Aerodynamic Study of Blended Wing Body
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The document presents an aerodynamic study of the Blended Wing Body (BWB) aircraft design, focusing on its advantages such as fuel efficiency, higher lift-to-drag ratio, and increased payload capacity compared to conventional aircraft. It discusses the structural integration of wings, propulsion systems, and fuselage to enhance aerodynamic performance while reducing operational costs. The study concludes that BWB configurations can significantly reduce fuel consumption and support larger passenger capacities, marking a potential future direction for commercial aircraft design.
![29248 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh
1988. To meet the future demands in air transportation, the concept of BWB was
introduced by McDonnell Douglas, (now part of the Boeing Company) in 1988. [1]
The idea of BWB is to provide single lifting surface by stretching the entire wing
span of the aircraft. BWB has a thick airfoil shaped fuselage section that combines the
engines, wings and body. [2] The key advantage of BWB is that it minimally
distinguishes between wing-fuselage and fuselage-tail, and has a more “centered”
volume than a conventional aircraft. There is no tail and conventional fuselage in
BWB. The BWB design approach is to maximize the overall efficiency by improving
the propulsion system, the wings, and the body into an integrated lifting surface that
offers great potential to substantially reduce the operating costs while improving
performance.
Figure 1.1: Blended Wing Body Aircraft
The concept of Blended Wing body was introduced almost 25 years ago. The idea
was to build a new type of aircraft that would allow the aircraft to carry more
passengers. The BWB aircraft is not a fully novel concept because it was considered
by Horten, Northrop, and others from the mid 1930s to the mid 1950s, but was
abandoned due to stability and control issues. In addition, BWB aircraft was
previously called „Tailless Airplane‟ and „Flying Wing Aircraft‟. [3]
Figure 1.2: Northrop N1M „Jeep‟, by Northrop Corporation, USA](https://image.slidesharecdn.com/yashparikh8-150512090255-lva1-app6892/85/Aerodynamic-Study-of-Blended-Wing-Body-2-320.jpg)
![Aerodynamic Study of Blended Wing Body 29249
Figure 1.3: Horten Ho I by Horten Brothers, Germany
Need of Blended Wing Body
A typical study reveals that a twin deck of A380 aircraft can accommodate 550
passengers comfortably [4] but if BWB is implemented, the passenger capacity will
be 800 passengers with a reduction in fuel consumption of the aircraft and increase in
the passenger capacity. [5] Despite of the long list of the shortcomings; BWB
passenger configurations possess three serious advantages such as high L/D ratio due
to a decreased relative wetted area, favorable load distribution along the span and
possible engine noise shielding. Ikeda et al. [3] studied that BWB configuration gives
greater performance including a large improvement in a high L/D ratio of wing also
evolutionary improvement in composite structures and engines. BWB offers a
reduction in operating costs while improving an aerodynamic performance and
flexibility for both passenger and cargo mission. R. H. Liebeck et al [6,7] studied that
due to the shape of the BWB configuration, it burns 27% lesser fuel, had 15% lower
takeoff weight, 27% lower total thrust, and 20% higher L/D ratio as compared to
conventional aircraft.
Figure 2.1: Lift v/s Weight Distribution of a Conventional Aircraft
Figure 2.2: Lift v/s Weight Distribution of BWB
In Fig. 2.1 and Fig. 2.2, the black portion indicates the conventional aircraft and
BWB respectively. The blue colour shows the lift distribution of conventional aircraft](https://image.slidesharecdn.com/yashparikh8-150512090255-lva1-app6892/85/Aerodynamic-Study-of-Blended-Wing-Body-3-320.jpg)
![29250 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh
and BWB whereas red colour indicates the weight distribution. [8] The wing in
conventional aircraft is the main contributor to generation of lift while the fuselage of
BWB generates lift together with the wing thus increasing the effective surface area.
Case Study
Wisnoe et al. [2] shows that for very large transport aircraft, BWB concept is often
claimed to be superior compared to conventional configurations because of less fuel
consumption and higher L/D ratio. The BWB concept aims at contributing the
advantages of a flying wing with the loading capabilities of a conventional aircraft by
creating a wide body in the center of the wing to create more space for passengers and
cargo.
This paper focuses on aerodynamic study and preliminary design of BWB
configuration to be used as UAV made by Wisnoe et al. [2]. The aerodynamic
characteristics such as lift co-efficient and drag coefficient are calculated and
compared.
Figure 3.1: Dimensions of Half BWB Model Made by Wisnoe et al.
Fig. 3.1 shows the dimensions of BWB half model used for the research.
In aerodynamics, angle of attack specifies the angle between the chord line of the
wing of a fixed-wing aircraft and the vector representing the relative motion between
the aircraft and the atmosphere.
