Warning about OS 50 Stock Bearings

[TRAMTRAN]

This is the third time I have seen this happened at the field and I have seen some people reported in this forum. I took this picture one of the guy in the field yesterday, he has about three years of experience in heli nitro. Stock Bearing got broken and depris got in the piston and made what you see in the picture.

[baddraptor]

It is fairly common in some hypers for the rear bearing to fail. If you have an engine that eats bearings even aftermarket bearings will fail just as fast. Some eat em within 2 gallons, some never eat them.

[BarracudaHockey]

Usually they tell you long before they come apart, if they sound like they are rattling at idle its best to do the bearings.

[tec548]

Order the rear bearing that uses the steel bearing cage from BOCA Bearing. I had that same thing happen to mine several times...

Joel

[AutumnSummers1]

Let me guess, it was a ceramic bearing??

[Forced_Induction]

i had the same thing happen. i ordered the ceramic hybrid stainless steel bearings from boca to replace them. i hope they work a bit better

[fifialfa]

same thing happen to me, i already change with ceramic bearing but didnt change anything..so better stay with the ordinary one cheaper, just remember to change it when the sound of the engine rattling.

[Forced_Induction]

fifialfa:
the ceramic bearing went on you just as fast?

[BarracudaHockey]

Yep, also you might check out the prices on http://www.rc-bearings.com or http://www.vxb.com boca is nice but rather proud of their inventory.

[AutumnSummers1]

Guys, I do not suggest that you use the ceramic bearings in the os 50. They give no warning
before they go unlike the stock ones.
I had creamic in mine and it felt like new when I done a rebuild so I did not replace it .
I put a piston , ring, wrisp pin and sleeve in it and got three tanks out of it before it blew
up , the rear bearing exploded and trashed the new rebuild. It made me sick
I am not the onlyone who has had this issue. trust me

[Forced_Induction]

AutumnSummers1:

The bearing that i ordered is the ceramic hybrid.

https://www.bocabearings.com/main1.aspx?p=product&id=3956&n=MR6002C-2RU%20TH9/C3

i hope this one wont go on me or itll be off to the hobby shop for a new engine. the last repair was 30$ shy of a new engine anyways.

[TRAMTRAN]

Even Ceramic Bearings go bad on OS 50? I never heard any report about ceramic bearings go bad in a short period of time, I might be mistaken.

[KG4HFV]

Just wondering, when did you guys buy your engines. I have been told that I am on borrowed time with 130+ flights on my hyper. Engine is still like new though. I purchased my engine in september and have been using it nonstop since. Ordered it from tower while they were out of stock for a little while and after they got some fresh ones in one was sent to me. Has any of the newer engines been giving anybody problems? I have heard of people going a long time on original bearings like 200-300 flights but they are very few and far between. Is this a problem that OS is trying to fix or are they just living with crappy bearings?

[baddraptor]

FYI, the hypers are kind of hit and miss as far as the rear bearing. That being said, I have one that has over 350 flights on it and another that is approaching the 200 flight mark.

There seems to be no rhyme or reason to it. My buddy had one that lasted around 4 gallons. We tune the same and use the same fuel, even the same helis. I am just lucky I guess..:smokin:

[fifialfa]

yes force, i happen to used a ceramic bearing from rc bearing, very expensive compare to stock bearing..but same quality

[Forced_Induction]

well, its not a problem anymore. i found out when i got home that the bearing set i ordered was for the wrong engine, so i stopped by my LHS and found out that they had 1 more TT 53h redline in stock. im gonna give this one a try.

[RC-Bearings]

Guys, I do not suggest that you use the ceramic bearings in the os 50. They give no warning
before they go unlike the stock ones.
I had creamic in mine and it felt like new when I done a rebuild so I did not replace it .
I put a piston , ring, wrisp pin and sleeve in it and got three tanks out of it before it blew
up , the rear bearing exploded and trashed the new rebuild. It made me sick
I am not the onlyone who has had this issue. trust me

I would say that I have a lot more experience with ceramic bearings than most on here and I can tell you that the NORMAL failure mode is the same for hybrid ceramics as for all steel bearings. It is almost always the outer race that starts to fail causing the noise at low RPMs. Anything that would cause a ceramic ball to fracture would destroy a steel ball.

[highland flyer]

Hi Paul On my hyper 50's when using the OS supplied rear bearings..we went through 8-10 between two of us last season and on dismantling the bearings the initial problems seem to stem from the inner race chroming breaking away in little chunks crossways on the race. There was only mild discoluration on the outer race but only at BDC..unless the engine was run for some time after the bearing was noisy.

It does seem very hit or miss and I suspect quality is/was a prob with the OS items. Eventually I replaced mine with an alternative brand of similiar construction as the OS bearing.. BUT also changed from Raptors to 2 x 600N's and have replaced one bearing in approx 800 flights..

[RC-Bearings]

HI back, highland. There is some misconception going around that bearings have some kind of chrome plating. This is not the case at all. Standard bearing steels are a high chrome content carbon steels. One of the commmon alloys is GCR15. Stainless steels used in bearings are the heat-treatable 440 series. They are magnetic. The non-magnetic forms are far too soft for bearings. Another thing to consider is that stainless steels heat treated to bearing hardness (R60) will not be completely stainless but are considered corrosion resistant instead.

The little cracks you see on the races have been identified by my supplier's engineer as caused by micro annealing. This means that microscopic sections are heating above the heat treat stability temps (over 385 F) and collapsing under the load. Most likely cause he could come up with was ultra low viscosity oils or poor lubricant film.

[highland flyer]

thanks, Paul that makes perfect sense as we also changed fuels which I forgot to mention above... we switched from Magnum 20% to Wildcat 30% 3DLV. I'm in the UK and we were not the only ones to experience the problems..

cheers Brian

[RC-Bearings]

Wow, when do you get good weather to fly up in Inverness? I go to Perth every month or so! They joke that the only time the weather is good is when I go up there!