Estes 10021 B6-4 Bagged Rocket Engines with Starters and Plugs 3 Pack The Estes B6-4 engine is a versatile and dependable choice for launching standard-size model rockets. Designed for rockets weighing less than 4.0 ounces, it provides a solid boost with a 4-second delay for smooth parachute deployment. Ideal for beginner to intermediate rocketeers, the […]

Estes 10055 B6-4 Bagged Rocket Engines Flight Pack Ready to boost your mid-sized model rockets? The Estes B6-4 Engine Flight Pack delivers consistent performance with a 4-second delay and 0.8-second thrust duration-great for rockets up to 4.0 oz. With a total impulse of 5.00 N-sec, it offers a reliable balance of power and stability for […]