The Most Useful Windmill

Aaron Locke and Stephanie Morse


Green energy is a very popular topic in the world, and one example of green energy is the use of windmills to produce energy. We are both aware of the kind of windmills that are currently being produced, which have three identical blades

Problem or Need Statement

We know of the several different designs that have been considered in making windmills. Over the decades, there have been windmills with different designs [see below]. We want to know what windmill design will be most efficient in producing energy.


What are the best methods/resources for building and testing these model windmills?

Will a simple house fan be an appropriate source for wind?

How will we effectively measure voltage?

State of the Art

The types of windmills that we will build:
1. Flat, Smooth, Tri-Blade
2. Basic Pinwheel
3. Quadra-blade with air holes
We have designed a system to test each of these windmill designs. We built each system, the three blade, the pinwheel, and the four blade, so that it could be placed on a DC battery. We are using a multimeter to measure the energy output from each windmill. We will use a fan to generate wind that will then power the windmills.

Specifications and Metrics for the Solution


1. Attach one type of windmill to the DC Battery.
2. Mount DC Battery and Windmill on upright rod.
3. Begin the fan and timer.
4. Record the energy output on the multimeter for five minutes.
5. Shut of fan.
6. Repeat steps one through five for the other two windmill designs.

The Multimeter: an electronic measuring instrument, that is able to combine several measurement functions into one singular unit. There are two categories of multimeters; analog and digital. It has the ability to measure voltage, current, and resistance.

The Fan: The fan is a simple house fan that has three speeds; slow, medium, and fast. Using it will produce a constant flow of wind that will help to successfully measure energy output. We will be using the fastest setting.

Brainstorm Alternative Solutions

There are not many alternative solutions to this experiment. It is very black and white. Built, test, observe. We cannot travel to places with actual models of these times of windmills simply because of lack of resources.

The path we have chosen is much more hands on and will be useful in discovering our own results.

Identify Priority Alternatives/Implementations

There are many different ways to test this question...including...

1. Basic Research: there may have already been an answer to this problem. Just search the web and find the answer.
2. Conduct Interviews: in the upper valley, there are many green programs that have plenty information on wind energy. Asking them could be an option.
3. Testing: Making our own small scale models of different windmills and testing them.

We decided that making out own models of windmills would be the best option for testing this. That way we can collect original data and see specificially the pros and cons of different models, and make an educated decision to which one should be made on a large scale model.

Beginning this process, we were a bit apprehensive. It required a great deal of knowledge of architectural design. We used straws and regular paper at first to find the best way to make each windmill. By working on a smaller scale to begin with, it made making the actual windmills much easier.

Sadly, our windmills were crafted and left in the basement of one of our homes. In a mere case of bad luck, a ladder fell from the wall, crashing the windmills. This set us back tremendously. Much of the extensive work we planned to do was taken up by the process of rebuilding the shattered bases and appendages. We were forced to cut back on our agenda and only focus upon the basics.

Implement Solution and Test

We Built:
The windmills were made out of different materials, and because of that, they were each very different.

1. Flat, Smooth, Tri-Blade: this was the smallest and lighest of the windmills. It was made out of balsawood, a very light would that is easy to work with. We sanded the wood to make it more aerodynamic. They were tilted a bit inward and to the left. Our thinking was, if the wood was tilted, it would be more likely to take wind and move faster.

2. Basic Pinwheel: the pinwheel was the easiest to make. It only required a heavy-duty paper. We used posterboard. We took instructions off a craft website to make the pinwheel and when it was finished, it was very simple to attach to a base.

3. Quadra-blade with air holes: This was easily the most difficult to build. We went through a process of first using tough paper, but realizes that balsa wood was necessary. We used sheetrock knives to cut small holes in the wood to let air pass through while the blades spun. Again, we allowed it to attach to the base.

We Tested:

The testing for this was really interesting. We hooked up the multimeter to the DC battery. The other end of the DC battery was what had the actual windmills mounted upon itself. At first, mounting the windmills upon the DC battery posed a problem, but only some small technical changes were needed. When we tested it, we had one person be the scribe. The scribe's job was to watch the multimeter and record the changes in volts that the windmill produced through the DC battery. The second persons job was to regulate the fan and to record time. Each windmill recorded for five minutes.

During testing, we did not measure total energy output. Although that seems contradictory, we wanted to find the average voltage output. So instead of adding the different recorded voltages together, we found the average of each thirty-second period to find which was more efficient in producing energy.


During the first trial, we observed two serious and preventable problems...

First, the windmills needed to held down in someway to prevent them from flying off the table.
Second, sometimes the windmill itself would come off from the DC Battery.

To fix them from flying off the table, we screwed them into the wood of the table, which secured it without problem.
We tightened the windmills at the middle point to make it more secure on the DC Battery.


Average Voltage


Our experiment showed a lot of data to be interpreted. First, was the general pattern of each windmill. Through the graphs, we can see that around 3:00, each windmill had generally sustained it's average voltage output. We concluded that this happened simply because by this time, they had reached their peak speed that could be allowed with the wind that was being supplied. The pin-wheel and the quadra-blade with air holes had the most distinct straight lines between minutes three and five. The pinwheel, however, had a higher average than the quadra-blade with airholes. When the third windmill is taken into perspective, the smooth, flat, tri-blade, it reached the highest voltage numbers and was continuing to increase when we stopped timing it at five minutes.

In order of highest voltage output...
Lowest) Quada-Blade with Air Holes
Middle) Basic Pinwheel
Highest) Smooth, Flat, Tri-Blade

Our conclusion on why this happened is quite simple. The windmill with the highest voltage output was also the lightest windmill. The Quadra-Blade with Air Holes was substantially heavier because it had four appendages. The pinwheel, although made of paper, had a high surface area making it weigh more than the tri-blade. The Tri-Blade was simply lighter and more aerodynamic than the other two. It's design allowed it move quickly and continue to produce a high voltage simply because it moved faster than the other two.

Lastly, the data we collected helped to reaffirm was we previously thought. All along, we were rooting for the tri-blade, seeing as how it is the chosen windmill to be placed around the globe. Our data shows that the light, thin, but effective windmill is the correct choice.


When we began this project, we wanted to test three different windmills to see which produced the most energy. Through many problems, including having our windmills destroyed, we reached an answer. We concluded that the windmill with the smallest mass and least amount of surface area was the most successful in producing voltage in a five minute period. The smooth flat triblade was the most effective in producing voltage when wind was applied. The other two were either to heavy or took to long to gain momentem, which resulted in them not producing the same high amounts of voltage.

If we were to repeat this project, not only would we keep our windmills in a safe environment, we would also try to find alternatives to the measurement process. The multi-meter often seemed a bit erratic and did not give clear, definitive results. Also, we would find a different material to build the four-bladed windmill. The excess amount of balsa wood that was used made it heavy, which impaired it in the long run.


Thank the people who have helped you complete this exploration.

Additional information on these sections can be found on the inquiry model page.