Use at your own risk. For the 29mm version and pictures of what the assembled tower looks like, go here: https://www.thingiverse.com/thing:2538353
This is a 3d printed end support for a launch tower for 38mm high power rockets. This is still a work in progress, but I've done one flight with this with minimum diameter 38mm rockets and a Loki J1026 motor (the Loki K627 is the only bigger commercial 38mm high power rocket motor). So far, everything worked great.
This launch tower is designed to slip over a standard 80/20 1010 square launch rail, so you can use it at any launch without any additional equipment. Be sure the check the fit onto the 1010 rail as some have finishes (or other things) that make their dimensions slightly different.
Bill of materials:
A little more than 1kg of PETG or similar filament. This is what I used: http://amzn.to/2y7Z0zs
4x #10 1-14" machine screws
8x #10 washers
4x #10 lock nuts
6x 1/4-20 x 4" lag bolts
1x 1010 launch rail (or use your club's launch pad)
2x aluminum extruded L
3x 3/4" EMT conduit
Adhesive backed Teflon tape. Here's what I used: http://amzn.to/2wn9Hlc
- Print 2 of the parts (takes approx 40 hours each plus about 0.6kg of filament)
- Sand/file/buff/machine the EMT conduit to remove any bumps that would damage your rocket
- Test fit the 3d printed parts on the 1010 rail, EMT conduit & extruded L. You may need to sand, file or Dremel a few things to get the perfect fit.
- Trim extruded L and/or EMT conduit to fit. Deburr the ends so they'll slide onto the 3d printed parts (For the 4' extruded L I used, trimming the EMT conduit to 44-3/16" worked well.)
- Sand/file/adjust the 3d printed parts as required
- Slide both 3d printed parts on the 1010 rail
- Screw the 1/4" lag bolts into place in the holes where the EMT conduit mounts. IMPORTANT NOTE: If you don't put these bolts in the 3d printed parts, the launch tower will likely fail which could be extremely dangerous or deadly.
- Tape one side of each EMT conduit with the PFTE/Teflon adhesive tape.
- Support one end of the EMT conduit with something to keep them level and slide into one of the 3d printed parts. Make sure the Teflon tape faces where the rocket will go. I used some car washing sponges to prop up the EMT. Repeat for all 3 EMT conduit pieces.
- Slide the other 3d printed part and EMT conduit into place. Depending on the fit, this may take some force. Use extreme caution not to damage your 3d printed parts when assembling the tower. If you damage your 3d printed parts, throw them away and print new ones. Do not use damaged parts in your rocket launch tower!
- Once all three EMT conduit pieces are in place, slide the extruded L pieces into place. Drill 3/16" holes through the L using the holes in the 3d printed parts to guide you.
- Use #10 machine screws, washers & nuts to attach the L pieces to the 3d printed parts.
- Test fit your rockets, inspect, & go fly!
Print at 95% infil or greater. Your prints need to be perfect, so make sure your layer adhesion is excellent and you use a good filament. Do not skip any of the metal parts and do not use any 3d printed part that has damage.