Tail Output Shaft Replacement...

[copterboy]

I have replaced the tail output shaft with a new stock one but, the belt pulley seems really tight in the cnc gear box.
Has anyone done the same work and found same problem?
If so how did you fix it? I'm thinking about slicing a bit off the pulley with a sharp knife to stop any binding with the bearing, do you think this would be ok or should I be thinking about replacing the output shaft bearings too?

[copterboy]

I've still not got round to doing this but I remembered the full manual shows the tail output shaft being installed in a cnc gear box. With a closer look at the pics (no. 31 and 33 on inside back cover) it appears that the collars of the pulley have been cut off! So I'm gonna get on with it this weekend.

Also, I noticed in another thread that the V1 alu. trex output shaft will be a straight swap for the CNC gear box. I'll report back with what I find for future reference. Am I on my own on this one??

Here's a pic for comparison...borrowed it from MNWiz on previously mentioned thread (hope you don't mind!).

http://i38.tinypic.com/wr1h09.jpg

[mnwizard]

I just looked in my "hanger".

The CNC tail for the Belt comes with the plastic shaft.

The CNC tail for the Trex comes with the metal shaft.

However, the Trex CNC tails are often sold as Belt tails or Belt compatible.

In short, if you have the actual Belt or ESky branded CNC tail, it uses the plastic shaft.

Esky recently started shipping the 2.4Mhz Belts and they digital servos in them with white nylon arms. I've heard that they are changing the CNC parts too, but I haven't seen the newest ones yet.

[Heli Yea!]

MN my belt came w/those digital servos it wasn't 2.4g just the 72mhz plastic RTF. They stopped production on the analog ones a coupple/few months back. They are only going to sell those now but they are still 8grams of crap!

[copterboy]

Hopefully e-sky are listening to their customers feedback! I have ditched all my stock servo's for the TP SG90's -i had digi one's but they're still a pile of :BSSand now I've replaced the stock Tx/Rx for DX6i Tx and 6200 Rx.

The heli's responsiveness has improved with the servo mod, and interference has now stopped but this binding problem has been around for ages and as a result, I'm not actually doing much forward flight with the belt because of all the twitchin and glitchin I'm getting from the binding problem.

My theory on this one was that the distance between the bearings in the CNC tail gear box is smaller than plastic gear box. The bearings seem to protrude inside the cnc gear box more and to compensate - you need to cut down the collar on plastic pulley/shaft.
Has anyone compared the pic above to the manual? The pulley collar looks much smaller! I just wanted to know if anyone found this to be true before I start cutting things to pieces!

[Heli Yea!]

OK Copterboy, I just checked the manual but better yet I checked my tailbox and spares. the shaft that is in there has the collars. also this is the same shaft that comes with the plastic box(its the only I have/ever had). I have a spare tail cnc tail box it doesn't come w/the shaft when I installed my cnc tail box I took the shaft out of the plastic tail box and put it in the cnc box NO MOD NEEDED. Check your belt for a twist( It needs 1/2 twist only. Yours could be twisted 1 and a 1/2 times witch would give you proper rotation but would also bind.), tention also be sure that the bearings are running smooth. hope that helps.:thumbup:

[copterboy]

Well I've had the tail in bits today and checked over everything you guys suggested. I've done a 6hr heli-build marathon today, but it was pefect weather for staying indoors and working on it! :bawl &:badair: (Raining & Windy!!).

I took out the new tail shaft I put in last week and got my calipers on it from collar to collar - 9mm. I put my tail box together w/out shaft and measured the distance inbetween bearings - 8.6mm!!! So I found the plastic pulley is to big for the CNC tail box by 0.4mm...thanks e-sky!!!! So if you just shave about 0.2mm to 0.25mm off each side of the collar to stop it binding, you will be fine.

My trex alley tail pulley is 7.6mm so I'm gonna order one for my belt next week and get some 0.5mm shims to make up the difference - can't wait!!!

I also checked the belt and bearings as suggested. The belt was ok (1/2 turn), but the bearings do not run smooth. I think the flights/hovers I have attempted since I installed it have now damaged the bearings.....more ruddy work!!!!!:arggg:

Soooo, please can you guys offer any advice on how to remove/replace bearings on the CNC tail box - they seem to be stuck fast with something? Many thanks once again:noteworthy

[Heli Yea!]

I haven't had to change the bearings yet.:dontknow My guess is you'll have to use heat.

