Aerodynamic Typical Light Aircraft vs Large Commercial Jet Design Features - Essay Example

Comparison between the Aerodynamic Typical Light Aircraft and Large Commercial Jet Design Features Introduction When designing an aircraft, the aircraft design engineers normally take into consideration many factors. These include the manufacturer’s and customers’ demands, physical and economic constraints and safety protocols among other factors. It is also noted that for certain aircraft, the design process is regulated by the nation’s airworthiness authorities. However, the design process normally begins by identifying the intended purpose of the aircraft. In this regard, fighter jets, which are light in weight, are designed to perform high speed manoeuvres (Cumpsty 2003, p 124). Commercial airliners on the other hand are designed mainly to carry cargo, payload, or passengers according to Kundu (2010, p.3-8). This hints the level to which the two aerodynamic designs may differ. While the two types of designs differ in numerous ways, certain design features are quite similar. This paper will compare and contrast the aerodynamic design features of a typical light aircraft and a large commercial jet. The P2006 T-Light Aircraft Pascale and Nicolosi (2006, p.2-4) note that in the past decade, Tecnam Aircraft Industries has been deeply engaged in the development, design and manufacture of more than 10 light and ultra light 2-seat aircrafts characterized by high or low wing configurations. One such light aircraft is the P2006 VELT (Very Light Twin), manufactured by the company in 2006. This is a 4-seat aircraft with two engines (Rotax is normally used for ultra light aircrafts 912). This light aircraft has very unique aerodynamic design features to assure its stability and good control. One such feature of the aircraft is its low propeller revolution speed as well as low engine drag. The combination of the two aspects coupled with streamlined fuselage give good aerodynamic efficiency. Engine design and position The weight-to power ratio of the P2006 VELT engine is favourable according to Pascale and Nicolosi (2006, p.4). This is due to the fact that the weight of the engine is lower than that of one Lycoming. In addition, Pascale and Nicolosi note that the engine frontal is lower to allow wing-mounted streamlined nacelle, thereby reducing drag penalty arising from the twin engines. This ensures that stability is maintained during take-off and landing. The lower revolution speed provides higher propeller thrust at low flight speed, which improves the stability of the aircraft during take-off and climb performance. Wing design The wing of the P2006 VELT aircraft is designed taking into consideration the need to have good flight performance and low structural weight according to Pascale and Nicolosi (2006, p.4-8). The wing span of the aircraft is set at a value of 11.2 m to allow for easy control and stability. The interior part of this aircraft’s wing is rectangular to simplify flap contraction. The wings of this aircraft are also made of aluminium material to enable the aircraft to be as light as possible. Fuselage, Nacelle and Tail Design The fuselage of this aircraft is designed so as to have low parasite drag. Its shape is characterized by a favourable low value of fuselage wetted area over fuselage volume. The aircrafts nacelle is very small and well streamlined credited to the compact engine. The aircrafts is also fitted with an all-manoeuvre stabilator to increase the aircraft’s longitudinal control (higher tail efficiency) and for stick-free stability. The aircraft also has a vertical tail designed for minimum control speed (VMC) in One Engine Inoperative (OEI) conditions. Pascale and Nicolosi (2006) argue that a slightly higher value of minimum control speed with respect to all stall speed had been chosen for the aircraft to guarantee good and safe takeoff characteristics. Weight Characteristics The weight of an aircraft is a key component that needs much attention during the design process according to Nicolosi and Pascale (2003). For the P2006, the body of the aircraft is made of aluminium alloy. The aluminium alloy is used to make the body of this aircraft because it is light in weight for easy control and operation. Boeing 777-commercial aircraft The Boeing 777 in flight The Boeing 777 is one of the most recently designed commercial aircraft, used for transporting passengers and cargo. The aircrafts has special aerodynamic design features to enable it lift all the weight without any control or stability problems being that its design incorporates the latest technology. The engine of the Boeing 777 is very large and heavy and is mounted under the wing. Its machine is powered by a Rolls-Royce