ENGINES FOR MODEL ROCKETS. 3 - C6-5 Engines. 3 - Igniters. 4 - Igniter Plugs. 001614 - C6-5 Engines Description. The Estes C6-5 engine is a single stage engine designed for model rocket flight. This engine is a standard engine designed for flights in rockets weighing less than 4 ounces, including the engine. Each package includes 3 engines, 3 igniters and 4 igniter plugs.