SOLVED - Another *Upgrade* One Way Slipping

[MichaelChad]

More background HERE.





It's been a great build and setup for the most part, there's always a few ghosts to scare off on a new build. Still have a couple of issues that persist. I originally completely ignored the notion that the issues I had at the end of the maiden day were related to the new one way but was able to confirm that it was in fact the new one way slipping!





I was originally flying with the grease that came in the upgraded assy., it came pretty full so I didn't add any. That is the state in which the initial slip occurred. Yesterday at the field it was obvious within the first 20 seconds that there was a loss of power in a simple hover. Quick check of the logs showed HS increasing while in actuality it was diminishing, obviously the motor is still turning so one of two things are slipping. I verified the pinion is not slipping, but in bench testing the one way, the clutch slips very easily if power is quickly applied from the freewheeling state. Gently applied force results in a complete lock, but as soon as it's un-loaded and then quickly re-loaded, it just keeps slipping. Several in-flight tests loading and un-loading the head to try to get it to grab, autoing, then spooling back up etc... it's still slipping.





It was very cold out, and the stock grease seemed to be very viscous at that temp, so I removed and cleaned it out completely, then replaced with the stock OWB grease with a number of different lubes. I noticed during the R&R that the inner sleeve was polished and holographed a bit where the pins engage the inner sleeve, I assume this is probably normal. I could only find one datasheet for this particular sprag (see attached), and it listed several options for proper performance, but the only ones that used a viscous grease were the sealed key style bearings, so I tried once with the stock OWB grease (cleaned out the stuff that came in it, and replaced with gaui OWB grease), once with superlube synthetic grease, and once with tri-flow. All three had the same issues, the first 2 would stay locked for longer, but the tri-flow did much better when it comes to quickly loading it. It would chatter instead of just slip, but within 20 seconds of a simple stable hover, they would all start slipping and nothing could make them catch again.





I just ordered a replacement from rcbearings, and inquired with a local dealer who advertised a "higher quality/industrial grade" clutch. They don't look too bad to buy separately, unless you but the TSA replacement which is $80 LOL. I'm a little stumped as to why mine is slipping when there aren't many examples of it happening to others.





Got a few new lubes to try, some 5w MO, 10w MO, and some ATF in hopes I can combat the cold temps with a less "sticky" lube. Cleaned out and added the ATF lastnight, but on the bench I can still slip it by quickly spinning the main gear.





Hoping someone can tell me I'm way off base on the lubrication, or there's some silly shim or screw or magic dust that was missing in some of them, or I'm out weekend #2 on my new bird . Gonna have to re-install the stock hub, and then baby it with that cannon ball motor just to get some stick time today.

[heathy]

Same problem here too. Brand new upgraded one way slips before getting in the air.

[MichaelChad]

Yeah, something's off. To be clear I don't in any way think this is related to a bad design, but rather manufacturing. Too many guys flying them with no complaints to think this is more than a bad run of parts. I notice a few things that make me think the tolerances were off while manufacturing the clutch.

I emailed Empire about it, im sure they'll make it right, and if its a more widespread issue, im sure they'll fix that too.





Chad

[velocity90]

And again

https://www.helifreak.com/showthread.php?p=4842525

X7 one way mod

[MichaelChad]

I've already done the mod (before the maiden), and have since verified twice that its not the sleeve that's slipping. The type and amount of lube I put in the one way has a tremendous effect on how much, and in what way it slips, but after spending the afternoon working and testing it today, it still slips every time, in nothing but a simple hover.

Originally Posted by velocity90

Last time

https://www.helifreak.com/showthread.php?p=4842525

X7 one way mod

Chad

[velocity90]

Are you sure you have the one way in the proper direction when reassembling it? We have 5 at our field that did the mod and the oneway is simply amazing.

I did apply a lot of grease just like the manual stated.

[MichaelChad]

Originally Posted by velocity90

Are you sure you have the one way in the proper direction when reassembling it? We have 5 at our field that did the mod and the oneway is simply amazing.

I did apply a lot of grease just like the manual stated.

Yes, absolutely positive. It lifts off, I don't think it would if I had it upside down.

