balancing blades - how far do you go ?

[chansen1953]

Hi guys,
I always balance every set of blades, regardless if used or not.
I used to just add some tape layers to the light blade. on woodies this is fine, as it usually is not many "layers" of tape out-of-balance.
With CF blades, I have found a pair to be quite a way ouit. I tried drilling some holes and covering with tape. but after 4 holes, I started to think about adding weight to the other blade. It turned out that a dime (5 cents here !! ) was about the right weight, about 2 cm from the tip. Now that is quite alot of weight !!!. It should have rung bells, but no I stupidly added the weight, stuck it down with tape, and of course it flew off, and just missed myself and someone else. scared the !@#$ out of me. !!. It was CVA glued in place, but later I ditched the balde as bad idea, too much risk !!
Basically I should have just tossed the blades as being too different, or try to match with another CF blade.
My question is , If a few bits of tape will not balance, then should I be looking for a different pair of blades to balance ??
What other tehcniques can be used to balance blades besides tape or drilling a hole, filing off a bit if CF ?

[bigdawg86]

Well I don't know about you, but you may want to reconsider where you are getting your blades from! I have had a few blades that were off by a bit, but tape is always a better option. Electrical tape is what I use because its heavy enough and sticks great. I wouldn't suggest any drilling because that now creates a weak spot in the blade that if breaks can create a safety hazard if it hits you. And as far as using coins haha... not even going there. Honestly I use fiberglass blades from xheli and they are always matched pretty well by weight, but like anything else its the static and dynamic balance that trumps weight. I have had zero problems with them and they are 4 buck a pair and around 22g each. Sure thats 4g heavier than a set of align carbons but unless your whipping out 3D it doesn't matter. I think the most I have added to get it right was 1g of tape, but that was only one set and who cares if your just doing forward flight and basic loops? I know you never mentioned tail blades, but I would be more cautious about budget CF or Fiber tail blades because they are spinning 4x's faster and even the slightest difference will cause HUGE vibration issues. I prefer a quality set of plastic tail blades because they are perfect everytime. Hope that helps!

[chansen1953]

thanks bigdawg,
Yes, It may have just been a single pair that was mismatched. I seem to have accumulated many pairs of blades, and since I have put thewm all inot a bin, I don't really know which brand is which now.
I quess if they don't match too well, , try another pair !!
I have never really thought about the tail blades, and I have been using some that have worn down a bit due to tail strikes etc. I usually spin it up to top speed with no blades, just to check for any vibrations, and there appears to be none.
thanks again bigdawg

[B2TheEYo]

Never add objects to blades.. The stupidest thing I've ever seen done in this scenario is someone secured double sided RAZOR blades to his 450, to cut the shoe strings of two shoes up on a freaking power-line. Spells danger, especially if one of those babies came off at 400Kmph..

Usually I check the center of gravity, ensure their close and than balance. On a 450, you can cheat it quiet a bit.. Anything bigger it's said that it becomes more and more of a concern.

I'd refer to Finless bobs heli 101 videos on blade balancing, schooled me on quiet a few things in that video!

And if your curious, yes the idiot got the shoes down from the power line, and promptly crashed his 450.

[psilo]

On my bigger birds I simply buy good quality blades and they rarely need balancing. I don't generally even check them unless there is a problem when I put them on the heli! On the 450 I check for CofG, adjust and then balance.

[sutty]

I've been buying good quality blades for my 450, Radix, and have given up even checking them, they were always perfectly matched when I did, but they are expensive. You know what they say, you get what you pay for, and I think this is pretty much true. Anway, I had a few individual blade, crash survivors, and tried to pair them. I was amazed at how much they were out, and just abandoned it as a bad job.

