The Estes B4-4 is a reliable, single-stage 18 mm engine designed for model rockets weighing under 3.5 ounces. With a balanced 4-second delay, it's a perfect fit for smooth, stable flights and consistent recovery deployment.
Each 3-pack includes three engines, four starters, and four starter plugs—everything you need for several successful launches. Ideal for hobbyists and STEM projects alike, the B4-4 delivers steady performance with every flight.
The Estes B4-4 Rocket Engines are ideal for mid-powered model rockets that demand a steady climb and reliable deployment. These single-stage, 18 mm engines offer a balanced performance with moderate thrust, making them a great choice for both new hobbyists and seasoned flyers looking for consistent flight results. The B4-4 is specifically designed for rockets weighing less than 3.5 ounces, including the engine, and provides dependable altitude and ejection timing for small to mid-size models.
These engines feature a thrust duration that supports a smooth boost phase, followed by a 4-second delay that allows rockets to reach peak altitude before recovery system deployment. This delay makes the B4-4 especially suitable for rockets with moderate drag and stable flight characteristics. Whether you're launching in a park, field, or on a certified range, you can count on a satisfying launch profile with every flight.
Each package includes three B4-4 engines along with four starters and four plugs, giving you everything needed for multiple launches. The extra starter adds an extra level of convenience and value—ideal for those who like to be prepared on launch day. Estes' attention to safety and performance ensures that each engine delivers the reliability that model rocket enthusiasts have trusted for decades.
Whether you're conducting a classroom demo, building your personal fleet, or hosting a weekend launch session, the B4-4 engine is a proven performer. Its moderate power and predictable deployment make it a smart option for a wide range of Estes kits and compatible low- to mid-weight rockets. Get ready for consistent results and fun flights with this time-tested engine.
Estes B4-4 Model Rocket Engines are compatible with a large number of Estes rocket kits, including but not limited to:
Total Impulse: 5.00 N-sec
Time Delay: 4 Seconds
Max Lift Weight: 3.5 oz (99 g)
Max Thrust: 13.20 Newtons (3.0 lbs)
Thrust Duration: 1.10 Seconds
Length: 2.8 in. (7 cm)
Diameter: 18 mm
Weight: .68 oz. (19.3 g)
Propellant Weight: 0.27 oz (7.6 g)
