Winglet on Aircraft

Inspired from eagle's wings, winglets are applied on aircraft's wings. Same principle applies to eagles, winglets reduce wintip vortices, small wing vortex that formed at the wing tips due to air pressure difference. High pressure on the lower wing works its way up to the low pressure on the upper wing and curls around it. Having these vortices on the wings reduce flight efficiency and enhance drag. 

Winglets reduce drag and result in better cruising speed. Not only that, operators take advantage of this drag reduction by controlling cruising speed, reducing fuel consumption. In general, longer wings would generate better lift for aircrafts. However, longer wings would mean weight addition and it's not ideal. Installing winglets would result in same lifting force as longer wing would. The advantage is that wings with winglet would generate the same amount of lift force than ones with longer wings and without winglet. 

Winglets on aircraft reduce drag making flying more efficient. This include fuel saving up to 5% with carbon dioxide emission reduction up to 5%. The percentage may not be magnitude but 500,000 gallons of fuel is saved per airline per year just by adding winglets on aircraft's wings.

Reference

http://www.airspacemag.com/flight-today/how-things-work-winglets-2468375/
http://www.airspacemag.com/flight-today/how-things-work-winglets-2468375/

Reflection- Sathveer Roopah

The most interesting part of the subject was how the use of natural concepts found in nature could help us in developing necessary solutions which could solve for issues in developing new technology that can help the sustainability for human beings on this planet. The basics of using biomimicry to solve for human problems is a very suitable approach but still very controversial if the subject addressed cannot be executed with proper engineering tools and equipment’s. Hence making the best of the subject we have, the relation of mechanics to natural behaviors can be related and found a way to bring the technology together. In our case, the subject helped the team to learn more about the fascinating eagle and its wings. The eagle has a very large wing span that helps the big bird in fast flight for attacks and other maneuvers. Compared to the other birds eagles have separate feather tips at the end of the wings which allows the reduction of drag forces along the body. Hence by implementing the technology in modern aircrafts., the industry of aviation can help in reducing the overall usage of fuel consumption for planes as drag forces would be reduced Hence increasing the sustainability of the industry and remain a competitive part of the traveling industry. Also with bigger planes coming into play, this technology can be used to develop a sensible way of operating big aircrafts around several airports and reach out more passengers than before as the winglets can help in developing small wings for big planes.

The design of such product using the basics of eagle winglets can be very interesting in the way the product responds to the sustainability and reliability. Hence implementing such technology to the aircrafts, the cost saving is increased, less energy is used and less pollution occurs. The fact that natural resources of fuel is depleting rapidly, we should think outside the box to find new ways of reducing the dependency on fossil fuel by increasing efficiency on the aircraft itself. Hence it is advisable for the solution to be implemented and used based on its simplicity and low-cost production.

Based upon previous group studies carried out for other modules at the university, team work is always a better point of working out a project. Various ideas and different concepts/point of views can be found from the team as the brainstorming process goes on. Working as a team can help in having different point of views and help in generating new ideas that can be potentially lifesaving or revolutionary if the engineering tools and techniques are applied properly with a good team work. Moreover, working as a team, we can achieve completion of the project in time and thus with even distribution of tasks among the team members, learning is never ending process as knowledge is shared.

Reflection by Wen Yong Xiang

The most remarkable idea of biomimicry inspired by an eagle is the winglet of an aircraft. The features from the eagle’s wings have inspired aircraft companies to create winglets at the tip of the wings. This winglet reduces the formation of vortex created at the end of the wing. Therefore, it significantly reduces the drag force and this helps to increase the efficiency of the aircraft. As mentioned in the blog earlier, it could save tons of fuel in a long run and this eventually save cost and the environment.

The implementation of the winglet on the aircraft’s wings is patentable as it increases the efficiency and sustainability of the aircraft in the long run. As drag reduces, the energy required for the aircraft to fly up reduces as well. This will reduce the fuel consumption and therefore cutting down the operation cost. Currently, there are numerous designs available in the market but our design is easier to be manufactured than the rests because of the simplicity of the design.

The team consisted of 5 members including myself. The tasks were distributed evenly to all members. Therefore, each member has a specific and meaningful task to complete. Through this, this assignment is successfully completed within the due date. 

Conclusion

It has been concluded that addition of winglet on aircraft's wings would reduce drag and result in more efficient flight. It heavily reduced wingtip vortex which adds the drag coefficient. The inspiration of this genuine design came from one of the most fearsome predators in the animal kingdom - eagle. 

Danial's Reflection

The most interesting proposed used of biomimicry that was developed was the inspiration of eagles that significantly reduced drag on aircraft. Drag has always been an issue in vehicles, especially when it come to flying vehicle where efficient flight is important. Simple change of wing design, by adding winglet on wingtips, would drastically reduced air vortex, causing lesser drag. It may save around 1 or 2% of energy, but in terms of fuel saving, it could save up to thousand tons of fuel in a year per flight. This resulted in significant positive outlook. 

