bureaucb

Hello All,

I'm trying to find out instructions on replacing the tail gears. I've managed to break down the assembly as far as the gears exposed but I can seem to figure out how to remove the gears from the shafts that are still connected to the tail that I don' t know how to remove too. Maybe someone would be so kind as to explain (step by step) how to change the tail gears? I know I would be very grateful and I'm sure others would benifit too..

Thanks in advance,

earlwb

I was hoping someone who had replaced the gears before would speak up. Surprising that none of them replied.
I haven't had to replace the gears on mine yet. I bought the gears as spares, but I haven't damaged them yet.  The gears look to be a light press fit onto the shafts. So you will need to pull/push them off and pull/push them back on.

bureaucb

I went ahead and finally figured out how so I am going to write some instructions so that it might help some else in the future.  Should be done soon.  Thanks for your reply.

earlwb

Please do write up something about how to do it. You aren't the first, nor are you going to be the last one with the problem.
I am glad you solved the problem.

martin_

You can put a shim behind these little tail gear, i made it from a verythin lexan with a leather punch, it help maintaining a tight mesh and the gear last longer.

I stripped mine trying to lauch in grass 5 min out of the box, but since the shim, i'm still on the second set without stripping it.

bureaucb

Hi Martin,

Thanks for the tip!  It seemed like these gears will strip if  you look at them wrong!

The three things that I think are poorly designed are the gears, battery box (real thin plastic and cracks easily) and the landing gear (atleast for my landings

I found that the cnc metal landing gear fits nicely http://www.cnchelicopter.com/servlet...DX450SE/Detail
so no more busted skids.

Now if I could just find a better battery box...

The way I fly I might be better off putting the blades on a tank.  I know, keep practicing on simm.

erdnuckel2

why are you looking for a battery BOX?? A piece of CF on the skids, velcro on the battery and all is good (should work with ANYheli ... even though Imainly know it from LamaV4 size (340mm)

bureaucb

Hi Erdnuckel2

Please excuse my ignorance but what is CF?  I keep cracking the battery box which is the bottom part of the CB180Z somewhere in the frame.  I still have a very bad habit of killing the throtle when I get in trouble (too close to building or tree).  A lot of times it is because the wind has it and I can't bring it back.  I'm thinking about getting the upgraded version or maybe a CCPM with the 3 axis gyro.

erdnuckel2

No worries,

CF is Carbon Fiber ... just attach a little plate to the underside of the body/onto the skids and put some industrial strength velcro on it. The opposite velcro part on the battery and it holds (in case of doubt secure with a rubber band or similar ... with the small helis (340mm rotor diameter) this works perfect, I dont see why it wouldn't work with bigger ones (even if they are from Walkera ...)

FDflier

Maybe I posted in the wrong thread. I'm new. I posted about my experience with the gear issue in the other 180Z thread.

Jeff

earlwb

I remember some guys were stripping out the gears fast. So when I got mine, it looked like the plastic wasn't a self lubricating type of plastic. so I gave them a little tiny dab of some silicone grease. It seemed to work as I didn't get any gears to fail. I did buy a spare gear set, just in case though.
But it is worth it to check the gears to ensure they are meshing good. I can see where the gear mesh could be too loose or too tight.

bureaucb

Yah, I just stripped the main gear (Arrghh) and have to wait a week to get new so I ordered a bunch of all gears.  I'll have to try that grease and see if it helps.  Is the gap on the main gear set the same as a belt CP?  I use a folded piece of paper to set the gap on the belt.

earlwb

I can see using the piece of paper method. But you might want to use a thinner piece. Those gears are getting pretty small.
I have replaced the motor several times on my Heli-Max heli's as they are brushed motors and not brushless. I haven't needed to use the paper method on them yet. Maybe I got lucky and have a feel for it with the small motors and gears, I don't know.

FDflier

I ended up cutting a 2-3mm collar or bushing from a stripped gear, installing it on the forward end of the tail shaft, and then the gear itself. I have flown several times since including some wrecks without the gear shifting on the shaft. I also lubricated the gears. It may be too early still but it seems to be the cure.

Jeff

bureaucb

Hi FDFlier,

That sounds like a plan too.  My gears got held up in customs for a week (Arrggghhh) so it looks like I'll be wait a little while longer to put all these great ideas into action.  Still working on that instruction bit on how to replace the gears.  Found an exploded view of the parts on Walkera's web site so I'm going to try and take pieces of it to show what I'm talking about.  I'll post it here and it can be a work in progress where everyone can comment and make changes, laugh loudly or whatever.  At least there will be some place where people like myself can get an idea of how to change the gears without too much trouble.

FDflier

My gear fix seems to work fine, however I got a bit cocky and crashed in the house. Unfortunately I didn't get off the throttle fast enough and stripped the main gear. Parts are on the way.

As far as instuctions go, It's pretty straight forward. You will need to remove the tail boom from the main chassis and then remove the seven screws to split the mounting block for the boom. The gear that strips has for me always been the forward gear on the boom itself. The gears just slide onto the carbon shaft with friction (there is a flat on the shaft too). By simply filling in the space behind the gear with an old gears' collar (cut to length needed) you'll keep the gear from being able to back further onto the shaft. I believe the 90 degree angle cases them to want to slide backwards.

Good LuckJeff

martin_

That gear problem is very annoying, when you mesh correctly the tail gear assembly, you now start to snap the tail drive shaft.

As for the spur gear, you need to put the motor pinionmesh as tight as possible, in fact right at the spot tono backlash, you will still stripsome spur gear in bad crash, but not in light crash or hard landing in grass.

I use E-sky big lama trimmedBlade, they are softer and lighter and muchmore resistant.

bureaucb

Funny you should say that, I just got the new gears in.  Taken all the suggestions and guess what!  Snapped tail shaft!!!  I give up, no.. no I won't.  I'm too stupid to give up.  Guess I'll just have to wait for a new tail shaft.  Oh well, atleast I will have some more instructions on repairing this thing.  I sure wish CNC would come out with some newer upgrades for it. 

Double-R

Hi, all. New here. Just had  the same experience day-before-yesterday as "bureaucb". Snapped the tail drive. I have a ton of spare parts, but, of course, no tail drive shaft. Got 'em on the way.

bureaucb

Anybody know how to get the bearing off the tail shaft without breaking the shaft or the bearing?  Mine seems stuck.  I wanted to keep the shaft intack because I have some carbon fibre rods that can be shaved down to fit.  I know the dust is dangerous but if I do it under water it should be ok.

Double-R

I'll let you know, if I get to it first. Tail's drive shaft just shipped 10/15.

bureaucb

Believe it or not, I just made a tail shaft using a piece of carbon rod from a heavy duty training kit.  The rod is the same size around so I cut it to length and shaved off the ends to match the broken ends leaving enought on so I would not have to shim it out.  I would not recommend this method since working with carbon fibre can be hazardous.  Just wanted to see if I could do it.

FDflier

I have stripped no gears or broken the tail shaft since making the mods I suggested. I greased the gears when rebuilding. I have crashed several times since then, once destroying the canopy, ripping the landing gear off and bending the flybar pretty badly, but have not ruined the tail gears. I think the grease lets them ratchet without stripping a tooth.

Jeff

bureaucb

Hi Jeff,

What type of grease did you use?  I tried silicone spray but I guess that just wears off to quickly.

Thanks

Double-R

I used some DANCO Silicone faucet grease - available at HomeDepot. I've not stripped any gears since then. I think my tail drive shaft was likely on its way out by then.
Rob