OS 50 SX-H destroyed, pls help me find out why?

[Cobra78]

Hello all,

I will just introduce ,yself since this is my 1st post. I have been around this forum for about couple of months and started flying Raptor 50 about a month ago.

Have 78 flights on it and on 75th flight I had a flameout and had to auto ( a more experienced flyer was showing tricks so he did the auto).

Glow plug was gone bad it had 75 flights on it replaced it and it run great put 3 more flights and all was good.

Today when I tried to start it, it just did not start or died immediately, chekced the glow plug and replaced it. but no luck so took the engine apart and here is how I found the engine, piston and head were pealing and the metal peals caused the crankcase destruction.

So even though I am new to helis I am not new to engines flying planks for 3 years,

Did I run the engine to lean? I had always noce trail of smoke at all throttle settings and experienced fliers said all good.

IR temp gauge never showed more than 190F at the head so is this lean running or something else. Can this go under warranty if it is not lean, it is <1 month old.

I guess with the cost of piston+head and due to damage at the crankcase I better buy a new engine.

thanks,

[WayneBrown]

this looks like a bearing failure to me.
What fuel are/were you using?
When you turn the crank now, does it feel notchy or smooth?
send it in for warranty, and wait, or buy another as a backup.

[Cobra78]

Yes you are right, I just took apart everything and the rear bearing is gone here are some pictures, It was running good and did not have any problems with it did not sound strange but I guess it just did not happen in 1 flight. I am missing at least 3-4 balls in the bearing wow. what a mess it created.

I am using S&W 15% synthetic heli.

the engine is destroyed the parts are more than new engine,

Only the carb is not damaged, crankshaft seems okay too.

Will this go in warranty?

Thanks,

[flyinfool]

Man that’s ugly.

It does not look like it was run lean

There are several possibilities here.

1. I cannot tell from the pics if the back plate has a grove worn into it or is that just a shiny ring. If it is just a shiny ring, that is normal. If there is a grove worn in the back plate from the end of the crankpin that may be where your metal chunks came from that are embedded into the head and piston.
The most likely cause of the crank hitting the back plate is not having the fan properly installed.

2. Since the engine stopped running, the glow plug element may have fallen out of the plug and into the running engine. When the engine stops running due to a bad glow plug and the element is missing from the plug, it is a good idea to pop the head and see if the old element is still in the engine.

With that amount of damage, I would also inspect the cylinder liner very close especially around the exhaust port for any damage there as well.

My guess is that all of those chunks in the piston and head are the old glow plug element.
If an engine burns out a glow plug it should keep running, it just will not start the next time you try to run it. If the engine stops running, it means that the element has fallen out of the plug.
It is possible to damage the engine even just from it spinning down after loosing an element. Or turning it over with the starter and a coil of wire loose in the engine.

Out of curiosity, was the plug the OS plug that comes with the engine?
I have seen a number of OS plugs loose there elements at the end of their life, I have never yet had an Enya #3 lose the element. If you compare the two plugs, the Enya has a thicker / stronger element.

[flyinfool]

Wow I have never seen a bearing go that catastrofically in the 35+ years that I have been in theis hobby.

I have always heard strange noises and replaced the bearing before total failure.

Send it in under waranty. Often even if they do not waranty it the may offer a new engine at half price.

You mentioned that the engine had 75 flights on it. That would be around 7 or 8 gallons.
My stock OS 50 bearings start to sound bad and get replaced at arouond 4-5 gallons.

[Cobra78]

Jeff thanks for the response

The backplate was just shinny and no groves, the crankshaft did not have any play in it.

On the flight that glow plug failed the engine was running and it started to run irregular up in the air and died, the coil element was just still in the plug but a lot smaller surface are left.

I think the damage was done over some time since I don't have any trace of couple of balls from the rear ball bearing.

The glow plug was OS 8 that came with it and had 75 flights with it, I guess I should have changed it earlier, but the metal pieces I had in the engine were just too much to be glow plug, but I will remove the head next time if a glow plug goes bad.

It is nasty,

[DavidH]

In my 15 years of flying helis. I have seen bearing failures like pictured above several times. Those type bearing failures usually give no warning. The downside is the loose parts rattle around in the engine while it is running. That is what does all the damage.
You might try sending it in under warranty and see what Hobby Services will do.
They may replace the engine or repair it. Or they may offer to sell you an engine at a discount. You will have nothing to lose by sending it in. You will need to send a purchase reciept with it.

David

[WillJames]

I bet HS will take care of you, the top of the piston does not look like it was run lean at all. Sorry to see your loss, OUCH! :arggg:

[SteveL]

I saw a brand new OS 37 do this. It probably had about 1 gallon of fuel through it. The chrome on the bearings came off. HS replaced the engine with no questions. It made a terrible racket when it went.

BTW if you loose an element while the engine is running it will die. These are glow engines not diesels. A chemical reaction on the wire keeps it glowing after the engine is running.

[KevinT]

Cobra78

I just got my OS 37 back from Hobby Services. After numerous flight, and almost 10 months of use the rear bearing failed. One ball bearing split, and went all the way through the engine. Everything was totally destroyed. I sent the remains back to hobby services, and two weeks later the engine was back, and totally repaired. At No Cost to me!
It is back in, and running great :)
Send it in right away.
Best of luck

[RC-Bearings]

I saw a brand new OS 37 do this. It probably had about 1 gallon of fuel through it. The chrome on the bearings came off.

