Things You'll Need:
- Triangular Ruler
- Marker
- Duct Tape
- Thread
- Nut and bolt
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Step 1
Use a triangular ruler to find the center of gravity. A triangular ruler is a 12-inch long, 3-sided ruler. Two sides lay flat, one sticks up and acts like a pivot that can be used for balancing. Lay the triangular ruler down on a table or other flat surface. Place one rotor blade on the edge of the ruler, centering the blade until it hangs level. With a marker, mark the point where the blade touches the ruler. Repeat the process with the second blade.
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Step 2
Lay one blade on top of another and compare marks. If the marks are more than 1 mm apart, change the center of gravity that is closest to the blade tip by moving the mark that is closest to the root of the blade onto the other blade.
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Step 3
Add small pieces of duct tape to the back of the blade that you made the new mark on. Check the blade on the triangular ruler each time you add a piece of tape until it balances on the new mark you made.
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Step 4
Put the blades together with a nut and bolt. Spread the blades out as if they were in flight, straight out from the central hub.
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Step 5
Tie a piece of thread around the blades at the central point. Make sure the thread is in line with the center of the blades or it won't balance properly.
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Step 6
Lift the blades by the thread and allow them to hang. If one blade points up and one points down, proceed to the next step because they are still not balanced.
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Step 7
Cut duct tape pieces and add them one at a time to the blade that pointed up in order to make it heavier. Make sure you alternate putting equal pieces on either side of your center of gravity mark. Lift the blades by the thread between adding tape to check progress. When they hang level with each other, they are balanced and you're ready for fun!