Trent 800 engine which weighs about 8.2 tonnes after installation. Cupsty (2003, p. 7) notes that since most lifts are generated by wings, hanging the engine under the wings where they can easily be carried is a noble idea. The reason for putting the engine below the wing is to reduce wing-root bending moment thereby making it possible to reduce the necessary strength and weight of the airplane. This helps build stability and makes the aircraft easy to control. Considering the number of people it carries, it measures about 246 ft, with a wing span of 222 ft at a height of approximately 65 ft. The aircraft also has a total of 24 wheels out of which 24 are used as landing gear. It is also noted that the fuselage of the aircraft is designed in such a manner as to reduce fuselage over fuselage volume. The Boeing 777 also has a streamlined nacelle. The tail is vertically designed for minimum control speed. Moreover, the aircraft is fitted with stabilators to increase its longitudinal control. Differences in Design between the Booing 777 and the P2006 It is apparent that commercial aircrafts differ slightly from the light aircraft in terms of aerodynamic features. This is mainly attributed to the different purposes for which they are designed. For instance, it is seen that lighter aircrafts have lighter engines which are not placed below the wings as is the case with the commercial aircrafts seen with the Boeing 777 (Fielding 1999, p.17-26). For the Boeing 777, the wing engine which is also large and heavy is positioned below the wing to enable the aircraft lift the heavy weight without any control or stability problems. It is also evident that the Boeing 777 is larger and longer compared to the P2006. It is argued that since Boeing is meant to carry many passengers than P2006, its base area has to be wide to increase stability. In addition, commercial aircrafts have more wheels than the lighter aircrafts. This is meant to help maintain stability and improve the landing gear because of the weight according to Kundu (2010, p47-53). Unlike the lighter aircrafts like the P2006, commercial aircrafts have a relatively large fuselage to enable them have low parasite drag. The nacelle of larger aircrafts like Boeing are also relatively larger and less streamlined compared those of lighter aircrafts. Design Similarities between the Booing 777 and the P2006 Many similarities can be seen with the two categories of aircrafts, one such being the weight characteristics. It is apparent that in both the aircrafts, the body is made of aluminium alloy to make the aircrafts lighter. This feature makes the aircrafts easy to fly and control. Furthermore, in both the aircrafts, the wing spans are all low, placed at a figure of about 11.2 m, and are both made of aluminium alloy. In both cases, the wings are rectangular to simplify flap contraction according to Kundu (2010, p47-53). Nevertheless, the wings of the commercial aircrafts like the Boeing 777 are long, about 222 ft, to increase the plane’s stability when on flight and when changing direction. It is also apparent that both aircrafts are fitted with stabilators to increase longitudinal control. Both aircrafts also have vertical tails designed for minimum control speed. This enables the aircrafts have safe take-off characteristics. The only difference is that, the Boeing 777 has a larger and longer tail due to the weight it lifts and controls. Conclusion It is apparent that aircrafts are designed taking into consideration the purposes for which they are intended. This paper has brought out these elements with regard to the aerodynamic design features of the two aircrafts that have been discussed. Lighter aircrafts, for instance, have lighter, less powerful engines compared to commercial aircrafts. In addition, the positions of these engines also differ because of the weight that they are supposed to lift. Differences have also been seen with the wing-size and length, nacelle, tail and fuselage. Similarities also exist mainly in stabilators, wing spans and weight characteristics. References Cumpsty, N. 2003, Jet Propulsion: A Simple Guide to the Aerodynamic and Thermodynamic Design and Performance of Jet Engines, Cambridge University Press, Cambridge. Fielding, J. 1999, Introduction to Aircraft Design, Cambridge University, Cambridge. Kundu, A. 2010, Aircraft Design, Cambridge University Press, Cambridge. Nicolosi, F., & Pascale L. 2003, P2002 light aircraft design: evolution of a low-wing ULM. Aerodynamics performance, stability and flight dynamics, XVII congress AIDAA, Rome (Italy), 15-18, Pascale, L., & Nicolosi, F. 2006, Design and aerodynamic analysis of a light twin-engine propeller aircraft. Tecnam Aircraft industries, Caoria (Naples), Italy. Read More