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Phil Noel · 02-22-2010, 06:37 PM

The demands on any heli engine is quite different then the demands on the same engine in an airplane. That is why the most important difference between a nitro airplane engine, and its' helicopter equivalent, is the carburator, not the heat sink which is more visible.

As you throttle back on the airplane engine, its' rpm drops. So the fuel draw will drop also, as will the amount of fuel required to turn the prop at the lower rpm. Very convenient.

Not so in a heli engine. Here we see the load drop as we drop pitch, but we set up a throttle mix to keep the engine/rotor speed the same as when it is wide open. This means that as we lower the load on a helis engine, we do not lower the rpm of the engine. Consequently, the fuel draw stays high, but the amount of fuel required for the lesser load, drops!!

As you can see, the metering system requirements of the heli's carb is very different then those in an engine driving a fixed pitch airplane prop.

Also, as the heli engine will be operated at a constant high rpm throughout the flight, it is important to break it in properly by preferably running it in a low load setting, while it is at, or close to, the rpm you will be flying at.

Unlike nitro engines, it is best to run them in at a leaner setting then you would with a ringed nitro engine. It is best to break them in at needle settings that would be much like the settings you will be using for normal flight. But what you do want is a slightly higher oil content for the break in.

There are many great oils available for our R/C heli gasoline engines, that all work well. The synthetics are the best because they do not generate as much internal coking as do the others. But if you run too heavy an oil mix, even they will coke up the engine faster then would be desireable.

Since I discovered Amsoil Sabre 100:1 (I use it at 65:1) about 5 years ago, I have stuck with it.

http://www.amsoil.com/storefront/atp.aspx

Unfortunately it is a bit hard to come by. As there are a number of fellows locally that have also discovered its' great lubing qualities for their gasser engines, we usually get together and order a case of the 8oz. bottles to devide among ourselves.

02-22-2010, 06:37 PM	#59
Phil Noel RCC Expert Contributor I am: Phil N. Join Date: May 2004 Location: Lower Mainland B.C. Radio of choice: Futaba 14MZ # of RCs: 15+ Feedback: 0 / 0% Posts: 951 Total Props: 11	Re: New Century Radikal G20 Gas Helicopter The demands on any heli engine is quite different then the demands on the same engine in an airplane. That is why the most important difference between a nitro airplane engine, and its' helicopter equivalent, is the carburator, not the heat sink which is more visible. As you throttle back on the airplane engine, its' rpm drops. So the fuel draw will drop also, as will the amount of fuel required to turn the prop at the lower rpm. Very convenient. Not so in a heli engine. Here we see the load drop as we drop pitch, but we set up a throttle mix to keep the engine/rotor speed the same as when it is wide open. This means that as we lower the load on a helis engine, we do not lower the rpm of the engine. Consequently, the fuel draw stays high, but the amount of fuel required for the lesser load, drops!! As you can see, the metering system requirements of the heli's carb is very different then those in an engine driving a fixed pitch airplane prop. Also, as the heli engine will be operated at a constant high rpm throughout the flight, it is important to break it in properly by preferably running it in a low load setting, while it is at, or close to, the rpm you will be flying at. Unlike nitro engines, it is best to run them in at a leaner setting then you would with a ringed nitro engine. It is best to break them in at needle settings that would be much like the settings you will be using for normal flight. But what you do want is a slightly higher oil content for the break in. There are many great oils available for our R/C heli gasoline engines, that all work well. The synthetics are the best because they do not generate as much internal coking as do the others. But if you run too heavy an oil mix, even they will coke up the engine faster then would be desireable. Since I discovered Amsoil Sabre 100:1 (I use it at 65:1) about 5 years ago, I have stuck with it. http://www.amsoil.com/storefront/atp.aspx Unfortunately it is a bit hard to come by. As there are a number of fellows locally that have also discovered its' great lubing qualities for their gasser engines, we usually get together and order a case of the 8oz. bottles to devide among ourselves. __________________ Phil Noel Leisure-Tech Products Last edited by Phil Noel; 02-22-2010 at 06:47 PM.