RC Glow Engines

What is a Glow Engine?

Electric models use small motors, powered by battery cells. Those motors should not be confused with glow engines — which are actual internal combustion power plants that form the heart of any “gas” or “nitro” powered R/C model. 

Most nitro 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 1.2 cu. in. (80cc to 20cc) — a variety that satisfies virtually any model’s power requirements.

Glow engines cannot be operated with the same gasoline you’d get at a filling station pump. They require a special fuel, called “glow fuel.” It contains methanol as the base, with varying amounts of nitromethane 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. When you get your new engine, first examine it carefully for any obvious defects. Read the operating instructions closely. If the manufacturer suggests a specific procedure for breaking in the engine, by all means, use it! 

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

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 nitro modelers to start. Two-strokes are easier to operate, less vulnerable to problems if misused, and deliver more power for their size and weight.Two-Stroke Engine

Four-Stroke

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.Four-Stroke Engine

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 modeler uses a recoil starter, Electric 12V Starter or Starter Box 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.

Tower Hobbies has many books available with helpful information about glow engine operation and maintenance.

How do I care for a glow engine?

If you take good care of your engine from day one, it will reward you with a long life of optimum performance. Proper maintenance is not difficult. Some of the best tips include:

  • Keep your engine clean.
  • Keep your engine dry.
  • Use an after-run engine oil
  • Use a brand-name fuel that contains at least the amount of oil recommended by the engine manufacturer. 
  • Use fuel with the proper percentage of nitromethane, as recommended by the engine manufacturer.

Other types of R/C engines 

Models designed for first-time R/C hobbyists will not require any power plant other than an electric motor or 2- or 4-stroke glow engine. Other types of engines are used at more advanced levels of the hobby, however. For example, some R/C jets are powered by ducted fan engines, and some large-scale aircraft use genuine gasoline engines similar to those found in chainsaws and “weedeater” lawn tools.

What accessories will I need? 

For whatever engine that you order (or is included with your model), check the “Accessories Needed” link on its towerhobbies.com product page. There, you can quickly find out what additional items are required to run it.

All glow engines will require glow fuel, fuel line and spare glow plugs. You may also need a muffler or tuned pipe. Most model airplanes require an engine mount, which may or may not be included with the kit. All model airplanes and many boats will also require propeller(s).

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