Annex A - Group Research Proposal

Investigation of how the shape of the blades affects the volatge produced by a wind turbine.

Nishtha, Durwa, Wei san, Xavien

School of Science and Technology, Singapore


The question is how the shape of a blade of a wind turbine affects the amount of voltage produced. The aim of this project is to find out which shape of the blade is the most efficient in producing the amount of voltage so that we can decrease the amount of pollution in the atmosphere by producing our electricity by the wind, which is a never ending and green source. The next thing that was in our mind was how to solve this question? We solved it by making our own set ups of different blade shapes so that we can find out the most efficient and effective blade shape that will contribute to helping us get an answer to our question. Now you might be thinking how is this useful to me?

In the long run it will be useful not only to science but also humans. We humans are using fossil fuels at an alarming run and fossil fuels are not never ending. They will end and then what? How will we live- caveman days again? Well that when the wind turbines come into picture. Wind turbine uses wind to generate electricity. Wind is a never ending and green resource.

1. Introduction

Type of research:

-Construct a model: 
Theoretical sciences and applied mathematics

1.1 Our Background Research

We want to find out which set of wind turbine blades is the most effective and efficient. Making a small prototype would be a breeze.

Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives.

Ancient mariners used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are becoming fans of this renewable energy, and you will be blown away by the statistics. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small fraction of the world's energy.

Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These contraptions look like giant airplane propellers on a stick. The wind spins the blades, which turn a shaft connected to a generator that produces electricity. Other turbines work the same way, but the turbine is on a vertical axis and the blades look like a giant egg beater. As wind turbines are a very popular and renewable source of energy in many countries, and many governments, companies and the average commoner have used it to convert wind energy into electricity as early as 200 B.C.

The amount of electricity these turbines produce is quite shocking. The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines erected in a backyard can produce enough electricity for a single home or small business.

Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments offer tax incentives to spur wind-energy development, which really makes for a wind of change.

Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also variable: If it's not blowing, there's no electricity generated.

Nevertheless, the wind energy industry is booming. Globally, generation more than quadrupled between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China.

Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind.If wind energy was to be producing 20% of the world's electricity, we could get rid of go one-third or more of the greenhouse gas emissions from fossil-fuel power plants.

Citation:Geographic, N. (n.d.). Wind power. Retrieved from

1.2 Research Question

After taking a much closer look, we got to know that anything that moves, including air, takes energy to move. Energy of motion as we know is kinetic energy.nWind turbines take the kinetic energy out of the wind and converts it to kinetic energy , hence using the electrical energy to do various things. There are 2 basic types of wind turbines: vertical axis (look kind of egg beaters) and horizontal axis (look like airplane propellers). 

Horizontal-axis wind turbines are most common.

Each wind turbine has these parts:

-Rotor or Blades, which convert the wind's kinetic energy into rotational kinetic energy.
-Nacelle or the housing for the drive train along with a gearbox and a generator. These are the parts that convert the rotational kinetic energy of the rotor into electricity, just like the motor in this experiment. 
-Tower, which supports the rotor and the other parts.

Since we want to research on the size and shape of the blades of a wind turbine some questions that came across our minds are:

-How does the shape of the blades affect the electricity produced by a wind turbine?

-How does the place we put the fan and the wind turbine affect the amount of electricity produced?
-How does the angle at which we place the blades affect the amount of electricity generated?

Citation:Harris, E. Save the earth science experiments. New York: Lark Books.

1.3 Hypothesis

-The longer and broader the blades of the wind turbine are, the more electricity is produced.

1.4.1 Independent Variables
-Shape of blades 

1.4.2 Dependent Variables
-Electricity produced

1.4.3 Constant Variables
-Speed of wind 
-Type of motor used 
-Type of rubber band used 
-The length of the wires used 
-The amount of time the voltage is measured

2. Methods

2.1 Equipment list:

  • Rubber bands  x15
  • 3 volt DC motor  x4
  • Measuring Tape  x1
  • Wire cutters  x2
  • Insulated tape  x1
  • Voltmeter or multimeter  x2
  • Large paper clips  x30
  • Scissors  x2
  • Wood  x3
  • Cork  x5
  • Masking tape  x1
  • Electronic Portable Fan  x1
  • Marker  x2

 2.2 Diagrams

Our sketches of the set-up (not drawn to scale):

Figure 1 shows how the experiment is going to look like when we are testing the blade ( this is only half of the full thing Figure 2 which is below is the other half, which will connect the wires to the motor)

Figure 3 shows Template A, one of the blade sets.

