Oil in autorotation bearing?? - RC Groups
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Jan 09, 2008, 12:42 AM
Registered User

Oil in autorotation bearing??

My autorotation one-way bearing is a little oily. This is understandable after a few years of flying with main shaft bearing oil seeping down there. Now it is starting to not clutch very well. It grabs to fly, but fails to clutch sometimes on shutdown.
The rollers, and roller holding springs look fine.

Should a one-way bearing be cleaned absolutely dry with a solvent, or should there be a small amount of lubricant always in there to inhibit rust or for correct functioning?

Comments would be appreciated. Thanks, Russ.
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Jan 09, 2008, 12:47 AM
Our Daddy and Heli Junkie
Fred Bronk's Avatar
Hi Russ

The bearing should be clean but have a small amount of lube so it will work freely.

If it isn't grabbing well, check the shaft. If the shaft is polished the needle bearings won't grip as well, try roughing it up a little with 3m pad or 400 grit.

AMA next weekend!!
Jan 09, 2008, 06:27 AM
A man with too many toys
Flush all the old oil out first Ė some bearings come with very poor quality oil from the factory.

The type of oil is critical to proper operation. I use Tri-Flow oil available at most hobby shops. Also automatic transmission fluid would very well Ė some think itís the best.

I donít think I would be roughing anything up but I have never tried that. I have never had any problems when proper lubrication is used.

Jan 09, 2008, 09:53 AM
Our Daddy and Heli Junkie
Fred Bronk's Avatar
I am not saying to rough it up, just take off the polished look for a better grip surface.

Jan 09, 2008, 04:06 PM
Registered User
The problem is not the clutch properly grabbing and allowing spoolup.
Actually, the problem is that it doesn't release and properly slip during spool down.
Fortunately, I haven't needed to do an emergency autorotation.
Do we really think it should have some oil in it? I just got a new one from Mikado last night and it seems very dry.

Comments? Thanks, Russ
Jan 09, 2008, 04:26 PM
Registered User
I soak all my one-way bearings in auto trans fluid overnight. Its the highest synthetic fluid out there. If there was something better they would use that in transmissions.

Triflow is also a good lube and I use that on other bearings etc..
Jan 09, 2008, 05:01 PM
Das Universus Elektrikus
Albig's Avatar
Yep clean it real good and use some synthetic ATF.

Auto transmisissions have several big sprags in them depending on how many speeds they are.

If it doesn't release everytime it's worn out and time for new oneway sprag bearing and hub.
Jan 09, 2008, 11:44 PM
misskimo's Avatar
hey , I been known to use both , grease and triflo , triflo more than any though , havent used teflon grease in a while , that was in my MA machines, which Fred , I kinda understand what youre saying , but my MA Ions whats polished and never had a problem, well untill they wore down some, I got a shaft that came out of my trex , it wore it down about 30 to 40thousandth before it started digging into the shaft and look like waves , it got bad within a couply of flights and the tail started doing alittle wagging , filed it down , and flew 5 or 6 flights till the new one arrived.


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