What I've done on carbon fiber props is to get a plastic cap/plug (I use the positive/red plastic post cover off of a 12v auto battery). Put the prop together, put the plug in the centering boss of the prop, put a string through the centering boss, then hang it from the ceiling. I then drill a hole in the prop where it is hollow and inject epoxy (using plastic hypodermic needle) until it balances out. Close to what you're doing here but my method just varies a little bit. Thanks
For the first method, it seems that weighing the blades first is unnecessary as the only part that seems to matter is if the blades are balanced around the center hub when assembled.
Dusan, a couple questions please: 1) where do you drill a vent hole, it wasn't clear in your video. 2) What type of metal rod was that used to balance the E-prop? Have you tried heavier metals such as tungsten welding rod (Ebay)? 3) If one hole & metal rod is insufficient weight to balance, why not add one or two more holes/rods as needed? Thanks. Best balancing video I've seen.
I had a prop in which the balance filler get loose, it went down the prop (to the tip) and prop get badly unbalanced. When you shake the prop down - the balance filling was rattle inside. The Styrofoam insert get damaged too. I think you may consider to balance/weight the prop middle part (hub), usually made from wood or plastic.
I tried with the second method, the easy home made system and that is exactly how I balanced my rc helicopter blades and it worked good with small blades, But with helix cb prop id didnt. Once both blades weigh exactly the same and the CG is in spot, I test the prop with the ballbearing balancer and it looks s not balanced . It tips to one side. So I guess the prop mass isnt distributed the same, so what should I do? Add some weight on the tip of the lighter side?
Really, these props aren't DYNAMICALLY balanced from the factory? Good video. I guess what I should be asking, is have you checked one of the blades you've balanced this way ON a dynamic balancer to see how accurate it came out? With possibly asymmetrical mass concentrations (repairs) in the blade, I'n not convinced this is perfect, though I agree it is probably good enough. It would be an interesting test, anyway. I can think of one way that might work to weight badly out of balance foam core props. What if you drill the holes diagonally and intersecting (jigged) into the L.E. and use at least some carbon chop in the weight, in place of your regular thickener. You'd have to calculate the hole sizes and lengths to make sure the weight was continuous from the intersection to BOTH skins, but I bet it would work just fine. I would test such a prop to beyond any RPM it would see in operation (say what the manufacturer tested to) both to see the viability of the idea, and maybe each "fix" for several blades initially, anyway. Just a thought. I realize it would be a lot higher pain, but I guess it's that vs. the cost of a new blade that would be the determining factor, aye? It seems the manufacturers MIGHT be willing to work with you and test a few blades, if you sweet talked them. Depends on if they want their props fixed, or to sell new ones though, so maybe not.
Why don't you guys put a protective film on the leading edge of the propeller? This protects against grass, loose ties and even against small pebbles. As a bonus you can balance the prop by cutting away the small strips of this film.
Having the prop vented is beneficial for other reason. If the black prop gets hot on direct sunlight, the air inside expands. It's better to vent it than expose the prop to internal pressure
Dusan, thank for your help. This is really interesting!
glad to see that eprop very well balanced from the start.
what? e-props are the whorst. Seen so many unbalanced eprops that comes from factory.
What I've done on carbon fiber props is to get a plastic cap/plug (I use the positive/red plastic post cover off of a 12v auto battery). Put the prop together, put the plug in the centering boss of the prop, put a string through the centering boss, then hang it from the ceiling. I then drill a hole in the prop where it is hollow and inject epoxy (using plastic hypodermic needle) until it balances out. Close to what you're doing here but my method just varies a little bit. Thanks
Thanks
Great Video. Thank you!
For the first method, it seems that weighing the blades first is unnecessary as the only part that seems to matter is if the blades are balanced around the center hub when assembled.
Dusan, a couple questions please:
1) where do you drill a vent hole, it wasn't clear in your video.
2) What type of metal rod was that used to balance the E-prop? Have you tried heavier metals such as tungsten welding rod (Ebay)?
3) If one hole & metal rod is insufficient weight to balance, why not add one or two more holes/rods as needed?
Thanks. Best balancing video I've seen.
Thanks for the great video!
Nice
I had a prop in which the balance filler get loose, it went down the prop (to the tip) and prop get badly unbalanced. When you shake the prop down - the balance filling was rattle inside. The Styrofoam insert get damaged too. I think you may consider to balance/weight the prop middle part (hub), usually made from wood or plastic.
I tried with the second method, the easy home made system and that is exactly how I balanced my rc helicopter blades and it worked good with small blades, But with helix cb prop id didnt.
Once both blades weigh exactly the same and the CG is in spot, I test the prop with the ballbearing balancer and it looks s not balanced . It tips to one side.
So I guess the prop mass isnt distributed the same, so what should I do? Add some weight on the tip of the lighter side?
Really, these props aren't DYNAMICALLY balanced from the factory? Good video. I guess what I should be asking, is have you checked one of the blades you've balanced this way ON a dynamic balancer to see how accurate it came out? With possibly asymmetrical mass concentrations (repairs) in the blade, I'n not convinced this is perfect, though I agree it is probably good enough. It would be an interesting test, anyway.
I can think of one way that might work to weight badly out of balance foam core props. What if you drill the holes diagonally and intersecting (jigged) into the L.E. and use at least some carbon chop in the weight, in place of your regular thickener. You'd have to calculate the hole sizes and lengths to make sure the weight was continuous from the intersection to BOTH skins, but I bet it would work just fine. I would test such a prop to beyond any RPM it would see in operation (say what the manufacturer tested to) both to see the viability of the idea, and maybe each "fix" for several blades initially, anyway. Just a thought. I realize it would be a lot higher pain, but I guess it's that vs. the cost of a new blade that would be the determining factor, aye? It seems the manufacturers MIGHT be willing to work with you and test a few blades, if you sweet talked them. Depends on if they want their props fixed, or to sell new ones though, so maybe not.
Why don't you guys put a protective film on the leading edge of the propeller? This protects against grass, loose ties and even against small pebbles. As a bonus you can balance the prop by cutting away the small strips of this film.
There was tape on the blades numbnuts.
At %.24, you say the blade has to be vented, that's wrong, you can create a small vacuum which will suck the compound in.
how many props you repaired?
Hundreds
Having the prop vented is beneficial for other reason. If the black prop gets hot on direct sunlight, the air inside expands. It's better to vent it than expose the prop to internal pressure
@@SCOUTaviation Thank you, I never thought of that!
Thanks