Figure 4 shows Template B, one of the blade sets.

Figure 5 shows Template C, one of the blade sets.

Figure 6 shows Template D, one of the blade sets.

Figure 7 shows Template E, one of the blade sets.

Figure 8 shows all the different types of blade shapes we are experimenting with.

2.3 Procedures:

Making of the Wind Turbine:

1) Use the rubber band to attach the body of the motor to the end of the ruler. Be sure the shaft of the motor extends beyond the end of the ruler. The motor's leads or outlets will point towards the other end of the ruler.

2) Use the wire cutters to cut two 30cm pieces of insulate wire. The remove about 2cm of the insulation from each end of both wires.

3) Attach one end of the wire to one of the motor's lead's or outlets. Secure the wires with electrical tape. 

4) Tape the middle of the wires to the ruler to hold them in place. Attach the other ends of the wire to the voltmeter, which will measure how much voltage the windmill produces.

5)Use scissors and the cut out six pieces of cardboard from template A. This will be the first set of windmill blades.

6) Straighten out the bottom end of each of the paper clips. Tape each cardboard to the middle piece of the paper clip to make the windmill blade. The long end of the paper clip should stick out.

7) Repeat steps 5 and 6 to make 5 other blades. Stick the 6 windmill blades into the cork about 1/4 inch from the end. Space them equally around the cork.

8) Repeat steps 5 through 7 and make 4 other sets of windmill blades using the remaining four templates, B, C, D and E . Each blade on the templates should have a different shape.

In the picture above we have the template A,B,C cut out and D,E drawn out on the wood. We have also shown the straightened paper clips, corks and rubber bands.

2.3 Experimental Procedure:

1) Insert the motor's shaft through the centre of the cork. The blades should be at the far end of the cork, away from the motor. Make sure the shaft goes through the centre of the cork, so that the windmill does not wobble when it spins. 

2) Place the turbine at least 30.5 cm in front of a fan. Use a piece of tape to mark the position of the fan and the windmill. They will need to be in the same place throughout the experiment.

3) Now you will find out the best angle for the blades. Twist the blades so that they are perpendicular to the end of the cork.

4) Repeat Step 2, tilting the blades in small increments until the blades start spinning. When the blades start spinning, measure and record down the voltage produced. 

5) Keep tilting the blades of the turbine until you find the best angle that produces the greatest voltage. Record this voltage as your "Best" voltage produced.

6) Test the voltage at least 4 more times. Record the voltage each time.

7) Use the marker to mark the angle of the blades directly on the cork. Just draw a short, straight line beneath each blade. The line should line up with the angle of the blade.

8) Now you are ready to test the other blade shapes and sizes. Remove the 1st set of blades and insert the 2nd set of the blades. Turn the blades so that they line up with the marks you made in Step 7. The second set of blades should be at the same angle as the first ones.

9) Place the turbine in front of the fan, making sure that both are in the same places as they were in Step 2. Turn on the fan and record the voltage produced. 

10) Repeat Step 9 at least 4 more times and record the voltage produced each time.

11) Repeat Steps 8 to 10 with 3 other different shaped and sized sets of blades.

2.4 Risks and Safety:
-While cutting out the shapes, we might accidentally cut our own fingers hence, we will wear gloves to minimise the harm caused.
-We might also get electrocuted by the circuit hence, we will wear rubber gloves.
-While handling the motor, we might accidentally burn ourselves as it is hot,  hence, we will wear rubber gloves

2.5 Data analysis

  • Average the voltage produced by each blade shape.
  • Make a bar graph of blade shape (x-axis) versus voltage (y-axis).
  • Make sure to state which shape and sized blade produced the highest voltage.
  • For the ending of the report, conclude if the result and hypothesis coinceded together.

    3. Results

    The following shows the results collected after the experiment.
    Table 1 shows our results.

    Table 2 shows our results in bar graph form.


4.1Key Findings 

  • From the data we collected, we can to conclude that the surface area affects the speed at which the wind turbine turns. The greater the surface area of the blades, the faster the speed of the wind turbine which helps create more voltage. 
  • From the data collected we also got to know that shape indeed matters when it comes it the blade size. The broader the blade size, the more voltage produced.

4.2 Explanation of Key findings

The greater the surface area of the blades, the faster the speed of the wind turbine which helps create more electricity can be seen through the amount of voltage produced by the  respective blades. Since the blades differ in surface area, the result (which is the amount of voltage produced) changes accordingly.  If we were to compare Template A and B, A has greater surface area whereas B has lesser. Hence the A produced 0.008 volts whereas B produced 0.005 volts.