Figure 3.2: Angle of Attack α](https://image.slidesharecdn.com/yashparikh8-150512090255-lva1-app6892/85/Aerodynamic-Study-of-Blended-Wing-Body-4-320.jpg)
![29254 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh
Conclusion
At present, Boeing is planning to create a full size commercial BWB aircraft. They
have successfully designed and tested their X-48B hybrid wing aircraft along with
NASA. The stability and control of X-48B were similar to that of standard aircraft,
which was a proof of aerodynamic concept that demonstrated aerodynamic
supremacy. They are confident about the idea of BWB and it is assumed that near
future of commercial aircraft will be of BWB. [5]
From the case study, we have concluded that BWB can fly at very high angle of
attack. The maximum lift was given for α around 34º-39º. However, the wing was
installed at α around 8º. Hence the main contributor of the lift was the aircraft body.
The maximum L/D ratio was obtained at α = 6º (from wind tunnel experiments). This
represents the optimum flight configuration with optimum fuel consumption.
Hence it is also concluded that BWB configuration has not only high L/D ratio but
also low fuel consumption and increased payload carrying capacity than conventional
aircraft. Due to high Lift to Drag ratio of BWB, fuel consumption in it is very low
than the conventional aircraft.
Acknowledgement
The authors would like to present their sincere gratitude towards the Faculty of
Mechanical Engineering in Sinhgad Institute of Technology and Science, Pune and
Symbiosis Institute of Technology, Pune.
References
[1] Edwin Ordoukhanian, Azad M. Madni, 2014, “Blended Wing Body
Architecting and Design: Current Status and Future Prospects,” Procedia
Computer Science 28(2014), pp. 619-625.
[2] W.Wisnoe, R.E. M. Nasir, W. Kuntjoro and A. M. I. Mamat, 2009, “Wind
Tunnel Experiments and CFD Analysis of Blended Wing Body Unmanned
Aerial Vehicle at Mach 0.1 and Mach 0.3,” 13th
International Conference
on Aerospace Science and Aviation Technology, May 26-28, 2009.
[3] T. Ikeda, C. Bil, 2006, “Aerodynamic Performance of a Blended Wing
Body Configuration Aircraft,” 25th
International Congress of the
Aeronautical Sciences, 06.
[4] http://www.airbus.com/
[5] http://www.boeing.com/boeing/
[6] R.H. Liebeck, 2004, “Design of the Blended Wing Body Subsonic
Transport,” Journal of Aircraft, vol. 41, no. 1, January 04.
[7] M. A. Potsdam, M. A. Page and R. H. Liebeck, 1997, “Blended Wing
Body Analysis and Design,” American Institute of Aeronautics and
Astronauts, Inc. AIAA-97-2317.](https://image.slidesharecdn.com/yashparikh8-150512090255-lva1-app6892/85/Aerodynamic-Study-of-Blended-Wing-Body-8-320.jpg)
![Aerodynamic Study of Blended Wing Body 29255
[8] D. J. Thompson, J. Feys, M.D. Filewich, S. A. Magid, D. Dalli and F.
Goto, 2011, “The Design and Construction of Blended Wing Body UAV,”
49th
Aerospace Sciences Meeting, AIAA 2011-841, January 11.](https://image.slidesharecdn.com/yashparikh8-150512090255-lva1-app6892/85/Aerodynamic-Study-of-Blended-Wing-Body-9-320.jpg)
Aerodynamic Study of Blended Wing Body
- 1. International Journal of Applied Engineering Research ISSN 0973-4562 Volume 9, Number 24 (2014) pp. 29247-29255 © Research India Publications http://www.ripublication.com Aerodynamic Study of Blended Wing Body Pranav Mahamuni1 , Akhilesh Kulkarni2 , Yash Parikh3 1,2 (Department of Mechanical Engineering, Sinhgad Institute of Technology and Science, Pune, Maharashtra, India.) 3 (Department of Mechanical Engineering, Symbiosis Institute of Technology, Pune, Maharashtra, India.) 1 [email protected], 2 [email protected], 3 [email protected] Abstract In recent years, air transportation has increased between major cities. Conventional aircraft's lack fuel efficiency, high Lift to Drag (L/D) ratio, high payload carrying capacity since there has not been a major technological breakthrough in aerodynamic geometry. Hence, there has been a need to develop a new composite structure to push the boundaries of current technologies and to breathe new life into civil transportation. Blended Wing Body (BWB) bridges the gap between future requirements. The BWB configuration is a new concept in aircraft design which provides greater internal volume, aerodynamics and structural efficiency, noise reduction, and most importantly significant improvement on cost-per-seat-mile. The design approach of BWB is to maximize overall efficiency by integrating the propulsion systems, wings, and the body into a single lifting surface. BWB is a unique tailless single entity where the fuselage is merged with wing and tail. Blended wing body has flattened and airfoil surface which contributes higher lift than conventional ones. The objective of this paper is to study aerodynamic study of blended wing body layout. Keywords: Blended Wing Body (BWB), Lift to Drag (L/D) Ratio, Payload, Fuselage, Aerodynamic Study. Introduction In the past decade, fuel efficiency and noise reduction have proved to be the biggest challenges for aircraft manufacturers. Conventional aircrafts are not satisfying our needs in required manner. The seeds of future air transportation were planted by Dennis Bushnell, (now chief scientist of the NASA Langley Research Center) in
