Gear mesh prob.Tight motor.

[freefall]

I have the standard frame version with Z20 980 motor with gaui 14t pinion.
I used to race buggies and have a good idea of backlash needed and have also watched the finless vids on the 550 build.
The problem i get is when i set the backlash to what i think is correct the motor turns by hand very stiffly.And to get the motor turning freely again the backlash is very loose.
Here is a run down of what i have noticed.
Take off gears in frame run smooth.
Screw motor to motor mount and motor turns freely.
Screw motor and mount into frame with motor backed off and motor turns freely.
The more mesh i put onto the motor the stiffer it becomes.When i get the mesh to the point where there is slight backlash the motor is very tight and i can not turn the take off gear(in frame)with fingers.
I am going to try and post a picture of the pinion and gear mesh so you guys can give a opinion if it looks right,i think it is way to loose.BUT this is the point that it starts to bind the motor.
I might not have a problem but i thought the motor should feel the same with correct or loose backlash.

[Graeme67]

That mesh looks too loose to me. I set mine so that I can just feel freeplay between the motor pinion & gear.

[freefall]

I agree also. But any tighter and the motor will not turn freely by hand.
If you were to back YOUR motor up and then set the backlash correct does your motor feel different?
I am sure my motor ends up too tight.
I can not work it out.Why does the motor become very tight EVEN when there is still some backlash/movement.The pinion is NOT jammed up up against the gear.
Really need some help here.

[istandalone]

i had a similar issue installing my z20a as well. imho your mesh is too loose in those pics. this motor has some pretty strong magnets in it, and i believe what your feeling is the combo of the strong magnets along with the rest of the drive system of the heli making it seem too tight. check this thread that i started about a similar issue.
http://www.helifreak.com/showthread.php?t=65784

[Madedon]

As already stated in the other thread, in order to get your gear mesh loose enough is to put between your motor pinion and first gear a 2mm peace of paper and then push the motor as close as can to the main gear and then tight your motor to that position. Remove the paper and you are good to go...... This tip work very well with my h550

[istandalone]

i always eyeball it, and do the "jiggle" test. not one failure to date, through my whole rc career doing it this way. but yes if you want to be totally safe, use a thick piece of paper.

[freefall]

I think there is a problem somewhere.With no mesh the motor is smooth to turn.
And the gear train in the frame is also very smooth.
BUT, get the mesh anywhere near correct position and the motor gets tight AND feels unsmooth.
I have metal levers and also had to file ball screws down.
The paper being used for gearmesh is good normally like on my trex but on this heli its no good.
You have to mount the motor to the mount firmly AND also you have to screw the mount in the frame because this effects the mesh also.When the mount/motor is in place you can not get at the motor screws.
I really think that the strong magnets and geartrain are NOT the problem.
It feels like once every thing is screwed down something is out of line
All i know is that if i put slightly more mesh on the gears(look at above post)things get tight enough to cause probs with current draw i am sure.
Just to recap.motor turns freely/smoothly not mounted on mount.Turns freely bolted to mount.Turns freely
mounted in frame.very little gearmesh turns freely.Then when the gearmesh is set correct it becomes very tight even to turn the can by hand.No way can i turn gear with fingers.The geartrain is smooth without motor.

[mjdee14]

If you have another pinion gear try that, just in case the one you have was not made right.

Also with the pinion off...does it mesh perfectly with the main gear just holding it up to it?

Look at the way the tail drive meshes with the secondary gear....and compare

Of all the pains on this heli...setting gear lash is the most aggrevating. it's not just as easy aas slipping a piece of paper between the gears....

The lash changes when you bolt all 4 bolts in...and it's hard to keep the motor in the right place after you have spaced it....

maybe some have had better luck than me,ut it takes me about 8 tries to get it where I like it..

[istandalone]

you can also look up from underneath and just barely be able to see the mesh. i really don't have problems setting it.

[freefall]

Thats how i took the pictures of the mesh i have at present.
I agree this is way off but any tighter and the motor really gets tight.Tight enough i think to cause draw probs.
I have looked at the pinion and it looks ok.Have no idea what the prob is!!!!!

