Hi,

Recently l bought a Evo50. l used ~ 4 tanks of fuel (AT Racing: 15% nitro 20%oil) to break in.

After that, l was forced to set the needle to about 1/2 turn out from fully close or a few more clicks out in order to have enough power to lift off.
This is not right l guess becase as a new engine, the needle shouldn't be only half turn out for 15% nitro fuel.

If l make it to 3/4 out, it produces huge of smoke and doesn't want to take off before 75% of thottle and it sounds very rich.
then l tried to use a different fuel (10% nitro 20% oil), the different is another 1/5 turn out compare with AP racing fuel.

l'm not sure this problem is caused by the fuel or what, but when l tried different fuel, it has no big difference on the needle setting but only around 1/5 turn.

Anyone is flying a new Evo50 here? what is your engine setting?
Or could anyone give me an answer why my engine is running so lean?

My pitch curve is -2, 2, 5.5, 7,9
thottle is linear from 0-100%

Thanks in advance

Edmond

You have failed to mention what engine you are running,

Also make your pitch curve linear and adjust your throttle curve to give your correct head speed.

Next thing is the idle mixture and not the main mixture screw needs to be adjusted for hovering as the idle mixture range is controling fuel up to around 75% throttle opening.

My normal curves as an example:
pitch -9.5 to +9.5 linear
throttle: 1-0% 2-35% 3-42% 4-68% 5-100%
this is just an example as my setup is totally different to yours, you have to experiment yourself as no-one elses settings will be the same as yours even on an identical ship, start with the basic settings from the manual then adjust as required from thereto get a head speed you like.
Instuctions are not set in stone nor did they come down the mountain with Moses

Edit: forgot to mention, different exhaust pipes make a hugh difference in mixture settings, recently my zimmerman pipe failed, so for the rest of the day I borrowed a stock hiribo pipe from one of the guys, I had to retune and needed about 1 1/2 turn to get the damn thing to run, then got a curtis MP11 pipe and had to reune again, that fell in half so got a replacement zimmerman again and once again retuned, two weeks later the weather really changed and once again I needed to retune.

It never really ends, just keep at it and if your not sure how it's running always go rich and lean out again

my heli got a OS 50 SXH and the idle valve is factory set at the best performance position as it said in the manual. so l would expect no adjustment needed at the moment.

The needle that l talked about was the "mixture screw" since the idle valve is set.
l know different people would have different setting for their heli, but for the "mixture screw" would be very simular because if you got the same engine then you should have a very simular setting for the needle. l don't think an identical engine could operate with same eg. RPM or Max RPM in more than 1 turn while using identical fuel

anyone could say something about their engine setting and fuel used?

Thanks a lot

Never assume that the little chinese man that assembled your engine just before lunch break actually set it correctly!

And did you manage to read the rest of my post?

Here is an extract from the OS 50 manual

BASIC POSITION OF MIXTURE CONTROL VALVE
(Mixture Control Screw)
As delivered, the Mixture Control Screw is positioned at the center as shown in the sketch.
Mixture gets lean when the Mixture Control Screw is turned right, while mixture gets rich when the Mixture
Control Screw is turned left.
With a model helicopter, adjustments vary with combined various factors such as climatic conditions, fuel, muffler, main rotor, weight of the model, gear ratio, etc.
Therefore, Mixture Control Screw position varies with each model and set- up, and it is normal
if the Mixture Control Screw position is off center.

From here incase you dont have a copy:

http://www.osengines.com/manuals/50sx-h-manual.pdf

How about this....

The Mixture Control Valve (Mixture ControlScrew):
For asjusting the mixture strength at part-throttle and idling speeds, to obtain steady idling and smooth acceleration to medium speeds. The mixture Control Valve has been factory set for the approximate best result. First, run the engine as received, and re-asjust the Mixture Control Valve only when necessary.

do you fly planes?
what do you fly?

I fly helicopters at present, however I have been playing with RC IC engines for around 20 years.

It is quite clear that you are unable to accept that someone might know better than yourself and that they may acctually have some experience in running and tuning new engines, If you dont want advice then dont ask for it, just keep re-reading them there instructions and getting nowhere![&o]

Best of luck (your going to need it with your atitude)

l'm open for any advice from anyone and l do respect their experience & knowledge.

l do believed that thinking and understanding are different in everyone's mind, especially when confusion exist between communication.
So .....anyway, thanks for your replies and sharing your experiences

I have an Evo 50 with O.S. 50 SX-H. I've never under any conditions been able to use any more than 1 turn open on the main needle. Most of the time it's about 3/4 turns open. I questioned this myself since I've been running model engines for almost 40 years and I've never had one that needed a setting like this but that's the way this engine is. What ambient temperature do you fly at? The warmer it is outside the leaner the engine has to be set. Mine is typically about 3/4 turn on a cooler day (60-70 degrees) and 1 1/4 turns when it's hot and humid.

Mike

I run 30% heli fuel and my main needle is never more than 3/4 turn open. With 15%, I'd expect it to be closed even more than with 30%. As was mentioned before, set your throttle curve to control the headspeed. I think I only need 65% throttle to maintain decent headspeed in hover on my OS 50 powered Evo and max in normal mode is only 80% throttle.
Matt

Yea......
this is what l'm looking for....


l usually fly in an embient temp around 23~25 degrees; l'm flying at about 3/4 turn too with 10% nitro. and it is very sensitive at that point, only a few clicks will change a lot.

So....now l feel better with my engine because at least someone is having very simular question to me

l think the reason why the needle needed to be so small is the shape of the needle........ becasue this engine's needle is a bit different with the others.
this needle doesn't have a sharp end, so this may caused the problem. Or maybe l'shouldn't call this as a problem because this might be the characteristic of this engine.



thanks guys