Passionate Pursuit:
3D-Printed Rockets
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I embarked on this project as a Passionate Pursuit, a semester-long project funded by Olin College for one non-degree credit. The inspiration came from some work I had done over the winter break in which I worked with children (ages 3 and 4) from my former pre-school who wanted to design and build a functioning rocket/submarine. By some miracle, the project was a success and it made me want to take it even further.
After acquiring some basic model rocket supplies like a launch system, parachutes, engines, and wadding, I got to designing. The first iteration, the MR1, was designed with structural integrity in mind. The walls of the fuselage were likely much thicker than they needed to be, and the entire rocket weighed about 250 grams fully loaded. |
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The first launch of the MR1 was reasonably successful but definitely left some room for improvement. It reached about 400 feet after taking off at a slight angle, then the nosecone popped as it began to fall. Unfortunately, the parachute was a bit too tightly packed, so the rocket's nosecone turned into a large plastic missile and embedded itself into the snowy field. One of the biggest problems with this first design was that it was far too heavy and composed of too many pieces. In addition, the fins were attached to a twist-on cap at the bottom of the rocket that held in the engine. Although this made the engine very easy and convenient to remove and replace, it meant that the fins had very little surface area for attachment. This made it very easy for them to get slightly off-kilter, which resulted in a less-than-desirable first launch. One other minor problem was that the launch rod mounting tube on the side of the rocket was a bit longer than it needed to be, which resulted in friction during the takeoff that affected the rocket's height. The After a bit of tweaking and parachute repacking, the MR1 was launched again with a bit more success.
The second iteration, the MR2, fixed some of the design problems from the MR1. First of all, the fuselage walls were much narrower to cut down on unnecessary weight. The wings were attached directly to the side of the fuselage to ensure better attachment and orientation, and the launch rod mounting tube was significantly shorter to reduce friction. Although the design was significantly improved, the MR2's launches were plagued with some difficulties. The first launch of the MR2 could have been much more successful had it not been for one simple mistake: forgetting to remove the safety cap on the launch rod. This caused the fuselage to break apart and the rocket to veer slightly as it took off. A few days later after a quick repair, the MR2 was launched again. With the campus police watching on in interest, the rocket took off and reached an altitude of about 600 feet. Unfortunately, the repairs resulted in a piece of plastic interfering with the parachute deployment. As the rocket rose higher, it caught some unexpected wind and drifted toward the parking lot where it crash-landed between two very expensive cars. With the MR2 effectively destroyed, it was time for another redesign.
The third iteration, the MR3, worked almost too well. I designed it to have a much slimmer profile with even narrower fuselage walls. In addition, I experimented with new methods of attaching end caps to keep the engines in place and designed an effective, albeit a bit fragile, snap-on cap. I also wanted to try out switching to three fins instead of four to reduce drag on the rocket. The MR3's design also made the parachute much more likely to deploy by using a carefully determined tolerance for the nosecone that was tight enough to stay on during launch and loose enough to guarantee deployment during landing. When the MR3 was launched, it rose nearly perfectly straight into the sky and disappeared from sight in a matter of seconds. A group of friends came along to watch the launch and attempted to keep eyes on it, later spotting it with its parachute deployed catching wind as it blew into the woods. The MR3 was never recovered.
One problem I wanted to try to solve from the MR3 and all of its predecessors is that the rocket was assembled in about nine or ten total pieces. This made printing and assembly incredibly inefficient, so fixing this problem became a goal for the final iteration. The MR4 was the lightest rocket of them all, weighing in at about 1/3 the weight of the MR1. It consisted of just four pieces: the fuselage with attached wings, the nose cone, and a rigid snap-on end cap. In addition, none of the parts required support material, making the finishing and assembly process incredibly easy. It also utilized streamers instead of a parachute for easier deployment.
The first launch of the MR4 was more impressive than I was expecting; I estimate it reached an altitude of 1000-1200 feet. After seeing it come down into the woods, the search party went after it and found located it relatively quickly. The second launch resulted in a bit of a misfire; a combination of factors including wind and a slight misalignment of the nose cone resulted in the rocket spiraling out of control. Fortunately, it was printed in bright red to increase visibility and was easily recovered. There was practically no damage, which proved that the lightweight and efficient design was also durable. The third and final launch was similarly successful to the first one but came down in deeper brush and was recovered about a month later on a hike.
