Glowplugs for model engines

Glowplugs serve the same purpose in model engines, as spark plugs do in automobile engines. As in big engines, glowplugs are differentiated by their heat values.

Heat values of Glowplugs
Glowplugs are available in cold, medium and hot versions. We differentiate glow-plugs by the thickness of their glow wire and the size of the glow chamber. In addition the selection of the metal alloy (Platin-Iridium-Nickel) has a substantial influence on the heat value and durability of a glowplug.

Through a carefully balanced assortment of only 3 different types, robbe glowplugs are suited for nearly all applications. For new engines with high compression we recommend the robbe glowplug no. 4 (standard) and no. 5 (cold). Run-in engines may be equipped with the robbe glowplug no. 3 (hot).

 

How Glowplug Ignition Works
With a glowplug engine, ignition is initiated by the application of a 1.5-volt power source. When the battery is disconnected, the heat retained within the engine's combusion chamber remains sufficient to keep the engine running. Ignition timing is 'automatic': At higher rpm, the plug becomes hitter and, appropriately, fires the fuel/air charge earlier; at reduced rpm, the filament becames cooler and ignition is retarded.

When to replace the Glowplug
Apart from when actually burned out, a plug may need to be replaced because it no longer delivers its best performance, such as when:
- Filament coil has became distorted
- Filament surface has roughened while
- Foreign matter had adhered to filament or plug body has corroded
- Engine tends to cut out when idling
- Starting qualities deteriorate