[copterboy]

Hehe...time to get the plumber's torch out again then!!! :flamedevil
And I'll add some bearings to my parts order next week....roll on payday! Think I'll give my net-supplier a call to see if they can offer any tips - will be wary of any advice other than from you guys! Went to my LHS and asked for some threadlock this week - they didn't have any, but did show me a good selection of replacement screws. :lol:

on the ball HY:smokin:. Thanks again!

[mnwizard]

The bearings in the tail housing are a press fit and come out quite easily.

I place a half of the tail housing on my bench with the bearing side down, and push on the bearing with a 4mm hex end and it pops right out.

You can press the new ones in place with your fingers.

[copterboy]

Thanks for the tip Jack, maybe mine has just gone real tight cause of the binding issue then?

I'll try your method 1st (probably soak it in some WD40 first). If that don't work then will apply some heat on it too.

The bearings for the tail gear box are 03x06x2.5mm - so I just checked my usual supplier and they are out of stock. :thumbdown: I've gotta ring em about something else 2m, so will tell em I need some (and give them a chance stock up before I place order on Thursday).

Thanks again you two!

[mnwizard]

You can also pop it in a vise and use a 4mm socket to press it out.

[copterboy]

Thanks again Jack, I always look forward to reading a new post from you. That's what I love about this site!
I was stuck yesterday, but now I have 3 different ways to try it! :thumbup:

[copterboy]

My final word on this...here is the evidence. Only 0.25mm thick but my heli is better off without em!

http://www.helifreak.com/picture.php?pictureid=7531&albumid=1061&dl=1218411360&thumb=1 (http://www.helifreak.com/album.php?albumid=1061&pictureid=7531)

[mnwizard]

My final word on this...here is the evidence. Only 0.25mm thick but my heli is better off without em!

http://www.helifreak.com/picture.php?pictureid=7531&albumid=1061&dl=1218411360&thumb=1 (http://www.helifreak.com/album.php?albumid=1061&pictureid=7531)


:rolling

[copterboy]

MNWiz - I managed to get them out after a bit of a fight, they were just in very tight. I didn't realise how much pressure was needed to pop em out.

This problem has just taken a new twist today. Has anyone had to replace the bearings that hold the tail output shaft in the e-sky cnc tail?

My usual supplier does not stock them and said they may be a special part that is not sold separately (so I might have to buy a whole new tail box if I can't get these 2 bearings!). Supplier also said they will contact e-sky to see if they can supply some and, if they can, will take about 2 weeks to arrive. They are unusual because one side of the bearing has a collar to stop it from sliding out of the tail box (it's not the same as plastic tail bearing).

Any suggestion's would be welcome!!!

[mnwizard]

Soon as I can get to my bench I'll take a look at mine.

I'm surprised you had trouble getting the bearings out of the stock tail, mine popped right out. I'll have to try it on another stock tail. I'll take pics this time.

[Heli Yea!]

MN, he's talking about the esky cnc tail.:DOH

[mnwizard]

:DOH

[Heli Yea!]

Well CB my best tip at this point is.......:dontknow sorry.

[copterboy]

No worries guy's, I'll just have to wait and see on this one, will let you know what I find out from e-sky anyway.

I went searching through my sprares box last night and found the plastic align main blade grips each have 2 bearings of the same size but without the collar, so I have used these for now and threadlocked them in. I've just having a brew before I go outside and test it!!! Will post the results in later for you...my new carbon frames just arrived for my DTS mod, and I'm off 10 pin bowling today so have got enough to keep me busy & flying! :banana

[Heli Yea!]

Glad to hear CB, can't wait to see your next post!:thumbup:

[copterboy]

The bearing's work!!! :clappp

It's much better, but I still get the odd twitch from the heli (another mystery to solve). I am certain this is coming from binding in the main gear though, so will focus on that next. I could elongate holes for one of the cnc main gear Mounting Block's, but I'm gonna upgrade to the microheli main & lower gear first, as recommended by HYeah! Will see if that cure's it without re-drilling the MB holes in the lower frame.

Let's see what e-sky say about the stock bearing's, and I can crack on with the DTS mod now!!! :thumbup:

[mnwizard]

I spent some time last night trying to find the bearings you need, but it seems that they aren't sold seperately anywhere that I can find.

I just came accross this company -

http://www.smbbearings.com/Framesets/Extinner_frame.htm

I emailed them and they said that they were sure they could match them if they had a sample.

[Heli Yea!]

Hey CB I just thought of this but are the mounting blocks flush w/ the frame edges if not flip them over. There is a up and down side to them but as you well know not specified. Also I have a spare upper left frame that the servo mount broke off of. I might fart :badair: around with it to do the DTS. As usual keep us posted and I'll do the same!:thumbup: