OS120 Destryed... ***?!?!
 

Hey all!!
This happened yesterday morning:
- Flight no. 120 for this engine; bought brand new 3 years ago.
- Fuel as OS asks: 18% oil and 10% Nitro... fresh.
- 15x8 Propeller...
- Dead stick landing... just once, some time ago.

Any idea of what the cause might have been? Is that normal to have this massive damage?

I had a connecting rod break once, ys61 2c motor, I was pushing the motor pretty hard,, it happens

Was that caused by a broken con rod? You might consider calling OS and seeing what they'll do for you. It's amazing with some of the better companies how helpful they'll be when you tell your story and ask in a respectful manner.

Looks like a broken con rod to me.

Send it back and see what they say. The motor does not look abused.

Take the back plate off. You don't need to be a mechanic to take a look inside, it's just a few screws.

Guys; I know It's a broken rod that caused the hole there, the question is "what may have caused that rod breaking this way?"... I already dissasembled almost all the engine to make damage assesment:

1- Rod broke against the piston. Rod-crankshaft play is unnacceptable (don't know why!!!)
2- Valves clearances is OK (just overhauled two weeks ago following the precise indications of the manufacturer and using what they provide on the box)
3- Engine ran for only 120 flights (I counted them!!!) on 4 years (no, it's not abused, always used by the handbook). 8min/flight x 120flight = 16hrs running... not a big deal...

Upon your suggestion, I'll contact OS-Japan to see what they say.

Regards!!!

It would have been better if you had just left it as it was and not taken it apart if you are going to send it back. The manufacturers usually prefer that.

What were you flying it in, and what were you doing when it broke?

Well; I just removed the backplate...

Some JB Weld should fix that..., :cool:

Sorry. Send it to Hobby Services with a note explaining the circumstances. You might be surprised.

What's the issue with 'rod/crank play'? It does look babied, maybe a wristpin retainer or other part failed. By a valve 'overhaul', do you mean valve adjustment? I agree on not opening it up, I woulda fought the impulse and sent it back unopened.
Good luck.

I have had a rod break in one of my YS engines, it was well used though and it was just stressed over time and use. It didn't break the case though. I just replaced the piston and rod and all was well again. I have also had the crank pin break on a SK two stroke, that was just quality control from China, it was under warranty and was repaired for free.
In your case I would post the photos in the OS support forum and ask Bax about it but being on the net and only photos I don't think it will help a bunch. At least Bill can point you in the right direction about what to do with it.

Stay in this hobby long enough and you will eventually see it all ......................... :rolleyes:

Ok you bought the engine new three years ago but it has only had 120 flights on it in four years?

Since you ask; check this video... it's one of my tpical flights... https://www.youtube.com/watch?v=-CMz-y7VtQI

Yes, and I'm not proud of that...

Hey Grey Beard; can you please post me some direction to that forum? Is it here on RCU? Thanks!!!!

Yes Eddy...

Yes, it's on RCU. It's a sub forum. Go into giant scale gas engines then it has a glow engine forum. At the bottom of that is factory support and bill is there in the OS forum. Someone else may post you the direct url but it only takes me three clicks and I'm there.

Direct link to OS Support http://www.rcuniverse.com/forum/o-s-...s-support-133/

Just a thought, it could also be the inside bearing going bad that caused it to come apart. I had a Saito 80 that had the inside bearing let loose at full power, and the engine just destroyed itself. The over flow oil had aluminum mixed in where the rod was hitting the bottom of the case. It was beyond economical repair. Good Luck, Dave