How to Balance RC Helicopter Blades

Always balance the main rotor blades before the first flight.

Many RC helicopter companies claim the helicopter blades they sell are matched and balanced. This claim may not always be true and flying a helicopter without balanced blades can damage the aircraft. Balancing the rotor blades before the first flight should be standard procedure even if the RC helicopter is RTF (Ready to fly) or ARTF (Almost Ready to Fly.)



Blades that aren't perfectly balanced can cause unnecessary vibration, and problems with hovering or steering. Bolts can loosen or even break during flight, resulting in a crash. In extreme cases permanent damage can occur that render the helicopter inoperable.

Things You'll Need

• Electrical tape
• Permanent marker
• 2 wood boards, 2 by 4 by 18 inches
• Gram scale
• Wooden dowel 8 inches long

Instructions

1. Place the rotor blade on top of a dowel rod or other round surface to balance it. Balance the blades evenly from right to left to find the center of gravity. The center of gravity is the point at which the blade is evenly off the ground on both sides while perfectly balanced on the rod.

2. Place a colored piece of tape on the line for center of gravity or CG. You can remove the center of gravity mark later by removing the tape or markings with nail polish remover. Repeat the step for the second rotor blade.

3. Face the rotor blades in opposite directions and lay one on top the other. Match up the bolt holes and slide a bolt through. Check the center of gravity marks on each blade to see if they line up. If the marks line up, the balancing is complete. Proceed to Step 4 if the blades aren't balanced.

4. Weigh the blades to determine how far off balance they are. Anything more than 2/10-gram off from each other will cause problems. If the blades are out of balance by more than 2/10-gram consider sending them back to the manufacturer.

5. Place a bolt through the rotor blade holes to attach them as one unit. Place two 18-inch lengths of 2-by-4 lumber side by side. Balance both ends of the bolt atop the lumber so that the blades are supported and can freely move between the blocks.

6. Place a piece of tape in the center of the blade that is lighter. The lighter blade will be the one higher in the air. Place more tape on the lighter blade at the center of gravity until the blades become balanced. Try to use long lengths of tape to minimize the amount of tape used.

Tips & Warnings

• Electrical tape is easier to remove than other types of tape.

• Make sure the blades are tracking properly after balancing.

References

• RC Helisite: How To Balance Your RC Helicopter Blades

Resources

• HeliRush: RC Helicopter Forum