RCs That Have Glow Engines: While electric RCs have motors, some RC vehicles -- almost always hobby-grade -- have engines that are powered by liquid fuel. Those that use nitro fuel have nitro engines -- also called glow engines.
Why It's Called a Glow Engine: Engines that use nitro fuel have a glow plug. Similar to a spark plug, the glow plug is so named because a filament inside the plug glows when the plug is hot. An engine with a glow plug is commonly called a glow engine.