 Figure 1 shows the various kinds of blades.

Figure 2 shows our data.
  • The broader the blade, the more electricity it helps to generate. This can be seen through Template A and B, when they are compared. As an average reading Template A was noted as 0.008 volts and Template B was noted as 0.005 volts. It also coincides with our hypothesis which is the broader and longer the blade, the more electricity is generated.

Figure 3 and 4 show how broad the blades are.

4.3 Hypothesis

  • Our hypothesis is : The broader and longer the shape of the blade, the greater amount of voltage produced.

4.4 Further Evaluation of Hypothesis:

  • As this was a hypothesis driven research we had always had to keep our hypothesis in mind. Our hypothesis was also proven to be correct and this finding is supported by our experiment data.  This can be seen by when the blade shapes were broad, they tend to produce a higher voltage. But when the blade shapes thinner, they tend to produce a lesser voltage or not produce anything at all, take Template E for an example.

    From this we can conclude and prove that our hypothesis is correct. Our hypothesis is : the broader and longer the shape of the blades are, the greater amount of electricity produced by the wind turbine.

4.5 Areas for improvement:

There are several things which can be improved on. All experiments can be improved on!

  • Firstly, when we cut the blades out from the wood, a significant amount of wood which is not suppose to be cut is also cut off. Though the inaccuracies may be minor, but they do have an impact on the data we collect, since all the blades after cutting out has different sets of measurements, the data would not be as accurate. To prevent this we can always measure the measurements more, for example: the length is 8cm, we can always mark up till 8.5cm so as to get a 8cm when we cut out with a plus and minus. 
  • Secondly, when we cut out the blades and if we let everyone in the group cut it out, everybody will cut differently (their way of cutting is different), thus again a significant amount of wood which is not suppose to be cut off would be cut off. Though this is something very minor, but again the results would not be as accurate. We suggest division of labour, hence appoint one person to cut out the blades so the difference will be as minimal as possible.
  • Thirdly, when we want to test out our blades, then we should mark a distance from the wind source to the wind turbine. This plays a very important role as it affects fairness of the experiment. If one blade set is 20cm away from the wind source and the other is 30cm away, then of course the one which is 20cm away will produce a higher voltage. We suggest that marking a common distance will be effective and efficient as all would start from the same starting point.
  • Fourthly, when we should mark the cork consistently with the same angles on all the corks. This plays a very important role as the distance at which the blades are spread out should be equal as they affect the way the turbine spins. To prevent the shaky turbine, we should take a 360 degree protector and mark out 50 degree and then poke the blades in to ensure the equal distance.

5. Conclusion

Summary of Findings:
Within our findings, our results tell us that the surface area of the "blade" will affect the amount of voltage generated. The larger the surface area of the blade, the higher the reading of the voltage. We tested all of the blades with the same fan and the same fan speeds, and we saw very clear readings between the results. When we discussed the amount of voltage generated by each of the "blades" we saw a clear distinction between the blades with a higher reading and the blades with the higher surface area.

Practical Applications:
With the results we can confidently say that wind energy is an excellent source of renewable energy. Since the wind is effected by the Sun, the Human race can keep using it as a reliable source of energy. Saying that, the amount of energy you will be able to receive is down to where you place the Wind turbine, since it is reliant on the wind, if you place it where there is no wind, you will not be able to gain any energy. With the right amount of wind turbines, almost any sized city can be powered.

Areas for further study:
Further research can be done on the areas of "Wind speed", "Efficiency", and "How does a bigger size blade/motor help with the generating of voltage". More research can be done on how does outside elements effect the wind mill, such as gravity, temperature or different atmospheres (assuming we can build on a different planet)

6. Biblography

  • Geographic, N. (n.d.). Wind power. Retrieved from environment/global-warming/wind-power-profile/!

  • Harris, E. Save the earth science experiments. New York: Lark Books.!

  • 2013 wind energy installations stall in us, surge in china. (2014, February 6). Retrieved from

7. Acknowledgements

  • We would like to thank our school for providing us with an opportunity to experience what it is like to do an experiment all by ourselves and that to in our comfort zone. We would also like to take this opportunity to thank Mr Teng for his guidance throughout this project and for his useful tips. We would also like to thank our seniors for their help. We would also like to thank the Lab technicians for providing us with the materials and their patience. Thank you so much!

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