This project was incredibly fun and educational for me. It taught me how to examine the flaws in my own previous designs and find solutions and improvements. It also forced me to be creative with my design and 3D-printing practices; finding a way to make ten parts join together in a secure way was a fun challenge that gave me good experience with mechanical design and assembly. Finally, this project encouraged me to push the bounds of my own successes in asking myself how I can make already effective designs reach even greater heights. The project came to a satisfying culmination when I brought my final design back home to the same pre-school that gave me the initial inspiration to launch it off for a crowd of eager children.
The second iteration, the MR2, fixed some of the design problems from the MR1. First of all, the fuselage walls were much narrower to cut down on unnecessary weight. The wings were attached directly to the side of the fuselage to ensure better attachment and orientation, and the launch rod mounting tube was significantly shorter to reduce friction. Although the design was significantly improved, the MR2's launches were plagued with some difficulties. The first launch of the MR2 could have been much more successful had it not been for one simple mistake: forgetting to remove the safety cap on the launch rod. This caused the fuselage to break apart and the rocket to veer slightly as it took off. A few days later after a quick repair, the MR2 was launched again. With the campus police watching on in interest, the rocket took off and reached an altitude of about 600 feet. Unfortunately, the repairs resulted in a piece of plastic interfering with the parachute deployment. As the rocket rose higher, it caught some unexpected wind and drifted toward the parking lot where it crash-landed between two very expensive cars. With the MR2 effectively destroyed, it was time for another redesign.
The third iteration, the MR3, worked almost too well. I designed it to have a much slimmer profile with even narrower fuselage walls. In addition, I experimented with new methods of attaching end caps to keep the engines in place and designed an effective, albeit a bit fragile, snap-on cap. I also wanted to try out switching to three fins instead of four to reduce drag on the rocket. The MR3's design also made the parachute much more likely to deploy by using a carefully determined tolerance for the nosecone that was tight enough to stay on during launch and loose enough to guarantee deployment during landing. When the MR3 was launched, it rose nearly perfectly straight into the sky and disappeared from sight in a matter of seconds. A group of friends came along to watch the launch and attempted to keep eyes on it, later spotting it with its parachute deployed catching wind as it blew into the woods. The MR3 was never recovered.
One problem I wanted to try to solve from the MR3 and all of its predecessors is that the rocket was assembled in about nine or ten total pieces. This made printing and assembly incredibly inefficient, so fixing this problem became a goal for the final iteration. The MR4 was the lightest rocket of them all, weighing in at about 1/3 the weight of the MR1. It consisted of just four pieces: the fuselage with attached wings, the nose cone, and a rigid snap-on end cap. In addition, none of the parts required support material, making the finishing and assembly process incredibly easy. It also utilized streamers instead of a parachute for easier deployment.
The first launch of the MR4 was more impressive than I was expecting; I estimate it reached an altitude of 1000-1200 feet. After seeing it come down into the woods, the search party went after it and found located it relatively quickly. The second launch resulted in a bit of a misfire; a combination of factors including wind and a slight misalignment of the nose cone resulted in the rocket spiraling out of control. Fortunately, it was printed in bright red to increase visibility and was easily recovered. There was practically no damage, which proved that the lightweight and efficient design was also durable. The third and final launch was similarly successful to the first one but came down in deeper brush and was recovered about a month later on a hike.
This project was incredibly fun and educational for me. It taught me how to examine the flaws in my own previous designs and find solutions and improvements. It also forced me to be creative with my design and 3D-printing practices; finding a way to make ten parts join together in a secure way was a fun challenge that gave me good experience with mechanical design and assembly. Finally, this project encouraged me to push the bounds of my own successes in asking myself how I can make already effective designs reach even greater heights. The project came to a satisfying culmination when I brought my final design back home to the same pre-school that gave me the initial inspiration to launch it off for a crowd of eager children.
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