Groucho Duke's 38mm high power rocket launch tower

(4-fin version removed because it's missing part of one of the bolt holes.)

Updated with v2b and v2b 4-fin versions. These versions fit on a smaller build plate and are better overall designs. Unless you need the older (v2) version, I recommend using one of the new ones.

This is a 3d printed end support for a launch tower for 38mm high power rockets. I have flown from this tower with up to a Loki J1026 and set multiple world records with it.

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.

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

Bill of materials for the 3-finned tower versions is below. You'll need more of the screws, washers and extruded L angle if you're making a tower for a 4-finned rocket.

• A little more than 1kg of PETG or ABS filament. Do not use PLA or any other lower temperature filament for this.
• 4x #10 1-14" machine screws
• 8x #10 washers
• 4x #10 lock nuts
• 6x 1/4-20 x 4" bolts
• 1x 1010 launch rail (or use your club's launch pad)
• 2x aluminum extruded L angle (1/16" thick with 3/4 and 1/2" sides) - http://bit.ly/16thALAngle
• 3x 3/4" EMT conduit
• Adhesive backed Teflon tape. Here's what I used: https://www.amazon.com/gp/product/B00ZAUR6M0/ref=as_li_qf_sp_asin_il_tl?ie=UTF8&camp=1789&creative=9325&linkCode=as2&creativeASIN=B00ZAUR6M0&linkId=aabd3066efd8200f335fe836c3fc05a3

Contruction:

• Print 2 of the parts (takes approx 40 hours each plus about 0.6kg of filament, depending on your printer and settings)
• 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!