24mm Water Tower Rocket

thingiverse

A fun and interesting rocket modelled after an older style water tower made to fly of 24mm motors (Estes D or E, for example). It launches off a 1/4" launch rod. You will need spacers for shorter D type motorsTo build this rocket you will need the following:A 20oz Hot Cocoa can. I got mine as a generic brand from Cub Foods but they're identical to the 20oz Swiss Miss cans.BT-80 (66mm) body tube, about 170mm of it. You'll be cutting this to length during assembly.BT-50 (24mm) body tube for the motor mount. 95mm of this will accommodate an Estes E motor.Shock cord. I used Kevlar line.An 18 or 24" parachute. I think I used a 24". But mine fell nose first from the sky on the maiden launch and survived, so it's pretty tough for a rocket.4 24" long pieces of 1/4" dowel for the legs.And of course the 3D printed parts included in this design. I recommend using Polymaker LW-PLA (pre-foamed so it prints like regular PLA) to save some weight, but this should fly with regular PLA.As you're building, consider your paint scheme. For the example photo in this thing I assembled the tank and the legs together, put the ladder on, then painted that whole part as a unit. I painted the top separately and the feet got a "cement" like look. For my other "Warner Brothers" styled water towers I painted the tank WITHOUT the guard rail yellow, then painted everything but the feet red.Assembly Instructions:1) glue the 24mm motor tube into the "bottom" piece. The bottom of the motor tube should be flush with the bottom of the bottom piece (where the retainer twists on).2) glue the "engine block" piece on top of the motor tube.3) run your kevlar shock cord through the hole in the engine block piece and tie it around the motor tube below. Add glue to keep it from unravelling. Coil up the shock cord and put it inside the motor tube to keep it out of the way for a bit.4) Prep your hot cocoa container by cutting the bottom and top lips off. I did this by running an x-acto knife along the metal of the bottom edge, and along the plastic lid for the top edge. Smooth these edges out with a big piece of sand paper on a table.5) Glue one side of this container to the top of the "bottom" piece. You might want to test fit it first to practice the operation.6) Glue the 66mm tube over the motor retainer and down into the bottom piece. There are slots in the internal "fins" in this piece to accept the 66mm tube.While these two tubes are drying, you can use the "top" piece to keep them aligned, but do NOT glue that piece on yet.7) Once those tubes are dry, remove the top piece if you used it for alignment, and glue the "Guard Rail" piece down against the Bottom piece.8) Put the 4 dowels through the "cross brace" piece until that brace is about half way. Measure and make marks on the dowels from the top so you have the brace aligned the same distance and glue it in place. Be careful with this step because you could twist a dowel and break the cross brace.9) Glue the tops of the dowels into the bottom piece to finish forming the legs.10) Measure the distance from the bottom of the cross brace to the bottom of the dowels for each leg and assuming you're not perfect, cut them all to the length of the shortest one. Then glue on the feet. They're angled so rotate them so they rest flat.11) Glue the "Top" piece on the tank.12) Glue the "TopLadder" flush with the top of the guard rail over one corner (leg) of the water tower. Then glue sections of the "Ladder" piece to finish the ladder going down. You'll have to cut one ladder section short when you get to the bottom.13) Push the Shock cord through the rocket and attach the nosecone and a parachute. I put some flame resistant cloth on the line first so that I wouldn't have to use wadding.There are two retainers included in the design. The regular motor retainer is for standard motors that do NOT have a lip on them, like Estes D or E motors. The "AT" motor retainer is designed for motors WITH a lip, like Aerotech composite motors. It has additional space at the bottom to accommodate that lip.Decorate the rocket to your tastes. For this one I imagined a small town named "RocketVille" and since a lot of these small towns decorate their water towers with images and figures, I imagined how my fictional town would decorate their water tower. I found the little alien and spaceman on thingiverse (links below) and scaled them to fit.Alien: https://www.thingiverse.com/thing:3200672SpaceMan: https://www.thingiverse.com/thing:4164979For the maiden launch I used an E12-4. It flew fine but I had the chute packed too tight so it came straight down nose first. The rocket survived, however (lost the alien and spaceman) so I re-packed the chute and launched it again on an E26-4w composite motor. On that launch it snagged the launch cord and yanked it out of the controller. That hampered it's altitude and the rocket almost crashed again, but the chute came out in time.Flight video: https://www.youtube.com/watch?v=dSOthep5dOs