Part of the mechanical engineering degree is a mechE elective, and MechAero counts as such an elective. It isn't taught very often, and I was excited because I thought, based on the course description, that I would get to do a lot of analysis, especially analysis related to fluid mechanics. Instead, the course was almost entirely a mechanical design class with little to no support for learning to do mech design.
The Format of the Course
The goal of the class was for each team of three to four to build an ornithopter, a vehicle that flies by flapping wings. The first week, we weren't in teams yet, and we flew, took apart, and studied some toy ornithopters like the Cyberdactyl. The next week, Chris (who also taught Dynamics and MechSolids) talked for twenty or so minutes about how to model and simulate linkages, and then we split into teams and started working.
The project had four sections, each two to three weeks long. In the first part of the project, we designed a flapping mechanism. In the second section we designed two different mechanisms for the wings, and each method had to provide a difference in stiffness on the upstroke and the downstroke. After that, our goal was to get a flying model. Our first prototypes were due in late April, and we demoed our final ornithopters during finals week.
In each section of the project, we had an initial review where we presented to the class what we intended to do and what changes we planned to make from the last portion of the project. At the end of each sprint, we presented what we had done, went over what needed to be changed, and turned in a written report. The reviews were good for feedback, but they were really our only sources of feedback from Chris. One of the things I loved about PoE was how often Siddhartan checked in with the teams and brought up concerns. Chris was in class everyday, so we could ask questions if we had any, but we didn't have regular project-related contact with him. On the other hand, there was really good communication among the teams, so we were able to give each other advice and share extra supplies. That inter-team communication was the best part of the class.
Other than the short lecture on linkage modeling and some reference papers that Chris put in the class folder, there was really no material. The reference papers could have been helpful, but a lot of them were about ornithopters on a much smaller scale than any of us were working on, and even the more relevant papers didn't justify design decisions in ways that were useful to us. This was very much a doing class, and unlike PoE, where I know it was a class about integration, I'm not sure what the point of MechAero was.
My Team and our Ornithopter
I was on a team with two other juniors, both of whom work on the mechanical subteam of Olin's electric vehicles team. At first, I mostly worked on analysis while they mostly worked on design, but as the project went on, the project involved less and less analysis. I had almost no mechanical design or fabrication background, though, and this was not a context set up for learning it well. The sections of the project gave us stepping stones to a final product, but I needed different stepping stones. I felt like I was missing a prereq (though officially, I wasn't). I ended up learning some about CAD, fab, and what to think about while doing design (espeially through our mistakes), but I'm disappointed with how little I contributed to the later stages of this project, and while we were building the prototypes I spent a lot of time as a shop buddy. That was a necessary role, but I wasn't as useful as I wanted to be.
None of the four teams successfully built a flying ornithopter, though one team came really close. We think their ornithopter flew for about half a second before breaking; a really important part of their mechanism was just too fragile. All the ornithopters successfully flapped, and they all failed to fly for different reasons. Our issues were mostly with weight as well as friction due to poor tolerances on 3d-printed parts. (I'm also not convinced our gearing was ever what it needed to be.)
Here are a few CAD renders and pictures of what we ended up demoing:
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| CAD render of our full final ornithopter |
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| CAD of the flapping mechanism |
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| The ornithopter |
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| Underside of our final prototype |
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| Gear train |
So overall, the class wasn't what I expected it to be based on the course description, and it was also not a class I should have been in, despite the fact that I fulfilled the official prereqs. Feeling clueless and like I couldn't fully contribute meant that I could never really enjoy the class.
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