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Old 02-21-2018, 10:09 AM   #21 (permalink)
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Don't move the CG. You need to keep the weight in the middle. I checked out the tape. There are two versions, one is heavier by either 2 or 4 times. I was thinking worse case do 2 or three strips and use the opportunity to double check the CG and move to be consistent if already off which my blades are.
Too late, it's done. I rechecked the cg. It moved 7-9mm towards the root of the blades. I don't know what negative actions I'll have as a result. However, the weight is spot on now.
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Old 02-21-2018, 07:43 PM   #22 (permalink)
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How far apart are the cg's between the blades before and after?
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Old 02-22-2018, 03:03 PM   #23 (permalink)
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How far apart are the cg's between the blades before and after?
I'll need to measure distances of original cg on the blades to determine how far apart they were. (Which I don't see myself doing that.) I can tell you the cg moved inward between 7 - 9mm depending on the weight added. All blades are 154.4g now. I'm going w/that.
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Old 02-23-2018, 06:05 AM   #24 (permalink)
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I checked the CG of both a new pair of Rotortech 810's and two surviving non paired Edge 813's. Result was approx 2mm difference of CG on the RT's and 1.5mm on the Edge's with an accuracy of approx 1mm. I suspect the location of CG is almost as important as the total weight. When I calculate the difference of 8g between my two Edge's, if added at the root it will move the CG approx 15mm. That just seems too drastic if the CG of two blades is so close despite having 8g difference in weight.
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Old 02-26-2018, 02:27 PM   #25 (permalink)
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I'll need to measure distances of original cg on the blades to determine how far apart they were. (Which I don't see myself doing that.) I can tell you the cg moved inward between 7 - 9mm depending on the weight added. All blades are 154.4g now. I'm going w/that.
You can't just match weight. The COG must also be the same or you will have vibes.

Step 1 is to check the COG of each blade and make sure they match. Mark the COG of each blade to assist with step 2. If the COG matches then move to step 2. If not add weight to one blade on either end until the COG is the same.

THEN you move to step 2 which is to weigh the blades and add weight to the lighter blade ON THE COG until it weighs the same as the heavier blade. You cannot add weight anywhere other than the COG otherwise you have shifted the COG out of balance again.

Then and only then are both blades balanced properly both in weight and COG

Think of this way. You could attach a rock to one grip that is the exact same weight of the other blade. What do you think will happen when you spin it up?

Go to the Finless Bob video section of the forum and you can see him demo this exact same method if needed.

https://video.helifreak.com/?subpath...lancing101.wmv
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Old 02-26-2018, 08:24 PM   #26 (permalink)
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Thanks for the input. I'll double check everything.
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Old 03-05-2018, 07:14 AM   #27 (permalink)
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Well it's all over now. I got one test flight out of those blades. On the 2nd test hover the heli tilted and the blades dug into the dirt. Now I'll try to find a matched set of blades this time.
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