The Estes B4-4 is an 18 mm single-stage model rocket engine designed for rockets weighing up to 3.5 ounces or 99 grams. Its moderate thrust and four-second delay make it well suited for small to mid-size models that benefit from a smooth boost followed by a balanced coast period before recovery system deployment.
Each package includes three B4-4 engines, four starters, and four starter plugs, providing the essential ignition components needed for multiple launches with compatible model rocket equipment.
The B4-4 delivers a total impulse of 5.00 N-sec with a maximum thrust of 13.20 Newtons or 3.0 pounds. Its thrust duration is approximately 1.10 seconds, followed by a four-second delay before ejection. This combination provides steady acceleration and predictable recovery timing for compatible rockets.
Each engine measures approximately 2.8 inches or 7 centimeters long and has an 18 mm diameter. The engine weighs approximately 0.68 ounces or 19.3 grams and contains approximately 0.27 ounces or 7.6 grams of propellant.
The B4-4 is compatible with a wide range of suitable Estes model rockets, including models such as the Alpha, Wizard, Baby Bertha, Big Bertha, Viking, Generic E2X, Cadet, US Army Patriot, Mongoose, Dragonite, Hi-Flier, Athena, Phantom Blue, Bull Pup 12D, Crossfire ISX, Comanche-3, Nike-X, Corvette, Starship, and Space Corps Centurion. Its predictable performance makes it a practical choice for hobby launches, classroom demonstrations, STEM projects, and club flying. Always verify the rocket manufacturer's recommended engine configuration before use.
Purchasers and users of Estes model rocket engines are responsible for following all applicable local, state, and federal laws, regulations, and safety standards. Model rocket engines must be handled and used only as intended and in accordance with established model rocketry safety practices. Estes Industries, LLC disclaims liability for personal injury, property damage, or other loss resulting from misuse, improper handling, or unauthorized use of its model rocket engines.
