tail grip shims

Are there 12mmx7.5-8mmx.5 available for the tail grips yet?

The talk is that this is the fix for the tail wag that is present in quite a few models.

Very curious here too,...we have build 4 kits and 2 out of 4 have the wag. Assembling, disassembling polish, the shaft helps sometimes but some kits clearly don't have the wag out of the box....are the tailgrip shim alignment a possible cause or not ?

Hi,

not that I know. A few pilots have reported that replacing the thrust bearings did help, but I'm still waiting for such bearings to be returned to us so I can check what could be the issue. Right now we assume that maybe the cage holding the bearings is bent too much so it binds against the rings, under load.
But unfortunately not yet verified or ruled out :/

Kind regards

Eddi

Born to fly ...
forced to work.

Hmm not exactly whats going aroind. Whats going around is replacing the shim with one that stays in place. Specifically a 12x8x.5 between the radial and the thrust.

Hi,

well, the shim-thing is also known, but honestly if you align it properly when you mount the tail, even the smaller one stays put. It sticks properly on the bearing, with the greasy you put on the bearing anyway, so it's not too difficult to get it in.
Even if you fly like Marik Wiehenstroth for example it holds ;-) and for hundreds of flights.

But the thrust bearing thing has come up only recently, and only a couple of times as of yet. We still do not know exactly if there were bad bearings (cages actually) in a batch or not, or if the bearings (cages) have been crushed somewhere on the way from the supplier to the assembly.
You can feel it even if you hold the cage with the balls between thumb and index finger and rotate, if all balls rotate freely it should be OK, if one or more feel sticky, there could be an issue.

Kind regards

Eddi

Born to fly ...
forced to work.

Hi,

The discussion is (if I am right) about the shim in between the thrust bearing and the grip radial bearing. Is it possible that if it is not properly centered in the grip ( which has bigger OD ) it can obstruct free movement of the radial bearing under load ?

Greetz, Kurt

Hi,

only if it were to sit on the inner ring of the radial bearing. But once it's mounted properly, it won't move on it's own (by long term experience ...).

Kind regards

Eddi

Born to fly ...
forced to work.

I don't think anyone is debating the ability of the tail to hold, in fact it seems to hold fantastic. I think the issue is people don't want to see their Mikado Logo 700 wagging its tail in a hover or slower maneuvers. There are reports of it being resolved with what appears to be a more appropriately sized shim (12x7.5-8x.5). It would be nice to be able to order this direct from Mikado instead of Ebay/Thunder Tiger.

I will check my kit that's still in the box for the other issue you mentioned, my first kit did not have it. Thanks for the heads up.



Edited 1 time(s). Last edit at 03/03/2017 02:56PM by mc20piece.

Hi,

I mean, if you put it together properly, you shouldn't have the wag in the first place.
If you just throw all the shims and bearing parts into the blade grip, add grease, stir, then put the screw through it, well

I'm exaggerating ... a little

And if you have the wag, it can be this part but it can also be something else, that's what I want to say.

But in earnest, I will advocate this, no worries

Cheers

Eddi

Born to fly ...
forced to work.

Thanks for the follow up Eddi !

hi i don't think its a case of "putting it together properly" ,.... the stock shim can walk around inside the grip and if it does it will bridge between the inner and outer race of the hub grip bearings....
I hope that makes sense. ?

the cure as i discussed with Ralph is a 12mm shim which cannot move...
Its a great heli,.. I know I have two :-)
But there are always teething problems with a new design....
this is one with an easy fix ...
I do feel the correct shims should be availible to kit purchacers, hopefully this will be the case :-)

ps ,... Mine fly sooooooooooooooooo well,... I left a sponsored ride to fly Mikado at my own cost , it is not a decision I regret :-)



Edited 1 time(s). Last edit at 03/03/2017 04:52PM by rachel p.

My question is what was the thinking on changing the ID of the grip bore from 10 to 12 mm right at the edge of the radial bearing. Even going to a 12mm OD spacer, this forces it to sit on the step face and all of the centrifugal force restraint forces are placed here on the step, rather than on the face where the radial bearing sits which is designed with the intent to hold the grips in place. Was the intent originally to use a 12mm OD thrust bearing and have it sit on the step face like is being done on the main grips?

It seems to me that this design is putting the load point on the grip not at the face that holds the radial bearing, but rather on that step that holds the thrust bearing. Has the plastic grip been properly stress tested to insure it is strong enough for the loads that appear to now be placed on it?

Eddi alluded to fixing the spacer with grease to prevent its migration. Would not cleaning the inner face of the thrust bearing race and the shim and putting just a very small drop of CA to fix it to the face of the inner race of the TB not also work. If there are enough side loads on the grips to break that loose, then there will be more than enough side loads on grip that will move the spacer around if it is just applied with grease holding it into place.



Edited 2 time(s). Last edit at 05/31/2017 09:13PM by rcflyerheli.

Well, I finally came to a decision and did place the shim/spacer on the inner race of the thrust washer and applied just a tiny drop of CA to hold it in place, then assembled the grips. Happy to say that so far, everything is smooth and free. After the loctite cures on the grip screws, I will give it a runup tomorrow to check for vibrations, and then get the maiden and a couple flights if nothing bad happens on the maiden.

Hello, i´m assembly a new kit that i bought this week directly to mikado. I need to know if this problem with shims size is already solved or were i can get the shim´s with the size that fits without give me any problems!
Thanks for all the help

Please - one heli, one pilot, one thread - would be best for supporting customers.

Back to topic:

My heli colleques are at Venlo - so the answer may last a bit.

regards (EN) / Gruss (DE)

Rainer Vetter

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Hi,

we are using these shims since 2011 on the Logo 800.
If you make sure that the shims are in right position during assembly you will never get trouble with them, they can not move during flight.
On the next batch there will be the new shims included.

I'm starting assembly mine, can I have the new shims for it?

Hello,

the new shims aren´t available yet.

were these ever changed?

I’ll take that as a no

I told you that the 12mm washers are already changing
and in return servo
and check the thrust bearings
The tail control is smooth
the vbar does not show me any vibration

there is something else that I can do that drives me crazy

thank you

ok from the top, here is how i build mine......
Before I even build the tail box I dismantle the brass bush out of the tail slider, apply brasso ( a brass polish) and work this up and down the tail shaft until its perfectly free ..... I clean both the bush and the shaft with brake cleaner and oil both with a light oil, triflow is good,.....
then I am super careful with the build of the tail , especially the thrust bearings,... I usually build them cup side inward and make sure the thrust bearing is assembled the right way round , with the larger id to the inside.... and greased with a good quality grease.....
I use a rubber safe (silicone ) grease on the damper o rings.....
I also change the shims out to a 12mm o/d but I have just built the latest kit 2019 spec and am going to try the OeM shims first....
I also squeeze the pitch links gently with a pair of pliers when they are attached to the tail grip... I also do the same on the tail pushrod ball links
this should be good to go.....
oh just a question..... the front torque tube bevel gear is all the way home ????? its quite a push to fit it !
I hope this helps you and this only applies if you have a slow tail wag thats very noticeable in the hover !