Weekly update :)

[Ali Forelli]

Hi guys,

We had another productive week! First, I want to officially announce that we have selected two drivers for the competition, Irina and Missy! We will have a team hangout sometime so we can all get to know the drivers.

There is a Visitas fair on Monday in MD G114 from 10am-noon. It would be awesome if we could get people to sign up for times to hang with the car and answer any questions pre-frosh might have. Sign-up sheet here

Engine:

Mike McKenna from the NW Labs machine shop finished our engine head, and it looks great! Nick and Joe have been working on making some new bearings (hooray for green training!). Sean is working on connecting the starter to the engine, and potentially changing the layout so that we have more room. Joe also installed a new throttle cable (and the whole process was about 400% faster than last time haha).

Chassis:

Sam and I are working on getting the seatbelt channel cleared out. We'll have to drill a bit of carbon out of the middle. Also, if anyone wants to take over the seat belt design, let me know! It shouldn't be too complicated. We need to pick seatbelt configuration, order parts, and install hardware attachments on the chassis.

Body:

We need to map out the holes and channels to cut in the new bottom pan for the body. Let me know if you can help out! Ideally, we will attach the bottom pan to the chassis next week.

Wheel fairings - help needed!

I really don't have time to design or build wheel fairings, so we could use 2 or more people to take charge of this part of the car. A few people have said that they would work on fairings, but so far there has been no progress. We really need people to be committed to this project. I can't force you to participate, but I also can't build everything myself. If you haven't worked independently on something before, this could be a great learning experience. Research wheel fairings and existing designs, figure out what fabrication methods we are able to achieve, and then come up with a design that is feasible for our available equipment to produce. If people are more interested in either design or fabrication, you can team up and split the work. Please let me know if you would like to be involved!

The sad saga of windows:

As most of you know, I have been spending a lot of time working on window fabrication. I have learned many ways how not to make a windshield! This week, I finished the window mold (pictured below) in preparation for thermoforming at MIT. Unfortunately, the guy who runs the MIT machine shop wasn't able to make it to our scheduled meeting. Even more unfortunate, the piece I designed was the wrong size for the thermoformer in that shop. Shout-out to Maddie, Rachel, and Sean for coming with me to MIT and keeping me calm during this extremely sad and frustrating time. We were able to try a different machine in the MIT architecture shop (also pictured below), and the results were okay, but not as good as we hoped.

 

Moving forward, we have to decide between a few options:

1. Use the plastic formed yesterday at MIT - we can use the whole front curve if we don't mind the folds in the plastic, or we can cut portions of if and do a multi-paneled windshield.

2. Make a mold that fits in the MIT thermoformer - we can either cut the existing mold into a smaller shape, or make a new one. If we decide to go this route, I would lean towards designing a new wooden frame and then detaching the fiberglass top from the current mold and cutting it down to size. I would expect this option to take about a day to redesign, a day to make the frame and get materials, a day to finish up the mold, and a day to go to MIT and make the window (processes are always faster the second time around). However, before committing to this option, we would have to see if the 21"x21" mold would create a window large enough for our purposes (this is shrinking the original design by about 23% which is a significant size reduction). If this size is too small, then the extra fabrication time is not worth it. We would also need to order another sheet of PETG, and we would have to consider the shipping time and how far that could set us back.

3. Go back to the original 3D printed design - the small thermoformer in the teaching labs produced great results for 10"x10" panels, so we could design the windows with this fabrication technique in mind. We could either make more 3D printed parts, which could either make separate 10"x10" window panels, or we could put 2 pieces together to take advantage of the slightly larger area the thermoformer can handle (potentially 10"x18" ?). We could also just use the 3 pieces I have and see if multiple of those pieces could be placed on the front, since the curvature is approximately the same.

4. Find a larger thermoformer - the GSD might have one?

5. Use the melted plastic method - using this method, we were able to make sections of panels that are smooth enough for windows after we cut off the perimeter material that didn't melt uniformly (using PETG rather than Lexan)

6. Try to bend a sheet (or multiple pieces) of PETG or Lexan to approximate the front curve of the car.

7. Use a camera and have 3 small windows from the 3D printed parts for a backup mechanism.

​I think we need to commit to a method and move forward with window installation soon, because this part of the car is preventing me from working on other important pieces. I know that I personally need to work on knowing when to declare something "good enough" instead of always aiming for the full potential. Time is definitely a concern here. Let me know if you have any opinions!

That's all for now - see you on Sunday!

Ali

[Joseph Pappas]

Wheel fairings are modeled and in the drive. If someone who is laser trained wants to cut them, by all means, otherwise the hotwire crew will take over.

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