Engine died in flight

[goolfietis]

Engine today

Was flying today with my gas converted R60 - everything went well, I even tested it with underslung mount...

After that decided to fly a little bit around... Maybe five minutes later noticed, that RPM increased a little bit (that is only by sound - no tacho).. I`ve REVMAX mouted on heli, so it was a little bit strange... Landed to check is sensor is working - everything was OK. Started flying around again - maybe 3-4 minutes later engine stopped in the air - and I made it - my first real and sucesfull auto...

On the ground found that engine didn`t rotate freelly - it was stucked...

After disassembling found, that piston welded to cylinder... Piston ring is stucked in it`s groove - maybe that was the reasson?

Engine is G231PUH, running on A92 gassoline with 50:1 synthetic oil. Gear ratio is 7.58, blades 700 NHP..

Needles is somethere 1 1/2 or slighly leaner... REVMAX was set at its minimum RPM (i.e. 9500). After putting mount on, I increased RPM slighly...

After sucesfull auto, engine temp was 180C (356F):confused:

Any ideas what happend?

tomas

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[rotorhead58d]

too lean

[WayneBrown]

too lean, not enough oil.
You killed it man..

[lperagallo]

What oil were you using? I want to stay away from that:thumbdown: 50:1 is really not a good ratio to use. While many will jump in and say they run 100:1, you'd better know how to tune an engine perfectly or you will get what have.....a fried engine.

I use 3.5oz per gallon of 87 octane gasoline and have a smooth running, powerful engine.

Lou

[rbort]

And I 2nd Lou! I use Amsoil at 3.5oz per gallon and everything is happy. There is no reason to INCREASE the chances of burning the engine up by dropping the oil content. Basically your oil is your safety margin, more of it will give you more tolerance, less will give less. I've found my mixture to be a good balance between performance and protection.

-=>Raja.

[rotorhead58d]

i've never worked on a gas heli in my life, but i know what a lean fried piston looks like.

[Gr4yb3ard]

Hey! Rotor!,

Did'nt know you had a gasser dude!... Yup, that got lean, I see by the plug. Any chance there was fuel starvation?

Not that I'd say YOU killed it, the mix and settings sound good for a start. 2strokes are like that though, I've had a couple try to kill me.

What are you flying up here? Lemme know or PM me.

Gr4yb3ard

[stunts4u]

I use "Klotz" brand of synthetic oil on my gassers. Product R-50. I mix it 25:1 on my Zenoah 80cc twin. Klotz is a grade 5 synthetic (which is top of the line) vs those organic lubricants. To make my heavy camera ships run cooler, I use Coleman lantern fuel rather than high octane. The lantern fuel is 55 octane. I also use the factory settings on the carb at 11/4 top & bottom.



Just my 2 cents worth.

[goolfietis]

Thanks all for sugestions...

It`s easy for you in USA to get all the products like coleman, Klotz etc... Here in Europe it`s a little bit more difficult, especially in Lithuania.They just stoped selling A92 grade (I think 87 in US standarts) gas here...

Is it good to use A95 gas in G231?