One way failure

[smith512]

Got nearly two gallons on the new N7 yesterday and today.  During my end of day inspection today, I noticed my one way was very tight and notchy.  Brought it home, tore it down and found this.....



the top brass bushing was pretty much seized on the one way sleeve, which in turn got hot and tried to seize on the mainshaft.  The top brass bushing has some discoloration, but otherwise looks ok, but will not go on to the one sleeve without significant force.  Trying to install the one sleeve into the bottom brass bushing also requires force and when in place the one way sleeve does not rotate very freely, you can feel it drag on the brass bushing, and the one way bearing now make a clicking noise when I spin the one way sleeve in it (I do not have press and have not tried removing the one way bearing from the hub).  I had no difficulty installing the bushings or the one way sleeve during my initial build.  I used a tiny tiny bit of locktite on the brass bushings to install them into the hub.  So not sure if I did something during assembly that may have caused this issue.

I am at a loss friends. I am not sure what happened or why it happened, unsure if I had mistakenly done something incorrectly during assembly and am looking for any suggestions, opinions, etc.

Oh ya, other than this small issue, the heli flew fantastically!! It has been a long time since I had a 90 nitro and I had forgotten the power, smoothness and presence in the air.  I thought my N5c was going to be my goto heli, but the N7 has made me "reconsider" that.  Awe what the heck, they both fly so well, I can give each equal time in the air!    

[mdu6]

he top brass bushing was pretty much seized on the one way sleeve,

No where in your description do you talk about the 317-505 Auto Hub Delrin Shim (top & bottom= 2pieces).

Did you simply forget to talk (or install  ) them ?

A good tip is also to lightly sand the delrim sim - which I did not do at first but after a few flights the one-way would stick. Once sanded it works like a charm.

[smith512]

he top brass bushing was pretty much seized on the one way sleeve,

No where in your description do you talk about the 317-505 Auto Hub Delrin Shim (top & bottom= 2pieces).

Did you simply forget to talk (or install  ) them ?

A good tip is also to lightly sand the delrim sim - which I did not do at first but after a few flights the one-way would stick. Once sanded it works like a charm.

Delrin shim were installed top and bottom.  At the time of assembly, I did not feel I had to sand the delrin shims.  (I remember sanding one of the shims on my E7 many moons ago to get the oneway clearance just right - but I was happy with everything when I put the N7 together).

[Kevin Feil]

Smith,

 I haven't had this happen except way back in the N5 days, but that old design is long gone. I personally would shoot Matt a PM and recap on your initial post with pics. He will surely be able to answer you quickly and more importantly         (correctly). Keep us posted.

BR,

Kevin

[flyalan]

One possibility. One or both of the bushings was ever so slightly misaligned. By that I mean canted. This would account for your problem. 
I ran into this with a friends E7. His one way became stiff. We pulled out the main gear assembly. It looked like one of the brass bushings was not completely seated. He had also used red loctite. I took the hub and applied heat. Use a socket to tap both bushings down. That solved his problem.
When I install the bushings I try to let the whole one way hub sit until the loctite is set. Alternatively you can use a little heat to help the setting process. Do this with the one way sleeve in place. This will also ensure that the bushings stay flat and aligned.

Cheers
Alan

Sent from my SM-N900V using Tapatalk

[Jean-Luc Bolduc]

Bushings loctited but not aligned correctly sounds most likely culprit as Alan mentioned.

[smith512]

Well, I think you guys might be right about a misaligned bushing.  I just cant come up with anything else. 

I polished the one way sleeve and mainshaft and polished the inner OD of the bushings, cleaned out the one way bearing, relubricated it with triflow oil and reinstalled everything - taking care to ensure proper alignment.  It is smooth as butter, I mean REALLY smooth and no "slop".

Hopefully I can put it up in the air soon to test it out - it is working well on the bench and I have no reservations about it working properly in the air.

Thanks for the help friends! 

Steve

[flyalan]

Just happy you have it resolved

Cheers

Alan