The design of the aircraft wingtip is patentable as it proved significant results in efficient flight and energy savings. Currently, there are many winglet designs that has been patent, each has its own distinctive feature with its uniqueness. 

Working as a team has made this project easier as more members are available to complete certain tasks. Huge project or assignment such as this can be easily broken down into smaller, easier and more meaningful tasks, which can be assigned by every member. The tasks can be easily be finished in this manner. 

Nazween's Reflection

The interesting part of an eagle is that it is able to control flight which enables the eagle to control the drag acted upon the wings. This happens when the eagle control the feathers angle and direction by contracting or relaxing the wings muscle which allows the air to pass through at different surface areas. By doing so, an eagle is able to be swift and dive down to capture prays. This is most probably the most interesting feature to be mimicked onto real life scale.

It has already been patented and applied on real life scale. This shows that there is a value or market for the design. It helps reduce drag and makes it more fuel efficient which is highly affordable compared to previous designs. Also, airline companies have been studying further on the length of the winglet of the aircraft that can be applied to current airplanes to reduce the drag.

Since its semester 8, everyone is busy with their own task and activities that everyone can ship in little by little to ensure that the blog is run smoothly. Without them, it would have been a burden to even handle all the researching and blog writing individually. Also, having more ideas and sharing them makes it easier to brainstorm and think of ideas.

Reversed Engineering Worksheet

Design Worksheet

The following figure is the varieties of winglet designs that are currently available in the market.

Figure 1

Method for induced drag calculation

Airbus A320 aircraft’s specifications are taken and the total drag of the aircraft is calculated using the following formula. 

Figure 2

Where;

Cf -Skin friction drag coefficient

F-Form factor

Q-Interference factor

Swet-Wetted area of the surface

Sref -Wing area

Rec = Reynolds number of the component

V = Velocity

l = component characteristics length

u = kinematic viscosity for that flight condition 

Figure 3 

e - Span efficiency or Ostwald’s efficiency factor

AR – Aspect ratio

Cl – Lift coefficient

Λ – Sweep angle

Take-off performance calculation

The take-off distance of an aircraft is the total distance covered by an aircraft to clear the obstruction of height about 35 ft.

Figure 4

The above figure represents the standard take-off velocities that should be maintained during the take-off. In this work, the motive is to find the parameters associated with the take-off performance of an aircraft. Airbus A320’s specification is taken for the calculation and the take-off field length provided for the aircraft is 1500m. There are three phases in the aircraft take-off mission such as Ground roll, Transition to climb and Climb. Normally, the ground roll, i.e. distance covered by the aircraft on the ground before climb, is calculated by resolving the forces horizontally and vertically. The approximation formula for the ground roll is given by,

Figure 5

W = 78000 kg, 

C_L,max = 2.1 (approximate)

T (during take-off) = 24494 kg

S = 123 sq.m(calculated from wing span)

g = 9.81 (acceleration due to gravity)

ρ = 1.225 kg/m³ (density ground level)

A320 is operated with two CFM56-B engines where the take-off thrust for each engine is 23,500lbs. The total drag “D” in the above formula is calculated after substituting the values obtained from specification table. The total drag reduction is calculated from the total induced drag reduction for different velocities. Further, this total drag calculated with winglets is substituted in the ground distance formula in order to obtain the new total weight (W_new). The simplified formula for the W_new is given by the following equation,

Figure 6 

The take-off weight value for the same take-off distance is calculated for different values of total drag.

CAD Modelling

CATIA V5 R18 tool is used to develop the templates of different winglets and tip devices. Each winglet has been defined by a user feature where the user could choose between the types of winglet and modify the parameters associated with respective winglet model. A detailed description of the winglet templates are discussed in the following section.

Blended Winglet Template

Blended winglet template has been modelled with two different sections namely blended base and blended vertical. Blended base is a shape design model where it forms the intersection at the main wing tip chord and continues as a smooth curve to avoid the interference drag. The leading edge of blended base is formed by the conic section which depends on sweep plane, two tangent lines and two points which lies on the same plane. Radius of the leading edge could be varied by a real parameter and also it depends on base height associated with height parameter. The other parameters controlling the blended base were base span, cant angle, sweep angle and tip chord length figure 1(c). Cant and Sweep angles are made with respect to the base span line and not from root chord of the base. 

The later section i.e. the skeleton model of blended vertical is created in dependent with the blended base.  The leading edge is made tangent with the base leading edge curve in order to obtain a smooth surface. Blended vertical is also associated with a set of parameters which are height and tip chord length figure 1(c). 

