Main hub and one way bearing

[Chris Sexton]

Well I had a very good day at the field, ran 4 packs through my e7.

While attempting an auto from about 20 feet( weak I know but a big step for me ) I noticed the motor was still spinning and after the bird was on the ground the rotor seem to have some drag and stopped very quickly.

I disconnected the bearing and turned the rotor head by hand to see if it felt like it was binding. The motor spun with the rotor. I tried to hold the main gear and turn the head and the owb wouldn't release.

Once I got it home I started looking at it closer, and I tried to hold the main gear again, this time the owb released with a "pop" and the shaft spun free.

Also the main hub seems to have vertical play on the shaft despite the Jesus bolt being tight.

I am going to order a new hub and bearing and possibly a new main shaft, I want to wait and see if the hole in the shaft is deformed after the Jesus bolt wobbled around.

I am curious if anyone else has seen a failure like this before? I have seen worn owb before, but never the play in the hub.

I will check the main gear to make sure it didn't come loose for some reason, but is there anything else I should check?




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[steffgiguere]

Not on mine, you sure you didn't tighten the auto hub to much? It does not need to be really tight.

[Chris Sexton]

Not on mine, you sure you didn't tighten the auto hub to much? It does not need to be really tight.

I basically just bottomed out the nylock nut and called it a day. I will know if I screwed it up once I pull it apart. But I have decided to wait until the TT kit is out since that will like have a new autorotation hub and I have other birds to fly on the odd warm Midwestern winter day.


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[Matt Botos]

Have yet to have a one way do anything strange. Here are some things to check.

1. DO NOT use grease on the one way, the wrong grease will cause problems. Use light oil.
2. Bronze bushings need to be loctited into the hub.
3. Make sure all of your Delrin shims are in place. (Top and bottom of auto hub)

Thanks,

Matt

[churchyj]

Yeah I find cleaning all of the grease out of the auto hub from factory then applying some tri-flo makes them free as a bird.

[Chris Sexton]

Hmm I didn't know I needed to loctite the bushings. I didn't grease the one way. I will check the placement of the delrin shims.


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[Gregor]

2. Bronze bushings need to be loctited into the hub.

Which bushings are you refering to? I didn't see any bushings in the explode view (page A5).

[Gregor]

2. Bronze bushings need to be loctited into the hub.

Which bushings are you refering to? I didn't see any bushings in the explode view (page A5).

Anyone?

[Tommy Wagner]

They are in the hub I believe they are installed by the factory but come out fairly easy


Tommy

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[Magneto]

It would be nice if this info was in the manuel like no grease in the one way and locktiting the brass bushings in the hub whats going on here? Is there any thing else left out? Now I have to break this heli down!

[Chris Sexton]

Well my owb wasn't bad after all. I broke it down and what ha happened was a piece of the belt peeled off and lodged between the main gear and the auto gear. I went ahead and pulled the hub apart to be sure.

Not sure what happened to the belt, I think it was damage from when my idler pulley was too tight.

Ordered a new belt and prayed for TT kit


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[Gregor]

It would be nice if this info was in the manuel like no grease in the one way and locktiting the brass bushings in the hub whats going on here? Is there any thing else left out? Now I have to break this heli down!

  I kind of thought that was SOP for all one ways.  No grease, just light oil to keep the roller bearings free in thier tracks. As for the loctite on the bushings, yes, I would have appreciated the heads up before the kit was assembled. 

[stevehof]

Have yet to have a one way do anything strange. Here are some things to check.

1. DO NOT use grease on the one way, the wrong grease will cause problems. Use light oil.
2. Bronze bushings need to be loctited into the hub.
3. Make sure all of your Delrin shims are in place. (Top and bottom of auto hub)

Thanks,

Matt

Matt, are you saying that the one way bearing bushing is NOT factory Loctited into the hub and that this step is necessary for every installation? Or are you just saying to check it if we are having problems with the one way.

[Chris Sexton]

Have yet to have a one way do anything strange. Here are some things to check.

1. DO NOT use grease on the one way, the wrong grease will cause problems. Use light oil.
2. Bronze bushings need to be loctited into the hub.
3. Make sure all of your Delrin shims are in place. (Top and bottom of auto hub)

Thanks,

Matt

Matt, are you saying that the one way bearing bushing is NOT factory Loctited into the hub and that this step is necessary for every installation? Or are you just saying to check it if we are having problems with the one way.

I can tell you mine was not attached at the factory. It is squared away now. There will always be things that need revised in manuals. I am sure things like this will make it into the new manuals. The costs of having some of the firsts of something brand new. "bleeding edge" as my father calls it.

Still love this heli!


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[stevehof]

I did not assemble my E7 kt. However, I have assembled dozens of heli's and I never had to Loctite a one way bearing into a hub. Usually the bearing is a 'press fit' and done at factory level. In other words you need a bearing press to get the one way bearing into the hub. Are you saying the bearing assembly is not a tight press fit into the hub? It seems to me that everyone's E6/7 would have had a slipping one way assembly at first start up. What part of this concept am I missing? I have about 50 flights on my E7 and I haven't noticed any slippage....