[mjdee14]

In the pictures....are they all loose. The pictures are decieving because the pinion has points that don't show up clearly. They actually extend in between the gears and you have a good amount of gear contact.

As someone mentioned above i also do the jiggle test...feel the tail to 2nd gear mesh...you should feel how much play there is....now those are non adjustable.

Try for the same amount of play.

Unless your frame was drilled incorrectly and the pinion is riding at an angle, there should be no reason it shouldn't turn freely.

This is a real dumb question ( but I have to ask) You are turning the motor with no power to the esc or anything else ? The reason I asked was we had a whoel thread dedicated to how tough it is to turn the motor with power to the rx and esc. from your desciption of the problem I'm 99.9% sure you don't have power BUT ?

Some of the main gears are also not perfectly round and will bind on one side and be looser on the other...but if you can feel a little clicking or play between gears it should not be that hard.

[freefall]

Turning motor with no electrics connected at all.
The mesh is far less than the other non adjustable gears.
Am i right in thinking that there should be NO SIGNIFICANT change in motor tightness/smoothness between loose mesh and correct mesh.
What it feels like is....The mesh is really set tight and it is putting pressure on motor shaft.BUT this is not the case because it is meshed very loose.

[Vinger]

Had another look at your photos, compared to my standard pinion, yours look much differant. Maybe you were supplied with the wrong mod pinion. The Hurricane uses .8 gears.

[Basejump]

Did pinion come in Gaui packet .

[bpd964]

It looks to me like your gear or pinion pitch is different. Are you using Guai 550 pinion and Gears?

[Finless]

I have to agree that pinion doesnt look right... The teeth look too short! Also another thing to check is make sure the motor is not rubbing the aileron and elevator bell crank mounts that are part of the frame. I had to grind the curvature of mine a little when I put that motor in my frame.

Bob

[freefall]

Metal levers are ok for sure.
In the UK i could only get Gaui pinions.Has anyone else used these with no problem.
The part number is the same has in the 550 manual.
I have tried a 15t also and that is the same when the mesh is set correctly.
I only got this heli because the 3050`s i had spare fit (unlike the trex 500).I have got to the point now that i will proberly junk the heli.

[mjdee14]

There is a "ratchity feeling" with the motor installed that is more than the motor uninstalled.....

Why not try flying it....?

What you are feeling may be normal....

[Mikej]

Freefall,

Where abouts in the UK are you ? you are welcome to compare it to mine if you are near - I am in Henley on Thames, Oxfordshire.

Cheers,
Mike..

[odieser]

I just check all my pinions agains my main gear there is no space inbetween the teeth on any of them when I put them together.The problem appears to me that the teeth on the pinion is too short and squared off compared to mine.
Mark

[istandalone]

imho your likely just feeling the magnets of the motor, and the drivetrain and all together it just seems like something is amiss. if i didn't know better, when i spun my z20a by hand i'd have thought there was a problem with it. matter of fact, i did think there was a problem with it. it flys more then fine though.

[freefall]

The thing is.everything is nice and smooth,motor and geartrain.
But as soon as the correct mesh is applied i can not turn the maingear by hand,that cant be right can it?
If i set a loose mesh BUT still enough to work geartrain it as as smooth as silk.Move the mesh a fraction more and can barely turn the motor with fingers and it feels kinda rough.

[freefall]

Mikej,

I am in SE london.A pity i am not nearer to you.Thanks for offer of help.

[Mikej]

Here are some pics of my mesh - sorry they are a bits iffy, but it's all assembled. This is with about 75 flghts on it ...

I think that your mesh is too loose currently, you could always set the mesh corect, remove the main gear and run it up with just the one-way bearing shaft connected, if you trash the first gear it's only a few quid to replace and you can always give me the remains of the worthless heli for disposal ;)

[Mikej]

Another thought - how does it feel if you spin the motor the wrong way - just turning the OWB shaft backwards ?.

I am building up another 550 that is on it's way over from HK - I am getting a Z20A 980Kv with that so will be able to give you a direct comparison.