A 3 engine cluster Estes Pro Series II style booster. It's design to use 3 ESTES 29mm F15 black power motors. The sectional view shows the flame tube that will pass and channel the ignition gases to ignite second stage.

I plan to use this booster as stage 1 of a 3 stage MAMMOTH (Estes kit). Stage 2 (Estes Pro Series II E2X Booster) will use a single F15 and third stage will be also a F15. I wonder how high it will go, I expect will over 2,000 feet ( possible need FAA waiver).

The entire booster is 3D printed on a Creality 3D® CR-10 large format (300/300/400) 3D printer. Be warn this part will not fit normal desk top printers. The model is 284.0/284.0/233.0mm. Also it take almost 60 hours to print.