Hello!!! Could someone explain to me the difference between Hot and Cold plugs??? Thanks in advance...

GENERALLY, a hot plug is used with low percentage or no nitro fuel and a cold plug is used with high percentage nitro fuel. There are a multitude of variables in between, such as engine compression, barometric pressure/air temperature, type of exhaust system used, prop used, etc., but that is the basic idea. An engine using low nitro content fuel will generally have a lower internal combustion temperature and often needs a "hot" plug to run/idle properly. If you used the same hot plug with high nitro content fuel, you would run the risk of overheating the engine (nitro basically makes the combustion hotter).

Not unlike hot and cold plugs used for automobiles.

Does that answer your basic question? If you need more specifics, I'd suggest seeking assistance from someone with a more "scientific" background who is knowledgeable/has expertise in this area.

Hope this helps!

Nav:

If you've played much with gasoline engines, consider the plug heat to be the setting of the ignition timing.

Hot plug is advanced, the cold plug is retarded.

Bill.

Ya, but what's the difference? More Platinum, less Platinum, thicker winding, thinner winding etc, etc. Some one explained it to me once but I can't remember the answer. Happens more and more these days.

Denis

Thanks to all of you for your help!!!

Hot or cold refers to the plugs ability to dissipate heat. A cold plug is designed to transfer more heat than a hot plug and under the same set of conditions the cold plug would operate at a lower temperature. Glow plugs that operate in high nitro, high compression envoironments need to transfer a lot of heat so that they do not contribute to detonation or simply fail prematurely. That is why high performance engines ( such as racing) use cold plugs. On the other hand low nitro, low compression engine glow plugs need to retain heat in order to facilitate a smooth running engine from idle, transition and hgher speeds.

Navpro,

Check out the latest issue of Model Airplane News. There is a great article on what exactly a glow plug is and does. The author is writing another article for next month, I believe, covering how to choose one for specific applications.

Being relatively new to RC I found it very informative.

Eric