Introduction: Model Rocket With GoPro Nose Cone
Several years ago I made this: GoPro Model Rocket.
It was completely scratch-built and very complicated, and I've been nagging myself ever since to make an easier, better version. And this is it!
To simplify things right off, I started with a store-bought kit: the E-motor updated version of the classic Estes Cherokee model.
Modifications were made to the kit to allow carrying a camera, with the main change being a 3D printed, 2-part nose cone/camera pod I designed using Tinkercad.
The design was very simple to create, even with me being a complete novice to 3D designing and printing.
The rocket has been flown successfully many times now. Read on for all the details!
Step 1: Completed Model Overview
The new nose pod has top and bottom 3D printed parts with a clear section in the middle where the camera and an altimeter sit, wedged tightly into a piece of stiff foam.
The clear tube is from a plastic soda bottle.
When the camera is in position and turned on, the clear tube is placed over it and all three sections are simply taped together with electrician's tape. It's low-tech but works great.
A model rocket shock cord is what connects the rocket body tube to the bottom of the nose cone, with the parachute typically attached to the nose cone or close to it.
I took a different approach with this rocket and attached the shock cord to the top of the nose pod, with part of it actually sitting externally during the launch (the strip of white elastic showing in the first photo).
This way the nose pod hangs upright during descent, making camera footage so much better.
Check out the launch video and then we'll dig into the build.
Step 2: Launch Info
The total launch weight of this rocket is 11.5 ounces, and it has been flown successfully on Estes D12-5, E9-6, and E12-4 motors.
It was launched 6 times over the course of a couple of days. A 3D printed nose cone is relatively heavy compared to other types of model rocket noses, so this approach is not ideal if you're shooting for as high an altitude as possible. However for hobby rocketry like this, the most important thing to me is seeing successful launches and recoveries. Slightly larger and heavier rockets have slower and more realistic takeoffs, and they're less likely to vanish from sight and get lost. These two aspects lead to a much more enjoyable experience, especially for kids.
Step 3: Supplies
Here's what I used:
- Cherokee-E Estes Model Rocket kit. From what I can find, these are only available at Hobby Lobby stores. But any taller model that flies on D or E size motors should work, or you could always just build your own from scratch.
- Small GoPro-style camera
- Printed nose pod pieces (top and bottom)
- Plastic soda bottle with cylindrical mid-section, that fits around the camera. Cheap brands of soda like Shasta or Western Family often come in this type of bottle.
- 3D printer + filament. I have a Creality CR-10
- Miscellaneous rocket building supplies and launch equipment
Step 4: Designing Nose Pod Parts in Tinkercad
If you're not familiar with Tinkercad, you should just go in and start playing around with the shapes to see what it's all about. It's really easy to use!
When I was a kid I played around a lot in PowerPoint, making images by stretching, copy-pasting, aligning, rotating, and grouping simple shapes together.
Tinkercad uses all these same basic functions, but with a variety of 3D shapes to start with. You just push and pull to change sizes and shapes, or you can manually enter your desired dimensions for more precision. There is also the ability to group (or merge) negative "hole" shapes with solids, which creates hollow voids.
To design the two nose pod parts I began with calipers to get the needed real-life dimensions of the body tube and clear plastic tube.
The top nose part was designed using three simple shapes: half sphere, paraboloid, and tube. After adjusting to the desired dimensions, the paraboloid shape is turned into a negative "hole" and centered within the half sphere shape. These are then stacked onto the tube shape and grouped together, making a bowl-like hollow shape with an open bottom. The internal negative paraboloid shape makes this piece able to be printed without any additional supports.
The bottom nose part was designed similarly using basic shapes, however it was slightly more complicated. It's not perfect or as slick as more experienced designers would create, but it worked.
I'm including the .stl files here for anyone interested.
Step 5: Print
The designs were opened in Cura and settings adjusted to print with 1mm walls and 20% infill, then sliced and printed.
The parts were printed using basic PLA filament on a Creality CR-10 printer.
To get started with the basics of 3D design and printing, check out some of the site's classes on the subject: https://www.instructables.com/classes/tagged/3d-pr...
Step 6: Prime and Paint
I sprayed the nose pod pieces with a couple coats of primer, lightly sanded with 220 grit sandpaper, and then sprayed them with gloss black spray paint.
Step 7: Start Building the Rocket
I began building the rocket kit according to the instructions that came with it, but with modifications as outlined in the next steps.
Step 8: Larger Launch Lugs on Stand-offs
Launch lugs are little tubes that are fixed to the side of a model rocket that hold the rocket to the guide rod on the launch pad.
These allow the rocket to travel straight until it has enough speed to stay straight on its own.
I opted to make larger lugs than what came with the kit so it could be launched from a tall 1/4" launch rod. If you're interested, here is an instructable covering my homemade Model Rocket Launch Pad.
These new lugs were made with pieces of plastic drinking straw, which had thin painters masking paper glued around them. The paper shrinks tightly as it dries around the plastic and provides a glue-able surface to either glue the lugs directly to the rocket body, or in my case, to small pieces of balsa that act as stand-offs.
The launch lugs need to stand off from the rocket body in order for the launch rod to not interfere with the bulbous nose pod.
Step 9: Upgraded Shock Cord
For this rocket I opted to make an upgraded shock cord that is half kevlar cord, and half 1/4-inch elastic cord.
The kevlar portion was fixed to the motor mount tube as shown in the photos (see photo notes for details). The elastic portion is tied to the top end of this, just below the upper mouth of the rocket body tube.
This way the kevlar portion is near the heat and sparks, while the softer elastic portion is what rubs on the upper mouth of the body tube when the parachute is deployed. The theory is that the kevlar portion will last much longer and give me more flights, while the elastic at the top end will make "zippering" the body tube less likely
I ordered a small roll of 1mm kevlar cord, 15m in length on amazon.
Step 10: Finish Building Rocket
This particular rocket has a body made of two tube portions that are glued together with a small cardboard sleeve. These were joined together and the new launch lugs were attached.
The motor mount assembly was then glued in place according to the kit's instructions.
Step 11: Nose Cone Shock Cord Mount
As I mentioned earlier, the shock cord is mounted to the top of the nose pod.
A piece of kevlar cord with knots on either end was epoxied into a small hole drilled in the top of the nose cone part, so just a tiny loop was sticking out of the top. I attached a #10 fishing swivel to this loop.
Step 12: Camera Mount and Soda Tube
To mount the camera and altimeter to the lower half of the nose pod, I used a piece of foam floor mat with cut-outs made to simply wedge the gear in place.
This foam disc was hot glued to the lower pod part.
The middle section of a soda bottle was cut to the needed height (see photo notes for details).
Step 13: Shock Cord and Parachute
A four-foot length of 1/4" elastic from the sewing section in the craft store was used as the top half of the shock cord.
The kevlar portion was fished out of the bottom of the rocket and tied to the end of the elastic, then fished back up through the top. The elastic portion was tied to the swivel at the top of the nose cone. Drops of white glue were rubbed into the knots to keep them from coming undone.
A larger parachute was made using a piece of plastic table cloth material (found in the party aisle at the superstore). This is a 30" round chute with a 4" spill hole in the middle, attached to eight four-foot lines made of kite string.
Step 14: Go Launch Some Rockets
The body was painted with white, orange and red spray paints.
Ready for launch day!
Step 15: Success!
This project requires familiarity with building and launching mid-power model rockets, but zero prior experience with 3D design and printing. I'm proof of that! : )