Rocket Project

Our goal:

Our goal with this project is to build a rocket that has a stable enough flight path to reach at least 400 feet.

This is our first rocket, so we're also learning new things, and experimenting with new tools and materials. This rocket will be almost 100% 3D printed. This is done because, first we as a team, are very familiar with 3D printing, and second its the cheapest option. As high school students with a limited budget, we need to find the best quality at the cheapest price.

This website is like a book, it will take you through each thing we did step by step.

Where to Start?

The firs thing we did to start off this project was to find model online of a already built rocket. We settled on this model HERE. We chose it only because it looked the easiest to build and is modeled to be 3D printed.

I printed out the model but I wanted a bigger rocket. So, we decided to reprint it at 150%. This was the basis of my rocket. The model provided didn't have any space of any avionics, and I wanted to have onboard tracking electronics so that were I stated.

Designing the Avionics Tray

v1 of the avionics

This is the first version of the avionics. The goal is to hold 2 pcbs on each side, but we only modeled one here. It was very bulky and I knew we could do better.

v2 of the avionics

This is version two of the avionics. We simplified it a lot, and it can now fit 2 pcbs, the only problem is its too heavy for the rocket,

v3 of the avionics

This version is a lot better for the pcbs, as it takes less space, but the battery's are too high up for the center of mass and so it always wants to fall down.

v4 of the avionics

This version we kept for quite a while and I thought it was pretty good, as it solved all our problems. We wanted to make another version though because we wanted to save on weight.

v5 of the avionics

This version is not fully 3d printed, and it uses carbon rods to support the top and bottom. This significantly saves on weight and also gives the batteries support in the middle between the pcbs.

final version up close.

To the right is the tray fully built and ready to be put in the rocket. We eventually will cut down the carbon tubes but We left them longer just in case.

PCB Design:

now we have to design the pcbs.

*The main objectives of the pcb are:

log the altitude and temps
record when the parachute deploys
reaches apogee.
launch the parachute charge

We're going to use Arduino Nano for all these tasks. We're also recording all data on an onboard SD card. To monitor temperatures and altitude, we'll use Adafruit MPL3115A2. When designing the PCB, we aim for a width of 30mm to match the avionics tray specifications.

The screw terminal is just for power

We've decided to split the work into 2 PCBs. The second one's task is solely to activate a relay. The first design is inspired by Richard Nakka's Experimental Rocketry Website, where he created a parachute deployment system using the 556 IC. The 556 IC combines two 555 timer ICs, which will trigger the deployment of a fuse to ignite a charge.

Once the PCBs arrived, we realized the original designs were too complicated for our needs. Instead, we opted for a simpler approach: using relays controlled by the Arduinos. The relays will toggle on and off, shorting batteries to ignite fuses, achieving the same functions with streamlined operations managed entirely by the Arduinos.

So, for version 2 of the deployment, we just used a relay that is connected to a transistor. Pretty simple circuit.

Redesigning the Rocket

So now we have the full rocket built, but its too heavy for a small c6-5 motor. It weights 264g without anything inside it. So, lets make it lighter, I want it to be under 200g.

The whole rocket is 3D printed a seen in the picture. We resin 3d printed the nose of the rocket can with the hook, and at first I really liked it. But, later we realized the nose doesn't need to be as big, and heavy.

So, back to the CAD we went. First, we designed a basic shape that we liked and printed it out. We added two squares on top to attach the parachutes, replacing the rings from the first version to save space and weight. We also gave the white filaments a fresh coat of paint. When you place them side by side, the improvements are noticeable.

Next is the middle body part of the rocket were the avionics will go. We're going to use the same model as we really liked the look and structure of it but the avionics are pretty short at only about 110mm long. That means we can cut it down to fix the avionics perfectly.

Now for the bottom cans. These models are fairly complicated, so it will be a bit more tricky. The main weight is in the fins. If we could somehow remove the weight in the wings, that would shave most of the weight off this part.

Instead of using PLA, we wanted to try something different. First, we made molds of the fins. We tried 3 different materials. The first and the last ones were both impregnated with carbon fiber sheets. The first was [place holder, I forgot the name]. This was the one on the left in the picture. It didn't turn out too well and had a lot of air bubbles. It was also about as heavy as the PLA.

The second one was polyurethane, and it turned out well, but again it was too heavy. The third one was epoxy resin. This one again had air bubbles but was significantly lighter than the other ones.

Rocket Motor Testing:

The next step was to create something for the parachute deployment system. What we designed were these small pill-shaped objects that can fit gunpowder and a bit of packing paper, with a hole at the top for a fuse. Here we are testing it with a small amount of gunpowder.

Next, we wanted to test it in the actual rockets. We built rigs to hold them, here they are:

They turned out great, exactly what we wanted. The only thing is, we forgot to connect the parachutes to the noses of the rockets, so we'll have to redo them and make the connections.

Open Rocket simulations & Data:

Now that we've got the basic rockets outlined, we wanted to run them through simulations. We used OpenRocket and calculated some things. First, it predicts that with an E16 rocket motor, we can achieve an apogee of 243m (729 ft). Additionally, the maximum velocity is about 70m/s (210 ft/s). If you want to see all the weight calculations, we made a spreadsheet with all the data HERE.

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