Again, I don't think this is something to be repaired. Its not assembled improperly, nor is it a crappy one way. Frankly I had so much confidence it couldn't be the one way, I chased everything else first. I think they just got a bad batch of free wheel clutches from the MFG. I noted after today that the polishing on the inner sleeve is pronounced at the top and bottom, and nearly non-existent in the middle. I think the fingers are cupped on the inside bearing surface, so its only really making full contact in 2 very small places.








Chad

[MichaelChad]

So I got my replacement clutch in today, and let me just say wow is it well made by comparison. The cage fits nicely into the housing, all the edges and lines are clean and sharp, the spring actually loads the cams into the open position (They're also 0.1mm longer), and best of all I can not get it to slip by hand!

I mounted it to the main shaft with the head, off of the heli, and stood on the grips (upside down). I reefed on it 50 different ways and couldn't even get it to click much less slip. The real test will be when I get it off the skids (today/tomorrow), but I'm feeling encouraged!

If you need one you can find a replacement here FE423Z - RCBearings.com.

I'll report back after I get a chance to put it through the paces. Sucks to have to spend another $24 to fix a fix that had to be modded in the first place, but at least if Gaui had a bad batch of upgraded hubs, we have another avenue. Also if you have a busted clutch, you may not necessarily need to replace the whole assy!

Side by side - THe original has less than 5 actual flights on it, first time it slipped it became a 2 way.



Notice the one piece cage on the aftermarket part



Original Gaui Clutch in Housing - Note the cage floats inside the hub, which causes the cams to change attack.



Aftermarket FE423Z in Housing

[RC-Bearings]

Our bearing uses a machined cage vs a stamped one. Also, instead of a circle wire ring, ours has an actual spring to hold the cams in place. Overall, a much more robust design.

[velocity90]

Original upgrade oneway has a spring., no wire!

[RC-Bearings]

Originally Posted by velocity90

Original upgrade oneway has a spring., no wire!

You are correct! The one that I saw had a wire ring holding the bearing together. I assumed that this one was the same by the pictures.

[MichaelChad]

Pretty simple fix, new one way clutch from RCBearings, and I got almost 30 flights in this weekend without a single issue.

Bigger motor now, and actually got to fly it long enough to really beat it up for a while. Sucks to have to buy parts for a brand new upgrade, but at this point I'm too happy about flying it to even care!

I received an email back from EmpireRC.com, they are forwarding on to Gaui. If you had problems with a new upgrade one-way in the US, you can email them with the purchase date, and the vendor, and they'll be able to send better batch information to Gaui. They seem pretty interested in stopping the flow of bad ones. Good on them!





Chad

[RC-Bearings]

I don't know if this will help the Gaui OWB, but I spoke with my OWB supplier and they said that using lube with any kind of friction modifier such as moly, teflon, EP additives, etc will cause slippage. Unfortunately, most lubes have these things in them to prevent wear. For this OWB, wear isn't the issue, slippage is. I am looking for a commercial lube that will work properly.

[MichaelChad]

Yes, I actually tried some more traditional one way lubes on the new gear, and no dice. It only worked with the gaui one way grease. Tried fresh Gaui grease on the stock one 3 different times though, and it still slipped.



Amain had a few different one way greases in bulk, so I ordered a can of each. Next time it comes apart I'll see if those will work.





Chad

[RC-Bearings]

How about something with little or no additives, such as 3in1 oil? Or even WD-40? It doesn't have to be grease.

[MichaelChad]

What about tri-flow? Tried it on the old one but not the new.





Chad

[RC-Bearings]

Originally Posted by MichaelChad

What about tri-flow? Tried it on the old one but not the new.





Chad

I believe Triflow has Teflon. Bad.

[RobertAbles]

Paul, this is good news with your replacement bearing.

A lot of guys use transmission fluid in the OWB for the additive issues you speak of, works very well.

[RC-Bearings]

Originally Posted by RobertAbles

Paul, this is good news with your replacement bearing.

A lot of guys use transmission fluid in the OWB for the additive issues you speak of, works very well.

ATF would be good. I don't think you need to flood it. A couple of drops should do the job. You just want to keep the fingers loose.

[MichaelChad]

FYI I used two different types of ATF in both the new and the old one. It could barely sustain a hover, sometimes it would slip just trying to spool up.

I think it (ATF) works in a standard type OWB, but I couldn't find anything used in a typical OWB that worked in this sprag type clutch.





Chad