Shipping Arcturus

On August 10 the whole team was able to breath a sigh of relief. Arcturus was dropped off at the port, and on its way to Australia (you can track exactly where here). We were essentially done, we couldn’t work on Arcturus anymore, and the next time we would see it would be in Darwin. we had worked tirelessly to get to this point.

As previously mentioned UPS is sponsoring the shipping of Arcturus to Australia. They were extremely helpful with not only the shipping but with working out the paperwork, and the other logistics. However there was still paperwork, and lots lots of it. We weren’t just shipping our car, but also all of our tools, and supplies that we needed, as well as our hopes and dreams. So how this all actually got shipped was in our trailer. we loaded Arcturus into our trailer, and then filled the space below it with all of our supplies, tools, etc. The team then had some great time to bond over looking up every item we were shipping, and finding their official classification. The other big hurdle was shipping our batteries, which are Lithium-Ion. Lithium-ion batteries have great energy density but also are very temperamental, and can catch fire if put in the wrong conditions. We worked with a packaging company to package the batteries so that they would be safe for the whole shipping process.

The Trailer all packed

Now with all the paperwork and packaging done it was time to actually drop off the trailer at the port. There was one problem with this though. Freight ships like big rectangular boxes, and our trailer is definitely not one of those. So first we had to have our trailer put in a shipping container. To prevent any hick-ups we wanted to be at Harbor Freight, who was putting our trailer in said containers, when they opened at Newark Port. This meant we had to leave Boston at 0200; we some how managed to leave at 0130. By the time we reached New York City the sun was rising which gave us some nice pictures. Once we got there it was surprisingly easy to drop off the trailer. Once they opened (we arrived almost an hour early) we just had to complete some final paperwork, and then just parked the trailer by their warehouse, and headed back. It felt a little anti-climatic for such a long journey to get to this point, but it was nice to no longer have to worry about what needed to be done on Arcturus. Although I think I wasn’t ready to accept that Arcturus was finished, as that night I dreamed about working on Arcturus and all the things I had to do on it. But now Arcturus is in Australia, and soon we will join it for the Bridgestone World Solar Challenge.

Sunrise over NYC

Bridgestone World Solar Challenge PRIMARY LOGO

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Road Trip to Detroit

As we previously mentioned, the team went to Detroit in July! Though the purpose of the trip was for wind tunnel testing, that activity only took one day, so we spent the rest of the week doing some serious road testing and practicing for the upcoming Bridgestone World Solar Challenge. This week of testing gave us valuable experience, allowed for design optimizations to be made, and gave us critical data on Arcturus’s power draw.

For those not familiar with Michigan, they have some very snowy, cold winters, which leads to many of their roads having pot holes. This was great for testing our suspension, but after proving our rugged design, it was time to allow the drivers to have some comfort in the form of a smooth road. We eventually found a suitable route in a rural town outside of Detroit. While driving out in the countryside, we noticed that there was a large thunderstorm forming on the Doppler RADAR. Fearing there might be hail, and with our trailer a few miles away, we sought the only feasible shelter, a gas station. This was definitely a good call, as, within a few minutes of parking Arcturus, a torrential downpour began.

Arcturus at a gas station

This testing was good, but we quickly became limited by the speed limit on our chosen route, so we graduated to testing Arcturus on rural highways. After speaking with the Superintendent, we were able to set up “camp” at a school along the highway we had chosen to test on. The route also had some good hills, which was great for testing.

Beyond testing the car and training our drivers, the road trip was great for meeting people and doing some informal outreach. Almost all of the people we met in Michigan were very kind and intrigued by the car. In fact, one of the teachers we happened to talk to ended up tweeting about us:

We left Michigan at the end of the week. Everyone was exhausted from seven long days of testing and fixing. This week provided great practice and road time to prepare for the 2015 Bridgestone World Solar Challenge. We even managed to get back to Boston in time to get the people who flew in for the week to the airport for their flights out. Check out the pictures from the road trip.

Bridgestone World Solar Challenge PRIMARY LOGO

Arcturus Wind Tunnel Testing

On July 27 Ford donated valuable wind tunnel time that allowed the team to accurately characterize the aerodynamics of Arcturus. Ford has been supporting our team for over a decade: Tesseract, Eleanor, Chopper del Sol, and now Arcturus have all been tested at Ford’s wind tunnel facilities. Ford’s Driveability Test Facility is in Detroit, MI, which is 798 miles from our shop. So we made the 15 hour drive out there with the goal of determining the aerodynamic properties of Arcturus. The most important of these is the power loss caused by drag, which is described by the equation below. P is power lost; ρ is the air density; v is the velocity of the car; A is the frontal area of the car; and Cd is the coefficient of drag.

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The frontal area and the coefficient of drag must be found experimentally. To determine Arcturus’s frontal area, Ford projected a large LASER over the car onto a screen. The dark areas on the screen can then be integrated to find the frontal area.


At first yarn tufts taped to car were used to visualize air streams at the surface of the car while the wind tunnel was running.

To characterize the coefficient of drag, the drag on the car was measured at various air speeds and angles (since C will change with wind direction).  At cruising speed Arcturus has approximately the same amount of drag as sticking your hand out the window on the highway.  

Smoke was then used to visualize airflow above the car’s surface.

 

Pictures from the day:

Test Driving at Palmer Motorsport Park

This Monday (13 July) we had a great day of testing at Palmer Motorsport Park, a new 2.3 mile track located less than two hours from the shop in the hills of Massachusetts. Palmer Motorsport Park was generous enough to donate to us this track time making them one of our newest sponsors. This track testing was extremely helpful for, as it allowed us to stress test the dynamics and handling of the car, while not having to worry about other cars on the road. We were able to push the car at high speeds through the course’s steep hills and tight turns safely. The drivers gained valuable experience with the car in these conditions and learned to drive the solar car efficiently to conserve battery energy.

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The day began rather early at our shop. We quickly loaded our gear into the truck and chase car, and headed west for Palmer, MA. Along the way there we were able to practice driving as and chase and lead for the solar car; although Arcturus was in the trailer, so some imagination was required. Once we arrived we were graciously greeted by the Owner and Caretaker, and we are able to quickly unload with their help.

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In the first few laps of testing we found a few minor improvements that could be made. Once we had implemented these Arcturus was running even better than before. We were then able to focus more on getting the drivers more comfortable with Arcturus, and the track. Each driver did a few slow starting laps to get used to the course’s tight turns and hills. Then each successive lap was bumped up to a higher speed. By the end of the day each driver was driving at high speeds, while also managing to be very energy efficient. They were able to better understand how to drive Arcturus at high speeds with minimal power draw, and practiced coasting and using regenerative breaking on the many downhill parts.

At the end of the day we had gotten in a good 7 hours of testing, had gathered valuable data for strategy, and even more important driver experience.

Check out some of the pictures from the day:

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