Introduction: Bullet Bill Rocket
First Prize in the
Bullet Bill is a character that has appeared as an enemy in almost all of the Super Mario games from the very beginning. There are a few varieties, and their look and behavior has changed over the years. Like me, I'm sure you've been killed by a Bullet Bill many times.
I enjoy making crazy, non-traditional model rockets. I built regular ones as a kid, and I still find it extremely rewarding to test out new building methods and trying to push what I can do with simple, inexpensive materials.
I thought it would be neat to build a life-size Bullet Bill model rocket, as it provided all sorts of great challenges. I ended up building two versions, both of which I thought were beautiful in many ways, and they taught me a lot of new tricks.
Version 1 is covered briefly in steps 1 - 3. I began this first attempt with most of the planning focused on how to create a lightweight, visually accurate model of Bullet Bill. I didn't think much about its flight-worthiness until it was complete. At that point, I knew it surely wouldn't fly well, but thought, "Well, lets just go shoot this off and see what happens."
It didn't end pretty. The video is in step 3.
For version 2, which the photos show here, I applied the building techniques I learned with version 1, but paid closer attention to giving it a shot at actually flying. It was scaled down a bit, and built (somewhat) more like a real model rocket. The video of the launch of version 2 is in step 15.
Take a look at the steps involved and if you have any questions, please feel free to ask!
Step 1: Version 1 - a Quick View
This is a quick view of version 1. Both versions were built from foam core, cardstock, thin painters' masking paper, and lots of glue. Version 1 was 19 inches tall, and 12 inches in diameter (without the fins attached).
Construction details were very similar for both versions, and will be covered fully in steps 4 - 14.
Step 2: Version 1 - Finished Details
I was quite proud of the finished result of this rocket and was tempted to not even shoot it off, knowing the likely consequence.
For both versions, the launch rod goes directly through the middle of the rocket, and a cluster engine setup is used.
Step 3: Version 2 - Homemade Rocket Tube
After all the work for version 1 and the awful launch, I was surprised at how quickly I wanted to get back to this. I couldn't go down like that!
I began version two by making a homemade paper tube. I've been making my own rocket tubes for a few years, and I'll be honest--it's tricky, and can be messy and frustrating. But it is very rewarding to make your own lightweight rocket tubes.
I figured out this method through a lot of trial and error. I found that using a straight piece of pvc works best as a blank. I cut out strips of brown craft paper, and roll one tightly onto the blank. This is taped in place at the ends of the paper strip, making sure the edges of the strip don't overlap each other, and the entire strip sits snugly on the tube.
A second strip is painted with white glue (or wood glue) that has been watered down about 1 part water to 4 parts glue. This is carefully rolled over the first strip, being sure to cover the seams. Three or four layers of craft paper can be done, although for this I only did two. Each layer needs to be quickly rolled and pressed into place. The paper is extremely porous and the glue bonds the paper almost immediately, so you only get one chance. I've tried all sorts of other adhesives, and only white and wood glue have worked for me.
A final layer is added in the same manner, only using painters' masking paper. This type of paper is thinner and less porous than the craft paper, and takes finishing much better. It is sealed with a coating of the watered-down glue, and then lightly sanded with 220 grit sandpaper.
The paper tube is cut from the pvc and is slid off to dry. If you spread the glue thin and evenly, and don't stretch the paper too much, the tube will dry straight. If not, you'll have a warped and worthless tube, which I have made a lot of!
Step 4: Engine Mounts and Fins
The engine mounts were made using store-bought tubes that fit the size engines I was using (D- and E-size), and foam core.
Fins were made with 1/4" balsa. When gluing things like wood and paper, it's always best to put a thin layer on both surfaces, wait a few seconds, and then put them together. Once each fin was dry, fillets were added with more glue.
The most useful tools for this project were a circular protractor for laying out angles, scientific calculator for figuring radii and such, metric rulers, exacto blades, cutting mats, and a couple of good compasses.
Step 5: Bullet Bill Nose Cone
In version 2, Bullet Bill is the nose cone. This was made with a skeleton of foam core, just like version 1. The design was laid out on paper, carefully cut out with exacto blades, and pieced together like a puzzle. This was all glued with regular white glue. Once the glue was dried, I used a sharp utility blade to shave off the square edges of the circular pieces on the dome.
If you're interested in making something like this, I've attached a PDF with scans of the plan I made for version 2. The plan may not be precisely the same size as my original once you print it out and piece it together, but it should help you get going.
If you just want to make a lightweight model of the Bullet Bill character, it should work well for you. Cut out the cross section-piece and use it as a stencil to trace and cut out six pieces from foam core. Match a compass up to the plans to determine the various distances needed to lay out the circle pieces. Use a protractor to lay out where the notches will go to fit the cross pieces. Study these pictures carefully to see what you need to do. It will be challenging, but you'll get it!
Step 6: Nose Cone to Tube Transition
The bottom of the nose cone had to receive the top of the tube snugly, but not too tight. This should, in theory, pop off when it's time for the parachute to come out and bring the rocket safely back to the ground.
This area was made with light card stock.
Step 7: Bullet Ridge
The ridge on the bullet was made with pieces of card stock that were carefully measured, cut out, and glued in place.
Step 8: Covering
I found that painters' masking paper is a great covering for this type of model. Each piece of covering is cut out separately, painted entirely with watered-down glue, and quickly glued in place. As the glue-wash dries, the piece of covering stretches and becomes tight.
A light coating of glue over the entire surface helps strengthen the covering.
Step 9: Rocket Body
The rocket body was made of foam core that was built directly onto the tube and covered in the same manner as the nose cone.
Step 10: Painting
A few coats of primer were used to seal up the paper and make it ready for the final coat of paint. The rocket was painted with two coats of flat black spray paint.
Step 11: Details
I made some stencils to help me lay out the details for the rocket. The details were painted on with craft paint, and the rocket received a light coat of lacquer to seal it up and make everything shine.
Step 12: Parachute
The parachute was made from rip-stop nylon. I hit the edges with just a touch of flame to melt them and keep them from fraying.
Step 13: Launch Preparation
I did some balance tests and determined that I needed to add about 2 oz. to the nose to make this flight-worthy. I cut out one of the panels on the nose, added the right amount weight, and patched it up. The final flight-ready weight was just a little over one pound.
The parachute, wadding, and nose cone had to be prepared for launch with the launch rod in place. Three D-size engines were used.
The launch pad is homemade, and the launch controller is a modified Estes cheap-o that I hook up to my cordless drill battery. For cluster engine launches, I have an octopus-like attachment that works very well.
Step 14: Version 2 - Launch Video
Step 15: Final Thoughts
Bullet Bill version 2's flight was fantastic. The rocket flew straight, and it flew high.
The parachute failure just killed me, though.
It was due to a stupid, avoidable oversight in the design. When the chute deployed, it went straight into the nose cone, and there it stayed. If I had built a paper cylinder of some kind inside the back of the nose cone, it would have prevented the chute from being shot up inside of it and getting stuck. You can basically see what happened at the end of the video, and here in photos 4 and 5.
Overall, I was very happy with this project. Thanks for taking the time to look at this. Let me know what you think!
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