View Full Version : Raptor 90 SE Oneway Bearing Question????
Is there a way to lube them so they work more than a few flights?? SERIOUSLY. I did a search and couldn't find much info other than "get a UK Autorotation Hub (with oneway)".
I have tryed 2 kinds of grease/ triflow oil/ Soaking the hub with the problem bearing in Mobil One 15-50 weight motor oil and I always get the SAME result. After 3 or 4 flights it is froze. I take it apart and tap on the oneway clutch shaft and it frees it up as if it's perfect. The routine repeats.
I then bought a new OEM Raptor autorotation Hub and you guessed it. I does the exact same thing. 3 flights and it's stuck. I now have 80 flights with this being the routine.
I will now order a UK Hub but I just thought I'd ask before I try one last day of flying with the stock units.
OK and one other dumb question. It flys the same weather the oneway is stuck or not. I am sorry but I don't know it's purpose...I don't autorotate and is this where it's needed?
Thanks for the info guys.
Eric
emoe,
I have the same R90SE with about 20 flight, and no problems with the oneway.
Are you using the reinforment ring over it? is it all the way down ? how tight is it?
I read somewhere that over tightening of the ring deformed the bearing and this lead to seasing.
From my experience in other fields other than helis, I learned to mix greases and oils to find the right balance.
This has been a trial and error process, but this is what I do and I haven`t had a problem.
A one way bearing is a bearing that has needles or rollers instead of balls. The cage( is the metal that separates rollers) has an angled shape that allows rollers to spin in one direction and in the others the get "pinched" thus blocking itself between the cage and the outside casing. So there is an extra movement on the rolers besides spinning.
The oil has to be thin enough to allow this movement to be fast or else if you use a grease too thick, the rollers will stick and it will eventually start slipping ( wont pinch)
You first have to know how fast it will turn. the auto rotation bearing is a fast reaction bearing from 2000 to 0 in a second. This also means you have to use a light oil.
The problem with light oil is that you have to replace it often. the spinning motion sends it flying all over the place and you end up with a dry bearing.
what I do is first apply a medium thickness STICKY grease all over the rollers, pushing it all the way into every space.(It`s a bit rudimentary , but check stickyness between your fingers, try it , it should feel a bit like gum)
Mount the shaft ( It will feel hard to spin) and start applying light lube (tryflow or similar,but not WD-40)2 drops and spin it a few times , then repeat until it stars to spin with less resistance.....and its ready.
You should add a drop of ligh oil every 4 flighs or so. If you oil it too much you will loose the grease.
Before mixing grease and oil check first compatibility. Some cannot be mixed. I have used with good results Thick silicon oil mixed with tryflow .
hope this helps
Iher
I do have the reinforcement ring on. I don't think I have it on too tight. I just snug it for tightness. I would think that if that were my problem I would see a issue right away, not 3 flights later but I try it looser.You have given me some hope. I will try your method of lube too.
Thanks for the input. Any other input or experience with Stock Hub/One way is greatly appreciated. Eric
rotorhead58d
06-17-2008, 09:33 PM
look in the main forum. there was a good convo about what kind of grease to use, and some very knowledgable people gave their two cents.
I have had a Raptor 90 SE and a Raptor 90 STD.
I flew both without the reinforcement ring and never had a one way seize up. Keep in mind I did regularly pull them apart and use TriFlow Oil.
I just sold my Raptor 90 SE to fund an Avant AURORA project. But the 90SE has had at least 10 gallons threw it and never an issue.
What is the purpose of the reinforcement ring?? Is it common to fly without it?
I actually thought it was to sit on the 4 allen bolt heads for the gear to stop them from backing out....but that doesn't sound like reinforcing. Does the oneway bearing have such force within the hub that the outer walls of the hub may flex to the point of needing reinforcement?? Thanks for your input.
guygate88
06-18-2008, 09:38 AM
Here's my 10 cents - I had the same problem, I noticed after lubing the bearing and pushing the cogs back together the Auto unit would run freely almost all the way in until the last 2 or 3mm, when I pushed it home and fitted the circlip it would tighten up. I rubbed down the shaft and the inner brass bearing ends with some 1200 paper and it seemed much better. I actually use white grease with PTFE but it does tighten up again every gallon of fuel or so.
What is the purpose of the reinforcement ring?? Is it common to fly without it?...
......Does the oneway bearing have such force within the hub that the outer walls of the hub may flex to the point of needing reinforcement?? Thanks for your input.
Some people fly with out it.
I think you are right on the money about the fact that the outer walls are too weak. this makes sense because these tipe of bearings need to be stiff enough to block the rollers.
My maintenance lubing practice is :
-Every 3 flights- one drop of tryflow on head bearings, swash, main shaft ( where swash and slider move) trust bearings in blade holders, tail blade holders and slider.
-Every 8 flights - heavy silicone or graphite grease on main shaft and tail shaft.
-Every 20 flights- I disassemble every major moving part ( tail assembly, head, gears and one way) , to clean and regrease. where needed.
There is never too much oiling. A dry part Is prone to imediate premature wear.
Well just an update. I did get and use specific one way bearing grease. I took my time and put in on each roller and inbetween. I repeated this 4 times and rolled the grease in with the clutch shaft. Then today I put a gallon through the Raptor and the bearing is still doing fine. I am just use to my Trex 500 and 450 which I can almost throw any ole grease in the one ways and forget about them for 200 flights or more before regreasing. Anyway thanks to all of you that contributed. I am pleased that the Raptor 90 doesn't need a UK hub to work well. Thanks again. Eric
Helirat
06-20-2008, 03:32 PM
I would like to add if after using the oneway bearing grease
and you still have problems with the bearing locking up.
Then you mite want to try what I do.
Take some Brake cleaner and get all the grease out and just use some
Transmission fluid ( ATF ) to lube the bearings .
I do this and have no problems with the oneway bearing locking.
Actually I think grease causes dirt and clutch dust to stick on the bearings hence locking them up.