Blade Balancing

[Helifino]

What is the proper method for balancing blades?

I have the stock plastic Align blades for the Trex 450 XL. I have purchased one of those blade balancing gizmos. The picture that illustrates using it shows the blades with the leading edges opposing each other(just as they would be if installed on the heli). This build dvd that I have on the Trex(worthless by the way,save your money), shows balancing the blades with the leading edges facing the same direction so that both blades form one long straight line.

1) Which way is correct?

2) If they are not balanced:
a) Do you use tracking tape?
b) Where do you place it, near the tip? Does it matter?
c) What if you only need a little piece of tape to balance, wouldn't using tracking tape to track the blades throw it off balance again?

3) If the blades are balanced:
a) Wouldn't using tracking tape throw them out of balance?

Sorry, I thought this was covered in a back issue of the mag, but I could not find it.

INQUIRING MINDS WANT TO KNOW! :confused:

[tdswan]

OK.....I'm assuming you have a see-saw type of balancer. According to the manual on my balancer, they're supposed to be on it as if they're installed.

FIRST: (on a T-Rex, this is probably kind of worthless) Check the CG (center of gravity) of the blade by placing a single blade across the balancer and finding the point at which the blade balances perfectly. Place a mark on the blade at that point and repeat for the other blade. Then compare the marks to make sure the CG of both blades is within 1/8". If not, you first have to add weight to the end of one of the blades to get the CG's lined up with each other. This is very important for larger blades. The T-Rex and small electrics will probably not notice the difference unless the difference is large.

SECOND: Once you get the CG correct, you move on to getting the blades in balance. You place them on the balancer and of course, add weight to the lighter blade AT THE POINT OF THE CG (centered on the CG) until they are balanced. Voila! You're done! I like to use the UN-weighted blade as my master blade and put that plade in the master grip on the heli (the one you set up the pitch curves on). I put some sort of mark on the master blade AND grip with a sharpie or something so I always know which blade goes where.

I use clear packing tape on my blades for weight. T-Rex blades will probably only need regular scotch tape, etc.
EDIT: if you want, I'd put the tracking tape on one of the blades first, and then balance them unless it throws the CG off a lot OR you can use the tracking tape to get the CG closer. Yes, tracking tape will possibly throw off the balance on smaller blades, so it's really up to you which order you put it on. I don't balance my T-Rex blades so I don't know how much it would throw it off. Big blades usually don't get thrown off too much by a small piece of tracking tape.

I know....I'm back-pedalling. :eek:

[CLM]

By the way, use the wood blades that are included with the Trex kit and let the kids use the plastic ones for play-sword fighting, use them on the heli you will need to buy booms :)

Chris

[Helifino]

Thanks Troy, I'll give it a try.
I'll also ditch the plastic and go for the woodies!

[Helifino]

Found article on blade balancing in issue #3.

[helidad]

TDSWAN what do you mean about having a master grip and blade. is that necessary or does it just make it easier to set up the pitch curves? also you like to have your heli set up mechanically as close to perfect as you can get. i have a caliber 30 and it has fixed length control rods. my mechanical set up is not even close to being dead on. any suggestions on what to do. any info on setting up my heli would be greatly appreciated. :confused:

[tdswan]

The master blade and grip is the one that you set the pitch curves up on. I usually mark it with a sharpie or scribe it or something, then I also put the blade that I DIDN'T put any weight on onto the master grip just in case my mark gets rubbed off. Then for adjustments on blade tracking, you'll adjust the linkages on the other grip. That way you don't mess up your pitch curves.
I'm not familiar with the head setup on a Caliber 30. It does seem strange that the control rods are fixed length. There must be somewhere to adjust it to level the swash and track the blades.