Vertical and horizontal reference area of the blended template model are calculated and given as an output parameter figure 1(c). The height parameter for both sections of blended template does not represent the vertical height but the length of respective lines. The exact vertical height for the blended template is given as an output parameter named “reference leading edge vertical” from which the reference area is calculated based on the root chord and tip chord of the respective section. Similarly, the horizontal span of entire blended section varies with the cant angle and also with base span length. The total projected span is calculated by measuring the length of projected leading edge line which shown as green dotted line in figure 1(a) and figure 1(b).   

Figure 7

Figure 8

 1. Do you think your product, building, or system would work if manufactured?

Yes, because the methods of designing were based on the literature reviews. The necessary calculations were conducted to apply the mathematical solutions into the design of the winglet. The design was drawn in the CAD software for better precision. Then, the CAD model will be simulated by using the computational fluid dynamic (CFD) software to get the required results. The CFD results will be compared to the experimental results. If all these methods were conducted carefully and accurately, the numerical results will be similar to the experimental results. The results obtained that meet the objective of the construction of winglet will definitely work in real case scenario if manufactured according to the design.

2. Do you think that you could raise funds to pay for manufacturing? How would you go about raising funds?

Yes, definitely.

·        Get sponsorships from the companies (technical or financial) that are related to the airplane industry.

·        Raise funds is to pitch the idea to the public through crowd funding website, PitchIn

.

3. Do you think that many engineers explore solutions from nature into their inventions?

Yes. In the past, Engineers had used concepts and inspirations from nature in their inventions. One of the example is the invention of Velcro that is based on nature. In this modern era, sustainability of the product is the main concern as more Engineers look into biomimicry to improve the current inventions today to adopt more sustainable traits for future generations to come.

Furthermore, biomimicry provides design techniques to optimize engineering products or systems. An example is the re-derivation of Murray’s law, this determines the ideal diameter of the blood vessels by providing equation for tube diameter.

LITERATURE REVIEW: EAGLE'S EYE

The eagle eye is among one of the strongest weapon in the animal kingdom, with eyesight estimated to be able to reach up to distances 4 to 8 times more than the normal average human eye, with an ability to spot a rabbit up to 2 miles. Although the eagle’s physical features differ from the human, the eyes though can be of the same size as those as humans. The eagle can also speed up to high speeds during chases, hence the ‘eagle eye’ is the best ability the eagle possesses to stay focus on the prey. The eye continuously adjust itself by making use of the ball curvature to keep a good focus point on the prey at ground level and by keeping an accurate perception throughout the attack. Perched from a branch high up, the eagle eye needs to be up in good conditions. The eyes have fierce looks and this is due to a bony ridge found above its eyes and the amount of bare skin found between its eyes. The ridge helps in protecting the eyes from protruding objects such as branches or preys which are fighting back to escape. As for the feathers, they usually do not grow on the area near the eyes.

The bird of prey also has an eye that can capture a wider range of color spectrum than the human eyes can, thus allowing them to be able to differentiate small changes in coloration and shades which helps for a better eye resolution and clarity which in turn helps during the hunting. Other studies have shown that the eagles have an eyeball which can be larger than the brain in term of weight and size although it is the same size as the human eye. It was also found that the back side of the eye is flatter than the human one hence allowing for the better vision of the bird. But there's no way to know what these extra colours, including ultraviolet, look like. Suppose we wanted to describe the colour of a tomato to someone who was born blind. We would not be able do it. We cannot even guess what they are subjective sensation of ultraviolet light is. Young eagles cannot spot fishes in water as their eyes have not fully developed the anti-reflection error. As they grow older, this error is corrected and the eagles can start the hunt. Another reason for why their parents must keep them until they are fully grown. However, the eagle eye cannot operate as it does during day time.

The eagle’s retina fovea has more of cone cells and rod cells, with a density of one million cells per millimetre square as compared to 200, 000 for the human eyes. Eagles possess a second fovea which enables better and sharper vision, and also has three eyelids. The phenomenon of an eagle turning its head almost 270 degrees, is attributed to the fact that the eye also turns unlike humans, as the eyes are tightly locked inside the socket.

Eagles tears are also known for moistening the eyes as they contain the chemical Isozymes which protects against salt water and bacteria, thus preventing infections. The iris has a pale yellow colour, compared to darker colours for the humans, but both entities have the white area called sclera, but in the case of the eagle, it is hidden beneath the eye lid. The pecten is also a very important aspect of the eagle’s eye, as it helps in nourishing the retina by keeping a healthy pressurised flow of fluid, absorbs light to minimise reflection error, helps in perceiving motion creates protection from sunlight and senses magnetic fields.

Most eagles do not suffer from any vision problems, as the eagle would starve to death from not being able to hunt and that is why ladies and gentlemen we do not see blind eagles. But researchers at the University of Maryland, have cooked up a vision experiments for the eagle. One screen displayed a zebra stripped pattern and the bird gets a treat for landing on it. The scientists have varied the width of the stripes to test the eagles’ acuity as the check for the distance the eagles begin to veer in the correct direction. 

