OS 50 Flame Outs

[ChrisE]

I have a new OS 50 in a Sceadu, engine has only been run in. The motor will stall on me mid flight for no reason. I mixed up a new batch of fuel freshly purchased from the store. Replaced all fuel tubing. Installed new No 8 plug. As I am in the process of fine tuning the low and top end needles I have trouble in trying to get the model off the ground as it will stall on me just before almost lift off. If I manage to get past this point and obtain lift off. The model will run OK and for no reason can and has stalled on me mid flight. When I pinch the fuel line during idling the motor will reave up prior to stalling. During idling the motor sounds like it is coughing.
Any suggestions as to what is happening and how to sort it out.

ChrisE

[deanmax]

This is a after though but remember this what happens when the heli is in the air and coming down to fast we gun the throttle and then the engine dies and then the heli because more torque and more pitch a engine that doen't respond right dies. We want a good fast throttle without loading up or dieing out and that is self control on our part NOT TO PANIC.

I'm good at leaving out sentences so if you don't get what I meet email me and let me know. (deanmax@tds.net)

Have you had any luck at it yet if not I had experience this problem and it was a peace of fuel tubing that was so thin and tranparent in my carb at the needle port you couldn't really see it but after taking the carb apart and holding the needle port up to light it look like fuel but wasn't. I'm sure when I slid the fuel line on the tank brass tube that was where it happen. It made my needle so sensistive one click oneway or the other it was lean or rich.
It's hard to get a heli engine running right in the machine but one way I have over come this without takeing it apart and putting the engine on a test stand is to remove the blades (watch out for the flybar paddles) and start the engine and after idle gun the engine if it dies down without smoke from the exhaust it's lean and if it smokes and babbles it's rich. This is just a quick throttle movement up to about 60% throttle and back down.
By removing the low and High end needles and fuel line you can clean the carb on the heli by blowing air or fuel backwards through the low end needle and to get the low end needle back. When putting the needles back, turn the low end needle back in until it stops don't force it or it grove the needle light pressure then back out one turn good starting place. High end 1 and 3/4 turns and remember up to half throttle you are using the low end neddle so get the engine to respond from idle to half or even close to half so it doen't die out (too lean) or hessitate (too rich) You catch on pretty quick you hear the engine when you give a pretty quick throttle responce the engine pick up then wait 5 sec then do it again after 4 or 5 times go to the high end and do the samething except from now idle to 60 or 70% throttle. If you have away to check the temp it helps. If you can hover you will find the the engine should run around 235 deg. temp alittle less on temp about 10 to 15 deg. on the rich side but the engine will last longer.
Hope this helps its works for me when I'm a 45 min drive back to home and its noon.

[hawkman]

Get a set of headloaders so you can run it on the ground......then do the faultfinding......do bear in mind that once you sort the engine out you will need to retune once the blades are back on.....Headloaders are great but they dont truly replicate what the blades are actually doing.....collective and cyclic inputs will vary the overall load placed on the engine.

Its sounds like a mixture problem to me....but I dont know that size of engine......go right through the fuel system again.....is the fuel in the tank nice and clear? if the fuel is shaken about due to vibration it can foam up and release airbubbles into the carb....which is not good.

Rob

[deanmax]

That's all true too. And I should of said remove the rotor head come to think of it down to the swashplate for safety but then it does add a little weight at start on the engine so it would be closer to ideal performance.

I would like to know about a headloader is it something I could make? Or do you know of a picture I could look at?
I have used a water turbine for real turbine to put a load on them when setting them up but that has been along time ago well just before my back got hurt in 1995. Is this what you mean?
(this is a real sore subject for me all because of the state and their doctor and he was going to show me and he did lost everything to never fly or work again) I was an aircraft mechanic and a pilot with my own planes well anyway I have my models now.
About the air bubbles I haven't had any problems with mine yet (that is yet) because you never know. But at start he has the problem so I was thinking it would be to soon because it takes a little time to get enough air bubbles to foam the fuel. But I fly centry helis 30 and 50 size and you could be right.
I have other helis too, older ones but never had to put a header tank on. I will when I fly 3D to be safe I just don't want to take a chance.

I was thinking too when I first start my engine after putting it in my heli I zip tie my heli to my picnic table so I don't have the tail swinging around so I can gun the engine. I do a one thousand one count from idle to full throttle and wait a one thousand 1 to one thousand 5 count between each time, so it gives the blades time to slow up a little and if it's rich, it will give it time to load up. And then when I think everything is right I slow the blades down not all the way because this gets hard on the clutch and one last time from idle to full throttle then shut it down and check the engine temp.
I said to to run the temp at 235 deg remember that that's the high side because water will boil at 220 deg. and a even flame burn is a 100'/sec so it's better to keep it around 220 deg on model air cooled engines its just 235 deg you get the most out of the engine and there is no more it will give without recking it.
Full size cars the temp is at 180 deg. to 190 deg. even freight trucks and full size airplanes so everything about engines running good and proper has to do with the temp of the engine and fuel mixture.
I hope this helps someone.
Let me know about a headloader please.

[deanmax]

did you get the engine running? I just happen to be going through the OS engine manuals to see what they said about set up and pretty much said what I said or the other way around if you get a chance let me know thanks.

[shanee86]

Sounds to me like maybe a tuning issue or your motor isn't getting enough fuel maybe a fuel filter restricking it. We had one on mine and we tuned and tuned and had it were it wouldn't get off the ground much then come back down etc. But we found out it was fuel filter was clogged. So we took it out don't know if you tried that but gave us trouble and we checked lines etc before that.

[deanmax]

Yes: that is another part to check, sometimes it is just that simple and it is the last thing I always check when it should be the first and I miss the whole day of flying because I didn't check the filter. And know I need to retune the engine.
It's funny how it get that transparent hair on the screen and where does it come from?
Also I've had some of the plastic filters come apart. There is these blue ones, it has something to do with the fuel and setting just one day go to check it and a little tug and apart it comes. So know I use metal screw together.
Good start on the web page and good luck on the store it's nice to work for yourself.

[chaos]

Headloaders:
http://revolutionmodels.co.uk/acatal...ssories_8.html
http://www.rcmarket.org/HEADLOADERS-p-16281.html

You didn't mention fuel filter... maybe you forgot to mention it. Anyway, check for flake of something in there.

There can be a little metal flake in the carb that rattles around and sometimes gets in the way just by slop luck and other times doesn't bother anything. You can unscrew the nut that holds the needle valve in and pull that assembly out and check in there. OS is notorious for shipping clean engines but poo happens sometimes.

And just to cover all the bases, maybe the servo is actually shutting the engine off. If you have failsafe set to do this and loose signal then.. off it goes. If you can capture a helper to watch the throttle arm while you run it up on the ground with no blades it would help to know for sure if the throttle did the dirty deed. Bad servo or bad RX or bad TX could account for it.