This is highly unlikely since the balls are not chrome plated. The steel used in bearings is a chrome alloy. The chromium is in the steel, not plated on.

[SteveL]

Paul,
After careful consideration, I have decided you are probably correct. :roll:

However, maybe you could shed some light on what happened. The bearing was not rusty or burnt looking; it looked like the chrome (that does not exist) chipped away. The bearing retainers were all still intact. Have you ever seen a bearing do this and what causes is? It would just about have to be a defect in this instance because the motor had very little time on it. :dontknow

[RC-Bearings]

Without actually seening the bearings it is hard to say. Bearings are made from some pretty hard stee, around Rockwell 64 or harder. There are a number of things that can cause failures such as work-hardening, false brinnelling and of course, rust. You usually see much more damage to the races than the balls as the balls can continue over the smooth parts of the races. I would guess that a ball failure would be the result of a material defect if the rest of the bearing wasn't in bad shape.

[SteveL]

Thanks
BTW those are some great prices on bearings

[thenewguy]

The bearings are the first thing I replace on a OS 50. My first motor bearings went bad in 1 gallon of fuel. I order the ceramic ones from RC bearings. Flew the motor to death. I just got a new OS 50 and order bearing right away. There have been alot of post about the os 50 bearing problem on the other web pages(rr). I read as much as I could on this subject after mine failed. You should send it in for warrenty for sure. :D

[AVIA]

On RunRyder, there is a lengthy discuddion about the OS 50 H bearing problem. You are not alone apperently.

I was not aware of any 37 problems however.

The word on the Runryder forum is after market bearings.

[HelicopterJohn]

Cobra78,

You don't have a unique problem. OS50 engines develop good horsepower and run great, but if you hear any extra noise or a different sound in the engine it is bearing time.

What you see scattered all over the piston and cylinder head are little pieces of the rear bearing. The scars on the side of the piston are from where a piece of the bearing got lodged in one of the cylinder ports and wiped out your piston. I have also seen some of them with chunks knocked out of the top of the piston near the ring groove and broken rings. This issue existed in the OS50 SX-H and the OS50 Hyper is identical engine except for the carb. and cylinder head. I can't speak for the ceramic bearings, but utilizing the regular bearings you had better listen real close and pay attention to engine performance at about 7 to 8 gallons of fuel. Some of these engines have shorter lives and others seem to last longer, but the rear bearing really takes a pounding and have a history of failure.

OS has a (2) year warranty on these babies and you need to keep your receipt to receive warranty service. You should not have any problem getting it fixed under warranty as I would think Hobbies Services has a waste basket full of the destroyed rear bearings.

I have seen a couple of these engines at our flying field in the last (2) months that looked just like yours so don't feel like the Lone Ranger.

I have worked on plenty of these engines. Some that were found early and only required a new set of bearings and a good cleaning. Others were ready for a trip to OS Repair Depot or the spare parts bin.

It is a shame that a motor like this that develops great horsepower and performance can't have a longer life between bearing change outs.

I am a loyal OS Engine guy, continue to purchase their products and hope design improvements are made in future engine models.

These are just my opinions, observations and other may have differing opinions and I respect their views.

:(

[RC-Bearings]

These are just my observations based on reading every thread I can find on this subject.

1. The OEM bearings either last less then 7 gallons, or they last forever.
2. Almost any replacement bearings of the proper type lasts much longer.
3. Cool Power fuel was mentioned more often with failed bearings.

I have some suspicions that there may be an assembly issue at the factory since most engines repaired after the initial failure seem to be fine.

I wish I could offer more here but that seems to be it.

[HelicopterJohn]

Hi Paul,

I could be wrong but I think the reason Cool Power is mentioned more than others is because it is probably one of the more popular fuels sold.

I have a question for you being you are in the bearing business.

I notice that some of the OS engines had a plastic/delrin ball bearing retainer. Is this a good deal or not??????

Have you heard of any bearing failures of the OS50 when they were rebuilt using the ceramic bearings? Just wondering as I may try a set in the future. I know they are more expensive.

Thanks in advance for your valued input.

:)

[RC-Bearings]

Sorry this took so long to get answered! I didn't get the email notification I guess.

The plastic retainers are usually a very strong ployamid plastic material. It is used because it can take the heat and in the unlikely event that it fails, it won't do nearly as much damage as a steel retainer.

I have has one ball failure in all the hundreds of ceramic bearings I have sold. I consider this a fluke as a lot of my bearings have been running for years with no problems.

[Gunner]

Cobra,
I just got my OS50 engine back from Hobby Services. I only had about 30 minutes of hovering on it before it burned out. I was still just breaking it in. I had the needle turned out rich but apparently, a couple of head bolts were loose which let the engine run lean and destroyed the piston. Since I was flying by myself and new to the hobby, I couldn't tell by listening to the engine or observing the smoke that it was lean. At any rate, I sent it in under warranty with an explanation of what I thought happened. They rebuilt the engine and returned it to me totally free of charge and in less than 2 weeks door-to-door. Send a letter of explanation and a copy of your receipt. I bet they'll cover it under warranty.