Electricity Generating Kite!

Imagine, a children's toy generating all of your electricity needs. That is the reality of kite power! Kites mounted with turbines fly autonomously generating power on a megawatt scale! I have always been infatuated with kites. Their simple movement and calming effect seem to interest every child.

For this reason, I have created a power generating kite, to explore the future of alternative energy. This easy to follow instructable will show you how you can make your own power generating kite on a budget. Although it may not be a permanent solution, kite power shows how many interesting ways there are to generate power. 

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Step 1: Background

Our search for a key to future energy development can be found in wind energy. As the sun warms the earth’s surface, the atmosphere is warmed also. Warm air weighs less than cold air, which make it rise. The cool air then moves in to replace the warm air. This movement of air is what causes wind. In the 1st century, a Greek man named Heron of Alexandria created the first windmill. A wind generator attempts to convert the motion of air into electricity or in some cases, mechanical power. It is one of the oldest forms of renewable power generation in human history.

The quest for creating a revolutionary wind generator that has the potential to compete with fossil fuels starts with the wind. Modern wind turbines like the Enercon E-126 is highly engineered. Standard tower to turbine systems, no matter how highly engineered they are, have limitations. First, they cannot rise above 500 feet. They are tied to the constraints of a tower. They are heavy and extremely difficult to transport. They are expensive, and not cost effective enough. They do not produce enough power to be competitive with fossil fuels. Modern wind turbines are getting larger and larger, it seems they have reached their height limitations. Some say “the wind turbine,” is the most efficient design for converting the motion of the wind into mechanical or electrical power. I am here to tell you, it is not.

A man named Miles L. Loyd from Livermore, California wrote a seminal paper titled, “Crosswind Kite Power.” This paper describes a concept for large-scale wind power production by means of aerodynamically efficient kites. By using the same principles as airplane construction, these kites can transverse the wind at very fast speeds. The methodology used in Mr. Loyd’s paper lays the foundation for the study of power-producing kites. Mr. Loyd writes, “Recent development of large wind turbines has led to a high degree of refinement in their design. These turbines are near optimum for available materials and processes but the single-unit power output in limited to a few megawatts.” Through the years thermal and electric power have replaced windmills in many applications. Windmills, in recent years, have only gained recognition due to their connection with alternative energy. Kites have barely been considered.

A kites’ surface converts the motion of the wind into lift or motion of the kite. Conventional methods for power generation using a kite have involved mounting turbine to the kite. Moreover, some methods include the kite pulling its tether which in turn pulls on a generator producing power. In this project an entirely new perspective on Airborne Wind Turbines (AWT) will show the potential of kite based wind energy.

Up until now, airborne wind turbines have been stationary, only to face the wind, like the Magenn Air Rotor System featured on the right. A system like this is not only unimaginative, but it lacks the size and area of a ground based wind turbine. The only advantage Magenn delivers is that it functions at higher altitudes, soon. A kite system, as proposed in this project would not simply face the wind like the Magenn air rotor system, but such a kite would fly in a predetermined path downwind from the tether point and the kite motion would b e redirected to transverse the wind. The kite would fly in an orbital axis, is the same sense that a wind turbine’s blade flies transverse to the wind. The wind would not only be supporting the kite in this system, but it would also be generating usable electricity. The kite in this case, would mimic the rotational movement of the tip of the wind turbine. The tip of the wind turbine is one of the most efficient parts of the mill which constitutes the last 25% of the blade. In some cases, the tip of the wind turbine produces 75% of the power generated. The tip is rotating at the highest velocity due to the fact that it is sweeping the largest part of any of the blade.

In this brief talk, Saul Griffith unveils the invention his new company Makani Power has been working on: giant kite turbines that create surprising amounts of clean, renewable energy.

Step 2: Getting the Kite

There are so many types of kites on the market. Big ones and small ones, choosing a kite is a difficult process. For this instructable, I chose to use a sport kite. There are many reasons, but the most notable is that a sport kite is the most aerodynamic type of kite on the market. This type can reach speeds of 50 mph, and a high quality kite for this instructable is very important.

