As tribute to SpaceX’s inaugural human spaceflight, we built our own rocket swing, complete with motor actuated landing legs, take off/landing pulley, and coaxial dragon capsule emergency escape. Captain Delilah saved everybody with her amazing red button. Huzzah!
Here’s the Make video- extended cut:
This one took about a day for the main parts and another day or two to wrap up some details. I wanted to have it ready in time for the real Falcon launch party- so we managed most of it pretty quickly. The total cost for this was around a dollar because I didn’t have any paper mâché junk mail handy I had to actually buy a newspaper! The rest I had lying around.
It runs on one 3.7v LiPo battery- this runs the landing leg motor (& a little gearbox that was once a sweeper assembly on a roomba). This motor worked out really well because I didn’t want to use limit switches. You can buy these online but they’re kinda expensive. If you do, and you want the STL for the pulley (it has a hex axle) let me know! It draws around 500mA at stall and has enough power to hoist all 3 legs. (I actually tagged on a pair of NiMh AA’s specific to the motor circuit to improve the speed- but still good). All I had to do was add a pulley and string it up. There are some fiberglass struts along the top section, which support that assembly as well as strategic parts of the rocket shell. The two wooden discs form the body and welded steel cables and a loop support the swing assembly. I probably could have skipped the cables entirely and used the corrugated plastic board to support her 35lbs, but with this much overkill I can swing too!
Some particularly observant folks may notice that 80’s wallpaper interior of this rocket- that’s because this plastic sheet was formerly a prop from our stranger things halloween/Xmas project. It really makes for a cozy retro rocket interior as well. Actually, I should mention that it’s not a coincidence that the rocket diameter is 1.27″. That means you can use any 4’x8′ sheet of material as a surround. If I didn’t have this 5×10″ available, I may have used my flooring trick again (like I did for this starfield ceiling). Depot has giant rolls of flooring that I sometimes use when I want an uninterrupted, flexible, large sheet of something.
The ignitors are made from a random LED lighting PCB I had lying around, and some .004″ diameter nichrome I picked up on amazon for a toy project some years back. That part is pretty tricky- particularly for the emergency dragon capsule as 4 ignitors are wired in parallel, and we want them to all reliably ignite at the same time, so it takes some time to balance that out. My shorted segment was a probably about 1/2″ on those. They are fairly delicate each draw less than an amp at 3.7v. When you connect them and if you want a better chance of post-launch survival, you can connect them to the firework fuse as far away from the orifice as possible. Even so they run pretty hot at 3.7v so don’t get your hopes up and don’t hold your ignite button on too long.
I think the rest is pretty evident in the video- the legs are also corrugated plastic- the folded joints end up being pretty durable, really. The motor just runs to a spring loaded DPDT momentary switch wired in H-bridge configuration with center off. I have a supply of these on hand for manual motor control and they are super handy.
I added a plastic pulley and string guard alongside the steel pulley for the capsule eject functionality. The rope is standard Home Depot grade 1/2″ diameter- it’s pretty bouncy though- I’d have tried to get something with less stretch if I didn’t have this already on hand. The rocket can’t (well, shouldn’t) really support much weight all by itself. It would be best to keep it supported by the rope- we try to keep it low while loading Delilah up and increase tension as she sits down. Takes a little practice. The fireworks are the standard ground spinners you can get even in non-firework states. They fit nicely into the escape engines- note that some of these crackle and/or explode.. you don’t want those- just the ones that spin. They are hot glued in place and easily removed/replaced using a hair dryer.
The “engine” is just a 6″ sparkler type firework- another type that usually sits on the ground but is inverted in this application. Of note- if you do try this, make sure to have extra material to enclose the area where sparks and fire are shooting around. Nobody wants cooked toddler legs- especially your kid.