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Who can tell the the HS position on OS 110-P

Old 06-27-2010, 10:23 PM
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Default Who can tell the the HS position on OS 110-P

Hi everyone,
My OS110-P,using 15*8APC,15%coolpower,peak RPM~=8000,but the HS needle is only 3/4 turn ,is it too lean?

thank you.
Old 06-28-2010, 08:58 AM
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Default RE: Who can tell the the HS position on OS 110-P

The high-speed needle will be whereever it must be so that the engine runs normally. Normally, we would expect the high-speed needle to be at about 1-1/2 turns out from closed when the engine's been leaned to peak RPM. If the needle must be turned in much more than that, then we'd suspect that the needle seat in the carburetor or the needle, itself, have been damaged.

If the idle needle was set to be too lean, then you would have the needle farther out to lean it.

We normally run an APC 15 x 8 propeller on the FS-120 Surpass III, so a 15 x 8 would be a bit on the large size for the 110. Try a 14 x 8.

You can safely run the engine into the mid-to-high-9,000's with no problems at all. 8,000 RPM on the 15 x 8 would be about right, we'd think.

If the engine runs normally at your 1/2-turn out from closed, and it will run the tank until it is empty without having an RPM drop, then the setting is correct. You do not want the full-throttle RPM to decrease as the tank empties. That would indicate a too-lean setting.
Old 06-28-2010, 08:33 PM
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Default RE: Who can tell the the HS position on OS 110-P



If the idle needle was set to be too lean, then you would have the needle farther out to lean it.
and
You do not want the full-throttle RPM to decrease as the tank empties. That would indicate a too-lean setting.
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I can't understand ,would you mind explain it ,thanks</p>
Old 06-29-2010, 08:56 AM
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Default RE: Who can tell the the HS position on OS 110-P

I can't understand, would you mind explain it, thanks
Our replies in BOLD.

If the idle needle was set to be too lean, then you would have the needle farther out to lean it.
When the idle needle is set too lean, the high-speed needle must have a much richer setting to compensate, so that it would be more than 1 turn out from closed.

You do not want the full-throttle RPM to decrease as the tank empties. That would indicate a too-lean setting.
Our mistake. You have the pumped engine. The above comment does not apply to a pumped engine.

Here is our instructions for tuning a pumped engine:

Your O.S. Max engine with pump should be set up in a slightly different manner than a non-pumped engine. Most modelers tend to get them set with the mixture too rich.

One sign your engine's not adjusted correctly would be surging at full throttle. This almost always means it's too rich. Also, the idle may be too rich no matter what you do to the idle mixture. If the idle is leaned a lot, but it's still too rich, the high-speed needle's too rich and needs to be properly set.

To get a good setting, you need to use a tachometer. Once the engine's had enough running to accept being leaned to peak RPM, use the tachometer to lean the engine to its peak.

At full throttle, lean the engine until the RPM stops increasing. Continue to lean the engine to the first sign of RPM drop or detonation. When you get to that point, richen to the point just before you had the RPM drop or detonation and leave the needle there. DO NOT lean to peak and then richen your usual 1/4-1/2 turn.

With a good-quality fuel, the pump system will insure that the engine receives enough fuel. The regulator in the system will make sure that the mixture stays correct as you change the throttle positions. Fly the engine to see how the mixture may change as the engine unloads in the air. You may have to lean or richen slightly, depending upon how it acts. Once you've found the proper setting, you should note the change from the absolute maximum lean position. Now you have a repeatable setting for your engine.

Newer O.S. engines with pumps have a broader range for the needle setting, but you can use the same method for all of them.
Old 07-04-2010, 05:27 AM
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Default RE: Who can tell the the HS position on OS 110-P

thank you Bax.
Today I use 14*8APC,the max rpm is 9000,and the static thrust is only about 4kg

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