Looking at kites, one of the best retailers I have found is Prism Kites [1]. They have very well made kites, and my experience with them has been pretty positive. Looking that the sport kites they sell, we can see the variety they have. For this project, you could use any of their sport kites, but the one that I prefer is the Jazz.

"Simple, rugged and affordable, the Jazz outperforms every beginner stunt kite in its class. It’s a zippy little wing that packs up small so you can take it everywhere. Leave it in the car, at the beach house, strapped to your motorcycle...because you never know when you’ll get the urge to fly.

The Jazz’s deep wing profile and tough hybrid glass/carbon frame means you can safely hand it off to anyone for a test drive. In the air, it’s quick but remarkably stable and easy to control, even for a low-time pilot. Engineered and built to the same obsessive standards as our top-end equipment, it’s a simple, compact little gem that will get you up and flying with a grin.

Designed for beginners, the Jazz has a 55-inch wing span but folds down to 25 inches long so it can be packed in a suitcase or backpack. Easy instructions are printed on the case so they're always handy. Quick, stable, and easy to control, the Jazz will fly in winds as low as 5 mph, a plus for inland pilots, and also perform in winds up to 25 mph for trips to the beach. The ready-to-fly package includes two 65-foot low-stretch Spectra lines, winder, and flight straps." - from prismkites.com


[1] http://www.prismkites.com/

Step 3: Turbines and Generators

Now that we have our kite, we now need to generate electricity with it. How can we do this? We need a couple of this to do this including a propeller/turbine, a motor/generator, and some wire.

Go down to your local hobby shop, and go down the propeller aisle. For a wind turbine, most people choose a three bladed design. I chose a propeller from my hobby shop with 3 blades and a blade length of 2 inches. (picture below)

The next thing we need is the generator. Now, going back to simple electronics we know that an electronic motor can also function as a generator for electricity by working in reverse. For this project, we can go cheap and use a hobby electronic motor from Radioshack. [1]

Now that we have the turbine and generator down, we can move on to assembly.

[1] http://www.radioshack.com/product/index.jsp?productId=2102828

Step 4: Assembly

Take your rod of carbon fiber and cut it into 2 one foot pieces. These will protrude from the leading edge of the sport kite and will be the place where the turbine and generator is mounted. Attach one end of the rod to the leading edge connector (J) with duct tape, and the other end to the leading edge (A). Refer to the parts of a sport kite in the image below.

The rod should protrude from the leading edge about 7-8 inches in such a way that the tip of the blade does not hit the leading edge. This will provide a sturdy spot to mount the generators.

Next, tape a majority of the motor to the end of the carbon fiber rod as seen in the picture. I used a 1 inch dowel to provide a sturdier mount, and you can do the same but it is not necessary.

Also, assemble the circuit seen below with a 1n4001 diode. A 5 volt regulator should be used to prevent a voltage overload or even a fire! A simple tutorial on five volt regulators is easy to find with Google. Add the regulator also. Mount all of the electronics with duct tape to the spine (B).

I attached an identical turbine/generator to a 2 by 4 to use as a control. I have a graph of the output of the kite, which I will post in the future.

The last thing we will need to complete the circuit is a rechargeable battery. I like Sparkfun, so this battery [1] seemed fit. (picture below)

After a good amount of flight, the battery will be fully charged and you will have renewably made electricity!

[1] http://www.sparkfun.com/products/341

Step 5: Fly It!

Get ready! Lay the kite on its back. Face it into the wind then pull on the dual lines of the kite. It will fly into the air. To control it, pull on the left string to tilt it left, and the right to tilt it right. All of this time, the turbines on the kite will be spinning and generating clean electricity!

In the future, you could use conductive wire instead of kite string to fly it. Instead of connecting the output of the motor to the battery, you will connect it to the wire which will lead to the ground. This way, you can generate electricity while flying the kite.

Have fun, and be safe! Thanks for viewing the instructable, and rate it if you like it!