B4-4 Engines JustRight The standard 18 mm diameter

The standard 18 mm diameter makes the A8-5 compatible with many Estes kits used in education

This parachute helps students apply concepts such as gravity

Explore Single Stage and Two Stage Flight

sustained boost that supports safe

strengthens STEM instruction

B4-4 Engines JustRight The standard 18 mm diameterThe Estes B4 4 Engine is an excellent educational tool for classrooms, science clubs, and STEM enrichment programs. This 18 mm, single stage engine is ideal for student built model rockets weighing less than 3. 5 ounces, offering a reliable and predictable flight experience that supports hands on learning in physics, engineering, and aerospace topics. Its moderate thrust and 4 second delay give students time to observe key phases of flight, from