OS50 blew up today

[blakka_1]

Lovely sunny day here in the UK so I thought I would take the R50 out for a blast.

Got to the field and done the usual checks, headspeed, and engine temp, the head speed was at 1870 which is great so i done a couple quick circuits and light 3d so I could get the engine up to temp so i could check the engine temperature. Landed and put my finger on the engine backplate and was able to hold my finger on it for 8 seconds +, which is great. Took off again with loads of smoke puffing from the muffler telling me that the engine is happy and on the rich side.

Was doing the usual again throwing the heli about and stuff when I heard the engine going lean " high pitched whining sound" so I brough the heli down onto the skids and before I could lower the throttle to cut the engine speed it popped, the engine just cut on its own, not good. Went to pick the heli up and could see the motor smoking and could hear it sizzling and crackling - not good :( .

Took it back to the flight line and went to check the engine temp again and sure enough it was fire hot, couldnt even hold me finger on the backplate for a second without being burnt. Tried to start her up again and surprise surpise no compression. So looks like a new engine is on the cards, OS50 hyper :D . Haven't taken the engine apart yet but expect the piston to be busted.

My question to you guys is - why the hell did it pop?, engine was nice and cool, lots of smoke, still had room for more power as it seemed to be under powered as i was running it rich so could of gone leaner. I'm baffled.

Lets here what you guys think.

Cheers :)

Nigel

[capebob]

Well, if you are still using the terrible clunk line that comes with Raptors and other Asian helicopters I would guess that it collapsed and leaned your engine. Just one of several possibilities but I've seen this many times. When I build Raptors I always change the clunk line.

[blakka_1]

capebob im using the thick heavy duty Miniature Aircraft clunk. However I will still check my clunk to make sure it has not collapsed like you mentioned.

Thanks :)

[WayneBrown]

fuel could have foamed up, the pressure tap could have come loose from the muffler, the muffler could have come loose, fuel line could have pinched..
there is a myraid of reasons this could have happened. inspect everything, it's probably something innocent and small..

[Hotshot Charlie]

Fuel line in the tank, being soft, can really mess up an engine quick !!!

[blakka_1]

Well I had time this afternoon to strip down my engine and have a look at what happened. Well it's no surprise that I have a huge hole in the center of my piston and the piston is brown so that's the sign of my engine going lean. New engine on the way.

However I checked all my fuel lines and clunk lines and all are fine. So i am still very confused as to why the engine piston just blew up like that. Maybe it was just me and i tuned it badly that day. Well whatever made it go lean I guess i'll never know, that's the beauty of helis :wink: .

Pictures should be up in a couple hours.

Thanks for all the help guys. :)

[RCfan]

Bummer! Had a similar mishap with the OS61-SX on my Futura SE. First tank of the day, about half-way thru it and pop -- it's auto time. Couldn't identify the cause, which has me real worried since I ended-up getting a new engine; went over the whole heli, nothing stood out. Other than cost, this is the only part of this hobby that I hate.

[dorfmann]

I think the carb bot clogged on the fuel side. If the lines are good, the carb is the culpret (sp?). That is the only "gauged" mechanism on there. I would talk to OS. How old is it?

[blakka_1]

Here is the picture I promised. Just a little lean :wink: .

http://www.helifreak.com/album_mod/upload/24c4ab8fa9956ff263386c0c766055a1.jpg

[WillJames]

Ouch!

[rob_jones]

Check the fuel inlet on the carb by removing the metal nipple. See if any trash is in there. Also pull out the needle valve and check it for trash.

I was buzzing around with my EVO 50 a while back and it literally went from fat and happy to screaming lean in about 5 seconds. I landed right away and started looking it over. It turned out the pressure line coming from the muffler split right at the nipple on the muffler. I was surprised that losing muffler pressure would lean it that much and that fast, but it did. I cut off about a half inch of the tubing, hooked it back up and it ran great again.

[blakka_1]

Thanks for the advise Rob, I checked all my fuel lines and I can't find any splits or holes. I will definatley go and check the fuel inlet on my carb as you said though.

Thanks again. :)

[WillJames]

Rob is right, Take that carb off and blast it out with alcohol if all your lines are all good.

[Laurens]

All I can see from that pic is...






HYPER TIME!!!!