Post by Jerrymac on Apr 16, 2013 1:54:15 GMT -5
Since the question of blade balancing seems to come up often on the RC forums, I thought I would offer my method for others.
First, the important thing is that the blades weigh the same, and have the same center of gravity, which is hard to achieve with a simple blade balancer, so, here is my method to balance blades.
Start by weighing each blade on a quality scale. I will use some random numbers for an example. Say one blade weighs 95.75 grams, and the other blade weighs 94.50 grams.
Place the light blade on the scale and drop pieces of balancing tape on the scale until the blade, plus tape, equals the weight of the heavy blade.
You now have 2 blades of equal weight and just need to know where to apply the tape to the light blade. Blades can be slippery, so, place a razor blade in a vise or other holding fixture, then balance the originally HEAVY blade on the razor and find the lenghtwise CoG balance point and mark it with a fine tip marker.
Now, place the blades on top of each other and drop a bolt through the grip holes to line them up, then transfer the mark from the heavy blade to the light blade. Place the light blade on the razor at the mark and see which way the blade tips. Apply the tape to the light blade at the point along it's length where it will balance on the mark that was transferred from the other blade.
You will now have 2 blades that weigh exactly the same and have the exact same lengthwise CoG. This method has worked very well for me.
I have seen videos of people rolling them on a main shaft first, applying tape to one blade to get the CG right, then applying more tape in a different spot, and sometimes to the other blade to get them to "teeter" right on a balancer. Never quite understood this concept.
I hope this helps anyone looking for a simple and effective way to balance rotor blades.
Any and all comments are welcomed.....
Jerry
First, the important thing is that the blades weigh the same, and have the same center of gravity, which is hard to achieve with a simple blade balancer, so, here is my method to balance blades.
Start by weighing each blade on a quality scale. I will use some random numbers for an example. Say one blade weighs 95.75 grams, and the other blade weighs 94.50 grams.
Place the light blade on the scale and drop pieces of balancing tape on the scale until the blade, plus tape, equals the weight of the heavy blade.
You now have 2 blades of equal weight and just need to know where to apply the tape to the light blade. Blades can be slippery, so, place a razor blade in a vise or other holding fixture, then balance the originally HEAVY blade on the razor and find the lenghtwise CoG balance point and mark it with a fine tip marker.
Now, place the blades on top of each other and drop a bolt through the grip holes to line them up, then transfer the mark from the heavy blade to the light blade. Place the light blade on the razor at the mark and see which way the blade tips. Apply the tape to the light blade at the point along it's length where it will balance on the mark that was transferred from the other blade.
You will now have 2 blades that weigh exactly the same and have the exact same lengthwise CoG. This method has worked very well for me.
I have seen videos of people rolling them on a main shaft first, applying tape to one blade to get the CG right, then applying more tape in a different spot, and sometimes to the other blade to get them to "teeter" right on a balancer. Never quite understood this concept.
I hope this helps anyone looking for a simple and effective way to balance rotor blades.
Any and all comments are welcomed.....
Jerry