Estes B4-4 Standard Engine(3) 010027 Some servos draw too much

Some servos draw too much power

deep finish

Experience faster acceleration

but may be compatible with other similar mini/micro crawlers as well

Compact 1/24 scale size for portability

Estes B4-4 Standard Engine(3) 010027 Some servos draw too muchThe 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 plugseverything you need for several successful launches. Ideal for hobbyists and STEM projects alike, the B4 4 delivers steady performance with every flight.