N5C auto bearing lock up

[bclark]

Hey, I have a N5C that I just purchased used. The autorotation bearing keeps locking up. I can break it loose and it locks back up on every flight. Do I just need to change the bearing? Anyone else had this problem?

[Chris Sexton]

Hello!

Pull the sleeve and check for cracks, also make sure the two bronze bushings on both sides of the OWB are loctited into place. When those are allowed to float they can bind and cause the hub to lock.

Make sure the OWB is lubricated with a fine oil, not grease.

[bclark]

Thanks for the reply Chris. I will check the sleeve, the bushings are not locktited. The gear assembly was out when I received the Heli. I pulled the sleeve out then to oil the brg. and one of the bushings fell out. Is green locktite suitable? Thanks again, Bill Clark.

[Rodney Kirstine]

As Chris mentioned, those bushings spinning in the hub can definitely cause issues like what you are seeing. By green Loctite, if you're referring to retaining compound like 609 or 620 then yes. I use 609 on mine. If you're referring to 290, I'd be really careful with it because it is a wicking thread locker and could end up in your bearing.

[bclark]

I will have to verify that. We use a generic brand at work. We use it for press in plugs. Were the bronze bushings originally press fit in the hub? I got the manual with the heli, but I don`t even see them in the picture.

[Rodney Kirstine]

If you use it for pressing in plugs, it's probably the right stuff but it would be a good idea to verify. The bushings aren't a press fit. They come assembled but the manual notes that they need to be secured with loctite. It's on page 37 of the N5C TT manual.

http://synergyrchelicopters.com/manuals/

[bclark]

I`ll look at that. I have the belt version and the manual that I have has both tails in it. Thanks for the help!

[Rodney Kirstine]

[bclark]

Hey, I`m still working on the auto bearing locking up on my N5C. Here`s what I have done so far: I loctited the bronze bushings. After I did that, the sleeve was snug when I installed it through the hub. So I bored the bushings out just a touch which fixed that. Went to the field today and the bearing was locked up after the first and second flights. I loosened the bolt going through the aluminum collar a little. Third flight it was locked up again, but it was free after the fourth flight. That was my last flight today. I thought that maybe I had the bolt too tight causing the sleeve to distort. Any more ideas? Thanks, Bill.

[Rodney Kirstine]

When you tighten the bolt that goes through the auto hub and main shaft, make sure you do not over-tighten it. If you get it too tight it can deform the spur gear hub and cause binding. Also, over-tightening that bolt can weaken it, causing it to break in flight. When you tighten that down, tighten it until the slack is only just taken up. It's even okay if there is just a little movement in that bolt/nut. That's a nylock nut and between that, and the way the cutout in the spur gear hub is cut to hold that nut, it won't go anywhere.

[bclark]

Thanks for the reply Rodney. I get what you are saying about the bolt. I still think that might be my problem. I have the belt version, they call it a lock collar in the manual I have. It doesn't have a slot for the nut, but I think it needs a longer bolt and new nut. I think I`m going to make a few more flights and see if it stays free. I also think it needs a longer bolt and new locknut. Thanks again!