- 2. 29248 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh 1988. To meet the future demands in air transportation, the concept of BWB was introduced by McDonnell Douglas, (now part of the Boeing Company) in 1988. [1] The idea of BWB is to provide single lifting surface by stretching the entire wing span of the aircraft. BWB has a thick airfoil shaped fuselage section that combines the engines, wings and body. [2] The key advantage of BWB is that it minimally distinguishes between wing-fuselage and fuselage-tail, and has a more “centered” volume than a conventional aircraft. There is no tail and conventional fuselage in BWB. The BWB design approach is to maximize the overall efficiency by improving the propulsion system, the wings, and the body into an integrated lifting surface that offers great potential to substantially reduce the operating costs while improving performance. Figure 1.1: Blended Wing Body Aircraft The concept of Blended Wing body was introduced almost 25 years ago. The idea was to build a new type of aircraft that would allow the aircraft to carry more passengers. The BWB aircraft is not a fully novel concept because it was considered by Horten, Northrop, and others from the mid 1930s to the mid 1950s, but was abandoned due to stability and control issues. In addition, BWB aircraft was previously called „Tailless Airplane‟ and „Flying Wing Aircraft‟. [3] Figure 1.2: Northrop N1M „Jeep‟, by Northrop Corporation, USA
- 3. Aerodynamic Study of Blended Wing Body 29249 Figure 1.3: Horten Ho I by Horten Brothers, Germany Need of Blended Wing Body A typical study reveals that a twin deck of A380 aircraft can accommodate 550 passengers comfortably [4] but if BWB is implemented, the passenger capacity will be 800 passengers with a reduction in fuel consumption of the aircraft and increase in the passenger capacity. [5] Despite of the long list of the shortcomings; BWB passenger configurations possess three serious advantages such as high L/D ratio due to a decreased relative wetted area, favorable load distribution along the span and possible engine noise shielding. Ikeda et al. [3] studied that BWB configuration gives greater performance including a large improvement in a high L/D ratio of wing also evolutionary improvement in composite structures and engines. BWB offers a reduction in operating costs while improving an aerodynamic performance and flexibility for both passenger and cargo mission. R. H. Liebeck et al [6,7] studied that due to the shape of the BWB configuration, it burns 27% lesser fuel, had 15% lower takeoff weight, 27% lower total thrust, and 20% higher L/D ratio as compared to conventional aircraft. Figure 2.1: Lift v/s Weight Distribution of a Conventional Aircraft Figure 2.2: Lift v/s Weight Distribution of BWB In Fig. 2.1 and Fig. 2.2, the black portion indicates the conventional aircraft and BWB respectively. The blue colour shows the lift distribution of conventional aircraft
- 4. 29250 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh and BWB whereas red colour indicates the weight distribution. [8] The wing in conventional aircraft is the main contributor to generation of lift while the fuselage of BWB generates lift together with the wing thus increasing the effective surface area. Case Study Wisnoe et al. [2] shows that for very large transport aircraft, BWB concept is often claimed to be superior compared to conventional configurations because of less fuel consumption and higher L/D ratio. The BWB concept aims at contributing the advantages of a flying wing with the loading capabilities of a conventional aircraft by creating a wide body in the center of the wing to create more space for passengers and cargo. This paper focuses on aerodynamic study and preliminary design of BWB configuration to be used as UAV made by Wisnoe et al. [2]. The aerodynamic characteristics such as lift co-efficient and drag coefficient are calculated and compared. Figure 3.1: Dimensions of Half BWB Model Made by Wisnoe et al. Fig. 3.1 shows the dimensions of BWB half model used for the research. In aerodynamics, angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Figure 3.2: Angle of Attack α
- 5. Aerodynamic Study of Blended Wing Body 29251 In the Fig. 3.2 the arrow is the vector representing the velocity of the air in the free stream around a stationary two-dimensional section of the airfoil. The upper red line is the chord line of the airfoil and the lower red line is parallel to the arrow. The angle α is the angle of attack. Figure 3.3: Visualization at α = 7° Figure 3.4: Visualization at α = 8° Fig. 3.3 and Fig. 3.4 shows the visualization of half model of BWB at angle of attack α = 7° and α = 8° The comparing parameters chosen for this study were: Lift Coefficient Analysis From experimental setup, the results obtained are as follows, Value of CL (Lift Coefficient) increases as the angle of attack increases until its maximum value at around α = 35° and decreases with lower slope. Value of CL max increases as the air velocity of wind tunnel increases. Hence CL max increases with increase in Reynolds number.
