Spur Gear Question

[rpolkinghorn]

Having a Spur Gear issues with my E5.  The video shows the Spur Gear pin notching out the Spur Gear.  I've upgraded to the 12T Spur Gear, this is the second one that has the same issue.  The pin seems to notch out the gear causing excessive tail play.  Anyone else having this problem?  I'm just a sport flier, no 3D and don't fly the heli hard at all.  Appreciate any comment or suggestions.

[Grimmy]

Good vid!  I know I have some slot between my tail and the gear that turns that spur gear.  I'll have to put it upside down and look to see if it's the same.

[rpolkinghorn]

This is the second 12T Spur gear that I've replaced, even replaced the shaft and gear pin just to make sure it wasn't an issue, learned from years of rebuilding hell's.

[Chris Sexton]

That's a strange one for sure. Let's you and I work together off line. Maybe have a phone conversation?

I'll shoot you a pm.


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[Barry Tilson]

I think mine is loose like this also. I haven't had be time to check it out. Any resolution on this?

[Chris Sexton]

Waiting on the mailman to know if it's resolved. Stay tuned.


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[rpolkinghorn]

Issue has been resolved.  After discussion with Chris it was determined that I did not loctite the spur gear pin to the shaft and spur gear.  With the slight movement of the pin in the spur gear it caused the damage to the spur gear.  Chris sent me a new shaft, spur gear and pin but used RED loctite to hold firmly in place.  If you use this modification please allow the loctite to completely dry overnight. 

After installing the new items in the E5, had 5, six minute flights on it yesterday and everything held perfectly, will continue to monitor but this should take care of everything.  Thanks to Chris for helping and providing the product.

[Chris Sexton]

I am very pleased to hear the new parts have sorted this issue for you, it was my pleasure to assist.

I do want to clarify, your parts may have had a defect. I have sent them off to Matt to confirm, but not using loctite shouldn't have caused this kind of rotational play.

Using RED or Green loctite on the pin and spur is a best practice, not required, but it will insure that there isn't any un-needed play in the tail drive train.

[Cliff Chmiel]

I just checked mine is very loose in the gear too, mine has the speed up too 12 tooth I remember putting it together and it snapped in nice. I never thought to put lock tight on the pin. Chris can you make up a parts list so I can replace everything that's loose. Thanks Cliff

[Cliff Chmiel]

The parts list so far that I can find are 320-408 spur gear shaft 320-407 spur gear pin 2mm. The gear is not in the e5 manual is it the spur gear 12t the same as the e7 320-112?  and should I replace the 54t gear?  I thought I should replace the 320-118 front bevel gear and replace the 11m pin 320-407 I used red lock tight on this pin and a new Allen and nylock, Mine is so loose the pin disappears in the gear, I have over 100 flights on her now. So glad I check I would lose tail rotor if that gear breaks in flights

[Chris Sexton]

Well it isn't going to break just have a bit of slop that is completely negated by the torque against the rotor. That said, the best practice of using red loctite or green on the small spur will make these gears last almost forever.

Yes if you want to run the 4.5:1 tail ratio you need the e7 12t spur. You shouldn't need to replace the 54t unless the gear is damaged in a crash.


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[Bob Heybrock]

Cliff, I see Chris has offered his expertise on the accurate part # for the 12T spur gear.

I have some minimal excessive free play on my E7 tail which prompted me to check my torque tube ends but they are fine, mine seems to be at the pin & spur gear but has not worsened and certainly doesn't even show any signs of disappearing.

My reply is really to you and rpolkinghorn, I wanted to share a great trick with RED Loctite that I use, apply a little heat and it cures/sets instantly, you will see it change from bright to dark red. I realize there can be other things in the vicinity that may not be able to handle heat so use caution but it takes relatively little heat. I use this method to seal my N5c muffler and I have found that it does not necessarily cure overnight, heat seems to be necessary. I use this when setting the torque tube bearings in position also, many uses, try it sometime with a couple of steel washers. I hate the thought of you having to wait overnight to fly when there's a faster way! This was about as big an assembly breakthrough for me as when I was introduced to CA accelerator "kicker!"

Hope this helps and you get things sorted out and flying very soon!

Bob

[Cliff Chmiel]

Thanks Guys, will get parts on order today, I flew 3 flights on Friday and 2 yesterday. Hope to have everything back together for next weekend

[mike_capflyer]

I had my spur gear explode on me.  The heli started making a ratcheting noise pretty much on spool-up so I brought it down quickly to land and when I did the spur gear exploded.  The force that caused it to break was so strong that it bent the small black screws holding it in nearly 90-degrees.  What the heck did I do wrong in the setup?  How do I prevent this from happening again?

[mike_capflyer]

I think I solved my own question, but it would still be good to hear from those who have been flying longer.  I had a 54T spur gear on it (due to stretching to 626 blades)  and think I swapped it -unknowningly- for a 52T and didn't check the fit between the new spur gear and the 12t spur gear it contacts.  Would that have done it? I put the 54t back on and there is no play between the 54t and 12t gears, does that mean it's too tight and I need to adjust the front transmission assembly?  I distinctly remember pushing that assembly as far back as it would go when I stretched the E5.