Integrated Fin Can for supersonic flights on 38mm minimum-diameter rockets
I have flown this several times to Mach 1.9 (according to RockSim) since the fins are perfectly aligned every time. All you have to do is print it (10% fill, normal speed print, with rafts) and epoxy the fin can a quarter-inch or so above the bottom (so you can use a ring of duct tape for motor retention) of a 18" (or longer) strong 38mm motor/body tube (it is perfectly sized for Blue Tube) and tape a golf ball to the top (range balls are free nose cone + weight, which you will need). If you have extra epoxy, lather it on the fins for a smooth finish and extra strength. The launch rod lugs, rail guides (which I highly recommend for rigidity) and fin fillets are built into the print. Ready to fly in 5 minutes with single use Aerotech motors (I have flown the J270, I140 and I280 to go supersonic).
Launch photos: https://www.flickr.com/search/?text=3d%20print%20rocket&sort=date-posted-desc&user_id=44124348109%40N01
Here is a talk I gave on 3D-printing and rocketry at MakerFaire: https://www.youtube.com/watch?v=IBMMPBpZeHo
Blue Tube supplier: http://www.alwaysreadyrocketry.com/about-us/blue-tube-2-0/
For 38mm flights, I also add a cheap aluminum GLR rail guide to the upper part of the motor/body tube (don’t use a rod for I or J motors; when I did, it snapped two legs off of my Aerotech Mantis launch pad, laying it flat! That’s some serious whiplash!): https://giantleaprocketry.com/products/components_launch_systems.aspx#Acme_Conformal_Launch_Guides
Single use Aerotech motors (can only be sold to people with Level 1 or Level 2 certification): http://www.wildmanrocketry.com/ShowProducts.aspx?Class=82&Sub=107&Sub1=118