I have an upcoming launch at a school with a small field. Kids will be launching on 1/2A6-2, but I'm hoping to demo something with a little more noise. So... I'm designing an extremely slow rocket built on 2 x Estes BT-80 tubes (1 for body, 1 for tube fins). It currently sims out to about 42 meters apogee on an Aerotech F44W-4. Question: Has anybody tried creating tube fins that are entirely closed (capped at both ends)? Any reason this wouldn't be safe?