Austis

Hi, how powerfull is a os50 supposed to be?
an how heavy planes is it powerfull enough to hover and pull out acceptable?

Cause I have on in a plane appr. 2.45kg, and it is just barely it can pull it out of hover, and the asp 52 engine seems to be a lot more powerfull.
(but the asp is not as reliable. not even close, my os dont quit in midair..it runs to I cut the throttle)
is that normal that the os50sx is not so powerfull?
using 15\15 fuel and os8 and 13\4 prop.

any help would be helpfull.

Bax

My Feedback: (11)

If you are using a 13 x 4 propeller, you've selected a too-large prop. Try a 12 x 4 propeller. Also, it looks like you are using a fuel with 15% oil content (that's what the 15/15 means: 15% nitro, 15% oil, correct?). That's too low. You should be using a fuel with no less than 18% oil content.

Austis

ok.. but is I going to get more power in vertical pullout if I am going down to a 12/4 prop?
I have heard that 14-4 is the ideal prop for 3d for this engine..
and 13-4 should be a much more powerfull prop than 12-4,, its bigger.. can the increasing rpm on the prop generate more power whith the smaller prop then???
So 15 oil is to low? hwat can be the consequense of continuing using it? Cause I cant find anyone that sell any 18% in my area. 15 is the standard everybody is using.

I need to learn so please explain good and full....

Austis

But how heavy planes is the os50sx able to fly 3d whit?
i mean what is the heavyest plane it would be any use to use it on?

Austis

And by the way... the 15% oil in the fuel I am using is a good quality so called aerosave oil... so I thought that 15% og that was just as good as 18%of oil of poorer quality..or am I misstaken here?

(its an all syntetic, high viscosity oil)

Austis

Are you there bax? I realy need to know the answer to my latest questions to if you please.. I want to know the most of my engines you know.

Bax

My Feedback: (11)

We have no knowledge of "aerosave" oil. It's not something we've seen in North America.

As far as aircraft weight is concerned, we don't have a number for you. 4-6 pounds should be OK for 3D, perhaps lighter, but it depends upon what you consider acceptable performance. Basically, though, for 3D-type flying, you want high engine RPM and lower pitches on the propeller. Turn the engine over 12,000 RPM and select the propeller that will turn that RPM and fly your airplane as you wish. You basically have to tune the airplane/engine/propeller combination to get the performance you want.

Austis

ok..
ill be trying to use a 12-4, then. and se if that helps, or else try other props as you reccomend,

But one last thing, about the oil:
You sayed I need at least 18%. (as also stated in my manual)But will that affect the power of the engine?
and since noone is selling more than 15% here, I either have to continue 15% or mix in som more oil by myself to my fuel.
But how important is that? noone I know use more than 15%. Never anything wrong whit theire engines. Can it be harmfull in anyway then?
And by the way, in the manual for my OS140Rx it says min15% oil. so why is it required whit more oil on my 50 than my 140?
and is only 3% difference of any imortance?

Hope you take your time to answer this for me...

Bax

My Feedback: (11)

We can only go by the recommendation by O.S. If the fuel is blended properly, you won't see any performance difference, if at all.

If you use less oil than recommended, you lose a margin of safety if you have a lean run. Smaller engines that turn higher RPM always need higher-oil fuel to insure that they receive adequate lubrication.