Main Rocket

Design Elements

Fig. 1: The original drawing of our rocket before the first launch. As you can see, we specifically planned out the rocket so the center of gravity would be above the center of mass. This is demonstrated by the two dots on the rocket. The one on the left is the center of pressure while the one on the right is the center of mass.

Before we could start physically building our rocket, we had to plan it out on paper, as shown in Figure 1. Not only did our rocket have to be able to launch as high as possible into the air, but it also had to be able to save the DataBot that was measuring altitude and CO2 levels for our rocket. To do this, we had to take into account where to put the DataBot. We decided to put the DataBot on the side of our rocket because we felt it would be the most beneficial for raising the center of mass of our rocket. Since we put it on the side, we could also add a counterweight that would increase the center of mass. Additionally, we decided to use four fins in the shape of quadrilaterals because of the success we had with four fins for the stomp and straw rockets as well as our knowledge of drag. These fins would be more aerodynamic than fins in the shape of triangles. Finally, we decided to make our nose six inches long (four inches out of the body) so it could be long but also secure within the rocket. We wanted our parachute to come out of the rocket, but not so soon that our rocket wouldn't be able to reach its highest altitude. Finally, we put the parachute inside of the rocket because we figured it would be the most convienient and simple way to deploy the parachute.

Although we ended up changing this design in the final launch (and even in the first launch by changing where the counterweight was placed), this design was a good starting point for us.

Fig. 2: Side view of our paper wrapping.

Fig. 3: Front view of our paper wrapping after the first launch.

Fig. 4: The engine inserted into our rocket.

Fig. 5: Bottom view of our rocket with the PVC pipe inside after the first launch. As you can see, the body wasn't burned because of the paper wrapping.

A key component of our design was how we inserted the engine into our rocket. Because we tightly wrapped paper around the engine (as shown in Figure 2), placed a paper clip into that piece of paper, and inserted a PVC pipe into our body (as shown in Figure 5), there was no way our engine would go through our rocket the wrong way. It also made it so we could reuse the body of our rocket, unlike other groups. As shown in Figure 3, the engine burned through the paper wrapping, protecting from burning through the body. This saved us so much time during redesign.

Fig. 6: Our first rocket along with the straws for the rocket to be able to sit on the launcher.

Fig. 7: Our first rocket. As you can see, we made our nose as sharp and curved as possible so it could be aerodynamic. Additionally, we built the fins just like we outlined in our design for maximum altitude as well as the least amount of extra mass below the center of pressure possible.

Fig. 8: Side view of our first rocket. The DataBot is represented by the wooden box closest to the nose of the rocket, and the counterweight is the lower wooden box. These opposite weights "cancel" eachother out on each side of the rocket and allow for us to manipulate the center of mass around the center of pressure.

Fig. 9: An idea we had for our second launch. We thought we could manipulate the foam to hold the DataBot while also deploying the parachute at the correct time. However, this idea didn't work because the foam was too difficult to cut and shape precisely enough to improve our rocket.

main rocket 11.mov

Video 1: Our final rocket design without the cup and parachute. We trimmed down our rocket by about an inch to make it lighter. We also took out the wooden nose and parachute device within the rocket because the parachute was packed too tightly for it to deploy from the inside of the rocket.

Fig. 10: Our final rocket with the adjustments made to the nose of the rocket. Underneath the red cup is the parachute connected to the DataBot and a wooden stand lightly connected to the body of the rocket.

Testing

Before we could launch our rocket, we had to make sure it was working properly so we could make last minute modifications if necessary. As shown in Videos 2-4, these tests helped us see that the most important aspects of our rocket worked, which was a positive going into the launch.

main rocket 15.mov

Video 2: Us testing the flight of our rocket before the first launch. As you can see, the nose faced the correct direction when the rocket was spun in a circle, meaning it worked extremely well.

1best.MOV

Video 3: Us testing our parachute with the mock DataBot. Just in case the parachute didn't work, we didn't want our actual DataBot to be at risk. So, we created a similar model that would replicate the mass of the DataBot.

main rocket 9.mov

Video 4: Us also testing our parachute.

main rocket 500.mov

Video 5: Us testing the rocket using the stomp rocket method. However, we failed to realize that since our second model's "cone" wasn't connected to the actual rocket, our cone would just go straight up without the body of the rocket. So, we had no way of knowing our rocket would work before testing.

First Launch

main rocket 14.mov

Video 6: Our first test launch. As you can see, our rocket didn't launch. This was because our ignitor wasn't inserted into the engine correctly. Once we fixed this issue by switching out the ignitor and inserting it a different way, our rocket launched.

main rocket 13.mov

Video 7: Our second test launch. As you can see, the rocket launched relatively high in the air, but it didn't launch high enough for the second charge of the engine to deploy the parachute. This was because the engine could only support 85 grams of mass, and our rocket was about 150 grams. Additionally, even if our rocket did have time to ignite the second charge before hitting the ground, the parachute was packed in too tight for it to deploy.

First Launch Error Analysis

Unlike other projects, we had the opportunity to look at the mistakes we made in the first launch and fix them for the second launch. First of all, we realized that the second charge of the engine wasn't a reliable and realistic ignitor for the parachute, especially since our rocket was so heavy. So, even though it was more aerodynamic, we scrapped our wooden nose for a plastic cup that could hold the parachute. Additionally, we wanted to keep the cup lightly attached to the rocket so the second our rocket fell to the ground, the cup and parachute would detach and save the DataBot. Additionally, because we moved the DataBot to the top of our rocket, we took off the counterweight to lower the mass of our rocket. Now, our rocket was about 112 grams, which was more reasonable than the previous 150 grams. We also added an extra straw so our rocket could launch from both rocket launchers.

Second Launch

main rocket 10.mov

Video 8: Our final launch. As you can see, the parachute deployed and saved the DataBot right before it hit the ground. However, the actual parachute was out of the cup since the peak of the rocket's altitude, meaning it got stuck before it could deploy. This was because the parachute got stuck on the fins and was stuck to itself.

week 4 stuff 2.mov

Video 9: Our final launch in slow motion.

week 4 stuff 3.mov

Video 10: The information recieved from the DataBot. The DataBot sensed CO2 levels in the air when it was launched. The point of the DataBot was to simulate the function of using robots to find concentrated pockets of air pollution to see how we could deal with it in the future. However, our rocket didn't launch as high as we would've hoped, so the CO2 levels didn't change a lot.

Second Launch Error Analysis

Although our rocket did end up working during the second launch, there were still some things we could've improved upon. First off, our parachute detached from the rocket much earlier than it actually deployed, meaning it got stuck before it could deploy. This was because the parachute strings got stuck on the fins of the rocket. In the future, we could keep the parachute farther away from the rest of the rocket, making sure that there is no way for the strings to get caught on the fins. Additionally, our rocket was extremely unreliable. Because the cup and DataBot weren't actually connected to the rocket, we weren't sure whether the rocket would fall apart or keep intact until we wanted it to. In the future, we should find a way to make our rocket more put together and reliable, especially for possible customer use. Finally, our rocket was too heavy for any CO2 levels to be read by the DataBot. In the future, we could find ways to cut down the weight of our rocket even more, or even use a double motor so our DataBot would be able to sense a change in CO2 levels. We could also find a way to make the cup more aerodynamic by adding a sharper tip or shaping the cup to be sharper by cutting it.

Page updated

Google Sites

Report abuse