# Constructing Basic PVC Wind Turbine – Blades

Subjects:

Math, Science

6, 7, 8, 9, 10, 11, 12

Title – Basic PVC Wind Turbine – Blades
Primary Subject – Science
Secondary Subjects – Math

 Constructing Basic PVC Wind Turbine Unit Introduction Basic PVC Wind Turbine Parts and Tools List Constructing Basic PVC Wind Turbine Procedures Building and Testing the Blades (below) What You Can Do with Your Turbine

Testing Blades on Basic PVC Turbines:

 Caution!!!: Never make blades out of metal or any sharp edged material because they could cause injury during testing. Blades tend to spin very fast (300-600 RPM) and can easily cut people if they have sharp edges. Always wear safety goggles when testing.

• To make blades, carve or cut different shapes and sizes out of a variety of materials (wood, cardboard, felt, fabric). Tape or hot glue them to the dowels. Students have made blades out of Styrofoam bowls, pie pans, and paper and plastic cups. Anything you find around the house or classroom can be made into blades!

As the crimping hub can be separated into two parts, you can try different creative ways to attach “blades” to the hub. One of the best blades we ever saw was made from a pizza pie box!!

• Before testing, check that the blades are securely attached to the dowel. If not secured properly, they may detach or deform as you test your turbine in high winds. We recommend using a combination of tape and hot or regular glue.
• Insert the dowels into holes on the crimping hub. It is important to tighten the hub when inserting the blades so that they do not come out at high speed.
• When attaching the blades to the hubconsider a few important questions:
• How close is the root of your blade to the hub? What do you think is optimal?
• Are the blades equally distributed around the hub? If not you can also have a set up that is out of balance.
• Have you secured the hub after you inserted the blades? If not they can fly out at high speed!
• Want to know how fast your blades are spinning? Get a Hangar 9 Micro Tachometer.
• Safety and Blade Testing Area
• It is important to wear safety goggles when testing blades.
• NEVER make blades out of metal or any sharp edged material as these could cause injury while spinning fast during testing.
• Setup for Testing
• It is important to clear this area of debris and materials.
• Make sure the center of the fan matches up with the center of the wind turbine. You may need to raise your fan with some books or a container.
• Some things to note about fan wind that reduces the efficiency.Fans create;
• Highly Turbulent & Rotational Wind — Blades may spin better one direction than another
• Highly Variable Wind Speed — Wind speed is about 10-13 MPH on high for a \$20 circular fan. Wind speeds near the middle will be much different than the edges.
• Limited Diameter — Blades bigger than the fan will not “catch” more wind — they will just add drag and slow down your blades.
• How to Clean Up Wind?
• Want some more “professional wind”? You can try to build a simple wind tunnel. Lots of plans can be found online (search term: classroom wind tunnel or go to www.kidwind.org).
• One simple way to make more laminar — smooth, straightened — flow is to build a honeycomb in front of your fan using milk cartons, 2″ PVC pipe or some other material.
• Going Outside?
• While you can use your wind turbine outside, you must make sure that you face it into the wind. This is because this turbine is not designed to YAW (or rotate) to face the wind. If the wind shifts, and the turbine cannot rotate, wind will hit the blades from the sides causing stress and inefficiency.
• For a wind turbine that can yaw, you can check out the KidWind Yawing PVC turbine on our website (www.kidwind.org).