Basic model rocket

Print the cone at 99% scale and print the fins and cap at 101% scale. Other wise they might not fit properly. Do not change scale of the body as it is sized to perfectly hold the engine.

The supports are because there is a small brim inside the rocket body that prevents the engine from pushing up out the nose. Use support blockers on the threaded parts of the body. The cap and fins do NOT need supports but the nose cone does.