Tail bearings loose on CF plates

[crabfu]

ok here is some observation about the tail and bearings that I'd like to share.

I noticed some of you guys mentioning the tail bearing loose on the cf plates from the poll post. I've had gone through 2 sets of tails due to this ( too bad gaui doesn't just sell the tail cf plates). I ended up getting microheli tail, which was great until crashes took it out piece by piece until it's done for... too much money to replace imho. Although the stock tail is very sloppy and loose, it does fine for my skill level.

So for you guys with cf bearing tail problems - northcarolinadan & jimgrant at least... did you use lube on the belt? The reason that this happens, I think is due to too much lube. Each time that I replace the cf to fix the problem, I find black lube around the bearing and cf hole... what I think is happening is that with too much lube on the tail belt, some gets into the hole between the cf and the bearing, and this probably loosens it and quickly wobble its way into a bigger hole, grinding the cf plates and making black lube around the bearing. For those of you that haven't experienced this, the hole gets too big for the bearing, and the tail shaft then gets loose, belts need to be tighter, and setting off all sorts of issues, like crazy vibration that throws off the gyro big time etc.... nasty little bug that took me quite some time to figure out :)

Anyway, it took me 2 sets of these cf tails to figure this out.... at least I'm pretty sure lube is to blame, wanted to know if that is the case for you guys as well. I've now have had many many flights on the new cf tail with very little lube, and it's been great with no issues.

-Crabfu

[northcarolinadan]

I do not use lube on my belts, the Gaui had PLENTY of lube on the belt when i got it. but, yes i did get the black around the bearing, i tore it down cleaned it then ca'd the bearing back in. i might need to try some epoxy next time. I just wish they had aluminum plates for the side, it would be much better. i also get side to side play in the tail box also.... what i need to do is tear it down again put a new shaft with pulley and epoxy the bearing in and see how long that works. or get off my ass and make the aluminum parts myself.

i have not had any crashes (except for once when the tail blew out, too high of gain ! ) and it gently hit a tree ( i was on the throttle hold !) but this was after i went through the tail once..

i am kinda bummed to hear about you experience with the micro heli tail, because i was just about to pull the trigger on that. guess i will think twice about it.

[crabfu]

Ah... mine cf plate hole got so big that there was no way to glue it back in... I thought lube was the problem, but hearing from you, I guess the bearing just like to get loose and grind it's way out of there regardless of lube.

MH tail is great, don't get me wrong... it's just a bit on the expensive side, and didn't last long in my hands. But that has nothing to do with the MH tail itself, just my bad flying :) I just can't justify the money for another one at my level....for the cost of one MH tail, I can get tons of stock tail parts for my twitchy crashy fingers. And the slop & fragile nature of the stock tail is very disturbing, but actually holds fine for what I do with it - which isn't much :) You can't get replacement parts for the MH tail, which really bites... but as far as performance to quality, it's great, just wish the price and parts were more affordable.

-Crabfu

[northcarolinadan]

maybe a better set of tail bearings might be the answer, i dunno. I wish I still had a mill at my dispense, i could make some aluminum sides in a snap. i can still make them but not as easy, just have to make sure the bearing holes are just right for it to work well, heck i even tried the sides from a hdx300 its close, and can be made to work, a bit longer, but the bellcrank for the pitch slider is off, so not worth it. better to make aluminum sides, besides, the design is screaming for it, the cf sides are all flat, uses flanged bearings, makes it pretty easy to duplicate unlike others. I do have a hunk of 1mm aluminum sheet, I need to check my drill bits to see if I can get a decent hole for the bearings. now to find the time...


Edit.. this might work out well, the bearing od is 5 mm, i have a step drill (good for drilling sheet metal) drill it for 3/16 (4.76mm) then ream until tight fit, just have to do 2 at once, then the holes will line up correctly..

[jimgrant]

Hi guys , for your information, the epoxy I used is 3M, the stuff the car bodyshops use to repair plastic car bumpers. its flexible, and I just put a line round the inside of the hole, and carefully refitted the bearing. rock solid now and no slop. just need to see how long it lasts. I reckon it was vibration that caused the problem

[jimgrant]

I should have mentioned, I cleaned the plates with meths first to make sure there was no trace of silicone on them

[xrbcoronalogoflyer]

i guess it would be a good preventive measure to check and make sure that the bearings are ca'd into the cf tailcase (per this pic)...

[sbmon]

I have the exact same issue. The cf gets eaten away from the outer race of the bearing. Metal as opposed to cf should have been used for the sides of the tail case for sure. I too had no lube on the belt, the tail is spinning some serious rpms so its only a matter of time before the bearing erodes the cf (even if you do ca it in place it too will eventually be worn off). If someone makes some decent metal sides (hint hint) I know I would buy them. I too was considering the micro heli tail but with lack of replacement parts and the price I would rather just get 2 guai tail units.

[jimgrant]

I have just received today a new spare tail casing complete 203670, and the bearing fit in the cf plates is atrocious from an engineering point of view. I will have to line the holes in the plates with epoxy before I can even think of using this part. Looks like an alloy/dural plate mod would be the way to go on this one.

[Buzzkill]

I bought two MH alum. tails for mine. I have crashed multiple times with them and haven't broke a single thing on the tail. Guess I'm just lucky. The MH tail is definately tougher than the stock tail. The way I see it is how many tails will you have to replace before it adds up to more than a MH $60 tail?

[rotorhead58d]

I bought two MH alum. tails for mine. I have crashed multiple times with them and haven't broke a single thing on the tail. Guess I'm just lucky. The MH tail is definately tougher than the stock tail. The way I see it is how many tails will you have to replace before it adds up to more than a MH $60 tail?

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