- 6. 29252 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh Figure 3.5: CL versus α Fig. 3.5 shows the graph of CL versus α. At α = 7°, it can be seen that the flow is still attached to the overall surface. At α = 8°, it can be seen that the flow has almost separated from the wing. Drag Coefficient Analysis The variation of CD (Drag Coefficient) with respect to angle of attack α taken at different speeds and mach number has been shown in Fig. 3.6 Figure 3.6: CD versus α Fig. 3.6 shows the graph CD versus α. It is observed that below 8° angle of attacks, the variation of drag coefficient is very slow and almost constant. Above 8° angle of attack CD grows at a higher rate as α is increased.
- 7. Aerodynamic Study of Blended Wing Body 29253 Lift Coefficient versus Drag Coefficient Analysis Figure 3.7: CD versus CL Fig. 3.7 shows the graph of CD versus CL. From experimental value, the value of the drag coefficient at zero lift CD0 is around 0.03. This is the minimum drag coefficient that the BWB has without producing any lift. When the drag coefficient increases the lift coefficient also increases until its maximum value CL max and then decreases. Lift to Drag Ratio Analysis Figure 3.8: L/D versus α Fig. 3.8 shows that, the curve of L/D is a function of angle of attack α. L/D ratio increases from a minimum value of 7.65 at α = -7° to its maximum value of 7.27 at α = 6°
- 8. 29254 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh Conclusion At present, Boeing is planning to create a full size commercial BWB aircraft. They have successfully designed and tested their X-48B hybrid wing aircraft along with NASA. The stability and control of X-48B were similar to that of standard aircraft, which was a proof of aerodynamic concept that demonstrated aerodynamic supremacy. They are confident about the idea of BWB and it is assumed that near future of commercial aircraft will be of BWB. [5] From the case study, we have concluded that BWB can fly at very high angle of attack. The maximum lift was given for α around 34º-39º. However, the wing was installed at α around 8º. Hence the main contributor of the lift was the aircraft body. The maximum L/D ratio was obtained at α = 6º (from wind tunnel experiments). This represents the optimum flight configuration with optimum fuel consumption. Hence it is also concluded that BWB configuration has not only high L/D ratio but also low fuel consumption and increased payload carrying capacity than conventional aircraft. Due to high Lift to Drag ratio of BWB, fuel consumption in it is very low than the conventional aircraft. Acknowledgement The authors would like to present their sincere gratitude towards the Faculty of Mechanical Engineering in Sinhgad Institute of Technology and Science, Pune and Symbiosis Institute of Technology, Pune. References [1] Edwin Ordoukhanian, Azad M. Madni, 2014, “Blended Wing Body Architecting and Design: Current Status and Future Prospects,” Procedia Computer Science 28(2014), pp. 619-625. [2] W.Wisnoe, R.E. M. Nasir, W. Kuntjoro and A. M. I. Mamat, 2009, “Wind Tunnel Experiments and CFD Analysis of Blended Wing Body Unmanned Aerial Vehicle at Mach 0.1 and Mach 0.3,” 13th International Conference on Aerospace Science and Aviation Technology, May 26-28, 2009. [3] T. Ikeda, C. Bil, 2006, “Aerodynamic Performance of a Blended Wing Body Configuration Aircraft,” 25th International Congress of the Aeronautical Sciences, 06. [4] http://www.airbus.com/ [5] http://www.boeing.com/boeing/ [6] R.H. Liebeck, 2004, “Design of the Blended Wing Body Subsonic Transport,” Journal of Aircraft, vol. 41, no. 1, January 04. [7] M. A. Potsdam, M. A. Page and R. H. Liebeck, 1997, “Blended Wing Body Analysis and Design,” American Institute of Aeronautics and Astronauts, Inc. AIAA-97-2317.
- 9. Aerodynamic Study of Blended Wing Body 29255 [8] D. J. Thompson, J. Feys, M.D. Filewich, S. A. Magid, D. Dalli and F. Goto, 2011, “The Design and Construction of Blended Wing Body UAV,” 49th Aerospace Sciences Meeting, AIAA 2011-841, January 11.
- 10. 29256 Pranav Mahamuni, Akhilesh Kulkarni and Yash Parikh