Balancing blades without a scale

[mjr_larkin]

Hey yall I can see the tail fin vibrating pretty wickedly. I never balanced the blades so I presume that's the problem. I bought the align see-saw balancer but it only does the job for larger blades. I haven't invested in a scale either so what's a good method to get these blades balanced? I know you can roll them on something like a spare main shaft to find the CG but that won't guarantee they are the same weight :/

[rotorhead58d]

r.lim posted how to do it by bolting them together at the grip holes, and had a very small device to balance them. ask him.

[mjr_larkin]

Thanks. the weird thing is that I just tested to see if the CG was at the same point on the blades and it is. So maybe the blades aren't messed up. Think i'll buy a scale to be sure.

[jimgrant]

Hey yall I can see the tail fin vibrating pretty wickedly.


Check the tail rotor shaft isnt bent, they are very soft and easily bent.. just spool up slowly and watch it to see if it wobbles.

[rotorhead58d]

Check the tail rotor shaft isnt bent, they are very soft and easily bent.. just spool up slowly and watch it to see if it wobbles.

as many crashes as i've had, never bent a mainshaft, or tail shaft

[stoatnchips]

rotorhead, do you remeber if R.Lim had an 'off the shelf' solution for the tail blades? i took his advise and got an XRB Blade balancer, which works great for the main blades. If anyone else is interested its Hirobo part# 0301-049

[rotorhead58d]

he told me the yellow blades on his 200 were cut down from a 450 ship.

[mjr_larkin]

Hey yall, I resolved the wikid tail vibrations by fixing a problem with the head. I first removed the head and left the main shaft and spun up. No vibration and the shaft looked real stright. I put the head back on and realized that one of the two small yoke rods was missing. Strange. I had a damaged yoke that I had laying around and pulled a rod off that one, put a little glue on the end and put it in the missing rod hold of the good yoke. I also adjusted a link by a half turn. Spun up and everything is so vibration free it's great. Will be even more great if it stops raining around here so I can give her a flight.

[crabfu]

Hey yall, I resolved the wikid tail vibrations by fixing a problem with the head. I first removed the head and left the main shaft and spun up. No vibration and the shaft looked real stright. I put the head back on and realized that one of the two small yoke rods was missing. Strange. I had a damaged yoke that I had laying around and pulled a rod off that one, put a little glue on the end and put it in the missing rod hold of the good yoke. I also adjusted a link by a half turn. Spun up and everything is so vibration free it's great. Will be even more great if it stops raining around here so I can give her a flight.

That happened to me too. I actually saw the rod on my desk while I was working on the heli with some other issue. I didn't think it was for the gaui, but for one of my million other projects and helis, so just pushed it aside and finished off my gaui.

Anyway, flew a pack with a missing rod, just ff to warm up, and it actually did fine with just one rod on the main rotor hub.... still haven't noticed the rod missing at this point. So on the second battery, I idled up, everything felt ok, went to do a flip, and lost all control half way through. As I went to negative pitch, washout must have slid down and slipped off the single rod. There was just no way to recover, throttle hold to minimize the damage, and down it goes. It wasn't until post crash inspection that I noticed the rod missing.... and realized DUH!!! that's what that little rod on the desk was....

It's now added in my every pre flight check... look at the rods guys, make sure you still have 2 before take off, especially if you are planning on going idle up :)

-Crabfu