Mini M&M Rocket

Last crawled date: 4 years, 3 months ago

While joking with my son that I need to stop buying Pringles because I keep making rockets out of the tubes, he held up a package of mini M&Ms we'd just bought for my grandson and said "I bet you'd make a rocket out of this!"
So I did. And here it is.
Build instructions:
There are two different versions of the fin unit.
1) Uses a BT-5 (13mm) motor tube. You'll need a motor block if you build that one. It's slightly lighter than the all plastic one, but more hassle. It works though. I built one this way. I believe the weight difference is negligible but this one may hold up better long term than the all plastic one.
2) An all plastic one sized for Estes 13mm motors. Held up fine for the one launch I've done so far, time will tell if it lasts for long.
Build Notes:
I use 250lb kevlar string as a shock cord. It's fire proof...enough.
I also use a small square of nomex cloth instead of wadding. These are both visible in the photo.
Use a streamer for recovery, it's a light rocket.
Drill a hole in the cap and run the shock cord through it, knotting it above the cap and gluing it in place. Then cut off the hinge. I didn't do this at first and 3 of the five rockets lost their cap at apogee when it got blown off the rocket. That hinge is NOT strong enough.
I had to glue 3 10-24 hex nuts to the lid for weight. They came off on the initial launch, you can kind of tell as it reaches max height in the video. Be sure to sand the lid before you epoxy them down (which is what I did the second time - and photo'd).
As an alternative, you can print the nosecone I've now included with this thing. 20% infill should be fine and it will weight the nose without gluing on nuts. There is a recess in the nosecone for the knot from the shock cord to fit.
This nose cone doesn't look as "stock", but it works fine and may improve performance.
These mini M&M containers have a seam from the molding you can see about 2mm from the bottom, I just cut there and sanded smooth. The fin unit then slips inside. Epoxy it in, then epoxy the fins down.
It's meant to be a fun cheap disposable rocket, basically, and I expect that over a few launches the tube might warp from the heat. But its easy to build and fun to launch.
I used an A10-3T in the video, but I think it was a bad batch as none of the four launches I did went as high as they should have. This rocket empty is only 27g, so I expected the flight to be higher. Nevertheless it flew fine as you can see in the video below.
https://www.youtube.com/watch?v=DaicyF86u1s&feature=youtu.be