Glow engines are small, 2-stroke engine
s that are used in radio-controlled
vehicles, including cars, helicopters, planes and boats.
They typically use glow fuel, which consists of a mix of methanol, nitromethane and lubricating oil. The oil is necessary as there is no inbuilt mechanism for lubrication. They typically have a single piston and cylinder.
They are called glow engines because of the way that you start them. A small glow plug is installed at the top of the piston. The glow plug is then made to glow red by connecting it to a big battery that warms it up -- this device is called a glow plug igniter. The engine is then started either using a pullstart or by using a starter box, similar to the way dragsters are started. Once the reaction gets started, the reaction becomes self-sustaining, and the glow plug continues to glow, and so the engine starts burning fuel and putting out torque.
They usually have a carburetor that controls the speed the engine is turning at. There are two variants, depending on the way it connects to the servo: barrel and slide.
There are usually several adjustment screws on a glow engine, the most important being the air-fuel mixture control screw. If there's too much air, not enough fuel, the engine will rev very high and likely be damaged. Similarly if it's got too much fuel, the engine will not run at efficiency or high speed.
Glow engines usually have to go through a complicated break-in procedure to make sure they work well where you are careful not to push the engine too hard.
They are commonly found in three sizes (measured in cubic inches): 0.12 (2.1cc), 0.15 (2.5cc) and 0.21 (3.4cc). Don't let the size fool you, despite the small size, these babies can frequently push out a horsepower or more. They run at high revs (about 25000rpm).
Well known brands include Picco, Ofna, Novarossi, Traxxas, HPI and OS.