Take your flights to the next level with the Estes F15-4 engine—a powerful mid-power engine designed for model rocket enthusiasts seeking longer thrust duration and higher lift capabilities. With 49.61 N-sec of total impulse and a max thrust of 25.26 Newtons, this engine is built to launch heavier rockets to stunning altitudes with confidence and control.

The F15-4 offers more than just raw power—it’s engineered for dependable, sustained flight. The 4-second delay provides a balanced coast period after burnout, ideal for deploying parachutes or other recovery systems at peak altitude. Its long 3.45-second thrust duration gives your rocket a smooth, graceful ascent, minimizing stress on airframes while maximizing trajectory efficiency.

This engine is a popular choice for larger rockets in the Estes Pro Series II line and other compatible 29 mm models. Its consistent performance makes it an excellent pick for hobbyists looking to upgrade from E-class engines while staying within the ease of single-use, black powder propulsion. Whether you're launching for sport, altitude records, or payload testing, the F15-4 delivers dependable performance every time.

With its powerful thrust profile, long burn, and mid-delay deployment, the Estes F15-4 is perfect for high-performance rockets weighing up to 21 ounces. Expand your launch capabilities and experience the next level of model rocketry excitement with this hard-working engine.

Compatible Rockets
Pro Series II Doorknob
Pro Series II Der Big Red Max
Pro Series II Nike Smoke
Pro Series II Optima

ATTENTION: Estes Industries, LLC and Echo Six LLC requires all purchasers and users of Estes® Model Rocket Engines to adhere strictly to all applicable local, state, and federal laws, regulations, and safety standards. The user assumes all responsibility for the safe and lawful use of Estes® products. Estes Industries, LLC and Echo Six LLC expressly disclaims any and all liability for personal injury, property damage, or other loss resulting from the misuse, improper handling, or unauthorized application of its model rocket engines.