders. As conventionally noted, winglets are said to save around 6 % of fuel usage hence cutting on the fuel costs that an airplane makes. However, it has been suggested that these merits on fuel saving only take place in particular high attitude flight areas. Further, it is alleged that the fuel saving ability that winglets provide to commercial aircrafts is 0.5 % (Vasigh, et al., 2012). The 0.5% has been proved by comparing short haul flights for non-winglet and winglet equipped airplanes that do not go above 33,000 feet. It was ascertained that the fuel saving for the winglet equipped aircraft was around 0.5% as opposed to 6% (Horton, 2010). Due to the publicity that surrounds Boeing’s winglets, the voices against the fuel efficiency claims have not been considered as much. The operational features of an airplane are altered by the winglets. Thus, the aircraft’s operation at higher altitude is alright. Nevertheless, above 39,000 feet, winglets are said to need a gentler climb to be as effective as an aircraft designed without winglets (National Aeronautics and Space Administration, 2010). If speed is present during climb, the fuel economy associated with the winglets becomes negative. That is it does not hold weight. Hence, it has been argued that after 10,001 feet, the aircraft no longer climbs at 330 knots but at 250 knots for 100 more feet. It is so to ensure that the fuel efficiency of the winglet-equipped airplane matches that of an aircraft without them (Anderson & Eberhardt, 2001). Thus, when an aeroplane is travelling in areas where it cannot move at high altitudes, then the fuel efficiency of the winglets is not achieved. In fact, travelling at low altitudes and high speeds proliferates the amount of fuel used. The amount of fuel used is increased due to parasitic drag, which occurs at high speeds and the weight of the winglets. Lift, is increased by winglets leading to higher cruise speeds for the airplane. It is so during ground effect. As explained by Federal Aviation Administration and the US Department of Transportation (2004), ground effect is a circumstance where an aircraft experiences enhanced perfromance when cruising at low altitudes. It is most substantial when the altitude is maintained at low level with low cruise speed. However, winglets raise the speed when power is switched off. Of concern is the ground effect during landing where winglets raise the probability of the runway been overrunn by the airplane. The reason being that the landing distance may be increased during ground effect. Moreover, the braking efficiency of the aircraft is reduced. Due to the weight of the winglet, additional modifications have to be made to the wings to ensure they are strong (Sengupta, 2014). It has been done by adding used uranium to hinder twist that the wing may experience (Federal Aviation Authority, n.d.). Thus, it is noted that winglets add to the cost by around 3 % on the added weight to that of the fuel carried. Conclusion The fuel efficiency availed by winglets cannot be assumed. However, it is notable that it does occur under various circumstances. Something that has not been put in the public domain like the publicity around the winglet design. Thus, opponents of the design argue that an airplane has to be flying at high altitudes and for long-haul flights. However, supporters of the design do not give any specifications. They only give the percentages on the fuel economy. References Anderson, D. F. & Eberhardt, S. (2001). Understanding Flight. New York: The McGraw-Hill Companies. Brady, C. (1999). Winglets. [Online] Available at: http://www.b737.org.uk/winglets.htm [Accessed 17 February 2015]. Dole, C. E. & Lewis, J. E. (2000). Flight Theory and Aerodynamics: A Practical Guide for Operational Safety. 2nd ed. Danvers: John Wiley & Sons. Federal Aviation Administration; US Department of Transportation. (2004). Airplane Flying Handbook: FAA-H-8083-3A. Oklahoma City: /r/flying Publishing Services. Federal Aviation Authority. (n.d.). Aerodynamics, Aircraft Assembly, and Rigging. [Online] Available at: https://www.faa.gov/regulations_policies/handbooks_manuals/aircraft/amt_airframe_handbook/media/ama_ch02.pdf [Accessed 17 February 2015]. Horton, G. (2010). Future Aircraft Fuel Efficiencies-Final Report. [Online] Available at: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/4515/future-aircraft-fuel-efficiency.pdf[Accessed 04 March 2015]. National Aeronautic and Space Administration. (2013). What is Aeerodynamics. [Online] Available at: http://www.nasa.gov/audience/forstudents/k-4/stories/what-is-aerodynamics-k4.html [Accessed 17 February 2015]. National Aeronautic and Space Administration. (n.d.). Transportation: Originating Technology/NASA Contribution. [Online] Available at: http://spinoff.nasa.gov/Spinoff2010/t_5.html [Accessed 17 February 2015]. National Aeronautics and Space Administration. (2010). Flight Environment Operations Flight Testing and Research. [Online] Available at: http://www.nasa.gov/pdf/601333main_NASAsContributionsToAeronauticsVolume2-ebook.pdf [Accessed 17 February 2015]. Ning, S. A. & Kroo, I. (n.d.). Tip Extensions, Winglets, and C-wings:Conceptual Design and Optimization. [Online] Available at: http://aero.stanford.edu/reports/Ning2008.pdf [Accessed 18 February 2015]. Rajendran, S., (2012). Design of Parametric Winglets and Wing tip devices – A Conceptual Design Approach. [Online] Available at: http://liu.diva portal.org/smash/get/diva2:547954/FULLTEXT01.pdf [Accessed 17 February 2015]. Sengupta, T. K., 2014. Theoretical and Computational Aerodynamics. Noida: John Wiley & Sons. Torenbeek, E. & Wittenberg, H. (2009). Flight Physics: Essentials of Aeronautical Disciplines and Technology, with Historical Notes. London: Springer Science & Business Media. Vasigh, B., Taleghani, R. & Jenkins, D. (2012). Aircraft Finance: Strategies for Managing Capital Costs in a Turbulent Industry. Fort Lauderdale: J. Ross Publishing. Appendices Diagram 1: a and b Shows the Blended Winglet Design Read More