Honest John for Loc 3" tubes (Updated version)

thingiverse

This should be made instead of my previous Honest John for Loc 3" tubes as this one is actually much more to scale.I have not built this rocket myself because I do not have the requisite body tubes, but it's modelled after my "Pringles" version and is only slightly larger. Theoretically it should fly just fine because that version has the CG well ahead of any configured CP I can generate in OpenRocket.You should be familiar with building high power rockets before attempting this. Though this rocket will be at the lower end of that spectrum, the particular techniques for HP rocket assembly and safety are not covered here.SUPPLIES NEEDED: Loc Precision 3" body tube. This tube should be cut to 440mm to keep the scale appearance correct.A 29mm or 38mm motor tube and retainer. Shock cord, of course. Screwbolts for the nosecone and shock cord mountA parachute, probably 45" or above3mm nuts and bolts (25mm long) PRINTING:There are two versions of each size of the fins, oriented for proper printing. Print the "Fin##_4X" version if you're miserly about filament and REALLY trust your 3D printer to print tall thin things with NO wobble to make layer lines. Or print the "Supported" versions, which print beautifully and you just need to snip the supports off and sand the fins a little. I had to move the z height in cura down .1mm to get the raft to form properly under the fin. Print the fins with some infill, for my Pringles version I used 10%. You only need 4 of the same fin so decide if you're using a 38 or 29mm motor mount and print the fins with the appropriate number associated with them.Otherwise use your best judgement. Nothing should need supports and everything is oriented for best printing. Things that need multiple copies have X in their name. You'll figure it out. It's not rocket science...well...it kind of is, but not that intense.BUILD NOTES:The design has the motor tube going through the tailcone, all the way through the bottom body tube and then up to about where the BodyBand is, but use the length you think best. Glue the retainer to the bottom of the motor tube, then glue the motor tube into the tailcone until the retainer is flush with the bottom. You can use the "TailConeTop" piece (don't glue this in), to insure straight alignment.The fins go through the slots in the tailcone and are glued to the motor tube. Test fit these first as you may need to sand the taps down a little. The fin should meet the motor tube on the outside. Note the bottom of the fins WILL NOT be flush with the bottom of the tailcone. They should be a few millimeters higher. Once the fins are in place you can remove the "TailconeTop" piece and do internal and external fillets. Toss the "TailConeTop" piece if you want. It could be glued in place once the fillets are done, but it's just extra weight and you don't need it.It's assumed you know how to mount rail guides and how to align them. Drawing a line on the body tube would help.There is a standoff base that goes inside the tube and has a spot for a 3mm nut in it. Glue the nut in. Drill a hole in the body tubes along the line you made where you think the standoffs should go (be sure to leave room for the shoulders of parts). Using a 3mm bolt (I think mine were 25mm long), glue the standoff to the outside of the rocket using the bolt through the tube and into the base to hold it in place. Don't glue the screw, you'll want to remove that. Consult the included image for detail if confused. The end result should be an inner base, an outer standoff, with the body tube sandwiched between them. Note that the standoffs have a smaller hole in them. This is for a 2mm rod (but a piece of 1.75 filament could work) that should jut about 3mm above the standoff. This helps align the RailCap or LugCap pieces. The 3mm screw should go through the cap you plan to use, through the standoff, through the tube and base and into the nut. The design allows you to switch between using rails to launch, or 1/4" rod. I'd probably opt for the rail on this model.There are two versions of each size of the centering rings. Pick the size that matches the motor tube you want and then choose whether you want the "notched" version or not. If you've glued in your launch standoffs you'll probably want the notched version as that notch should slide over the StandOffBase parts glued inside the tube. I'd try to make sure the centering rings aligned with the upper standoff so the base part fills the notch. You probably want to drill a hole in whatever centering ring you use for your shock cord to mount to.Glue the completed fin assembly with tailcone into the bottom of the body tube. If you used the notched centering ring, make sure it slides over those base parts inside. Hopefully you planned ahead and made sure that notch falls between two fins.The rest is straight forward. Glue the nosecone pieces together after putting an eyebolt in the bottom part. Attach your shock cord and parachute as you see fit. Put a suitable motor in it and have fun.Please post makes if you build this! I'd love to see them!