New To R/C - R/C Engine Terminology

R/C Engine Terminology
Here are some terms and function that may come across with various R/C engines.

Schnuerle Porting
A standard 2 stroke engine usually has one fuel inlet port on the side of the cylinder opposite the exhaust outlet. On a Schnuerle ported engine there are several fuel inlet ports on three sides of the cylinder allowing more fuel to flow to the combustion chamber. This gives more power than standard porting. A Schnuerle ported engine is usually a little more expensive because of the higher manufacturing costs involved.

Long or Short Glow Plugs
There are two lengths of plugs available. The short plugs are used on engines of .15 cu in displacement and smaller. The long plugs are used on all engines greater than .15. It is best to follow the manufacturers recommendations.

Idle Bar Glow Plugs
An Idle Bar Glow Plug has a metal bar across the bottom of the plug which prevents raw fuel from dousing heat from the element during idle. Idle Bar plugs have long been a topic of discussion at the flying field. Many flyers swear by them while others question their usefulness.

Long Stroke
The stroke of an engine refers to the distance the piston travels from top to bottom. In a Long Stroke engine this distance is a bit longer than on the standard engine making the engine stronger in torque and operation at lower RPM. Quite often an engine is "Long Stroke" if the stroke distance is greater than the diameter of the piston.

A Selection of PropellersPropellers
The size of an aircraft propeller is described by two numbers; the diameter times the pitch in inches. For example, a 10 x 6 propeller is a propellor of 10" in diameter with 6" of pitch. The diameter is simply the length of the prop. The pitch is described as the distance the propeller will travel forward in a perfect or solid medium at 100% efficiency in one revolution. That is to say, if you were to rotate your 10 x 6 propeller exactly once, your plane would move ahead 6", assuming this could be done with 100% efficiency.

Different sizes of engines require different size propellers to keep their operating RPM's within the optimum range. But it is useful to know, that the same size prop made by two different manufacturers could well perform differently. Experimentation is the best way to come up with the best performing propeller fro your particular engine and aircraft combination. As a guide to the right propellor to use on your engine see 'Choosing The Right Propellor'. Again, it's best to follow the manufacturers recommendations.

Engine Thread & Shaft Sizes
It is important in knowing the shaft size of your engine when ordering spinners, spinner adapter nuts, safety spinners and prop nuts.