A3-4T Engines

The Estes A3-4T engine is a single-stage mini model rocket engine built for lightweight rockets and designed to deliver consistent, reliable performance. With a total impulse of 2.50 N-sec and a peak thrust of 6.80 newtons (1.5 lbs), this 13 mm diameter engine provides a solid boost for rockets weighing up to 2.0 ounces (57 g). Its 4-second delay allows for a steady coast before the ejection charge activates—helping ensure a controlled flight and dependable recovery system deployment.

With a thrust duration of 0.60 seconds, the A3-4T delivers a quick, moderate-power lift-off that’s ideal for rockets requiring a longer delay before ejection. Whether you're launching a favorite kit or testing a new build, the A3-4T supplies reliable thrust and timing that supports a predictable flight path—perfect for hobbyists looking for dependable performance from a mini engine.

Each engine pack includes four A3-4T engines, four starters, and four starter plugs—everything you need for multiple launches. The included starters and plugs ensure reliable ignition with every flight, eliminating the need to purchase ignition components separately and making launch preparation simple and efficient.

Known for its consistent performance and Estes’ trusted manufacturing quality, the A3-4T is a dependable choice for model rocketeers flying lightweight rockets. Its proven design, balanced thrust, and predictable delay make it a go-to engine for reliable single-stage flights.

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