eliminating slop - is there any reason I can't use shims?

[Mrowka]

As I build and rebuild my 130X collection, I notice that some of my helis have some slop in the tail assembly somewhere.

I've been eliminating that slop using thin metal washers. Is there any reason I cannot do this?

If at all possible, I guess I'd like to find out before my negligence causes a catastrophic crash that destroys an electrical power substation, burns down the local orphanage, and decapitates the neighbor's dog in front of a bunch of horrified children.

[Heliwhisperer]

Where are you placing washers to eliminate slop ?

[Chris1683]

I have managed to get my 130x tails pretty solid and slop / vibration free by a few simple fixes:

1: make sure that the tail blades are balanced (I use the clear tape)
2: Check for any left to right play on the tail case bearings. Often they will slightly wear out the tail case and that leads to excessive play. A good fix I found is to ever so slightly coat the outside of the tail case bearings with CA glue and reinstall them. This will hold them in place and keep them from vibrating.
3: You can use #1 o-rings to clean up some of the slop on the tail grip ball links. They don’t have any from the factory but I haven’t seen any I’ll effect from using them.

If you still have any tail issues check your tail servo for any excessive play (if using the stock servo). Sometimes the brass nut can use a turn on it to retighten it.

After doing those tips to my 130X’s I can spool them up slow and there are no vibrations whatsoever and it’s smooth as butter!

[Mrowka]

Originally Posted by Heliwhisperer

Where are you placing washers to eliminate slop ?

Usually between the torque tube and the C gear or between the tailshaft and the D gear.

I should add that the tail rotors are all balanced and vibration free.

[Heliwhisperer]

I have never used shims to eliminate slop in the gear train.
Usually moving the tailboom in or out of the frame will get rid of excessive gear lash.


Play in the tailshaft left and right is due to the ''D'' gear hole wearing out,
or play in the shaft bearings


The only shim I have ever seen is in the Microheli tail case. They do not use a flanged bearing where the torque shaft inserts into the ''C'' gear


Placing a flanged bearing in this location eliminates the need for that spacer shim.


https://www.microheli.com/image/data...H-130X025S.pdf


HW.

[Mrowka]

The play in the tailshaft isn't left-right but in-out.

[Chris1683]

Originally Posted by Mrowka

The play in the tailshaft isn't left-right but in-out.

Do you mean in/out like the shaft is going further into the bearing slots?

Example would be if you are behind the heli and you grasp the tail shaft and pull it left and right, is there excessive play? Usually you can see the tail shaft collar moving back and forth if there is too much play. If that’s the issue you can try to Re-tighten the collar. If the actual flanged bearings are moving in and out of the tail case than that means the tail case is slightly worn around the edges wheee the bearings seat. That is usually the point at which I would either replace the tail case or use a minuscule dab of CA around the outside of the bearing and push it back into place.

[Liduno]

Am I confusing the 130 with the 180? I thought adding shims was the proper way to set the gear mesh between the B and C gears?

I haven't either heli in a while, so I apologize if my memory fails me yet again..lol

[Mrowka]

If I correctly understand your description, yes.

Little to no left-right play, but when I retighten the collar (using loctite and letting dry), it quickly gets loose again. If I use shims, it stays in place. Go figure.

I think this is because the flanged bearings are, as you intimated, loose. I will play with this and see what happens.

Originally Posted by Chris1683

Do you mean in/out like the shaft is going further into the bearing slots?

Example would be if you are behind the heli and you grasp the tail shaft and pull it left and right, is there excessive play? Usually you can see the tail shaft collar moving back and forth if there is too much play. If that’s the issue you can try to Re-tighten the collar. If the actual flanged bearings are moving in and out of the tail case than that means the tail case is slightly worn around the edges wheee the bearings seat. That is usually the point at which I would either replace the tail case or use a minuscule dab of CA around the outside of the bearing and push it back into place.

[Mrowka]

For those keeping score at home, I managed to zapa tail vibration issue in one of my other 130Xs.

I first tried balancing the tail blades. This didn't really make sense since the blades were balanced before and nothing obvious had changed to make them out of balance, but I try to be a good sport so I did that first.

Not only did this not help - whichever blade I added tape to - it only made things worse. Not much bearing play in this tailcase, either. Turned out that the problem was a worn D gear - what made the source of the vibration hard to find was that the gear was only slightly worn - not so much that the tailshaft would readily slide out of place or that the tail rotor was obviously slipping.

New D gear (and the removal of the tape I had been using in a futile effort to balance the blades) and the problem went bye bye!

My microscale contribution to the 130X knowledge bank.