What-is-Glow

Two-stroke vs. four-stroke

You'll quickly notice that many R/C models give you the option of installing a 2-stroke OR a 4-stroke glow engine. How do you know which is best?

Two-Stroke simply means that the engine "fires" (ignites the fuel in its combustion chamber) with every revolution of the piston. Generally, they're a good place for new gas modelers to start. Two-strokes are easier to operate, less vulnerable to problems if misused, and deliver more power for their size and weight.

Four-Stroke engines fire once with every two revolutions. They consume less fuel, sound more realistic, and provide more torque - but cost more, are harder to adjust and require more maintenance.

How does a glow engine work?

Most glow engines have a simple ignition system that uses a glow plug rather than a spark plug - so there's no coil, magneto or points. The glow plug is heated by a battery-operated glow starter; meanwhile, the modeller uses a 12 volt starter to turn over the engine. When fuel enters the combustion chamber, it's ignited by the heated glow plug - and with that, the engine springs to life, instantly gaining the momentum to continue running after all the starter accessories are removed.

The engine's carburetor supplies the fuel and air needed for combustion. It has several adjustments. A rotating throttle arm controls the AMOUNT of fuel and air that enters the combustion chamber. The high-speed needle valve controls the MIX or proportions of fuel vs. air at mid- to high-speeds.

The idle mixture screw is similar to the high-speed needle valve, except that it controls the mix of fuel and air when the engine is only idling. When you've adjusted the high-speed and idle mixtures properly, your engine should operate smooth and steady throughout its speed range.

What is a glow engine?

R/C models are powered in a variety of ways. Sailplanes, for example, need no power source other than nature. But they're the exception. Nearly all R/C vehicles, aircraft, boats and helicopters require something to propel them into action.
Most gas R/C models use a 2- or 4-stroke glow engine, sized specifically for that model. Typically, they range in displacement from .049 cu. in. to 1.8 cu. in. ( .8cc to 30cc) - a variety that satisfies virtually any model's power requirements.
Glow engines cannot be operated with the same gasoline you'd get at a garage pump. They require a special fuel, called "glow fuel." It contains methanol as the base, with varying amounts of nitro methane to increase the energy that the fuel can provide. Oil, pre-mixed into the fuel, lubricates and protects your tiny engine as it pounds out amazing power.