According to William Hodos, a distinguished professor emeritus at the University of Maryland who has studied the visual acuity of birds since the 1970s, two eyeball features confer eagles' sharper vision. First, their retinas are more densely coated with light-detecting cells called cones than human retinas, enhancing their power to resolve fine details just as higher pixel density increases the resolving power of cameras.

Second, they have a much deeper fovea, a cone-rich structure in the backs of the eyes of both humans and eagles that detects light from the centre of our visual field. Human fovea is a little shell or bowl, while in hawk or eagle it is a convex pit. Some investigators think this deep fovea allows their eyes to act like a telephoto lens, giving them extra magnification in the centre of their field of view.

Picture of Difference between eagle and human eye.

Eagle vision wouldn't change how we perform most daily activities, such as reading computer screens or the newspaper, or finding milk in a crowded refrigerator but how we perceive the world and use our eyes would certainly be different. It's perhaps easiest to consider our new powers in the context of how eagles use them: for hunting. 

On top of the ability to see farther and perceive more colours, we would also have nearly double the field of view. With our eyes angled 30 degrees away from the midline of our faces like an eagle's, we would see almost all the way behind our heads with a 340-degree visual field (compared to normal humans' 180-degree field); this would confer a clear advantage in hunting and self-defence.

With eagle eyes, we would swivel our heads constantly. To locate prey or any other object of interest in the distance, we would periodically turn your head to the side to sweep your fovea (telephoto lens) across your field of view. After spotting, what you're looking for in this manner, you'd redirect your head toward it and use stereoscopic vision  combining the viewpoints of both eyes to gauge distance to calibrate the speed of your approach.

Enhanced perception and hunting prowess would likely come with a few drawbacks, but birds probably have a greater proportion of their brain volume devoted to visual processing than other groups of animals. Now the question of what it comes at the expense of: most birds appear not to have a well-developed sense of smell or taste.It's more difficult to say how your more sophisticated cognitive processes would fare. "Birds have areas that seem to function like the cortex [the part of our brains responsible for memory, language and complex thought], but it's arguable. But in terms of their ability to solve problems and so on, they match what many mammals can do. Many birds have superb memory.

Maximizing our potential

Today’s scientist has used eagle eye properties to enhance visual abilities of human. If the human swapped their eyes for an eagle’s eye, the latter would be able to see an ant up a 10-story building. The objects in the line of sight would appear magnified, and everything would be brilliantly coloured rendered in an inconceivable array of shade. 

The physical properties of our eyeballs limit us to 20/10 or 20/8 vision at best. Natural vision that good is extremely rare, but research by David Williams, director of the Centre for Visual Science at the University of Rochester, and his colleagues may soon enable laser eye surgeons to achieve 20/10-or-better vision for a large percentage of patients, placing their visual acuity halfway between that of humans and eagles.

Williams and his colleagues used an instrument called a wavefront sensor to detect distortions in human vision. They shoot light into the eye and observe how it bounces back through hundreds of tiny lenses in the sensor. The aberrations in patterns created by those lenses serve as a map of the eye's mistakes. Customized surgical techniques are being developed to implement the results of patients' wavefront measurements, in order to correct their vision beyond 20/20.

References.

• Boothe, Ronald G. (16 November 2001). Perception of the Visual Environment. Springer. pp. 235–. ISBN 978-0-387-98790-3. 
• Dudley, Karen (1997). Bald Eagles. Weigl Educational Publishers. p. 10. ISBN 9780919879942. 
• Grambo, Rebecca L. (14 December 2003). Eagles. Voyageur Press. ISBN 978-0-89658-363-4. 
• Hutchinson, Alan E.; Silliker, Bill (1 April 2000). Just Eagles. Willow Creek Press. pp. 34–. ISBN 978-1-57223-277-8. 
• Potts, Steve; Ueblacher, Sigrid Noll- (2006). Wildlife of North America. Capstone,. p. 11-. ISBN 9780736884839. 
• Wood, Casey Albert (1917). The Fundus Oculi of Birds, Especially as Viewed by the Ophthalmoscope: A Study in Comparative Anatomy and Physiology (public domain ed.). Lakeside Press. pp. 90.
• "Human Vision Vs Eagle Vision - Insight Vision Center", Insight Vision Center, 2017. [Online]. Available: http://www.insightvisioncenter.com/human-vision-vs-eagle-vision/. [Accessed: 31- May- 2017].
• L. Science, "What If Humans Had Eagle Vision?", Live Science, 2017. [Online]. Available: http://www.livescience.com/18658-humans-eagle-vision.html. [Accessed: 31- May- 2017].