E5 spur gear clearance

[Wolf51]

Hi,

I'm in the process of stripping and rebuilding an almost new E5 airframe that I just bought.

Before I started stripping it down I checked gear clearances across the heli and found that they were quite close. No noticable backlash in the tail assembly, main hub feels free and smooth and the bevel gears in the gearbox are very close as well.
But I did notice a lot of freeplay between the mainshaft spur gear (52T) and gearbox spur gear (13T). If I hold the gearbox spur gear tight I can move the main spur gear around about 1mm, which seems a lot.
I didn't see any way to move the gearbox closer to the main shaft so can't see how to reduce the freeplay.
Is it normal to have this much freeplay between the spur gears?

Appreciate any assistance.

Thanks

[curmudgeon]

I've built three Synergy helis.  All three have tight spur gear mesh.  Maybe you can post of a video of the backlash for review by the experts in this forum.

[flyalan]

Hey There.


Actually the holes in the frame for mounting the transmission are slightly elongated to accommodate the 4.5:1 gear ratio option.  Please be sure your transmission is pushed fully forward before you tighten the screws.  The elongation is ever so slight but it does not take much.  I have not ever measured the free play between the spur gears but if your transmission if fully forward and the spur gears are not damaged you should be good to go. All of mine (7 total) have a little lash. 


Cheers


Alan

[Wolf51]

Thanks guys.

I've already stripped the frame, so can't get any video of the play that was there.

Alan, I've just had a closer look at the main frames and noticed the slight elongation of the gearbox mounting holes that you mentioned. They were packed with dry Loctite so they looked like round holes.
I've cleaned them out and expect the spur gear clearance will be ok if I push the gearbox forward when I get to reassemble the frame.

You wouldn't want to see the amount of Loctite that's been used on some screws and nothing on others when this frame was built first time. That plus a gorilla working the 2mm hex wrench.

I'll let you know how it goes when I do the re-assembly.

Thanks for your help.

[flyalan]

No problem. 
I am getting this mental picture of gorilla hands holding a 2 mm hex driver with a button head screw on the tip dripping loktite:-)  I wish I had some artistic ability. That would a a funny cartoon.

Cheers
Alan

Sent from my SM-N900V using Tapatalk

[Wolf51]

No problem. 
I am getting this mental picture of gorilla hands holding a 2 mm hex driver with a button head screw on the tip dripping loktite:-)  I wish I had some artistic ability. That would a a funny cartoon.

Cheers
Alan

Sent from my SM-N900V using Tapatalk

Alan, if that's the picture you got, I'd say you're right on the money. LOL.

That said, I don't mean to be overly critical of the original builder, we all have different ideas and methods.
I'm happy that I chose to strip the model and rebuild it to my own satisfaction.
It'll be done as good as I can make it, with the build manual and help of this forum when I need it.

Cheers.

[Wolf51]

OK, just to tidy up this topic.

I've re-assembled my E5 frame and moved the gearbox fully forward in the slotted mounting holes.
The outcome, as expected - nicely meshed spur gears with minimal backlash. 

Thanks for your feedback guys.

[flyalan]

Awesome!
Cheers
Alan

Sent from my SM-N900V using Tapatalk