As for the blades on my 600, I did try to balance them, they were Align blades, 600D?, but they were only a tiny bit out. At the FFFD 2009, Grant said, what's that tape on your blade, half laughing at me. It was one wrap of thin, inch wide, clear tape, half way along the blade and barely visible. As I recall both he and Gerd said that it really isn't worth bothering on bigger birds, if you have any half decent set of blades they will be matched well enough. I think I recall Grant saying that he never even bothers now. Think I still might be tempted to give them the once over on the balance though, well threaded rod and nuts that is, lol.

Cheers

Sut

[bigdawg86]

Another thing that helps with blade matching when you have alot of spares mixed up is to get a gram scale... You can get them anywhere online or even a local smokeshop, thats how I match my extra blades. Just weigh them all and put the weight on each blade with a sharpie so that there is no guesswork, just read the weight and go. Hope this helps again.

...and if you have a pothead inlaw like I do, just jack his gram scale and use that. Weed is bad for him anyways haha

[Luke Warmwater]

Originally Posted by psilo

On the 450 I check for CofG, adjust and then balance.

+1! Adding the weight at the CoG is crucial! On a see saw, a blade can be made to "balance" by adding different weight to different points of the blade. But this will still vibrate when it spins. It must be balanced with the CoG in the same place on each blade!

[Jonnyheli]

Lol at Sutty's story.

Im glad im not the only one that isn't too bothered.

My 500's tracking is so good that the blades make one pure spinning disk, there's no tracking issues what so ever and I have never bothered balancing them.

Last time I balanced a pair of blades was on my Belt cp. It's a hassel. You got to get the CofG right, then make sure they are the same weight. Then check again the the CofG hasn't gone off when adding more weight to a certain blade!

Like Gerd, if I see tracking issues when I fly the heli then I look into balancing the blades and checking the feathering shaft is straight and so on.

In Chansens case, I would have tried getting my money back on the blades and buying a better brand, like align or radix.

-Jonny

[redbird300]

Can't help it, I check and balance weigth and COG of ALL my blades if needed, cheap ones or expensive ones all the same, even tailblades ! Well, it never hurts I guess. Must be a maniac, lol. My only excuse is that my master was Erwin...

[knutenf]

Sorry to intrude, I`m just so exited to be able to hower my Belt CP, and feeling relatively in control, that I have to ask a question. Does anyone of you think that the Belt shaking extreamly at spin up could be due to that I haven`t balansed my 325 carbon align blades? They trac perfecly at speed. From previous experience I know that a lot of different things can cause inbalance, and Im `trying to track down as many as possible of them.

[Luke Warmwater]

Originally Posted by knutenf

Does anyone of you think that the Belt shaking extreamly at spin up could be due to that I haven`t balansed my 325 carbon align blades?

It certainly could be, although it could also be the Esky boogie that the Belt is known for!

I would check the balance. Even a vibration that seems to go away, doesn't really;- it just gets a lot less obvious at certain speeds. It is still there and more importantly, it is still wearing bearings!

[knutenf]

Right, thanks Luke, I`ll borrow a fine scale weight and see if it can fix the wooble.

[Ber60]

I balance every blade I can find on a heli, like redbird stated, just once, because I don't like any vibration.
You don't need a scale to do this, just follow Finless's 101.
As for spin-up shaking that is mostly due to the blades settling in there correct position or when they are to thight or too loose. I keep the mian blades relativly very thight but when I unfold them I take care that they are in the correct take-off position by pulling on the tips very hard, it never faild me

[redbird300]

Originally Posted by Ber60

I balance every blade I can find on a heli

Easy to say for you Erwin, that's not a lot of work if you only find one main blade and one tail blade, lol ...
https://www.helifreak.com/showthread.php?t=155621

[knutenf]

Originally Posted by Ber60

I balance every blade I can find on a heli, like redbird stated, just once, because I don't like any vibration.
You don't need a scale to do this, just follow Finless's 101.
As for spin-up shaking that is mostly due to the blades settling in there correct position or when they are to thight or too loose. I keep the mian blades relativly very thight but when I unfold them I take care that they are in the correct take-off position by pulling on the tips very hard, it never faild me

Thanks, your way will be my way from now on.